EP0421157B1 - Method for piecing broken yarn in a ring spinning machine - Google Patents

Description

The invention relates to a method for eliminating a thread break on a single, a cop-producing spindle of a ring spinning machine, in which an auxiliary thread of an auxiliary spool carried by a maintenance car is loosely placed on the cops of the spindle and attached to a sliver supplied by a drafting system, whereby after a piecing process is automatically checked whether the thread break is eliminated, and a ring spinning machine with a maintenance trolley for performing a thread break recovery.

It is known (DE-OS 17 85 236, DE-AS 23 51 312) to carry along an auxiliary thread in the automatic removal of thread breaks on ring spinning machines in a maintenance vehicle, which thread is used to carry out the piecing process. Compared to searching for the thread end on the bobbin, this has the advantage of requiring less time. In addition, this use of an auxiliary thread is advantageous in order to correct start-up thread breaks when there is no thread on the bobbin. In addition, a thread break repair can then be carried out on cripple heads in which the broken thread end lies outside the area to which the thread search device is delivered, which is usually dependent is delivered to the cop from the position of the ring bench. This application of an auxiliary thread, which is advantageous in itself for eliminating a thread break, causes difficulties in the subsequent work step, ie in the winder, in particular if this winder is to operate fully automatically. These difficulties arise when a first attempt to fix a thread break has failed, so that a thread piece of the auxiliary thread is then on the cop that has two free ends. On the one hand, there is a risk that in the case of automatic cop preparation, several thread ends are detected simultaneously, so that loops form on the cop and tighten, so that automatic cop preparation is unsuccessful. However, even if the cop preparation should succeed, the consumption during the winding process of the only relatively short auxiliary thread piece leads to a further interruption of the winding process, which is then usually connected with the removal of this cop and a new cop preparation.

The invention has for its object to provide a method of the type mentioned, with which the difficulties described can be avoided in a simple manner.

This object is achieved in that after an unsuccessful attempt to fix a thread break, the thread piece of the auxiliary thread used is removed from the cop before a further attempt is carried out.

In this way it is prevented that short pieces of thread of the auxiliary thread are on the cop, so that the work of an automatic winder is not disturbed. This is already carried out on the ring spinning machine while a thread break is being repaired, ie at a point in time at which this measure does not yet require any great time and technical effort.

In a first embodiment of the method it is provided that the piece of thread of the auxiliary thread wound on the cop during a failed attempt to fix a broken thread is blown off the cop and removed by means of a suction air flow.

In another embodiment of the invention, it is provided that the auxiliary thread is only severed and finally delivered to the cop after the success of the experiment has been determined, and that - if the attempt fails, the auxiliary thread is withdrawn from the cop.

To solve the problem is further in a ring spinning machine with means for spinning a thread from a sliver supplied by a drafting system and for winding the thread on a bobbin and with a movable maintenance carriage, which carries an auxiliary spool with an auxiliary thread, one of which upon removal of one Thread break a piece of thread is placed on the cop and attached to the fuse, it is provided that the maintenance car is provided with means for monitoring the success of an attempt to correct a thread break, which are connected to a controller, the means of the maintenance car for removing one from one failed attempt to use the auxiliary thread piece from the cop before another attempt to repair the thread break is made.

Further features and advantages of the invention result from the following description of the embodiment shown in the drawing.

The drawing shows a schematic representation of a spinning station of a ring spinning machine and a maintenance trolley operating there after an unsuccessful attempt to break the thread.

Each spinning station of a ring spinning machine that is equipped with a large number of similar spinning stations contains one Drafting system (10) which guides a fuse via a thread guide (11) to a runner guided in a ring bench (12). The ring bench (12), which can be moved up and down in accordance with the bobbin structure, has spinning rings which are each arranged concentrically with a spindle (13) on which there is a bobbin tube on which the spun thread forms a bobbin (14). is wound up. The spindle (13) is driven to rotate, for example by an electric single motor (15). In the event of a yarn breakage, the fuse provided by the drafting device (10) runs into a suction device (16).

A maintenance carriage (17) is assigned to the ring spinning machine and patrols along one or both sides of the ring spinning machine. The maintenance trolley (17) receives a signal that there is a thread break at a spinning position, which the maintenance trolley (17) must automatically remedy. The maintenance trolley (17) can also obtain this signal itself, for example via a detector (18) which is directed towards the thread paths of the individual spinning stations and which reacts accordingly in the absence of a thread, i.e. is delivered to the relevant spinning station. The detector (18) is connected to a controller (19) which controls the traction drive of the maintenance carriage (17) in a manner not shown in such a way that this maintenance carriage (17) stops at the relevant spinning position and carries out the removal of a thread break fully automatically.

The maintenance trolley (17) carries an auxiliary spool (20) with an auxiliary thread (21) with which the removal of a thread break is carried out. The auxiliary thread (21) is picked up by means not shown, known per se (eg DE-OS 17 85 236), placed on the cop (14) and in the runner on the ring ring spinning ring (12) and the thread guide (11) inserted. Subsequently, the auxiliary thread (21) running over a pressure roller (22) is fed to the pair of output rollers of the drafting device (10) in such a way that the auxiliary thread (21) connects to the sliver supplied by the drafting device (10), the feed of which to the suction device (16 ) is interrupted. The auxiliary thread (21) is then by means of a Cutting device (23) is cut so that the process of fixing a thread break is completed. The pressure roller (22) is arranged on a lever arm (24) of the maintenance carriage (17), which can be pivoted about an axis (25) and can also be extended in the horizontal direction. This drive is controlled by the controller (19).

There is always the risk that an attempt to fix a thread break will not succeed, so that afterwards a piece of the auxiliary thread (21) is wound onto the cop (14) and has two free ends. As already explained at the beginning, such a piece of auxiliary thread interferes with the subsequent fully automatic winding process. In order to avoid this disruption, the simplest solution is that only an automatic attempt to remove the thread break is carried out by the maintenance trolley (17). If the latter fails, the maintenance carriage (17) sets a signal at the spinning position in question, which an operator calls. This must then first remove the auxiliary thread (21) wound on the cop and delete the signal so that a retry attempt can then be carried out.

However, in order to ensure fully automatic operation, according to another solution it is provided that the maintenance carriage (17) itself is provided with means which remove the piece of thread of the auxiliary thread (21) wound up from the cop (14) in the event of an unsuccessful attempt. For this purpose, it is initially provided that the maintenance trolley (17) monitors the success of the attempt to correct a thread break. This is carried out, for example, by means of the detector (18), which reports the success or failure of the control (19). If a failure is found, the means for removing the thread piece of the auxiliary thread (21) are then actuated before a retry attempt is carried out.

The maintenance trolley (17) is provided with a blowing nozzle (26) which is horizontal with a drive (28) only indicated schematically and is vertically movable, which is controlled by the controller (19). This blowing nozzle (26) is fed to the area of the winding cone of the cop (14), ie the area of the ring rail (12). For this purpose, the position of the ring rail (12) is detected by a sensor (27) of the maintenance carriage (17) and reported to the controller (19).

The maintenance trolley (17) is also provided with a suction device (29) connected to a vacuum source, which can be adjusted horizontally and vertically with a drive (30) controlled by the controller (19) and shown schematically so that it has a funnel-like part Grips around spindle (13). The blowing nozzle (26) releases the wound auxiliary thread piece from the cop (14), which is then sucked off by the suction device (29). The suction device (29) is provided with a detector (31) which detects the thread length being sucked and reports it to the control (19). After a predetermined length, which is determined, for example, by a timer of the control (19), the wound auxiliary thread piece is completely suctioned off, so that the release process can be ended. In this process, it is to be expected that the broken thread end will also be detached from the cop (14) and also sucked off by the suction device (29). The suction device (29) is therefore provided with a separating device (32) which is controlled by the control and which is actuated after the suction has ended. The remaining thread end is then wound back onto the cop (14). During this process, it is useful if the spindle (13) is stopped. This can be carried out, for example, by means of an actuating element (not shown) of the maintenance carriage (17) which actuates a brake of the spindle (13) and / or interrupts the drive (15). After the thread piece of the auxiliary thread (21) used in a failed attempt has been removed, a repeat attempt can be carried out.

In another solution it is provided that the supply of the auxiliary thread (21) drawn off from the auxiliary spool (20) is maintained until the success of an attempt to correct a thread break has been determined. For this purpose, it is provided that the pressure roller (22) remains in contact with the lower roller of the pair of output rollers until the piecing success has been determined. The piecing success is then certain when the auxiliary thread (21) has taken along the fuse provided by the drafting system (10) for a certain time. Since the thread running between the drafting device (10) and the thread guide (11) is formed from the fuse and the auxiliary thread during this time, there is an increased volume, which is determined by a suitably designed detector (18) and the control (19) can be reported.

If it is found that the fuse has been taken along by the auxiliary thread (21), the control device (19) actuates the separating device (23) so that the removal of a thread break is completed.

If the detector (18) determines that no sliver has been carried, ie the attempt to break the thread has not been successful, the separating device (23) is not actuated, but the pressure roller (22) from the lower roller of the pair of output rollers of the drafting system (10) lifted. It is then possible to grasp the auxiliary thread (21) that has accumulated on the cop (14) during this time and to pull it off again. This can be done, for example, by the pressure roller (22) being controlled by the controller (19) in this case, being fed to the pressure roller of the pair of output rollers, so that the pressure roller (22) is driven in the opposite direction of rotation, ie in the pull-off direction. The auxiliary thread (21) returned can be picked up by a suction device (not shown). It is also expedient for this process if the maintenance carriage (17) has means for stopping the Spindle (13) is equipped, for example with an extendable pneumatic cylinder that can be fed to a spindle brake.

Claims (10)

1. Method of rectifying a yarn break on a single spindle in a ring spinning machine, wherein an auxiliary yarn of an auxiliary bobbin carried by a service carriage is applied loosely to the cop of the spindle and pieced to a roving supplied by a drawing frame, while it is automatically checked after a piecing operation whether the yarn break has been rectified, characterized in that, if the yarn break has not been rectified, the piece of auxiliary yarn used for this purpose is removed from the cop before a further attempt is made.
2. Method according to Claim 1, characterized in that the piece of auxiliary yarn wound onto the cop during an unsuccessful attempt to rectify a yarn break is blown off the cop and carried away by means of suction.
3. Method according to Claim 1 or 2, characterized in that the length of the piece of yarn drawn off from the cop is detected.
4. Method according to Claim 1, characterized in that the auxiliary yarn is separated and definitively delivered to the cop only after the success of the attempt has been established, and in that, in the event of the failure of the attempt, the auxiliary yarn is drawn off from the cop again.
5. Ring spinning machine having means for spinning a yarn from a roving supplied by a drawing frame and for winding said yarn onto a cop, and having a travelling service carriage which carries an auxiliary bobbin with an auxiliary yarn, from which, in the event of rectification of a yarn break, a piece of yarn is applied to the cop and pieced to the roving, characterized in that the service carriage (17) is provided with means (18) for monitoring the success of an attempt to rectify a yarn break, which means are connected to a control unit (19) which controls means (26, 29; 22, 23) on the service carriage (17) for removing from the cop (14) a piece of auxiliary yarn used in a failed attempt, before a further attempt is made to rectify the yarn break.
6. Ring spinning machine according to Claim 5, characterized in that the service carriage (17) is provided with a blast nozzle (26) which can be adjusted towards the cop (14) in the region of a ring rail (12) and is directed obliquely upwards.
7. Ring spinning machine according to Claim 5 or 6, characterized in that the service carriage (17) is provided with a catch-yarn device (29) preferably operated by suction.
8. Ring spinning machine according to one of Claims 5 to 7, characterized in that the catch-yarn device (29) is provided with means (31) for detecting the length of yarn picked up by it.
9. Ring spinning machine according to one of Claims 5 to 7, characterized in that the service carriage (17) is provided with a yarn separating device (32), controlled by the control unit (19), for separating the yarn picked up by the catch-yarn device (29) from the yarn joined to the cop (14).
10. Ring spinning machine according to Claim 5, characterized in that the means (18) for monitoring the success of an attempt to rectify a yarn break comprise a detector which detects that the roving is carried by the auxiliary yarn (21) running towards the cop (14), and only trigger the actuation of a separating device (23), for severing the auxiliary yarn (21), when the success of the attempt has been established.

Images