DE102018211537A1 - Weft insertion method on a loom and loom - Google Patents

Abstract

In a method for weft thread insertion on a weaving machine (1), a weft thread (5) is withdrawn by a certain distance by means of a return unit (9) arranged on an insertion side (ES) of a shed (2). The weft thread (5) is picked up by at least one insertion element, inserted into the shed (2) in a weft insertion direction (SE) and released after the entry by the entry element, with a side of the shed (2) opposite the entry side (ES) Weft thread end (5a) protruding from the shed (2) is produced. After the weft thread (5) has been released by the insertion element, the inserted weft thread (5) is moved against the weft insertion direction (SE) by means of the return unit (9) and the excess weft thread end (5a) is pulled back into the shed (2). A corresponding weaving machine (1) has a weft thread supply (6) arranged on an insertion side (ES) of a shed (2), at least one entry-side clamp, at least one entry element for inserting a weft thread (5) into the shed (2) in a weft insertion direction ( SE) and a return unit (9) arranged on the entry side (ES) of the shed (2) between the weft thread supply (6) and the at least one entry element for withdrawing the weft thread (5). The return unit (9) is designed and arranged on the weaving machine (1) in such a way that the weft thread (5) can be withdrawn against the weft insertion direction (SE) after it has been inserted into the shed (2).

Description

The present invention relates to a method for weft insertion on a weaving machine, in which a weft is withdrawn by a certain distance by means of a return unit arranged on an insertion side of a shed, the weft being gripped by at least one insertion element, in particular at least one gripper. The weft thread is inserted into the shed in a weft insertion direction and released after the entry by the entry element. This creates a weft end protruding from the shed on the side of the shed opposite the entry page.

From the DE 10 2015 217 356 B3 A weaving machine has become known in which several weft threads from different supply bobbins can be inserted alternately by means of a color selector. For this purpose, the color selector has a thread eyelet and a clamp assigned to each of the weft threads. By means of the clamp and the thread eyelet, the weft threads can each be presented to an entry element of the weaving machine and can be gripped by this. Since the thread eyelets and the clamps are moved back and forth between different positions during the weaving process, the thread length of the weft thread changes in its course from the weft thread supply to its respective clamp. In order to compensate for these different thread lengths occurring in the course of the weaving process, a thread return unit can be provided on the weaving machine.

A thread return unit is for example in the DE 35 24 727 A1 shown. In the weaving machine shown there, the weft is cut after the weft insertion and held by a pneumatic holding device in order to be presented again to the hook. In order to keep the weft thread end presented to the gripper as short as possible, the weft thread is again pulled out of the pneumatic holding device to a certain extent before it is gripped by the gripper. For this purpose, a finger is pivoted into the path of the weft thread by means of an actuating lever and the now shortened weft thread end is presented to the gripper. However, the weft thread end presented to the looper cannot be shortened arbitrarily, since this must still be able to be reliably gripped by the looper. Likewise, on a weaving machine with center transfer, the thread end must be able to be transferred safely to the take-up rapier. The thread end protruding from the hook of the hook is thus transported by the hook (s) to the other side of the shed when the weft is inserted, where it has to be cut off and disposed of as waste.

The object of the present invention is therefore to propose a method for weft insertion on a weaving machine and a weaving machine, by means of which the quantities of weft waste that occur can be reduced.

The object is achieved with the features of the independent claims.

In a method for weft thread insertion on a weaving machine, a weft thread is withdrawn by a certain distance by means of a return unit arranged on an insertion side of a shed. The weft thread is gripped by at least one insertion element, in particular at least one gripper, inserted into the shed in a weft insertion direction and released after the insertion by the insertion element. This creates a weft end protruding from the shed on the side of the shed opposite the entry page.

It is proposed, after the weft thread has been released by the insertion element, to move the now inserted weft thread against the weft insertion direction by means of the return unit and to pull the projecting end of the weft thread back into the shed. As a result, the end of the thread protruding from the shed on the side of the shed located opposite the entry side can be pulled back and integrated into the fabric, so that it no longer accumulates as waste. Since this only takes place after the weft thread end has been inserted, it is also not absolutely necessary to shorten the thread end presented to the hook before the weft insertion. The thread ends projecting over the fabric as waste on the right side, that is to say the side opposite the insertion side, can hereby be considerably reduced. If necessary, the protruding thread ends can also be pulled back completely into the fabric, so that it is not necessary to cut the fabric on the right side.

Likewise, a weaving machine is proposed with a weft thread supply arranged on an insertion side of a shed, with at least one entry-side clamp, in particular a movable hand-over clamp of a hand-over device, with at least one entry element for inserting a weft thread into the shed in a weft insertion direction and with a return unit. The at least one entry element is preferably designed as a gripper. The weaving machine can be with a mono rapier or with a Encoder and a slave gripper with center transfer.

The return unit of the weaving machine is designed and arranged on the weaving machine in such a way that the weft thread can be withdrawn against the weft insertion direction after being inserted into the shed.

According to a preferred embodiment of the weaving machine, the return unit is arranged for this purpose between the weft thread supply and the entry-side clamp, in particular the movable reach clamp of the reach-out device. The return unit is preferably arranged in the thread path of the weft thread in such a way that the weft thread is guided over the return unit during the entire weaving process. The return unit can hereby be actuated at different times in the weaving process, since the weft thread is always in the sphere of influence of the return unit.

In the method, the protruding end of the weft thread is preferably pulled back into the shed before and / or while the inserted weft thread is being beaten and or tied by means of a reed. If the weft thread is pulled back through the reed before the stop, it can be moved particularly easily through the open shed. However, it can also be advantageous to withdraw the weft thread during the weft stop or shortly before or during the setting. At this point, the weft thread is already held by the friction of the warp threads. There is therefore no danger that the weft thread will be pulled back too far by the return unit.

According to an advantageous embodiment, the inserted weft thread is deflected for withdrawal by means of a deflection element which can be driven by a drive. For this purpose, the return unit has a deflection element which can be driven by a drive and can be deflected from a rest position. The deflection element can be deflected from its rest position, for example by a linear movement, and thereby deflect the thread from its regular thread path. Alternatively, however, the deflection element can also be designed as a rotatably mounted lever and deflect the thread from its regular thread path by means of a rotary movement. According to a particularly advantageous embodiment, the rotatably mounted lever is designed as a two-armed lever. The return unit can hereby be made particularly space-saving.

It is advantageous if the deflection element has at least one thread guide element for the weft thread. As a result, the weft thread can be guided through the thread guide element at any time in the weaving process.

It is also advantageous if the return unit has at least one stationary thread guide element for the weft thread. A defined deflection of the weft thread can be achieved by the interaction of the thread guide element of the deflecting element and the stationary thread guide element. As a result, the weft thread can be reproducibly withdrawn by the same distance with each weft insertion.

According to an advantageous development of the return unit, the at least one thread guide element of the deflection element and / or the at least one stationary thread guide element is designed as a deflection roller. As a result, the thread can be guided particularly gently over the deflection element. The return unit is thus also suitable for sensitive weft threads, which could otherwise be damaged by the friction on a fixed deflection element or by large deflection angles on fixed deflection elements.

In the case of the method, it is also advantageous if the drive is given a change in position for retraction and the drive is moved in a position-controlled manner. The distance by which the protruding thread end is to be pulled back can hereby be specified exactly for the drive. This can ensure that almost the entire protruding thread end is pulled back into the shed. It is also possible in this way to adjust the distance by which the protruding thread end is withdrawn according to the requirements. For example, a different change in position can be specified for different applications. It is also possible to specify a different change in position from weft to weft if the type of fabric or the different weft threads used require this.

It is also particularly advantageous if the drive has a position transmitter. As a result, the actual position of the drive can be monitored at any time and fed to a control device. As a result, the drive can also be moved in a position-controlled manner, so that the length of the thread end, which is drawn back into the shed, can be achieved particularly precisely.

If the drive is moved in a position-controlled or position-controlled manner, it is furthermore advantageous if the drive has a force limitation or a force during the retraction Torque limitation is specified. In the case of a linear drive, a force limitation is specified, while a rotary drive is specified a torque limitation. This can counteract tearing of the thread by pulling it back.

In the weaving machine, it is also advantageous if the drive can be moved either force-controlled (in the case of a linear drive) or torque-controlled (in the case of a rotary drive) or position-controlled. As a result, the return unit can be used not only to pull the thread back by a defined distance, but also to tension the thread, for example to compensate for any excess lengths or to monitor the weft thread.

According to a particularly advantageous embodiment of the return unit, the drive is designed as a rotating magnet. This enables the deflection element to be positioned particularly precisely and is also available at low cost.

In the case of the method, it is also advantageous if the inserted weft thread is pulled back after being pulled back by an entry-side clamp of the weaving machine, in particular a movable hand clamp of a hand-in device, and is separated from a weft thread on the supply side.

Preferably, after the inserted weft thread has been separated from the supply-side weft thread, the supply-side, clamped weft thread is monitored by means of the return unit. In the weaving machine, the retrieval unit forms a device for monitoring the weft thread of a weft thread on the supply side.

According to a first, simple embodiment, the thread is only monitored for a weft break at one or more specific times after the separation. For this purpose, the thread is briefly subjected to a defined tension.

In order to be able to apply a defined tension to the thread, the return unit is advantageously assigned a thread clamp arranged between the weft thread supply and the return unit. As a result, the weft thread on the supply side can be clamped both by the entry-side clamp, in particular the reach clamp, and by the additional thread clamp.

To monitor the weft thread on the supply side, a tension is preferably applied to the weft thread on the supply side by the deflecting element of the return unit.

The thread tension can be measured and it can be concluded that there is a thread break. In order to detect a thread break, it is alternatively also possible to provide only a proximity sensor for the deflecting element on the return unit. When the tension is applied to the weft thread, the deflection element is deflected from its rest position, but does not reach its end position when the thread is intact. If the weft thread is now broken, the deflecting element is suddenly deflected into the end position, which can be detected by the proximity sensor.

Alternatively, to monitor the weft thread or to apply the tension to the weft thread, a force or a torque can be predetermined for the drive of the return unit and at the same time a resulting change in position of the drive can be detected. For this purpose, as already described, the drive has a position transmitter. If the change in position of the drive does not correspond to the one to be expected from the specified force or the specified torque, it can be concluded that there is a broken shot or another error.

According to a particularly advantageous development of the method, the thread is subjected to the tension not only at one or more points in time, but continuously from the point of clamping by the supply-side clamp until it is grasped by the entry element for the next weft insertion. For this purpose, the weft thread is preferably subjected to a constant tension. However, it is also conceivable to specify only a certain window with a minimum and a maximum tension with which the weft thread is acted upon during its continuous monitoring. As a result, the weft thread can be monitored for a thread break, for example on a weaving machine with several threads, even if it is not being inserted.

In the weaving machine it is therefore also advantageous if the return unit is designed to continuously monitor the weft thread on the supply side. The drive of the return unit can be acted upon with a preferably constant force in the case of a linear drive or a preferably constant torque in the case of a rotary drive for weft monitoring. Again, it is also advantageous if a change in position of the drive is detected at the same time by means of a position transmitter. A change in position with a constant predetermined torque or constant force, in turn, indicates the presence of a broken shot.

It is also particularly advantageous if the return unit is designed to monitor a function of elements involved in the weft insertion. The elements involved in the weft insertion would mean all elements of the weaving machine that handle the weft before, during and after the weft insertion. In particular, entry elements such as grippers, reaching clamps, eyelets of a reaching device, weft thread scissors and further thread clamps are understood.

In order to be able to monitor the function of the elements involved in the weft insertion, it is advantageous if a current position curve of the drive is recorded while the tension is being applied to the weft thread. In other words, the position of the drive is continuously detected by means of a position sensor. The current position profile is then compared with an ideal position profile. The ideal position profile can, for example, have previously been recorded in an error-free weaving cycle and stored in a control of the drive. For example, an atypical drop in the thread tension or a sudden change in the position of the drive can indicate that the thread was not correctly clamped by the reach clamp or that the thread has slipped out of the clamp of the reach device. A malfunction of the thread clamp assigned to the weft thread supply can also be detected by an atypical change in position of the drive. In a similar manner, the correct separation of the inserted weft thread from the weft thread on the supply side can be monitored.

If the current position profile of the drive deviates from the ideal position profile, an error message is preferably output. In this way, an operator is made aware of the malfunction, can seek out and remedy it.

According to an advantageous development of the weaving machine, the weaving machine has a plurality of clamps on the entry side for a plurality of weft threads, each of the plurality of weft threads being assigned its own return unit. In this way, errors in the weft feed can be recognized early and quickly eliminated.

• 1 eine Webmaschine mit einer Rückholeinheit nach einer ersten Ausführung in einer Situation kurz vor dem Schusseintrag,
• 2 die Webmaschine der 1 kurz nach dem Schusseintrag und nach der Freigabe des Schussfadens durch den Greifer,
• 3 die Webmaschine der 1 nach dem Rückholen des Schussfadens,
• 4 die Webmaschine der 1 nach dem Blattanschlag,
• 5 die Webmaschine der 1 nach dem Schneiden des Schussfadens,
• 6 die Webmaschine der 1 kurz vor dem folgenden Schusseintrag,
• 7 eine schematische Detaildarstellung einer Rückholeinheit,
• 8 eine Webmaschine mit einer Rückholeinheit nach einer zweiten Ausführung in einer Situation kurz vor dem Schusseintrag,
• 9 die Webmaschine der 8 kurz nach dem Schusseintrag und nach der Freigabe des Schussfadens durch den Greifer,
• 10 die Webmaschine der 8 nach dem Rückholen des Schussfadens,
• 11 die Webmaschine der 8 nach dem Blattanschlag,
• 12a die Webmaschine der 8 nach dem Schneiden des Schussfadens im Falle eines Farbwechsels,
• 12b die Webmaschine der 8 nach dem Schneiden des Schussfadens im Falle eines Pic-a-pic-Eintrags, sowie
• 13 die Webmaschine der 8 kurz vor dem folgenden Schusseintrag.

Further advantages of the invention are described on the basis of the exemplary embodiments illustrated below. Show it:

• 1 a weaving machine with a return unit after a first execution in a situation shortly before the weft insertion,
• 2 the weaving machine of the 1 shortly after the weft insertion and after the release of the weft thread by the gripper,
• 3 the weaving machine of the 1 after retrieving the weft,
• 4 the weaving machine of the 1 after the leaf stop,
• 5 the weaving machine of the 1 after cutting the weft,
• 6 the weaving machine of the 1 shortly before the following weft entry,
• 7 a schematic detailed representation of a return unit,
• 8th a weaving machine with a return unit according to a second embodiment in a situation shortly before the weft insertion,
• 9 the weaving machine of the 8th shortly after the weft insertion and after the release of the weft thread by the gripper,
• 10 the weaving machine of the 8th after retrieving the weft,
• 11 the weaving machine of the 8th after the leaf stop,
• 12a the weaving machine of the 8th after cutting the weft in case of a color change,
• 12b the weaving machine of the 8th after cutting the weft in the case of a pic-a-pic entry, as well
• 13 the weaving machine of the 8th shortly before the following weft entry.

In the following description of the exemplary embodiments, the same reference numerals are provided for identical or at least comparable features in terms of their design and / or mode of action. Furthermore, these are only explained in detail when they are first mentioned, while in the following exemplary embodiments only the differences from the exemplary embodiments already described are discussed. Furthermore, for the sake of clarity of several identical components or features, often only one or only a few are labeled.

1 shows a schematic representation of a weaving machine 1 with a return unit 9 shortly before the shot entry. The weaving machine 1 points to an entry page IT a weft supply in the usual way 6 on which a weft material, in particular a weft thread 5 . settled and a handover facility 8th is fed. The weft 5 this is done through an eyelet 16 the handover facility 8th led and can by a sufficient clamp 7 be clamped. The sufficient clamp 7 is in the present example between a feeder position Z in which the pinched weft 5 an entry element is fed, and a takeover position Ü in which the pinched weft 5 can be cut, movable back and forth. The return unit 9 is between the weft supply 6 and the hand clamp 7 or another entry-side terminal arranged. For clamping the weft thread 5 is between the weft supply 6 and the return unit 9 a thread clamp 18 intended. For cutting the weft 5 is a weft scissors 15 on the loom 1 intended.

The weft thread becomes the weft insertion 5 in a manner known per se, an entry element, here a gripper 4 , submitted and by this in a weft insertion direction SE in the shed 2 entered. The shed 2 is also in a known manner by the alternate lifting and lowering of warp threads 3 educated. There is still a reed for striking the weft thread 10 intended.

Is shown in 1 now a situation in which the movable hand clamp 7 just in the feed position Z located. The weft 5 is thereby between the eyelet 16 the handover facility 8th and the hand clamp 7 clamped and can thereby the gripper 4 be presented. The weft 5 is just by the gripper 4 detected.

The return unit 9 , whose function is described in more detail with reference to the following figures, has a deflection element according to the present illustration 11 on, which in the present case is designed as a rotatably mounted lever. The deflecting element 11 has a drive 12 (please refer 7 ) to move or deflect the deflecting element 11 on. The deflecting element 11 is with one or, as shown here, also two thread guide elements 17 provided over which the weft thread 5 is led. The deflecting element 11 is thereby able to weft 5 deflect from its regular course and thereby withdraw it by a certain distance or, depending on the version, also tension it. Furthermore are on the return unit 9 in the present case two stationary thread guide elements 17 arranged. This is in cooperation with those on the deflecting element 11 arranged thread guide elements 17 a defined deflection of the weft thread 5 reached, which in turn causes the weft 5 can be withdrawn by a defined distance. The deflecting element 11 is in one of its rest position R (please refer 7 ) shown deflected position.

2 shows a situation in which the weft 5 just entered and from the gripper 4 has already been released. The gripper 4 has the weft for this 5 captured and through the open shed 2 to the entry page IT opposite side transported. The sufficient clamp 7 has been solved for this and has been removed while the gripper 4 the weft 5 has entered from the feed position Z in the transfer position Ü emotional. Even the thread clamp 18 is solved during the weft insertion. The deflecting element 11 the return unit 9 is in the rest position during the weft insertion R (please refer 7 ). In this is the weft 5 not deflected, but runs largely straight through the return unit 9 in order not to impair the weft insertion. Because the weft 5 by the gripper 4 not directly at its end, but only between the reach clamp 7 and the eyelet 16 can be clamped, there is always a weft end when the weft is inserted 5a which after the weft entry on the entry page IT protrudes opposite side over the fabric. This is not integrated into the tissue and must therefore be separated from the tissue and disposed of as waste. To avoid this, the return unit 9 intended.

3 now shows a situation in which the weft end 5a has already been withdrawn by a certain distance, so that it is now inside the shed 2 and thus through the warp threads 3 can be tied off. The weft end was present 5a completely into the shed 2 withdrawn; depending on the design of the weaving machine 1 and of the fabric and the selvedges, it is of course also conceivable to continue a small piece of the weft end of the 5a over the shed 2 to survive. To retrieve the weft end 5a now becomes the deflecting element 11 the return unit 9 from its rest position R deflected. At the same time, the thread clamp 18 closed to further unwind the weft 5 from the weft supply 6 to avoid. The deflecting element 11 can thus by a certain, predetermined angle of rotation from its rest position R ( 7 ) are deflected, causing the weft end 5a by one to change the rotational position of the deflecting element 11 corresponding distance or thread length is withdrawn.

The deflection element is present 11 rotatably mounted so that the drive 12 (please refer 7 ) to retrieve the thread end 5a a change in the angle of rotation is specified. Of course, the deflecting element could 11 However, it can also be designed in a different way, so that the deflecting element 11 a change in position is specified accordingly. For deflecting the deflecting element 11 can the drive 12 position controlled. In order to achieve the specified change in position or the retracted thread length as precisely and reproducibly as possible, the drive can also be provided in an advantageous embodiment 12 to be equipped with a position transmitter and then to move the drive accordingly in a position-controlled manner.

After retrieving the thread end 5a or, if necessary, already during the retrieval into the shed 2 registered weft 5 by means of the reed 10 struck like that 4 removable. The shed continues 2 closed to the struck weft 5 to set. A situation is shown in which the registered weft thread 5 already through the reed 10 was struck and from which is still in the takeover position Ü sufficient clamp 7 was taken over and clamped. In this situation, the registered weft is 5 , which is within the shed 2 through the weft scissors 15 from the supply side weft 5 which are outside of the shed 2 to be disconnected.

5 shows a situation in which the entered weft 5 now from the weft thread on the supply side 5 was separated. Still has after cutting the weft 5 the sufficient clamp 7 with the stocked, clamped weft 5 from the transfer position Ü back to the feed position Z emotional. Like a comparison of the 4 and 5 shows, is created by moving the hand clamp 7 in the feed position 6 an excess length of the weft 5 because the transfer position Ü further away from the eyelet 16 lies as the feed position Z , In the present example, therefore, the deflecting element 11 the return unit 9 deflected a second time by a certain angle of rotation to compensate for this excess length. The position of the deflecting element shown here 11 is thus composed of the first change in position or change in angle of rotation to bring back after the weft insertion and the second change in position or change in angle of rotation to compensate for the excess length.
Of course it is, depending on the arrangement of the eyelet 16 , the feed position Z and the transfer position Ü also possible to do without the second retrieval or to compensate for the excess length in another way. The thread clamp 18 is still closed at this time. It goes without saying that instead of a thread clamp 18 a thread brake can also be provided around the weft thread on the supply side 5 to fix during the retrieval.

Is the drive 12 assigned a position sensor, the weft thread can be according to an advantageous embodiment of the invention 5 after retrieval using the retrieval unit 9 with a defined tension applied to the weft 5 to monitor. This makes it possible to break the weft thread on the supply side 5 determine and if necessary also the functioning of the terminals 7 and 18 to check. The drive is used to apply the voltage 12 not a change in position as previously specified for retrieval, but rather a defined torque or a defined force is specified. In the event of a broken shot or a malfunction of one of the two clamps 7 . 18 it is not possible to apply the defined tension corresponding to the specified torque or the specified force to the weft thread 5 applied. Rather, the deflection element experiences 11 or the drive 12 due to the missing fixation of the weft thread 5 a significant change in position, which can be detected by the position transmitter. A deviation in the weaving process can thus be concluded from a deviation of the actual change in position from the change in position to be expected due to the predetermined torque or the predetermined force. According to a particularly advantageous embodiment of the method, the weft thread 5 after retrieval until it is picked up by the gripper 4 continuously monitored as per the 8-13 is explained in more detail.

The reed continues 10 now move it back to its position away from the weaving point and the shed 2 opens again.

6 finally shows a situation in which the reed 10 has now reached its position away from the turning point and the shed 2 already opens for the following weft entry. The weft 5 is in this situation again through the eyelet 16 the handover facility 8th guided and between this and the hand clamp 7 stretched so that it is in the following weft entry from the gripper 4 can be recorded. If in the return unit 9 a certain length of thread is still stored, the deflection element is first used for the weft insertion 11 by means of its drive 12 ( 7 ) driven in reverse to bring it back to the rest position ( 7 ) to move and release the stored thread length. However, it is also possible that the return unit 9 stored thread length due to changes in thread tension or due to movements of the clamps and eyes has already been released again. The drive in the reverse direction is therefore not absolutely necessary. Furthermore, after taking over the weft 5 by the gripper 4 the Hinreicheklemme 7 and the thread clamp 18 opened to allow the weft insertion.

7 now shows a schematic detailed representation of the return unit 9 , As already described, the return unit points 9 one from a rest position R deflected deflecting element 11 on. The rest position R is shown here in solid lines, while two different, deflected positions of the deflecting element 11 are shown in dash-dotted lines.

For moving the deflecting element 11 instructs the return unit 9 a drive 12 on which by a controller 13 is controllable. The drive 12 can for example be designed as a servo motor or as a rotating magnet. The control 13 stands again with a weaving machine control 14 in tax-related connection to the movements of the deflecting element 11 to be able to execute the timing of the machine angle.

As already described, the return unit has 9 in the present case two stationary thread guide elements 17 on. Likewise, are on the deflecting element 11 here two with the deflecting element 11 movable thread guide elements 17 arranged.

The thread guide elements 17 are designed here as deflection rollers. This enables a particularly gentle, low-friction guidance of the weft thread 5 , The return unit shown here is due to the comparatively large deflection radius of the deflection rollers 9 also for sensitive weft threads 5 suitable, which could break with conventional thread guide elements such as eyelets and the like.

While in the 1-6 a weaving machine 1 was shown with only one weft thread, is now based on the 8-13 the method and the device for a weaving machine 1 with multiple weft threads 5 as well as a color picker 19 described. In order to avoid unnecessary repetitions, only the differences to the 1-6 described.

Again 8th Removable, there are several weft stocks 6 , in the present case two, on the weaving machine 1 arranged, each with its own thread clamp 18 , its own return unit 9 , its own eyelet 16 as well as its own clamp 7 assigned. The eyelets 16 as well as the clamps 7 are part of a color selector 19 trained handover facility 8th , The function of such a color picker 19 is well known and is therefore not explained further here. It goes without saying that instead of just two weft stocks 6 even more weft stocks 6 in an analogous manner on the weaving machine 1 can be arranged.

Is shown analogous to 1 a situation in which a weft thread to be entered 5 by means of being in the feed position Z sufficient clamp 7 the gripper 4 submitted and is currently being captured by this. The other weft 5 , which is not currently entered, is also in the associated handler 7 clamped, but which is in a position above the feed Z arranged waiting position W located so as not in the way of the gripper 4 to guess. There is also this weft 5 assigned eyelet 16 in an upper position in which the entry of the present lower weft thread 5 does not bother. As already described above, the deflection element is located 11 the return unit 9 in a deflected position and is initially used to insert the shot back towards its rest position R ( 7 ) driven to release the thread length stored therein.

9 now shows analog to 2 a situation in which the weft 5 of the lower weft thread supply in the present case 6 has just been entered and a weft end 5a via the shed 2 survives.

10 shows analog to 3 a situation in which the weft 5 or the weft end 5a of the weft thread supply shown below 6 just by means of the return unit 9 was brought back. The sufficient clamp 7 of the upper weft supply 6 is with the upper weft clamped in it 5 still in the waiting position W ,

11 shows analog to 4 a situation in which the now inserted weft thread 5 of the weft thread supply shown below 6 has been struck and is ready by the weft scissors 15 to be cut.

12a now shows the situation after cutting the weft 5 of the lower weft supply 6 , In contrast to the execution of the 5 is now the sufficient clamp 7 do not return to their feed position after cutting Z but in their waiting position W emotional. Analogous to the execution of the 5 This also creates an excess length of the weft thread 5 because the waiting position W closer to the eyelet 16 lies as the takeover position Ü , The return unit 9 was therefore used again to compensate for this excess length. It goes without saying that the excess length could also be compensated in a different way here. Likewise, the lower weft thread supply is now 6 assigned eyelet 16 brought into an upper position. By placing the hand clamp 7 in the waiting position W and spending the eyelet 16 In the upper position there is a problem-free, changing weft insertion of the different weft threads 5 of the multiple weft stocks 6 enables, as now based on the 13 is described.

To the other weft 5 the other, in the present upper weft supply 6 To be able to enter the eyelet 16 of the upper weft supply 6 moved from its upper position to a lower position. Likewise, the sufficient clamp 7 from the waiting position W in the feed position Z emotional. The weft 5 of the weft thread supply shown at the top 6 is now again between the eyelet assigned in 16 and the hand clamp assigned to it 7 clamped and can subsequently by the gripper 4 seized and entered.

In 12a the procedure was presented in connection with a change of the weft thread. In contrast, in 12b another method shown in which a weft 5 pic-a-pic is entered several times in succession. The weft 5 of the weft thread shown in the picture below 6 is by means of the hand clamp 7 just like in 5 shown, directly from the takeover position Ü back to the feed position Z transferred. Only when a weft 5 from another weft supply 6 The sufficient terminal is to be entered 7 with the pinched weft 5 in the waiting position W spent. Again, a second retrieval can be carried out by means of the retrieval unit 9 during or after moving the hand clamp 7 in the feed position Z be provided.

On such a weaving machine 1 with multiple weft stocks 6 it is particularly advantageous to use the return unit 9 not just to retrieve the weft end 5a , but also used for weft monitoring. It is particularly advantageous that the weft threads 5 , which are not currently entered and their binding 7 yourself in a waiting position W continuously from the time of their detection by the hand clamp 7 in the takeover position Ü until it is taken over by the gripper 4 can be monitored. As for the 1-6 the respective weft thread is described 5 applied with a preferably constant voltage, for which the drive 12 A preferably constant torque is specified in each case and the resulting change in position of the drive 12 is monitored.

It is also particularly advantageous that the return unit 9 also for monitoring the function of the elements involved in the weft insertion, such as the clamps 7 . 18 and the eyelets 16 or can be used to monitor the web process. For this, an ideal position profile of the drive 12 , hence the different positions of the drive 12 At different times in the weaving process, for example by measurement, created and in the control 13 of the drive 12 and / or the weaving machine control 14 deposited. This ideal position curve forms characteristic changes in the position of the drive 12 in the weaving process, which are assigned to certain processes of the weaving process. For monitoring the weft thread 5 and the function of the elements involved in the weft insertion 4 . 7 . 15 . 16 . 18 then the actual position profile of the drive 12 by means of the drive 12 assigned position transmitter (not shown) detected and by the controller 13 or the weaving machine control 14 compared with the ideal, stored position history. For example, it can be recognized when an eyelet 16 the color picker 19 has not moved correctly or the weft 5 out of the eye 16 or a clamp 7 has slipped out, as a result of this an elongation or tightening of the weft thread 5 can occur, which is an uncharacteristic change in position of the drive at this time 12 causes. It can also be determined in this way whether the sufficient clamp 7 has moved back correctly to the waiting position because when the weft thread is retrieved 5 the control unit always specifies a characteristic change in position of the drive 12 he follows. If this characteristic change in position does not occur, there may be an error in the movement of the reach clamp 7 are closed and, for example, the weaving process is interrupted and / or an error message is issued.

The invention is not restricted to the exemplary embodiments shown. Modifications within the scope of the patent claims as well as combinations of features, even if these are shown and described in different exemplary embodiments, are also possible.

LIST OF REFERENCE NUMBERS

1

loom

2

shed

3

warp

4

grab

5

weft

5a

Weft end

6

Weft reserve

7

Hinreicheklemme

8th

Hinreicheeinrichtung

9

retrieving unit

10

reed

11

deflecting

12

drive

13

Control of the drive

14

loom

15

Weft cutter

16

eyelet

17

Thread guiding element

18

thread clamp

19

color Picker

IT

entry page

SE

Weft insertion direction

R

rest position

Z

presenting position

Ü

over position

W

waiting position

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102015217356 B3 [0002]
• DE 3524727 A1 [0003]

Claims (27)

Method for weft insertion on a weaving machine (1), in which a weft (5) is withdrawn by a certain distance by means of a return unit (9) arranged on an insertion side (ES) of a shed (2), the weft (5) being pulled through at least an entry element, in particular at least one gripper (4), is detected, is inserted into the shed (2) in a weft insertion direction (SE) and the weft thread (5) is released after the entry by the entry element, whereby on the entry side (ES ) opposite side of the shed (2), a weft thread end (5a) protrudes beyond the shed (2), characterized in that after the weft thread (5) has been released by the insertion element, the now inserted weft thread (5) by means of the return unit (9) is moved against the weft insertion direction (SE) and the protruding weft end (5a) is pulled back into the shed (2). Method according to the preceding claim, characterized characterized in that the protruding weft end (5a) is pulled back into the shed (2) before and / or during the inserted weft (5) is beaten and / or tied by means of a reed (10). Method according to one of the preceding claims, characterized in that the inserted weft thread (5) is deflected to retract by means of a drivable by a drive (12) deflection element (11). Method according to one of the preceding claims, characterized in that the drive (12) is given a change in position for retraction and the drive (12) is moved in a position-controlled manner. Method according to one of the preceding claims, characterized in that the drive (12) is given a force limitation or a torque limitation during the retraction. Method according to one of the preceding claims, characterized in that the inserted weft thread (5), after being pulled back, is clamped by an entry-side clamp of the weaving machine (1), in particular a movable supply clamp (7) of a supply device (8), and by a supply-side weft thread (5) is separated. Method according to one of the preceding claims, characterized in that, after the inserted weft thread (5) has been separated from the weft thread (5) on the supply side, the clamped weft thread (5) on the supply side is monitored by means of the return unit (9). Method according to one of the preceding claims, characterized in that in order to monitor the weft thread (5) on the supply side, a tension, preferably a constant tension, is applied to the weft thread (5) on the supply side by the deflecting element (11) of the return unit (9). Method according to one of the preceding claims, characterized in that the weft thread (5) on the supply side is continuously subjected to the tension from the point of clamping by the clamp until it is gripped by the insertion element for the next weft insertion. Method according to one of the preceding claims, characterized in that a force or a torque, preferably a constant force or a constant torque, is specified for the weft thread (5) with the tension on the drive (12) of the return unit (9) and one Change in position of the drive (12) is detected. Method according to one of the preceding claims, characterized in that a current position profile of the drive (12) is detected by means of a position transmitter while the weft thread (5) is subjected to the tension. Method according to one of the preceding claims, characterized in that a control (13) of the drive (12) compares the current position profile with an ideal position profile, an error message preferably being output if the current position profile deviates from the ideal position profile. Loom (1) with a weft thread supply (6) arranged on an entry side (ES) of a shed (2), with at least one entry-side clamp, in particular a movable hand-over clamp (7) of a hand-in device (8), with at least one entry element, in particular at least one Gripper (4) for inserting a weft thread (5) into the shed (2) in a weft insertion direction (SE) and with one arranged on the entry side (ES) of the shed (2) between the weft thread supply (6) and the at least one entry element Return unit (9) for withdrawing the weft thread (5), characterized in that the return unit (9) is designed and arranged on the weaving machine (1) in such a way that the weft thread (5) after it has been inserted into the shed (2) against the Weft insertion direction (SE) can be withdrawn. Loom (1) according to the preceding claim, characterized characterized in that the return unit (9) is arranged between the weft thread supply (6) and the entry-side clamp, in particular the movable hand clamp (7) of the hand-in device (8). Weaving machine (1) according to one of the preceding device claims, characterized in that the return unit (9) has a deflection element (11) which can be driven by a drive (12) and can be deflected from a rest position (R), in particular a rotatably mounted lever. Loom (1) according to one of the preceding device claims, characterized in that the deflecting element (11) has at least one thread guide element (17) for the weft thread (5). Weaving machine (1) according to one of the preceding device claims, characterized in that the return unit (9) has at least one stationary thread guide element (17) for the weft thread (5). Weaving machine (1) according to one of the preceding device claims, characterized in that the at least one thread guide element (17) of the deflection element (11) and / or at least one stationary thread guide element (17) is designed as a deflection roller. Loom (1) according to one of the preceding device claims, characterized in that the drive (12) has a position transmitter. Weaving machine (1) according to one of the preceding device claims, characterized in that the drive (12) can be moved either force-controlled or torque-controlled or position-controlled. Loom (1) according to one of the preceding device claims, characterized in that the drive (12) is designed as a rotating magnet. Weaving machine (1) according to one of the preceding device claims, characterized in that the return unit (9) is assigned a thread clamp (18) arranged between the weft thread supply (6) and the return unit (9). Loom (1) according to one of the preceding device claims, characterized in that the return unit (9) forms a device for monitoring the weft thread of a weft thread (5) on the supply side. Weaving machine (1) according to one of the preceding device claims, characterized in that the return unit (9) is designed to continuously monitor the weft thread (5) on the supply side. Weaving machine (1) according to one of the preceding device claims, characterized in that the drive (12) of the return unit (9) can be acted upon with a preferably constant force or a preferably constant torque for weft thread monitoring. Loom (1) according to one of the preceding device claims, characterized in that the return unit (9) is designed to monitor a function of elements (4, 7, 15, 16, 18) involved in the weft insertion. Weaving machine (1) according to one of the preceding device claims, characterized in that the weaving machine (1) has a plurality of clamps on the entry side for a plurality of weft threads (5) and that a return unit (9) is assigned to each of the plurality of weft threads (5).

Images