EP1367159B1 - Process and device for bringing a clamped weft yarn to a bringer gripper of a loom - Google Patents

Abstract

Reduction of weft waste in a weaving loom having a weft insertion gripper, comprises clamping a weft thread following insertion of the weft thread into a loom shed by a weft presenting first clamp and by a weft holding second clamp on a weft insertion side of the loom shed; moving the clamps with beat-up motion of a reed; and cutting the weft thread between clamps. Reduction of weft waste in a weaving loom having a weft insertion gripper, comprises clamping a weft thread (7) following insertion of the weft thread into a loom shed by a weft presenting first clamp (13) and by a weft holding second clamp (18) on a weft insertion side of the loom shed; moving the clamps with beat-up motion of a reed (4) toward an axial extension of a beat-up line (8); cutting the weft thread between clamps while the clamps are still following the beat-up motion of the reed, to form a leading weft end (7A) of a weft yet to be inserted into the loom shed and a trailing weft end (7B) of an inserted weft (7C); continuing to hold the trailing weft end by the second clamp until beat-up is completed; opening the second clamp to release the trailing weft end and returning the second clamp into a starting position; and returning the first clamp still holding the leading weft end into a rest position. An Independent claim is also included for an apparatus for reducing weft waste in a gripper weaving loom, comprising reed; weft insertion gripper (10) for moving into and out of a loom shed; weft supplies; movable weft presenter (12) for each weft supply; weft presenting first clamp mounted to its respective movable weft presenter for movement between a rest position (12A) and a weft presenting position (12B) for presenting a leading weft end to the gripper; weft holding second clamp movable mounted in the weaving loom for at least partly following a movement of the reed; weft cutter (20) mounted in a stationary position next to the weft presenting position of the weft presenting first clamp next to a weft entrance edge (17) of the loom shed, where the cutter is effective between the two clamps.

Description

The invention relates to a method and a device for feeding a clamped weft thread to a rapier of a weaving machine according to the preamble of the independent claims, wherein the weft feeder and clamping device serves to minimize the weft drop in the manufacture of fabric on rapier looms.

1. 1. Das freie Ende wenigstens eines ersten und eines zweiten nacheinander in ein Webfach einzutragenden Schussfadens wird in jeweils einer Klemme jeweils eines Zubringerhebels einer Zubringer- und -klemmvorrichtung geklemmt. Die Hebel befinden sich dabei in einer Position A.
2. 2. Ein Schussfadenwähler wählt nach einem Steuerprogramm zwischen den beiden Schussfäden einen Schussfaden für einen Bringergreifer aus.
3. 3. Der betreffende Zubringerhebel wird in eine zweite Position B bewegt und bringt dabei den ausgewählten Schussfaden in den Weg des Bringergreifers, der den Schussfaden übernimmt.
4. 4. Der Zubringerhebel wird nachfolgend in eine Position C bewegt, die nahe der eintragseitigen Gewebekante in Fortsetzung des Bindepunktes eines Gewebes liegt.
5. 5. Der mit dem Fadenvorrat verbundene, vorgenannte Schussfaden wird nach dem Eintragen in das Webfach und nach dem Abbinden von der betreffenden Klemme in der Position C geklemmt gehalten.
6. 6. Der abgebundene Schussfaden wird nachfolgend zwischen der Gewebekante und der in Position C stehenden Klemme von dem bereitgehaltenen, geklemmten Schussfaden mittels einer Schussfadenschere abgeschnitten.
7. 7. Der betreffende Zubringerhebel wird nach dem Abschneiden des Schussfadens in die Position A zurückbewegt oder in der Position C gehalten.

To minimize the weft drop is from the EP 0 240 075 B a working method and an apparatus for carrying out the method known. According to the method, at least two weft yarn feeding devices are used for fabric production. The known working method can be characterized essentially as follows:

1. 1. The free end of at least a first and a second successively entering into a shed weft thread is clamped in each case a terminal of a feeder lever of a feeder and -klemmvorrichtung. The levers are in a position A.
2. 2. A weft selector selects a weft thread for a rapier after a control program between the two weft threads.
3. 3. The respective feeder lever is moved to a second position B, bringing the selected weft in the path of the rapier, who takes over the weft.
4. 4. The feeder lever is subsequently moved to a position C which lies near the entry side fabric edge in continuation of the bonding point of a fabric.
5. 5. The above-mentioned weft thread connected to the thread supply is, after entering into the shed and after setting of the relevant terminal in held the position C clamped.
6. 6. The set weft yarn is subsequently cut off between the fabric edge and the terminal C in position from the clamped weft yarn held by a weft cutter.
7. 7. The relevant feeder lever is moved back to position A after cutting the weft thread or held in position C.

The known method, together with the apparatus for performing the method to be described below, has a decisive disadvantage, which consists in the fact that each type of weft thread to be introduced inevitably has a different waste length. Thus, while the thread clamp closest to the fabric edge realizes a relatively short fall length, the weft drop of the weft threads held by the remaining thread clamps is comparatively progressively greater. The increase in the waste length is device-related and, as already mentioned, of considerable disadvantage. Another disadvantage is that the weft thread is cut in the region of the stop of the reed and thus has to be pulled out to the binding point. In order to achieve a waste reduction, the weft yarn must be withdrawn from a weft yarn retrieval device, also to ensure the required yarn tension for the next weft insertion.

To better illustrate the aforementioned disadvantages, the apparatus for carrying out the method should be briefly characterized. Thereafter, a device for presentation and clamping of weft threads in a rapier is known.
Said device essentially comprises a feeder lever with thread clamp for each weft thread to be inserted into a shed. The feeder levers are located next to each other and arranged approximately parallel to the entry side fabric edge. The first feeder lever clamp is closest to the fabric edge positions A and C, while the last feeder lever clamp is positioned furthest away from the fabric edge. This makes it clear that the free thread length between the fixed position of the thread scissors on the fabric edge and each terminal following the first terminal is to be regarded as a further disadvantage. The larger the thread length between the thread scissors and the thread clamp, the lower is in usually the necessary thread tension for the cutting process. In that regard, the known device does not ensure that the entry side of the shed always a proper cutting edge is achieved.

From the DE-OS 25 31 954 a controllable weft-clamping device with a plurality of nips is known, each nip is displaceable relative to a reference plane and further wherein the nips are arranged one above the other at equal intervals and one nip in the reference plane can be moved. In combination with known, controlled Schussfadenwählern, ie each nip of the controlled clamping device functionally assigned a controlled weft selector, on the one hand achieved in an advantageous manner that the weft thread to be inserted into the shed can be moved into a first reference plane and in this of the Bringergreifer is taken over without any problems. On the other hand, the clamping point in question can be moved in a second reference plane, which corresponds to the position of the binding point of the tissue. This ensures that when weft of the weft yarn to the binding point of the fabric, the weft thread is received by the respective nip of the clamping device and entry side of the shed between fabric edge and nip is kept curious. This is advantageous for the cutting process, the thread scissors arranged between the nip and the fabric edge. However, a minimization of the weft drop can not be achieved because the weft threads can not be presented to the Bringergreifer immediately.

From the DE 30 42 053 Cl is a loom with a device for reducing the weft drop known, which is particularly in terms of the provisions for reducing the weft drop and the provision for cutting the weft from the previously tied in the fabric weft thread as technically complex and prone to failure. If, as the invention teaches, the end of the cut weft yarn is to be held by pneumatic means, then it goes without saying that the end of the cut weft yarn can not be relatively short.

Finally, that teaches DE 197 39 853 C2 a weft feeder and -clamping device with a plurality of weft feeder with clamp, which are arranged in such a weaving machine in combination with at least one weft-return device and cooperate, that for all in a predetermined sequence to be inserted into a shed weft threads due to the taking place in almost one point addition of the weft threads to Bringergreifer a minimum of weft waste is realized.

The object of the invention is to provide a method for minimizing the weft drop while avoiding the disadvantages of the prior art and to provide a device for carrying out the method.

According to the invention this object is solved by the features of the independent claims.

It is essential to the invention that immediately after the insertion of the weft thread in the shed and prior to its impact by the reed to the fabric edge of the remaining between a thread guide and the entry-side fabric edge portion of the weft immediately after clamping by the feeder clamp and by the holding clamp and while the movement of the reed is cut by a cutting device arranged between the subjacent position of the feeder clamp and a holding position of the holding clamp and thereupon a rear weft end and a front end of a new weft thread are present, the holding clamp clamping the rear end of the inserted weft threading the stop movement of the reed all the way up to the binding point, after which the weft thread is struck at the binding point, the retaining clip is then opened and returns to the receiving position, and then further also the Fadenzubringer with the front end of an n new weft returns to its resting position.

Advantageous embodiments and further developments of the invention are specified in the dependent claims.

With the inventive provision of a movable, the movement of the reed following holding clamp in combination with the respective Thread feeder clamp and a remote from the stop edge cutter for the weft thread is achieved in an advantageous manner that the weft thread during the movement of the reed can be cut in the direction of the stop edge of the fabric. Furthermore, the movement of the yarn feeder is selected so that at least in the rest position and the sufficient supply the same thread tension. The advantages of this arrangement lie in the achievement of a very low weft drop, without having to provide a return device for the weft.

Due to the punctual addition of each weft color through the thread feeders, a uniformly low weft drop is achieved with each color.

The procedure and the timely control of the individual devices, such as yarn feeder, Bringergreifer, gripper rapier, reed, holding clamp and separator, is realized by an electronic weaving machine control. The drive of the devices may either be derived from the central loom drive or by independent drives controlled by loom control, e.g. Electromotive drives, done.

An apparatus for carrying out the method is disclosed in independent claim 12.
In accordance with the invention, it is essential to the invention that a holding clamp for the rear end of the inserted weft thread following the movement of the reed on the entry side fabric edge is provided, and that a cutting device is arranged near the point of contact of a thread clamp between the thread clamp and the holding clamp.

The invention will be explained in more detail below with reference to two exemplary embodiments.

Show it:

FIG. 1:

a schematic representation of a first embodiment of the weft feeder and clamping device with a circular Movement of the thread feeders;

FIG. 2:

a section of the device of Figure 1 or Figure 3 in the region of the holding clamp.

FIG. 3:

a schematic representation of a second embodiment of the weft feeder and clamping device with linear movement of the yarn feeder.

In Figures 1 and 2, the weft insertion side of a loom is shown schematically. The upper and lower warp threads 1, 2 extend through the weaving machine shafts 3 and through the lamellae of the reed 4 up to the binding point 5, at which each of the weft yarn 7 inserted into the shed 6 stretched by the warp threads 1, 2 is moved back and forth Web leaf 4 is struck against the stop edge 8 of the fabric 9. The weft threads 7 are introduced by a Bringergreifer 10 and a non-illustrated gripper rapier in the shed 6. The formed fabric 9 is continuously pulled down.

In the example of Figure 1, six weft threads 7 are shown, which are withdrawn from supply spools (not shown) and extend over a thread guide 11 to so-called Fadenzubringern 12, where they are held by a feeder clamp 13. Each weft yarn 7 is assigned a yarn feeder 12 with feeder clamp 13. The thread feeders 12 are formed as a bow-shaped pivot lever. In the drawing, a yarn feeder 12 is shown in its rest position 12A, wherein the feeder clamp 13, the end of the associated weft yarn 7 is stuck. Each yarn feeder 12 is pivotally mounted about a pivot axis 14 and can be pivoted between the rest position 12A and a sufficient position 12B, wherein the pivot axis 14 is selected such that it passes through the thread eye 15 of the thread guide 11 of the associated weft thread 7. This ensures that the distance between the eyelet 15 and the feeder clamp 13 and thus also the thread tension in each position of the yarn feeder 12 remains constant. In their present position 12B, all thread feeders 12 are located substantially at the same point of addition 16, as indicated in FIG.

Now, if a weft 7 is selected for the next weft insertion, so pivots the yarn feeder 12 from its rest position 12A in its presence position 12B near the entry-side fabric edge 17, wherein in Figure 1, only the feeder clamp 13 is indicated in the presence position. As a result, the selected weft thread 7 is brought into the movement path of the rapier 10. The Bringergreifer 10 takes the weft and brings him into the open shed 6 a. Approximately in the middle of the shed, the weft thread is picked up by a gripper rapier (not shown) and pulled completely through the shed. The rapier 10 then returns to its rest position outside the shed and is ready for the next weft insertion.

After weft insertion, the reed 4 is moved from its front position 4A in the direction of its stop position 4B at the binding point 5 and pushes the registered weft thread 7 in front of him. The yarn feeder 12 with the feeder clamp 13 is still in the presence position 12B. By the movement of the reed 4 exiting the fabric edge 17 weft yarn 7 is introduced into the feeder clamp 13 and clamped there.
At substantially the same time, the weft thread 7 is introduced through the reed 4 into a holding web 18 movably arranged on the lateral fabric edge 17 and likewise clamped there.

The introduction of the weft thread into the feeder clamp 13 and the holding clamp 18 can be assisted by a side hook 4 arranged on the reed 4, which ensures reliable insertion of the weft yarn 7 into the two clamping devices 13, 18. However, the use of a Hinreichehakens 19 is not mandatory and can e.g. be made dependent on the type of weft threads to be processed.

After the weft yarn 7 is reliably clamped in the feeder clamp 13 and the holding clamp 18, it is immediately cut by a cutter 20 stationarily arranged near the licking position 12B of the yarn clamp 13 while the reed 4 continues to move in the direction of its stopper position 4b.

The rear, cut end of the inserted weft thread 7 is now through the Retaining clip 18 clamped while a new front end of the weft yarn coming from the supply reel 7 is kept clamped in the feeder clamp 13 for re-presentation of the rapier 10.

As can be seen in particular from FIG. 2, the holding clamp 18 is arranged on a pivoting lever 22 which is movable about an axis 21. The movement of the pivot lever 22 is positively controlled and follows after the clamping of the weft thread 7 substantially the movement of the reed 4 to its stop position.

After the weft insertion, the pivot lever 22 is in an indicated in Figure 2 middle position 22A. When carrying out the stop movement, the reed enters the region of the position 22A of the pivoting lever. By a movement of the pivot lever 22 in the direction of the rearward position of the reed 4, namely in a position 22 B, the weft yarn 7 to be picked is gripped and clamped by the holding clamp 18. From the position 22B, the pivot lever 22 moves synchronously with the movement of the reed 4 in a position 22C, in which the reed 4 abuts the registered weft thread 7 at the stop edge 8 of the fabric 9. In Figure 2, the position of the reed 4 in the stop position 4b is indicated. In this position 4b, the retaining clip 18 opens and releases the end of the weft thread 7. The pivot lever 22 can now return to its original position 22A.

Meanwhile, the yarn feeder 12 also pivots back to its rest position 12A to make room for another yarn feeder 12. If the same weft thread is to be re-entered, the yarn feeder 12 can remain in its preswelling position 12A.

Figure 3 shows an embodiment of the invention with a linear yarn feed. The essential difference from the embodiment according to FIG. 1 is that each thread feeder 12, instead of a circular movement, carries out a purely linear adjustment movement in the direction 25 between its rest position 12A and its attachment position 12B and vice versa. The thread feeders 12 are in their allotted position 12B substantially all at the same Hinreichepunkt 16. The linear path of the yarn feeder 12 from its rest position 12A in the Hinreichestellung 12B is chosen such that the clamped weft yarn 7 is kept curious at least in the rest position and the Hinreichestellung.
After the yarn feeder 12 has brought the weft yarn 7 to be introduced into the letting position 12B, the yarn is picked up by the bringer rapier 10 and inserted into the shed 6. The subsequent process steps correspond to the steps described in connection with FIGS. 1 and 2.

LIST OF REFERENCE NUMBERS

1

Warp threads above

2

Warp threads below

3

Webmaschinenschäfte

4

reed

4A

Weave (entry position)

4B

Reed (stop position)

5

binding point

6

shed

7

weft

8th

stop edge

9

tissue

10

A giver

11

thread guide

12

yarn feeder

12A

Thread feeder resting position

12B

Fadenzubender Hinreichestellung

13

feeder clamp

14

swivel axis

15

eyelet

16

Hinreichepunkt

17

fabric edge

18

retaining clip

19

Hinreichehaken

20

cutter

21

axis

22

pivoting lever

22A

Swing lever (position A)

22B

Swing lever (position B)

22C

Swing lever (position C)

25

arrow

Claims (16)

1. A method for feeding a weft thread to a bringer-gripper of a loom, wherein a plurality of weft threads (7) is present and the initial section of each weft thread is clamped by an associated feeder clamp (13) arranged on a movable thread feeder (12), the method comprising the following steps:

   moving a selected thread feeder (12) with the weft thread from a rest position (12A) into a presenting position (12B),

   gripping the weft thread (7) by a bringer-gripper (10) and opening the feeder clamp (13) of the thread feeder (12),

   inserting the selected weft thread (7) into an opened shed (6),

   beating up the weft thread to the interlacing point (5) at the fell (8) of the cloth (9) by the reed, wherein, before beating up the weft thread, the portion of the weft thread (7) remaining between a thread guide (11) and the insertion-side cloth edge (17) is introduced into and clamped in the same feeder clamp (13), and at substantially the same time as the remaining portion of the weft thread (7) is introduced into and

   clamped in the feeder clamp (13), it is gripped and clamped by a holding clamp (18) arranged at the insertion-side cloth edge (17), wherein directly after being clamped by the feeder clamp (13) and the holding clamp (18) and whilst the reed (4) is still moving, the remaining portion of the weft thread (7) is cut by a cutting device (20) arranged between the presenting position of the feeder clamp (13) and a receiving position (22B) of the holding clamp (18) and thereupon a trailing weft thread end and a leading end of

   a new weft thread are present, characterised in that the holding clamp (18) clamping the trailing end of the weft thread (7) follows the beating-up motion of the reed (4) as far as the interlacing point (5), whereupon the weft thread is beaten up to the interlacing point, the holding clamp (18) is then opened and returns to the receiving position (22b), and whereupon furthermore also the thread feeder (12) with the leading end of a new weft thread returns to the rest position (12A).
2. A method according to claim 1, characterised in that the inserted weft thread (7) is introduced with the assistance of a presenting hook (19) into the feeder clamp (12) and the holding clamp (18).
3. A method according to claim 1, characterised in that the holding clamp (18) is arranged on a pivoting lever (22) movable about an axis (21), the holding clamp (18) receiving and clamping the weft thread in a receiving position (22B) of the pivoting lever, the pivoting lever (22) being pivoted together with the motion of the reed (4) into a rear beat-up position (22C) and the holding clamp (18) there re-releasing the weft thread.
4. A method according to claim 1, characterised in that a respective one of a plurality of thread feeders (12) pivotable about an axis (14) is used, each thread feeder in the presenting position (12B) occupying substantially one and the same presenting point (16).
5. A method according to claim 4, characterised in that the position of the axis (14) of the thread feeders (12) is selected so that on movement between the rest position (12A) and the presenting position (12B) and vice versa the weft thread is held under tension.
6. A method according to claim 1, characterised in that a respective one of a plurality of linearly movable thread feeders (12) is used, each thread feeder in the presenting position (12B) occupying substantially one and the same presenting point (16).
7. A method according to claim 6, characterised in that the linear path of the thread feeders (12) from the rest position (12A) into the presenting position (12B) is selected so that the weft thread (7) is held under tension at least in the rest position and the presenting position.
8. A method according to any one of claims 1 to 7, characterised in that the thread feeder (12) remains in its presenting position (12B) when the same weft thread (7) is to be inserted in the next weft insertion.
9. A method according to claim 1, characterised in that the motion of the thread feeders (12), the operation of the feeder clamps (13), the motion of the pivoting lever (22), the operation of the holding clamp (18) and the operation of the cutting device (20) are controlled in dependence on the machine angle.
10. A method according to claim 1, characterised in that the feeder clamps (13) and/or the holding clamp (18) are passively operated.
11. A method according to claim 1, characterised in that the feeder clamps (13) and/or the holding clamp (18) are actively operated.
12. An apparatus for feeding a weft thread to a bringer-gripper of a loom, wherein a plurality of weft threads (7) is present and the leading end of each weft thread to be fed is clamped by an associated feeder clamp (13) arranged on a movable thread feeder (12), wherein the thread feeders (12) are moved from a rest position into a presenting position and vice versa, the apparatus having a bringer-gripper insertable into the shed (6) and withdrawable therefrom again, and a cutting device (20) for cutting off the inserted weft thread (7) from a weft thread held ready, wherein the cutting device (20) is arranged close to the presenting point (16) of the thread clamp (12) in a stationary position at the insertion-side cloth edge (17), characterised in that a holding clamp (18) for the weft thread (7) that follows the motion of the reed is provided at the insertion-side cloth edge (17).
13. An apparatus according to claim 12, characterised in that the holding clamp (18) is arranged on a pivoting lever (22) driven movably about an axis (21).
14. An apparatus according to claim 12, characterised in that the thread feeders (12) are in the form of bow-shaped elements driven about a pivot axis (14).
15. An apparatus according to claim 12, characterised in that the thread feeders (12) are in the form of elements driven in a linear direction.
16. An apparatus according to claim 12, characterised in that a fixedly installed presenting hook (19) is provided between the presenting position (12B) of the thread feeder (12) and the cutting device (20).

Images