EP0458736A1 - Weft breakage repair in dummy shuttle looms - Google Patents

Abstract

The procedure for automatic weft break repair on projectile weaving machines is carried out with two devices. The first device, having a swivelling thread guide part (5,5'5") connected to a suction pipe (8), serves on the one hand to draw in a new weft thread and on the other hand to take a broken weft thread out of the shed from the entry side of the shed. The second device (30) serves to remove a thread rest from the exit side of the shed. For a weft break between supply package and a weft storage device, a bearded needle (9)comes into operation which is a component of the first device. This bearded needle makes it possible to leave the inserted weft thread in the shed and to weave it in. <IMAGE>

Description

The invention relates on the one hand to a method for automatically eliminating weft breakage in projectile weaving machines according to the preamble of claim 1 and on the other hand to devices for carrying out the method.

If the weft breaks, the weaving machine has to be stopped, the broken weft removed, the weft mechanism prepared with fresh thread and finally the weaving machine started again. The downtimes of the weaving machine caused by weft breaks can be reduced by automation, in which manual intervention by Weber is no longer necessary. Devices for the automatic removal of thread remnants in the event of weft thread breaks are already known (e.g. DE-OS 23 52 730). Devices for pulling a weft thread into a weaving machine, in which the thread is fed from a bobbin to an insertion member, are also known. Such devices (e.g. EP-A-0365472 (T.772)) have been developed for jet looms; but they can also be used with suitable adaptation for projectile weaving machines.

The object of the invention is to provide a method for automatic weft breakage elimination in which devices for removing the thread remnants and for pulling in a weft thread are combined in such a rational manner that individual components together used in various process steps.

The solution to this problem, as given by the characterizing features of claim 1, relates to a special device that enables automatic drawing in of the weft thread by means of compressed air. To the extent that it is appropriate for the explanation of the present invention, this device will first be described in somewhat more detail:

The weft mechanism with various functional elements is located between the thread store and the compartment entrance, namely projectile lifter (for feeding the projectile), projectile opener, thread dispenser, thread dispenser opener, impact mechanism, thread tensioner, thread brake, weft thread monitor, injector nozzle for the weft thread, scissors, centering wing and thread guide element with suction line. The weft thread is guided in a channel composed of pipe sections, which is interrupted in places for individual functional organs. In order that the weft thread can be deflected transversely to its running direction over individual distances, the tube pieces assigned to these distances are slotted in the longitudinal direction.

When the weft thread is drawn in, the thread tip is blown into the opening of the funnel-like thread guide member, which can be pivoted into the compartment entrance area, and is conveyed further into the thread guide member by suction. With the centering wing, which can also be pivoted, the weft thread is gripped and brought into a position in which it can be gripped by the clamp of the thread take-up device. The weft is opened with the scissors between the clamp and the centering wing cut the right length; the excess thread end is drawn off.

In the method according to the invention, which in addition to the retracting function also includes the removal of the weft breakage, the thread guiding member can be swiveled from a low to a middle to a high position in front of the compartment entrance. This swiveling movement can be used to pull a broken weft thread out of the shed.

The method according to the invention can also be used on multi-shot projectile weaving machines with color changers.

The dependent claims 2 to 6 relate to advantageous developments of the method according to the invention. The independent claims 7 and 8 relate to the two devices mentioned in the preamble of claim 1. Claims 9 and 10 relate to special embodiments of the second device. Finally, claim 11 relates to the first device, which is supplemented with a special functional element for repairing the weft breakage in the event of a break in front of the thread store.

• Fig.1 die Funktionsorgane vor dem Facheingang,
• Fig.2 eine Phase des erfindungsgemässen Verfahrens beim Entfernen eines im Fach gebrochenen Schussfadens,
• Fig.3 eine Vorrichtung mit Nadel zum Beheben eines Schussfadenbruchs, der zwischen Vorratsspule und Fadenspeicher entstanden ist,
• Fig.4 eine Vorrichtung wie in Fig.3 während einer spätern Verfahrensphase und
• Fig.5 eine Vorrichtung zum Entfernen eines Fadenrests von der Fachausgangsseite her.

The invention is explained in more detail below with reference to the figures. Show it:

• 1 the functional organs in front of the compartment entrance,
• 2 shows a phase of the method according to the invention when removing a weft thread broken in the compartment,
• 3 shows a device with a needle for eliminating a weft break that has arisen between the supply spool and the thread store,
• 4 shows a device as in FIG. 3 during a later process phase and
• 5 shows a device for removing a thread remnant from the compartment exit side.

The following components can be seen in FIG. 1: the starting piece of the injector nozzle 1 for the weft thread 13; the thread take-up clamp 2; the scissors 3; the centering wing 4 or 4 'in the rear or front position; the pivotable, funnel-like thread guide member 5, 5 'or 5˝ in the low, middle or high position; the swivel drive 6, which for example by the bevel gears 6a and 6b moves the thread guide member 5 '; a box 7, which symbolically stands for a thread brake and / or a thread monitor and / or an injector nozzle; a delivery pipe or suction line 8 through which the thread can be drawn off or blown off (arrow A); the reed 10; the warp threads 11 forming the shed and the fabric 12.

The situation shown in Figure 1 with the centering wing 4 in the rear position and the thread guide member 5 'in
The middle position is when a new weft thread 13 is drawn in. Following this situation, the centering wing swivels forward and the thread guide member downward, the weft thread sliding into the throat of the centering wing. The clamp 2, which can be pushed back and forth between the injector 1 and the scissors 3 (Double arrow R), grips the weft thread in the scissors, which can then be severed, the cut piece of thread being drawn off by the conveyor tube 8. In the position shown, the terminal 2 passes the thread tip to the projectile, not shown. Before launching, scissors 3 and centering wing 4 'pivot out of the trajectory. The registered weft thread 13 'is drawn in dashed lines. The injector 1 has a curved starting piece, so that the thread tip is blown against the opening of the thread guide member 5 'when it is drawn in. A construction with a straight starting piece would also be possible.

FIG. 2 also shows the functional organs at the compartment entrance, the clamp 2, the scissors 3 and the reed 10 no longer being drawn compared to FIG. 1. The thread guide member 5 '- here in the high position - additionally has a circular segment-shaped part 5a, over the edge of which the weft thread is guided. When pivoting down (double arrow S), the distances between the opening of the thread guide member and the injector 1 or the centering wing 4 '; thus the two thread pieces 13a and 13b can be drawn off in the form of the loop 13c (arrow H). When the thread guide member 5 is swung up again, the weft thread broken in the compartment is pulled a further distance out of the compartment (arrow G); at the same time, thread also emerges from the injector nozzle 1 (arrow F). During this swiveling up, a thread brake 7 is advantageously actuated in order to prevent the loop 13c from being pulled back (against the direction of the arrow H). The broken weft thread 13b can be completely removed from the compartment by pivoting the thread guide member 5 up and down several times. so that finally there is a corresponding situation as in FIG. 1 when a new weft thread is drawn in.

With a low roughness of the warp and weft threads, it is sufficient to make the pivoting movement of the thread guide member 5 only a few times and to continue the further removal of the broken weft thread from the compartment by suction alone. The segment-shaped part 5a on the side of the thread guide member 5 serves to deflect the thread 13b, thereby increasing the thread length drawn out per pivoting movement and thus reducing the number of pivoting movements required. The complete removal of the broken weft thread from the compartment is advantageously monitored with a sensor which is arranged, for example, in box 7.

If a weft break occurs, the loom should be stopped quickly so that the reed does not stop. A prerequisite for a quick stop is a sensor that registers the break during or immediately after the tearing process. This requirement can be met with a sensor that monitors the thread tension during the weft insertion. If it is not possible to stop the loom in time, the weft thread that has been struck must first be loosened with an additional device (see, for example, DE-OS 23 52 730), since otherwise there is a risk of a second breakage when the weft thread is pulled out Thread piece in the compartment is lost.

To pull in a new weft thread, the thread guide member only has to be pivotable between the low and the middle position. It is, however, in the method for eliminating shot breakage according to the invention necessary that the upright position can be reached, that is to say that the pivoting movement can be carried out by an angle of as much as 180 degrees. A swiveling movement through an even larger angle allows a correspondingly longer piece of thread to be pulled out of the compartment per stroke.

If the thread breaks between the bobbin and the accumulator, the inserted weft thread can be woven in; however, the thread in the memory must be removed before a new weft thread can be drawn in. This can be done using a hook needle, as will be explained in more detail with reference to FIGS. 3 and 4. In contrast to what is shown in these figures, the hook opening can also be directed towards the bottom.

The hook needle 9 is, for example, telescopically insertable into the area between the injector nozzle 1 and the centering wing 4 'in such a way that it comes to lie over the stretched weft thread 13'. After the hook needle 9 has been brought into the insertion position, further thread 13 is drawn off from the store by means of the injector nozzle. It forms a thread loop above the needle 9, which is directed towards the inlet opening of the thread guide member 5 '(middle position) and can be sucked in there. By suction on the thread guide member 5 'can then empty the thread store.

After emptying, the hook needle 9 is withdrawn and the centering wing 4 'brought into the rear position, as shown in Fig.3. When the needle 9 is withdrawn, the thread 13 is caught in the hook. Then a new weft thread 14 can be drawn in, which together with the thread 13 can now be inserted into the throat of the Center wing 4 arrives. This pulling in of the weft thread 14 is done, as has already been described above, the centering wing 4 being pivoted back into the front position and the thread guide member 5 'into the down position. After the clamp 9 has gripped the weft 14, the two threads 13 and 14 are cut together by the scissors 3 (not shown) (see FIG. 1) and the two thread remnants in the thread guide member 5 'are drawn off.

When the projectile is pushed back in the catch brake, the thread in the compartment must be pulled back accordingly so that the thread remains stretched. After the thread 13 has been removed from the memory, this task can no longer be performed by the thread tensioner. This tensioning function can take over the hook needle 9 in addition to its function described above; for this purpose, the corresponding retraction movement of the hook needle 9 can be carried out, for example, by means of a pneumatic lifting cylinder.

If the weft thread breaks inside the compartment, the thread piece on the exit side must also be removed. This can be carried out, for example, by means of a device which is explained with reference to FIG. 5. The catch brake 20 for the projectile 16 is in the background of FIG. 5. The lower brake shoe 21 and the projectile ejection channel 22 are indicated. Other components - namely, slide back, projectile opener, ejector, upper brake shoes - are not shown. In the foreground are the warp threads 11 forming the compartment and the fabric 12. A suction channel 30 can be swung in between the compartment and the catch brake 20. On the side of the suction opening of this suction channel 30 is a pivotable hook element 31 is arranged, with which the broken weft thread 15 can be held on the suction opening after a pivoting movement (arrow U).

By swiveling the suction channel 30 upwards (double arrow T), the weft thread 15 is pulled a little out of the compartment. In Figure 5, the upper position 30 'of the suction channel 30 is shown. After reversing the pivoting movement, the loosened piece of weft thread can be drawn off (arrow C), the hook element 31 also being pivoted back beforehand. By repeating the pivoting movement of the suction channel 30 and actuating the hook element 31 and finally by loosening the projectile clamp, the thread 15 can be completely drawn off.

Instead of the pivotable hook element 31, a clamp or another gripping element can also be provided. For example, a blowpipe 35 is also advantageously used (air flow: arrow B). With the blowpipe 35, a loop can be formed at the beginning of the thread removal from the thread 15 hanging loosely between the compartment and the catch brake 20, which loop can be reliably fed to the suction opening of the suction channel 30.

If the weft thread 15 breaks close to the end of the compartment, it can be torn out of the compartment completely and also thrown into the catch brake 20. In this case, a second blowing nozzle, not shown in FIG. 5, is to be provided, which is arranged on the side next to the catching brake 20 and with which the thread piece can be blown out of the catching brake 20 again in the direction of the compartment and thereby in front of the suction opening of the suction channel 30.

Claims (11)

Method for automatically eliminating weft breakage in projectile weaving machines with a first device for pulling in a weft thread from the supply spool to the projectile, this device having a thread store, various pneumatically operated thread guiding means and, directly in front of the shed, a pivotable thread guide element connected to a suction line, and with a second device to remove a thread remnant from the compartment exit side,
characterized in that a weft thread broken inside the shed is removed from the compartment entrance side by swiveling the thread guide member (5, 5 ′, 5˝) and simultaneous air intake through the suction line (8). A method according to claim 1, characterized in that the thread guide member (5) is pivoted between a low position and a diametrically opposite high position. Method according to one of claims 1 or 2, characterized in that by means of the pivoting movement of the thread guide member (5) the broken weft thread is only partially pulled out of the compartment and that the continued removal from the compartment is carried out only by means of the suction. Method according to one of claims 1 to 3, characterized in that during the Thread guide member (5) on the weft thread pulling movement is acted on the thread portion already drawn off with a thread brake. Method according to one of claims 1 to 4, characterized in that the thread tension for registering thread breaks is monitored with a detector and that the stop movement of the reed is stopped immediately after a weft thread break is detected. Method according to one of claims 1 to 4, characterized in that upon a stop movement of the reed immediately after the occurrence of a weft break, the struck thread parts are loosened with mechanical and / or pneumatic means before the weft break is repaired. Device for pulling in a weft thread and for eliminating weft breakage according to one of claims 1 to 6, characterized in that the pivotable thread guide member (5) has a suction opening on the side to which an element (5a) is attached which deflects the weft thread to be drawn (13b) and in this way the pull-up length per swivel movement is increased. Device for removing a remnant of weft thread from the compartment exit side when eliminating a broken weft according to one of claims 1 to 7, with a pivotable suction duct (30, 30 ′) and mechanical means (31) for holding the thread remnant on the suction opening of the suction duct (30, 30 ′) ). Apparatus according to claim 8 with a blowing nozzle (35) which blows at the compartment outlet against the suction opening of the pivotable suction channel (30). Device according to one of claims 8 or 9 with a blowing nozzle with which the thread (15) entrained by the projectile (16) can be blown out of the catch brake (20) in the direction of the shed. Device for pulling in a weft thread and for breaking weft breakage according to one of claims 1 to 6, with a hook needle (9), which is in front of a centrifuge wing (4), which is arranged in front of the thread guide member (5 ′), over the stretched weft thread (13 ′) can be pushed.

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