EP0229084A1

EP0229084A1 - Method and device for extracting defective weft yarns of a shuttle-less loom.

Info

Publication number: EP0229084A1
Application number: EP86903168A
Authority: EP
Inventors: Bruno Grange; Jean-Luc Dussart; Richard David
Original assignee: Picanol NV
Current assignee: Picanol NV
Priority date: 1985-06-14
Filing date: 1986-06-13
Publication date: 1987-07-22
Anticipated expiration: 2006-06-13
Also published as: WO1986007394A1; DE3670656D1; FR2583435A1; US4962793A; FR2583435B1; EP0229084B1

Abstract

Procédé pour extraire les fils de trame défectueux d'un métier à tisser sans navette, caractérisé en ce qu'on introduit, avant battage d'un fil de trame (4), au moins en cas de fil de trame défectueux (4), entre le dernier fil de trame inséré (5a) et ledit fil de trame (4) qui vient d'être introduit, un moyen actif (7) susceptible de dégager ledit fil défectueux afin de le pouvoir enlever à l'aide de moyens d'extraction proprement dits.Method for extracting defective weft yarns from a shuttle-less loom, characterized in that, before beating a weft yarn (4), at least in the case of defective weft yarn (4), is introduced, between the last inserted weft thread (5a) and said weft thread (4) which has just been introduced, an active means (7) capable of releasing said defective thread in order to be able to remove it by means of actual extraction.

Description

Method and device for extracting defective weft threads from a shuttle-free loom

The present invention relates to the automatic extraction of the crowd of defective weft threads during weaving on a shuttle weaving mé¬ tier, in particular on an air jet loom. More especially still, the invention relates to the release of a defective weft thread in order to facilitate its extraction.

This type of loom usually includes detectors for checking whether the weft thread which has been inserted into the crowd is defective or not and controlling the stopping of the loom in the event that said thread is defective. It is most often a pick folded over on itself. The extraction of the defective weft thread is carried out by the weaver who, with the crowd open, releases the defective weft thread which has been struck by the comb and cut on the side of its insertion and extract it manually. Various devices have been proposed recently for automatically carrying out this extraction. These devices include an organ which is external to the tissue being formed and which acts only when the detectors have signaled a defect.

According to French patent application 83.19156, the organ in question is placed on the insertion side of the loom, has an alternating movement in the direction of the weft through the crowd in the event of a fault and can move the defective wire in its active stroke. The defective weft thread is not stressed by the device until after threshing, that is to say after tightening of the weft thread. According to European patent application 83.107125.3 the organ in question is placed on the front of the loom and above the fabric being formed; in the event of a defect, it descends and is introduced between the defective thread and the fabric in order to release said defective thread. However, the introduction of said member is also carried out after threshing of the defective weft thread.

It goes without saying that the introduction of an extraction member between two weft threads pressed against each other is very difficult if not impossible.

The invention therefore relates to a method characterized in that, before threshing a weft thread, at least in the case of of defective weft thread, between the last inserted weft thread and said weft thread which has just been inserted, an active means capable of completely freeing said defective thread in order to be able to remove it using means of extraction proper.

According to this method, the weft yarn which has just been introduced into the crowd is checked before threshing and, in the event of a defective yarn, said active means is introduced between the last weft yarn inserted and the weft yarn which comes from 'being introduced, the active means are moved towards the comb to release the defective wire and the wire is extracted using' extraction means.

According to a variant, the method according to the invention consists in that, for each insertion cycle, the following three steps are carried out:

at. an active means is introduced between the last weft thread inserted and the weft thread being inserted, b. we check the weft thread which has just been introduced into the crowd, and c. if said thread is not defective, the active means are removed from the fabric and a new cycle is started, or c ', if said wire is defective, the loom being stopped and the comb being in the withdrawn position, the active means are moved towards the comb to release said wire using extraction means, and then inserted a new weft thread and we return to the second step b above.

According to this variant of the method of the invention, and unlike the aforementioned devices, the weft thread release member is perfectly positioned and ready to act at each insertion cycle, whether or not the weft thread is defective . If the weft thread is not defective, the release member is removed from the fabric; on the other hand, if the weft thread which has just been introduced is defective, the release member comes into action, without having to search for the location of the defective thread or to find its position relative to the fabric.

It is obvious that the invention relates to both said process in which the steps follow one another in the order a, b, c as in the order b, a, c.

Preferably, the defective yarn is extracted by suction using suction means placed on the insertion side of the weft yarn. It is another object of the invention to propose a device specially designed for the implementation of the above process. This device comprises, in known manner, weft thread detectors capable of identifying whether or not the weft thread which has just been inserted is defective and means for interrupting the insertion cycle and stopping the loom in the case where the detectors detect a defective weft thread. The device according to the invention also comprises:

- an active means animated by a double reciprocating movement, one vertical, in the absence of fault in the weft thread,. between a high position where said means is located between the last weft thread inserted and the weft thread being inserted and a low position where said means is below the fabric, and the other horizontal, in case of defect in the weft thread, between a rear position corresponding to the above-mentioned high position and a front position where the active means moves towards the comb. - means for extracting the defective weft thread.

Preferably, the active means comprises needles which penetrate into the fabric being formed when it is driven in the vertical movement and which push the defective weft thread towards the comb when it is driven in the horizontal movement. The needles of the active medium are repaired ties over the entire width of the loom, in sufficient number so that the defective thread is necessarily cleared from inside the crowd, whatever the origin of the defect, for example a needle every seven centimeters.

According to a preferred mode of the device, the vertical alternative movement of the active means is obtained in synchronism with the operation of the comb thanks to a system of ca¬ mounted on the axis of rotation of the comb. In particular, the active means comprises needles, a needle support which can slide vertically and horizontally in a housing, fixed on the frame of the loom, which comprises a resistor of com, pressure intended to keep the needle support in contact with the surface of the tilting member on which it is supported, and a tilting member intended to follow the cam path mounted on the axis of rotation of the comb during the movement of said comb. The path of the cam is such that, before threshing or striking the comb, the tilting member switches and the needle holder is in the low position, and in all other positions of the comb the tilting member is in the normal position. and the needle holder is in the high position.

The extraction means may advantageously consist of one or more suction nozzles, placed on the side where the insertion of the weft thread has been carried out. Indeed the defective wire having been previously released from the interior of the crowd by active means, a simple aspiration turns out to be sufficient to extract the wire.

In the case where, the detector having identified a defective weft thread, the operation of the loom is such that the insertion cycle is interrupted while the comb is in the striking position, the extraction device according to the invention also comprises loom control means intended to move the comb backwards, before the active means performs its reciprocating horizontal movement, according to the reverse operation of the loom.

On the other hand, in order to avoid any risk of defect damaging to the fabric in the event that, for one reason or another, the defective thread is not extracted from the crowd despite the proper functioning of the device, this- in the extraction means, a wire presence sensor which has the function of keeping the loom stopped in the event that the defective wire has not been extracted by said extraction means.

The invention will be better understood on reading the following description of an embodiment and the appended drawings in which: Figures 1 to 6 show schematic illustrations of the different stages of operation of the method according to the invention; FIGS. 7 to 15 show schematic illustrations of the different stages of the operation of a variant of the method according to the invention; FIG. 16 is a schematic view of a weaving loom equipped with a device applying the method according to the invention; Figure 17 is a sectional view of said device.

The device of the invention is mounted on a loom 1 with an air jet, comprising a comb 2 which moves in known manner in an arc of a circle around an axis 3 of rotation and which comes hitting, the crowd being open, the weft thread 4 being inserted against the other weft threads 5 already inserted in the fabric 6 in formation. One of the characteristic elements of the device resides in the active means 7, e.g., the needles, aligned parallel to the striking line of the comb 2, and driven by a double alternating movement, vertical and horizontal.

Before describing the device itself, it is important to understand the theoretical operation of the movement of the needles 7 throughout the weft insertion cycle. At the end of a weft insertion cycle, in the absence of a defect, the comb 2 is in the withdrawn position (FIG. 1) and the needle 7 is in the withdrawn position. A new tra¬ me wire 4 is projected (Figure 2) in the open crowd, along the comb p. ex. in a cavity 9 provided for this purpose. The comb 2 begins its striking movement and approaches the fabric 6 by driving the weft thread 4 (Figure 3). At this instant, the weft thread detectors placed on the loom 1 check whether the thread 4 is correctly positioned or has a fault. In the case where the wire 4 is correctly positioned, the comb 2 moves away from the fabric 6 towards its withdrawal position after having struck the said wire 4, the warp threads 8 cross and we then find ourselves in the end position of cycle illustrated in FIG. 1. On the other hand, in the case where the wire 4 has a defect, for example if the detector does not record the presence of the wire 4 all along the width of the fabric 6 the needle 7 is introduced, before threshing the wire 4, between the latter and the wire 5a-, the comb 2 strikes the fabric and moves away from the fabric 6 towards its withdrawal position, the warp threads cross and then the needle 7 moves horizontally (FIG. 5) and pushes the defective wire 4 towards the comb 2. The extraction means, for example a suction nozzle then starts and extracts the wire 4 from inside the crowd ( Figure 6) while the needle 7 first moves horizontally in the opposite direction and returns to the position of the figur e 4, then vertically to return to its starting position such that represented in FIG. 1. A new weft thread 4 ′ is projected into the crowd, is driven by the comb 2 in its striking movement and the cycle resumes from the step illustrated in FIG. 3.

Figures 7 to 15 show a variant of the process according to which the needle is automatically introduced into the tissue during each insertion cycle. In this case, at the end of a weft insertion cycle, in the absence of a defect, the comb 2 is in the withdrawal position (FIG. 7), and the needle 7 is in the high position, located between the last two threads. in the weft, the ^' wire 5a which has just been inserted and the wire 5b which had been inserted during the previous cycle; the warp threads 8 have crossed and the crowd is open. A new weft thread 4 is. projected (fig. 8) into the open crowd, along the comb into a cavity 9 provided for this purpose. The comb 2 begins its striking movement and approaches the fabric 6 by driving the weft thread 4 (Figure 9); during this movement, the needle 7 moves vertically from the high position to the low position where it is located below the level of the fabric 6, the fabric 6 receding continuously, the needle 7 passes under the weft thread 5a. When the comb 2 reaches the striking line (FIG. 10), the needle 7 has moved vertically from the low position to the high position and is precisely between the last weft thread 5a inserted during the previous cycle and the weft thread 4 which has just been inserted. At this instant, the weft thread detectors placed on the loom 1 slowly check whether the thread 4 is correctly positioned or has a defect. In case the wire 4 is correctly positioned

(FIG. 11), the comb 2 moves away from the fabric 6 towards its withdrawal position, the warp threads 8 cross and we then find ourselves in the end of cycle position illustrated in FIG. 7. On the other hand, in the case where the wire 4 has a fault, for example if the detector does not register the presence of the wire 4 throughout the width of the fabric 6, the comb 2 moves away from the fabric 6 towards its withdrawal position but in reverse of the loom (Figure 12), then the needle 7 moves horizontally (Figure 13) and pushes the defective wire 4 towards the comb 2. The suction nozzle then starts and extracts the wire 4 from the inside of the crowd (FIG. 14), while the needle 7 moves horizontally in the opposite direction and returns to the high position it had previously. A new weft thread 4 'is projected by air jet into the crowd (Figure 15), is driven by the comb 2 in its striking movement, and the cycle resumes from the step illustrated in the figure 10.

All the steps which have just been described require perfect synchronization between the movement of the comb 2 and that of the hands 7 depending on the axis of rotation 3 of the comb 2. The needles 7 are fixed at regular intervals, of seven centimeters, all along the needle support 10 which extends transversely over the entire width of the mé¬ tier. The needle holder 10 is movable in a housing 11 both vertically and horizontally, while the housing 11 is fixed to the frame 12 of the loom 1. The vertical movement of the needle holder 10 is ensured by the rod 13 and in spring 14: the spring 14 tends to push down the rod 13, the end of which consists of a roller 15 which bears on the upper part of the tilting member 16. When the tilting member 16 rocks , the rod 13 follows its movement and, under the action of the spring 14, descends, driving the needles 7 in the low position.

The tilting member 16 consists of an upper guide piece 17, having a U-shaped profile, in which the roller 15 can move during the horizontal translation of the needle holder 10. This upper piece 17, the surface of which guide is horizontal can tilt around the horizontal axis 18 which is fixed at its ends to the frame of the loom 1. One of the ends 17a of the part 17 rests on a compression spring 19 secured to the frame of the mé¬ tier 1; the other end 17b comprises, under the in¬ férieur surface, a retractable system 20, the lower part of which ends in a roller 21. The rolling roller 21 is supported on a cam 22 fixed on the axis 3 of rotation comb 2. The retractable system 20 is designed to ensure the following operation. When the axis rotates

3, in the direction of arrow S (FIG. 17) (striking movement of the comb 2), the roller 21 rolling first along the circular profile 22a of the cam 22, the part 17 is hori¬ zontale and the rod 13 is in the position which corresponds to the upper position of the needles 7 (FIGS. 7 and 8), then the roller rolls along the curved profile 22b of the cam 22 and the system 20 lifts the end 17b of the upper part 17, which then swings around the axis 18: the end 17a of the part 17 is pushed in by compressing the spring 19 and the rod 13 which bears on the guide surface of the upper part of the end 17a of the part 17 has a downward movement which corresponds to the lower position of the needles 7 (FIG. 9). Then when the roller 21 falls on the part 22c of the cam, the end 17b returns to a horizontal position as does the end 17a and the rod 13 returns to its initial position which corresponds to the high position of the needles 7 (FIG. 10). During the return movement of the comb 2, the axis 3 rotates in the opposite direction to the arrow S (movement of withdrawal of the comb 2), the system 20 retracts during the passage of the roller 21 over the curved part 22b of the cam 22, so that, during this entire return movement, the upper part 17 remains horizontal and the needles remain in the high position (figures 11 and 12) ,. The retractable system 20 comprises two feet these 23 and 24. The part 23 is fixed to the lower part of the end 17b of the part 17. The part 24 is solidai¬ re to the part 23 thanks to a horizontal axis of rotation 25; it has at its lower part the roller 21. The axis of rotation 25 is eccentric so that the part 24 is supported on the part 23 and cannot pivot around the axis

25 when the movement of the roller is in the direction of the arrow S (FIG. 17) along the profile of the cam 22. On the other hand, in the opposite direction, the part 24 does not bear on the part 23 and pivots around the axis 25, which corresponds to the retractable position of the system 20.

The horizontal movement of the needle holder 10 is ensured by means of a jack (not shown) which horizontally displaces the needle holder 10 in its housing 11 by a distance which corresponds to the displacement necessary to push the defective thread 4 towards the comb 2 (FIG. 13 ). The cylinder is actuated as soon as the comb 2 has reached its retracted position (FIG. 12), after a faulty weft thread 4 has been detected, then the cylinder returns to its initial position, causing the needles 7 to return. in the up and back position (figure 14).

The extraction means consist of one or more nozzles

26 suction, fixed mounted on loom 1. Preferably in the case of a single nozzle 26 and a jet loom air, it is placed near the compressed air injection nozzle which projects the wire through the crowd and mounted at the level of the first needle 7. The extraction means are controlled to enter action when, a defective thread 4 having been detected, the needles 7 have pushed said thread 4 towards the comb 2 thanks to the action of the horizontal displacement jack of the needle holder 10.

Of course, on the basis of the method corresponding to the previously described operation, it is possible to envisage other embodiments. For example, the vertical movement of the needles could be based on a system of jacks whose control and stroke will depend on the movement of the comb. It is also up to the person skilled in the art, depending on the type of trade and the space available for mounting the device of the invention, to select the optimal solution. In particular, the distance of seven centimeters between two needles is preferable for most air jet looms, since it corresponds to the usual spacing between the air injection nozzles along the loom. Similarly, the shape of the cam 22 and its profile are a function of the distance between the axis of rotation of the comb 2 and the needles 7, and of the angle of rotation during the striking and withdrawal movements of the comb 2; Figure 17 attached does not respect the exact pro¬ portions, but allows to view the different organs used. The needles should be enough flexible to possibly deform during the advance of the fabric, they will be very fine so as not to mark the finished fabric. Furthermore, the method and the device of the invention are not limited to the air jet loom alone, but apply generally to all the so-called loom-free looms.

Claims

CLAIMS.

1.- Method for extracting defective weft yarns from a shuttle-free weaving loom, characterized in that one introduces, before threshing a weft thread (4), at least in the case of weft thread defective (4), between the last inserted weft thread (5a) and said weft thread (4) which has just been introduced, an active means (7) capable of releasing said defective thread in order to be able to remove it from using actual extraction means.

2.- Method according to claim 1, characterized in that one checks, before threshing, the weft thread (4) which has just been introduced into the crowd and. that, in the event of a defective weft thread (4), the loom being stopped and the comb (2) being in the withdrawn position, the active means (7) are moved towards the comb (2) to release said thread (4) and extracting said wire (4) using extraction means (26), then inserting a new weft wire (4 ') and returning to the control step mentioned above.

3.- Method according to claim 1, characterized in that, for each insertion cycle, the following three steps are carried out successively: t ^β

at. an active means (7) is introduced between the last weft thread inserted (5a) and the weft thread being inserted (4), b. the weft thread (4) which has just been introduced into the crowd is checked, and c. if said wire (4) is not defective, the active means (7) are removed from the fabric (6) and a new cycle is started, or c ', if said wire (.4) is defective, the loom being stopped ¬ tee and the comb (2) being in the withdrawn position, the active means (7) are moved towards the comb (2) to release said wire (4) and said wire (4) is extracted using means d 'extraction (26), then insert a new weft thread (4') and return to the second step b above.

4.- Method according to claim 1, characterized in that extracts the defective weft thread (4) by suction.

5.- Method according to one of claims 2 or 3, caractéri¬ se in that, after detection of a weft thread (4) defective, the comb (2) is moved to its withdrawal position in mar¬ che back of the trade.

6.- Device applying the method according to claim 1, characterized in that the active means comprises a row of needles (7), parallel to the striking line of the comb (2).

7.- Device according to claim 6, suitable for the air jet loom characterized in that the needles (7) are spaced regularly, at an interval of seven centimeters.

8.- Device for extracting defective weft threads from a non-shuttle weaving loom of the type comprising weft thread detectors and means for stopping the loom in the case where a defective weft thread is detected, charac¬ terrified in that it includes:

- an active means (7) driven by a double reciprocating movement, one vertical, in the absence of a defect in the weft thread (4), between a • high position where said means (7) is located between the last weft thread inserted (5a) and the weft thread being inserted (4) and a low position where said means (7) is below the fabric (6), and the other horizontal, in the event of a fault weft thread (4), between a rear position corresponding to the above-mentioned high position and a front position where the active means (7) moves towards the comb (2),

- extraction means (26) of the defective weft thread (4).

9.- Device according to claim 8, characterized in that the active means (7) is driven vertically in synchronis¬ me with the operation of the comb (2) thanks to a cam system mounted on the axis (3) of rotation of the comb (2).

10.- Device according to claim 9, characterized in that the active means (7) comprises needles (7), a needle support (10) which can slide vertically and horizont¬ ment in a housing (11), fixed on the frame of the loom (1), which comprises a compression spring (14) intended to main¬ hold the needle holder (10) in contact with the surface of the tilting member (16) on which it is supported, and a tilting member (16) intended to follow the cam path (22) mounted on the axis of rotation (3) of the comb (2) during the movement of said comb (2).

11.- Dispos'itif according to claim 10, characterized in that the cam track (22) comprises two circular portions (22a and 22c) and a portion (22b) in peak and in that the tilting member (16 ) comprises a retractable system (20) retracting during the passage of the peak (22b) of the cam track (22) when the axis of rotation (3) of the comb (2) rotates in the direction of striking the comb ( 2).

12.- Device according to claim 8, characterized in that it comprises means for controlling the loom to move the comb (2) backwards, according to the reverse operation of the loom, when a weft thread defect (4) has been detected and before the active means (7) performs its horizontal reciprocating movement.

13.- Device according to claim 8, characterized in that the extraction means consist of one or more suction nozzles (26).