EP0232665B1 - Process and device for weft insertion into the shed of a loom - Google Patents

Description

The present invention relates to the textile industry and more particularly to an improvement made to non-shuttle weaving machines in which the weft is inserted from food reels (or equivalent supports) arranged outside the crowd.

Such machines use means for inserting the weft into the crowd of different types such as fluid jets, lances or pincer projectiles, kinetic energy of the weft thread, etc.

In most of these machines, the weft thread to be inserted is prepared in advance in length or picks corresponding to the desired width of width and stored successively in a reserve member before being introduced into the crowd.

In all these machines, the main problem which arises is that of the reintroduction of the end of the cut weft inside the reserve member. Such a problem which already arises in woven looms using only one type of weft yarn (production of plain fabrics) is found to be amplified in multi-frame looms used for the production of fancy fabrics and which require insertion, according to a programmed frequency, weft threads of different color and / or nature.

The present invention aims to solve this problem.

In the following description, the invention will be described applied to shuttleless weaving machines in which the weft is inserted into the crowd formed by the warp threads according to the technique known as "inertial insertion" and which makes the subject in particular of French patents published under the numbers 2,477,587 (US 4,509,563) and 2,495,196 (US 4,479,518). It is obvious that this is not limiting and that the invention could also be applied to any other weaving technique where similar problems could arise.

In general, this technique of launching by inertia, a technique according to which the weft thread is launched into the crowd in the form of a rolling loop, therefore involves preparing the pick before its launch. This preparation consists in accumulating a length of wire measured in a reserve, placed between the wire supply source (spool) and the side of the machine where the pick is to be inserted, then in extracting said wire from this reserve when its launch. As has been described in the two aforementioned patents, this extraction of the reserve can be carried out by the same channel as that by which the wire was introduced but in the opposite direction. This therefore necessarily involves a change in the trajectory of the wire during these displacements, on the one hand from the measurer delivering to the reserve and, on the other hand, from the reserve to the launching member in the direction of the crowd.

This imperative is clear from the teachings of French patent 2,477,587 (US 4,509,563). In the solution described in this document, the change of trajectory is done without special guidance, the wire being launched freely from one point to another to then be deflected in another direction. Such a technical solution, if it is satisfactory, is however difficult to implement, taking into account the fact that the wire passes freely near the launcher and that in this zone, disturbing air currents can occur, in particular when the launcher is of the rotary roller type. Indeed, the position of the wire can be deviated and its grip by the launcher disturbed.

FR 2 538 008 (US 4 544 001) describes a solution which makes it possible to overcome these drawbacks, a solution which, in general, consists, as is moreover mentioned in FR 2 506 795, of positioning waiting the end of the wire which has just been cut between the measuring device and the storage means. Such a standby is carried out in the zone extending between the entry into the reserve and the exit of the deliverer by means of guide conduits which, optionally, can be extended as close as possible to the wire cutting scissors at the edge of the fabric. When the loom is a loom for inserting various wefts according to a programmed sequence, it is necessary to have as many conduits as there are wires used to put said wires on hold after cutting before reinserting them into the reserve. It should also be noted, that in such a case, if one wants to pass the standby circuits near the scissors so as to reduce the length of wire to be removed, this involves lengthening and bending said circuits , therefore to lead to a very complex realization. Admittedly, this drawback can possibly be overcome, as is apparent from the examples illustrated by FIGS. 7 and 8 of this patent by placing said circuits at an angle, but then, the part of the circuit located at the outlet of the reserve and arranged opposite the pinch line of the launching rollers is distant from this line, arranged at an angle, which is detrimental to a good grip during the actual launching operation.

Finally, in all cases, during the reintroduction of the weft thread inside the reserve, the cut end is reintroduced first into said reserve, generally under the action of a current of air which pushes the wire and it may happen that this end agglomerates in the form of balls or, in general, takes a more or less sinuous shape which disturbs its scheduling and its withdrawal from the reserve during launching.

The present invention eliminates these drawbacks and therefore relates to an improved process, applicable not only in the case of one color looms, but also in the case of multi-color looms as well as a device allowing the implementation of said process.

In general, the invention therefore relates to an improvement made to the process allowing the insertion of picks into the shed of a weaving machine, process in which a metering deliverer feeds a storage member where a determined length of yarn is put in reserve, said length of wire being taken in the interval between the output of the deliverer and the storage member to be inserted in the crowd formed by the warp threads then pinched near the edge of the fabric and neck pée, the end of the cut wire being put in the waiting position before being reintroduced again into the storage member for a new insertion and is characterized by the fact that said putting in the waiting position of the end the cut is made in an independent circuit outside the path connecting the output of the measurer and the entry into the reserve, the reintroduction of the wire inside the reserve being carried out so that the cut end is reintroduced in shape of a loop taking place from a fixed point at the exit of the deliverer to the entry inside the reserve under the action of an air current, the weft thread not being resubmitted to the 'action of the deliverer only after being completely unwound and stretched under the action of a nozzle.

Thanks to such a process, the end of the wire released after cutting is therefore perfectly maintained and guided throughout its reintroduction phase into the reserve. Furthermore, such a method is particularly suitable in the case of multi-frame trades, said frames being kept perfectly separate from each other outside of their launch phase.

In summary, in accordance with the method according to the invention, after cutting the free end of the wire is kept in a waiting circuit and, during reintroduction, before the measurement begins, this free end is brought to the reserve by means which exert traction from a fixed point downstream of the measurer, which favors the entry of the wire very regularly inside the reserve.

The invention also relates to a device allowing the implementation of the method, this device being characterized essentially by the fact that temporary storage means (waiting lane) of the end of the cut wire are provided, between the output of the deliverer measurer and the cutting member near the selvedge, and this outside the path followed by the wire on the one hand, between the measurer and the reserve and on the other hand, when launching from the reserve to the inside the crowd, these means making it possible to keep the wire taut under the action of a current of air before it is introduced into the reserve under the action of the measurer.

When the invention is applied to a one-color loom, the storage member will be placed in the launch plan whereas in the case where the invention is applied to a multi-color loom, there will be as many storage members as types of picks to be inserted, said storage members being oriented so as to guide the wire in a plane intersecting the launching plane, the wires therefore being stored in n planes converging towards the launching plane.

• - la figure 1 représente schématiquement la mise en réserve, le lancement et la mise en attente du fil selon un premier mode de réalisation pour une insertion monotrame ;
• - la figure 1a est une vue de côté schématique de l'organe de mesure de la figure 1 ;
• - la figure 1 est une vue de côté schématique montrant plus particulièrement l'organe de lancement de la figure 1 ;
• - la figure 2 est une vue schématique d'un deuxième mode de réalisation conforme à l'invention dans le cas d'un métier à tisser multitrames ;
• - la figure 3 est une vue de dessus montrant plus particulièrement le circuit d'attente des fils de trame après coupe ;
• - la figure 4 est une vue de côté montrant la manière dont sont réintroduites les extrémités coupées à l'intérieur de l'organe de réserve et comment s'effectue la prise du fil pour le lancement.

The invention and the advantages which it brings will however be better understood thanks to the exemplary embodiments given below by way of indication but not limitation and which are illustrated by the appended diagrams in which:

• - Figure 1 schematically shows the reserve, the launch and the waiting of the wire according to a first embodiment for a single-frame insertion;
• - Figure 1a is a schematic side view of the measuring member of Figure 1;
• - Figure 1 is a schematic side view showing more particularly the launching member of Figure 1;
• - Figure 2 is a schematic view of a second embodiment according to the invention in the case of a multi-frame weaving loom;
• - Figure 3 is a top view showing more particularly the waiting circuit of the weft son after cutting;
• - Figure 4 is a side view showing how the cut ends are reintroduced inside the reserve member and how the wire is taken for launching.

FIGS. 1, ia, 1 illustrate an embodiment of the method according to the invention on a weaving loom in which the weft feeding is carried out from a single food spool (so-called "one color" loom) .

• - une zone A dite zone d'alimentation, permettant de délivrer et mesurer une longueur déterminée de fil de trame correspondant à la longueur de la duite à insérer;
• - une zone B dite zone de stockage et de lancement,
• - une zone C dite zone de mise en attente.

In general, it can be said that such a type of loom comprises, in accordance with the invention, for the insertion of the weft thread inside the crowd formed by the warp threads (1) which are separated in two plies (2,3) by the heddles (4) and which is limited by the fabric (5) by a conventional non-drawn comb, an assembly which can be subdivided into three zones, namely:

• - a zone A, called feeding zone, making it possible to deliver and measure a determined length of weft yarn corresponding to the length of the pick to be inserted;
• - an area B called storage and launch area,
• - a zone C called the waiting zone.

Zones A and B are produced in a similar manner to that which is the subject of French patents 2,506,795 and 2,538,008 (US A 4,544,001) and their structure and operation are as follows.

The feed zone A essentially consists of a metering deliverer (6), of any known type, for example of the type with rotating rollers (6a, 6b). The weft thread (7) comes from a food reel (8) and passes through a shield (9), a brake (10) and a guide (11) allowing it to be subjected to the action of the deliverer (6). At the output of the measuring device (6), near the tangency line (12) between the rollers (6a, 6b), is arranged an assembly constituted in a manner similar to the teachings of French patent 2,506,795 if this n '' is that it allows to guide a single frame and not several frames as in the case of this patent and which consists essentially of a chamber (13) in the form of a funnel, expression which will be used in the rest of the description, chamber which opens into a channel (14) constituted by a tube having a slot arranged in the plane of launching of the wire inside the crowd. Between the funnel (13) and the conduit (14), there is preferably disposed a nozzle (16) which keeps the wire taut at the outlet of the deliverer (6) and facilitates its introduction into the reserve itself, as will be seen in more detail in the following description.

The storage and launch unit B, meanwhile, is made in a similar way to of FR-A-2 538 008, (US A 4 544 001) and therefore essentially consists of a storage chamber (17) which is used to temporarily accumulate a determined length of weft thread (6) before launching into the crowd formed by the warp threads (1).

This storage chamber (17) comprises at its entrance a guide duct (18), oriented in the direction of insertion of the weft inside the shed and which is extended laterally by a split duct (19), which projects laterally with respect to the launching rollers proper (20a, 20b), the inlet (21) of this conduit (19) being arranged opposite the outlet (22) of the supply channel (14). A space remains between the outlet (22) and the inlet (21) to allow the thread to be taken up by the element (23), clamp for example carried by a belt in order to introduce the thread between the launching rollers (20a, 20b) at launch. Furthermore, in order to facilitate the introduction of the weft thread inside the reserve (17), a nozzle (24) is provided in the vicinity of the elbow formed between the conduit (19) and the tube (18), so as to breathe air inside said tube (18).

Generally, these two sets A and B of supply and storage / launching of the weft thread have, as said previously, a structure and an operation which is to be compared to those of the French patents 2 506 795 and 2 538 008 (us A 4 544 001). In summary, during the measurement of the weft thread before its insertion, under the action of the eyelet (11), the thread is brought between the measuring device (6), passes inside the funnel (13 ), the channel (14) for, through the conduits (19) and (18) to accumulate inside the reserve (17). During launching, the wire is gripped between the ends (22) and (21) of the channels (14) and (19) to be brought into the line of tangency of the launching rollers (20a, 20b) and is launched into the crowd under the shape of a loop (25) having a launched strand (26) and a held strand (27). As soon as the loop is formed in the crowd, the strand held (27) is taken by pliers (28) and is cut by scissors (29) located near the edge of the fabric (5).

In order to solve the problems of maintaining the end of the wire after cutting, as well as the reintroduction of this strand inside the reserve during the next measurement, in accordance with the invention the end of the wire located between the scissors (29) and the output of the measurer (6), and more particularly the end (30) of the split channel (14) disposed at the outlet of the nozzle (16), this strand of wire is kept on standby in circuit C , an essential characteristic of the present application. Such a standby circuit is constituted by an assembly whose structure is such that, in accordance with the method according to the present invention, said wire thus placed on standby is reintroduced inside the reserve (17) in the form of a taut dart, this being obtained by reintroducing it inside the channel (14) in a progressive manner and by keeping its free end against the waiting zone. In other words, the end of the wire between the outlet of the nozzle (16) and the chisel (29) is reintroduced inside the channel of the conduit (14) in the form of a loop (shown in points in Figure 1) which unfolds gradually to reach the entry (21) for introduction into the reserve (17). The measuring delivery device (6) is only activated when the wire is thus well repositioned, thanks to the combined action of the air coming from the conduits (16) and (24), which makes it possible to introduce the wire inside the reserve precisely. According to this exemplary embodiment where a single weft thread is used to make the fabric, the assembly for putting the thread on standby after cutting consists essentially of a chamber (30) formed of two parallel plates (31,32), chamber whose bottom (33) extends between the nozzle (16) and the scissors (29) and which is arranged substantially in the plane of launch of the weft thread. This chamber is subjected to the action of a suction nozzle (34) which keeps the end of the cut wire taut. The side walls of this chamber favor the guidance and the maintenance of the wire when it is reintroduced inside the conduit (14) when a new measurement has to be carried out.

Furthermore, in this embodiment, the distance going from the nozzle (16) to the scissor (29) is slightly greater than that going from the nozzle (16) to the zone of action of the nozzle (24) in the conduit. (18).

Such a method and device can easily be adapted in the case of multi-color looms as shown by the example illustrated in Figures 2, 3 and 4 which describes an embodiment for a four-color loom. In this exemplary embodiment, the same references as those used previously to define the different elements of the assembly according to the invention will be used by assigning them with an index a, b, c, d to differentiate the four wires.

According to this embodiment, the four wires (7ad) come from four coils (8a-d) and arrive in control eyelets (11a-d) after passing through the shields (9a-d) and the brakes (10a-d ). To measure the four wires, two meters (6 ', 6 ") are simply used, the wires being arranged in pairs on either side of these meters and being subjected to their action in due course. ) between the left side, the wire (b) on the right side of the measurer (6 ') as well as the wire (c) on the left side and the wire (d) on the right side of the measurer (6 ") .

The storage and launch assembly itself is identical to that described in the previous example and will therefore not be re-described.

In this embodiment, the supply of the wires to this storage and launching assembly is carried out, as previously, by means of an assembly comprising, for each wire a funnel (13a-13d), a blowing nozzle (16a-16d) and a split conduit (14a-14d) directed towards the insertion orifice (21) of the tube (19) disposed opposite the nip between the throwing rollers (20a-20b). Consequently, taking into account the plurality of circuits, the funnels (13a-13d) and conduits (14a-14d) diverge from each other so that their inlet is correctly oriented towards the nip of the measuring rollers (see FIG. 3 ) whereas, on the other hand, the split tubes (14a-14d) allowing the introduction of the wire inside the reserve converge towards this inlet (21).

As before, between the scissors (29) and the nozzles (16) is provided a circuit C for placing the end of the wire on standby after cutting.

Such a standby circuit is constituted by the juxtaposition of four circuits similar to that described in the previous example and which consist of four superimposed chambers 30a-30d consisting for example of plates. As is apparent in particular from FIGS. 2 and 3, these holding chambers are oriented to converge towards the launching plane proper.

Such a device operates in the same way as above, namely that after cutting, the free ends of the wires are held by suction nozzles (34) in the waiting chambers and that, during launching, initially , the free end is gradually unfolded under the action of the nozzle (16) to be introduced in the form of a loop which unfolds inside the split tubes (14) then, from there, is transferred to inside the introduction channel (19) leading to the reserve itself (17). The weft thread which must be accumulated in the reserve is subjected to the action of its deliverer only when this free end has been thus reintroduced to be stretched under the action of the nozzle (24) in the circuit leading to the reserve, the introduction can therefore be done in a perfectly taut manner.

Compared to the solution which is the subject of French patent 2,538,008 (US A 4,544,001), the present invention offers numerous advantages by the fact that there is precise guidance of the strand of wire between the outlet of the measurer and the scissors, strand which must be reintroduced later in the reserve and that, moreover, in the case where several different wires must be used, these wires are put on standby outside the very launching circuit which is therefore not disturbed.

In addition, during launching, the introduction between the launching rollers is carried out in a perfect manner since it is possible to arrange the conduit (18) for feeding the wire orthogonally to the launching rollers. Finally, such a solution makes it possible to modify at will the position of the food reels and of the metering deliverer relative to the profession, for example to arrange it orthogonally as shown in FIGS. 1, 1a, 1b or, on the contrary, parallel to the selvedge as shown in the example in Figures 2, 3 and 4.

Claims (7)

1. Process for inserting the weft lengths into the shed of a loom, of the type in which a metering-delivering device (6) supplies a member (17) for storing a predetermined length of yarns, said yarn length caught in the interval between the outlet of the delivering device and the storage member in order to be inserted into the shed formed by the warp yarns, said yarn length being then cut and optionally gripped close to the selvedge of the fabric, the cut end of the yarn being held over before being re-introduced in the storage member (17) for the next insertion, characterized by the fact that the cut end of the yarn is held over in an independent circuit (C) outside the path joining the outlet (30) of the metering device (6) to the inlet (21) of the reserve (17), re-introduction of the yarn into the reserve (17) being performed so that the cut end is re-introduced as a loop unwinding from a fixed point (30) at the outlet of the delivering device as far as the inlet (21) of the reserve (17) under the action of an air stream, the weft yarn being only re-subjected to the action of the delivering device (6) when it has completely unwound and stretched out under the action of a nozzle (34).

2. Device for carrying out the process claimed in claim 1, of the type comprising:

- at least one bobbin (8) feeding the weft yarn (7);

- at least one assembly (A) for delivering and metering a predetermined weft length corresponding to the length of the pick to be inserted;

- one assembly (B) for storing the metered yarn length before throwing it into the shed formed by the warp yarns;
characterized by the fact that means (C) are provided for holding over the end of the cut yarn, which means are situated between the outlet of the metering-delivering deviced (6) and the cutting member (29) close to the selvedge, and this, outside the path followed by the yarn, on the one hand, between the metering device (6) and the reserve (17), and on the other hand, when it is thrown from the reserve (17) into the shed, said means making it possible to keep the yarn in stretched condition before it is re-introduced into the reserve under the action of the metering device.

3. Device according to the claim 2, characterized by the fact in that the distance between the nozzle (16) and the scissors (29) is slightly greater than the distance between the nozzle (16) and the zone of action of the nozzle (24) into the channel (18).

4. Device according one of the claims 2 and 3, characterized by the fact that if said device is used with a one-color loom, the holding-over member (33) is disposed inside the throwing plane.

5. Device according one of the claims 2 and 3, characterized by the fact that said device is applied to a multi-color loom and comprises as many holding-over members (33) as there are weft lengths to be inserted, said storage members being oriented so as to guide the yarn in a plane cutting through the throwing plane.

6. Device according one of the claims 2-5, characterized by the fact the circuit (C) provided for holding over the cut yarn, before the next metering operation is constituted by a chamber (30) formed of two parallel plates (31, 32), and a base (33) which extends between the nozzle (16) and the scissors (29), whereas said chamber is situated substantially inside the weft yarn throwing plane.

7. Device as claimed in claim 6, characterized by the fact that said chamber (30) is subjected to the action of a suction nozzle (24) making it possible to hold the cut end of the yarn is stretched condition for re-introduction into the reserve under tha action of the metering device.

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