EP0291484A1 - Method for continuous thread feeding from bobbins and device for carrying out this method - Google Patents

Abstract

A system to ensure continuous thread feed from a series of spools carrying finite lengths of thread comprises a yoke or belt with spindles to carry at least two spools near guides to lead their threads on parallel paths opposite a device for entwining the leading end of one yarn with the trailing end of the other, when appropraite. The emptied spool is discarded for replacement or reloading. Activation of the coupling device is triggered automatically, e.g. by response to a photosensor detecting exposure of a controlling pattern on the spool core as the last of the thread is being removed. Specifically to compensate for halting of the yarn throughput during coupling of successive yarns, yarn delivery is via a device such as a dancing roller system to hold sufficient excess yarn to sustain delivery while input is interrupted for splicing of successive yarns and accelerated, temporarily, to re-establish the excess length as the first portion of the successive spool of thread is entrained. Pref. a portion of the trailing end of each yarn is discarded.

Description

The present invention relates to a method of continuous feeding of yarn from bobbins, more particularly allowing the continuous feeding of the weft yarns going to the weaving machines.

The invention also relates to a device implementing the method provided by the invention.

To continuously feed the weft threads of a weaving machine from the supply reels, an immediate change to a new reel must be ensured when the active reel is exhausted. For this, the coils are conventionally connected to one another by tying the end of the wire of a coil to the beginning of the wire of the coil which follows it. This traditional method has certain drawbacks, however.

A first drawback consists in the difficulties that can arise from switching from one reel to another. In addition, it often happens that the last part of the wire present on a spool is of poor quality because they were damaged when starting the winding.

Similarly, reeling anomalies can occur for the last part of the thread of a spool because the last turns present on the spool, instead of taking place regularly, slide on the spool and become tangled.

Another disadvantage of the traditional knotting of successive bobbins lies in the fact that for each new bobbin to be placed on the machine, it is necessary to detect not only the start of the new thread, but also the end of the previous thread, which can cause significant wasted time.

The invention presented proposes a method ensuring a continuous supply of thread and, in particular, a continuous supply of thread intended for weft insertions on weaving machines, carried out so as to systematically exclude the drawbacks of the traditional method mentioned above. . This invention has other advantages which will appear in the description given below.

According to the invention presented, the method of continuously feeding the wire from the supply coils mainly consists of the following sequence: unwinding a wire from a first supply coil; presence of a second coil whose initial end of the wire is placed near the moving wire unwound by the first coil; detection of the moment when the wire of the first spool is almost entirely unwound without being completely so; this moment once detected, stopping the movement of the current wire followed by the connection of the initial end of the wire from the second coil to the end of the current wire; sectioning of this wire, of which the residual part will remain on the first coil; resumption of wire supply from the second coil; finally, removal of the first supply coil carrying the residual wire.

It is clear that according to the method which we have just outlined, the last meters of wire present on each reel are rejected during the passage to the next reel, so that the defective ends of wire mentioned above are not brought in the weaving machine. It is also clear that all the drawbacks listed above and related to the traditional knotting method are eliminated by the method presented.

According to the method according to the invention, the device for monitoring the active supply coil, rather than detecting the exact moment at which the first supply coil is fully unwound, captures the moment when it is almost completely wound up, without the 'be completely, that is to say the moment when there are still a few meters of wire on the spool. In the case of weaving machines, this has the particular advantage that the time of stopping the supply of thread to allow connection with the next supply spool can be chosen optimally according to the weaving cycle. . Likewise, this early detection makes it possible to take all the measures to stop for a brief instant the feeding of the thread from the active reel, without however interrupting the insertion of the weft nor, consequently, the weaving. For example, one could choose to interrupt the supply of yarn to a supplier of a weaving machine by stopping the yarn guide arm when the supplier's drum carries a maximum quantity of yarn; in this situation, it is both possible to tie a new feed reel and take, on the drum, the number of pick lengths necessary for weft insertions during the passage from one reel to another. A variant of this method could consist in increasing the supplier's rotation speed for a short period, so as to provide an additional thread reserve on the drum. If such a reserve is established, the supplier may be immobilized for a fairly long period while providing the desired number of picks; in this case, there is ample time to tie a new supply reel. The device implementing the method provided by the invention mainly consists of elements intended to present the beginning of the thread of the new supply reel facing the thread being unwound, detection elements intended to follow the unwinding active supply coils and connection elements intended to connect the two wires when passing from one coil to the next coil. The construction of such devices is explained in detail in the following paragraphs.

• - Les figures 1 à 4 représentent un dispositif conforme à l'invention en vue d'illustrer pas à pas la méthode prévue par l'invention;
• - la figure 5 représente un agrandissement de l'élément portant le repère F5 sur la figure 2;
• - les figures 6 à 8 représentent graphiquement, en fonction de la réserve de fil présente sur une bobine d'alimentation, la vitesse de rotation d'un fournisseur et la réserve de fil présente sur le fournisseur, dans le cas où l'on a constitué une réserve supplémentaire de fil sur le fournisseur, comme décrit précédemment;
• - les figures 9 à 11 représentent un second dispositif conforme à l'invention.

In order to better highlight the characteristics of the invention, the description of some installations using the method provided by the invention will be found below, by way of examples without limitation, with reference to the accompanying drawings, or:

• - Figures 1 to 4 show a device according to the invention to illustrate step by step the method provided by the invention;
• - Figure 5 shows an enlargement of the element marked F5 in Figure 2;
• - Figures 6 to 8 show graphically, as a function of the wire reserve present on a supply reel, the rotation speed of a supplier and the wire reserve present on the supplier, in the case where there is built up an additional supply of wire on the supplier, as described above;
• - Figures 9 to 11 show a second device according to the invention.

According to FIGS. 1 to 4, the supply of thread 1 to a device such as a supplier 2 of a weaving machine can be carried out by the unwinding of the thread from a first supply reel 3, this thread passing through example with a guide eyelet 4.

To carry out the continuous supply of wire provided for by the invention, the installation as shown in FIG. 1 further comprises a second supply coil 5, a device 6 intended to present the start 7 of the wire 8 of the second supply coil 5 near the wire 9 of the first supply coil 3, a connection device 10 intended to connect the wires 8 and 9, as well as sensors 11 and 12 intended to monitor the reserves of wire on the coils supply 3 and 5, these sensors being connected, for example, to a control unit 13 responsible for controlling the connection device 10. The device 6 intended to present the start of wire 7 near the wire 9 unwound by the spool active consists, in the first embodiment shown, of two guide eyelets 14 and 15 placed side by side and through which pass, respectively, the wires 8 and 9; as well as a wire clamp 16 retaining the start 7 of the wire coming from the second supply reel 5. The connection device 10 can be either a knotter or a splicer. The splicing is a particularly suitable method because of its speed, because it does not cause any local weakening of the wire and because it guarantees the continuity of the wire; in other words, a spliced wire can be woven without compromising either the operation of certain sensitive organs downstream, or the final appearance of the woven product.

The successive phases of the operation of the installation are shown diagrammatically in FIGS. 2 to 4. At the stage illustrated in FIG. 2, the sensor 11 finds that the reserve of wire on the supply coil 3 is practically exhausted, but is not absolutely. The control unit 13 then deactivates the supplier so as to end the supply of the wire 1, and activates the connection device 10. The start 7 of the wire unwound by the second supply coil 5 is connected to the wire 9 of the first spool 3. The residual thread 17 remaining on the supply spool 3 is cut by the thread cutter 18.

These operations create the situation represented in FIG. 3, in which the wire can again be delivered to the supplier 2 by the supply device 1. The first supply coil 3, that is to say the bobbin 19 and the residual wire 17 are then removed from the spool holder.

In a following phase, a new supply coil 20 is mounted in place of the coil 3 almost entirely unwound; the wire of this new coil is then positioned in the wire clamp and becomes the start of wire 7. The sequence of operations just described can then be repeated, with a passage from coil 5 to coil 20 , similar to the previous passage between the coils 3 and 5.

The mode of detection of quasi-exhaustion of the coil 3 by means of the sensor 11 is illustrated in FIG. 5. The optical sensor 11, placed next to the supply coil 3, sends a signal 21 which is reflected by the coil 19 and which is detected by the sensor 11. It is clear that the coil 19 will only reflect the signal when the number of turns present is reduced and the surface of the coil 19 becomes visible. To ensure the reflection of the optical signal 21, the coil 19 can be covered with a highly reflective coating affecting, for example, the shape of a spiral ribbon 22.

As we have already mentioned in the introduction, the activation of the sensor 11 can be followed either by the constitution of an additional wire reserve on the supplier 2, before the termination of the connection from the start from wire 7 to wire 9. The conditions of this process are represented schematically in the graphs of FIGS. 6 to 8.

During the normal feeding of the wire 1 from a reel, for example the first supply reel 3 in the description above, the quantity of wire A present on this reel decreases regularly, phenomenon shown for reasons of simplicity by the downward curve 23 of FIG. 6. During the normal operation of the supply, the speed of the supplier 2, for example the number of turns made by the wire guide arm 24, can vary between a minimum value N1 and a maximum value N2, condition represented by curve 25 in FIG. 7. Generally, the reserve of wire R on the drum will also vary between two values R1 and R2, as represented by curve 27 in FIG. 8; this variation is due on the one hand to the variation in the number of turns made by the wire guide arm 24 and, on the other hand, to the unwinding of the wire 9 according to an intermittent movement at the start of the drum 26.

When unwinding the supply reel 3, the quantity of wire A will reach a predetermined minimum value A1 at a time t1, after which the sensor will send a signal to the control unit 13. From then on, the supplier 2 will switch to its maximum speed N2, to which it will be maintained for a given period X. It is clear that this rise in speed will have the effect of further reducing the quantity of wire A present on the first supply reel 3, at the same time as the reserve of wire R present on the supplier 2 increases. From the moment t2 when the wire reserve on the supplier 2 has reached a predetermined maximum value R3, the supplier will be deactivated and braked until it stops. However, the weaving machine remaining in activity, the maximum yarn reserve R3 will be brought back in a short time to an absolute minimum R0. At this time t3, the supplier will have to be activated again so that the drum 26 can deliver at least one length of pick during the next insertion. The period T corresponding to the total shutdown of the supplier 2, and which is substantially equal to the difference t3 - t2, here represents the connection time from the start 7 of the wire of the second supply coil 5 to the wire 9 of the first supply coil 3 using the connection device 10. It is clear that the size of the wire reserve R3 determines the length of this period T.

FIG. 9 represents a reel holder 28 consisting of a conveyor belt successively presenting the feed reels in front of the feed device and implementing the method provided by the invention. The device 6 mentioned above, and intended to present the start 7 of the wire of the second supply coil 5 near the wire 9 of the first supply coil 3, in this case consists essentially of the wire clamp 16 mentioned above, placed here near the guide eyelet 4, and a movable wire guide 30 which, when the first coil 3 is almost exhausted, can move the wire 9 a certain distance to place it in a substantially parallel position relative to the wire 8 of the second coil 5. This operation is illustrated in FIG. 10. After the parallelization, the connection device 10 is activated to join the wires 8 and 9 either by knotting or by a splice. Driven by the conveyor belt, the new spool is then placed in the position illustrated in FIG. 11. FIG. 11 also represents the way in which the start 7 of the thread coming from the following supply spool 20 can be sought by a wire finder 31. This can consist, for example, of a vacuum cleaner nozzle covering the surface of the supply coil 20 and capable of taking the start of wire 7, which can then, using an eye-catching device not shown in the figure, be brought before the wire clamp 16 to be retained there. The bobbin of the old supply coil, carrying the turns of residual wire 17, is evacuated.

It should also be noted that the spool holder 28 illustrated in FIGS. 9 to 11 requires only a single sensor 11, intended for controlling the quantity of wire present on the supply spools, since the transport belt will always have brought them in the same place when the wire is almost exhausted during unwinding.

The scope of the invention presented is in no way limited to the embodiments described by way of examples and shown in the accompanying drawings; on the contrary, this continuous wire feeding method from coils, as well as the installations implementing this method, are susceptible of multiple variants.

Claims (12)

1.- Method of continuous wire supply from supply coils, characterized in that it is essentially composed of a supply of wire from a first coil (3); the presence of a second supply coil (5), the start of the wire (7) of which is brought close to the wire (9) unwound by the first supply coil (3); detecting when the wire from the first supply reel (3) is almost entirely unwound without being completely unwound; the shutdown, following the detection of this moment, of the supply (1); of the subsequent connection of the start (7) of the wire coming from the second supply coil (5) with the wire (9) unwound by the first supply coil (3) and of the cutting of the residual wire (17) on the first supply coil (3); and finally the removal of the first supply coil (3) carrying the residual wire (17). 2. Method according to claim 1, intended for a continuous feeding of the thread intended for the weft insertions via the supplier of a weaving machine, characterized in that the detection of the quasi-exhaustion of the reserve of thread on the first supply coil (3) is followed by the constitution of an additional wire reserve (R3) on the supplier (2) by rotating the latter, for a given time (X), at maximum speed (N2), after which the supplier (2) will be stopped and the start (7) of the wire coming from the second coil (5) will be connected to the wire (9) unwound by the first supply coil ( 3). 3.- Method according to claim 1, intended for a continuous supply (1) of thread intended for the weft insertions through the supplier of a weaving machine, characterized in that, following the detection of the quasi-exhaustion of the wire reserve on the first supply reel (3), the supplier (2) is not stopped until the wire reserve (R) on the supplier (2) reaches an optimal level, the knotting of the beginning (7) of the wire coming from the second supply reel (5) and of the wire (9) unwound by the first supply reel (3) only taking place thereafter. 4.- Method according to one of the above claims, characterized in that the detection of the quasi-exhaustion of the first supply coil (3) is carried out by an optical device and on the basis of the reflection of a signal on the bobbin (19) of the first supply coil (3) when the latter is almost entirely unwound without being completely so. 5.- Method according to one of the above claims, characterized in that the beginning (7) of the wire coming from the second supply coil (5) is connected by a splice to the wire (9) unwound by the first supply coil (3). 6.- Method according to one of claims 1 to 4 above, characterized in that the beginning (7) of the wire coming from the second supply coil (5) is connected by knotting to the wire (9) unwound by the first supply coil (3). 7.- Device implementing the method according to one of the above claims, characterized in that it essentially consists of elements (6) intended to present one near the other, the beginning ( 7) wire coming from the second supply coil (5) and the wire (9) unwound by the first supply coil (3); sensors (11, 12) intended to identify the moment when the active supply coil is almost entirely unwound but not completely unwound; and elements (10) intended to connect the beginning of the wire (7) and the wire (9). 8.- Device according to claim 7, characterized in that the elements (6) intended to present one close to the other, the beginning (7) of the wire coming from the second supply coil (5) and the wire (9) unwound by the first supply coil (3), essentially consist of two guide eyelets (14, 15) placed side by side and guiding, respectively, the beginning of the wire (7) and the wire (9 ), as well as a wire clamp (16) retaining the start of the wire (7). 9.- Device according to claim 7, characterized in that the elements (6) intended to present one close to the other, the beginning (7) of the wire coming from the second supply coil (5) and the wire (9) unwound by the first supply reel (3), essentially consist of an eyelet (4) guiding the wire (9) of the first supply reel (3), of a wire clamp (16) retaining the start (7) of the wire unwound by the second supply reel (5) and having this start (7) near the wire (9) unwound by the first supply reel (3), as well as a movable wire guide (30) capable of acting on the wire (9) unwound by the first supply coil (3) to bring it against or practically against the start (7) of the wire coming from the second coil d 'feed (5). 10.- Device according to one of claims 7 to 9, characterized in that it also comprises a thread finder (31) for locating the start (7) of the thread of each reel (20) newly presented and d 'bring this beginning of the wire into the wire clamp (16). 11.- Device according to one of claims 7 to 10, characterized in that the detector (11) or the detectors (11, 12) mentioned above are optical sensors monitoring the coil (19) of the coil d power supply (3) active and working on the basis of the reflection of an optical signal (21) on this coil. 12.- Device according to claim 11, characterized in that the surface of the coils (19) of the supply coils used (3, 5, 20) is coated with a highly reflective tape (22).

Images