EP0292461B1 - Method for arranging the warp threads between the warp beam and the shed of a loom and for the realisation of the replacement of the warp beam, and loom for carrying it out - Google Patents

Description

The present invention relates to a method for rectifying the path of warp threads between the beam and the shed on weaving machines, and in particular between the thread carrier on the one hand and the chain breakers or frames on the other hand. See for example DE-A-2043420.

It is known that on weaving machines, a series of factors which may arise during weaving compromise the parallelism of the warp threads forming the web between the beam and the strips of the chain breaker or the heddles of the frame. The defects in the parallelism of the warp threads are mainly due to their lateral displacement during repairs after the breaking of a warp thread, when knotting a new thread to a too short warp thread (generally located towards the edge of the beam), following the inversion of a series of threads when knotting a new beam, following the irregular weaving of the beam, or even because the weaver touched the tablecloth by leaning on the machine to make a repair.

As the knotting of a new warp requires a good parallelism of the warp threads, these must be combed or brushed before the installation of the new warp. This operation requires a great deal of know-how, special equipment and a lot of time. In addition, manual combing does not necessarily ensure good parallelism of all warp threads.

The invention presented provides a method which completely excludes the drawback mentioned above during the rectification of the path of the chain strands as well as the beam changes. For this, the method presented essentially provides for a back-and-forth movement - the outward stroke and the return stroke may or may not be equal - between the chain ply and at least one of the machine members imposing a parallelism to the paths of the warp threads. It goes without saying that this relative movement can be obtained both by the movement of the warp threads, the organs of the machine remaining stationary (or vice versa), and by imposing a movement (by definition different) on the ply of chain and the relevant machine components.

The relevant parts of the machine will be the chain breaker and its blades, the frames and their healds, and other similar guiding devices. It is clear that the application of the method provided by the invention will have the effect of paralleling the warp threads which are not, by moving them in a relative movement relative to the frames and / or the chain breaker. .

After the stroke of the relative back-and-forth movement, the warp threads will preferably be immobilized by a clamping device to prevent them from crossing again on their return stroke.

Furthermore, the invention also relates to a method of carrying out beam changes during which the rectification of the path of the warp threads is carried out as described above, the assembled warp threads then being cut on the side of the device of tightening turned towards the beam, after which the threads of the new beam will be knotted to the already threaded warp threads and put in parallel.

Finally, the invention relates to a weaving machine implementing the method just defined.

• La figure 1 représente le problème du défaut de parallélisme des fils de chaîne;
• les figures 2 et 3 représentent deux états fonctionnels principaux du principe conforme à la méthode prévue par l'invention;
• les figures 4 à 8 représentent la réalisation concrète, sur une machine à tisser, du principe illustré aux figures 2 et 3, et permettant des changements d'ensouple sans risque de défaut de parallélisme des fils de chaîne;
• les figures 9 et 10 représentent le nouage d'un nouvelle ensouple;
• les figures 11 à 13 représentent, pas à pas, une variante d'installation mettant en oeuvre la méthode prévue par l'invention.

In order to better highlight the characteristics of the invention, we will find below, by way of non-limiting examples, the description of some variants as well as a weaving machine implementing the recommended method, with reference in the accompanying drawings, where:

• FIG. 1 represents the problem of the lack of parallelism in the warp threads;
• Figures 2 and 3 show two main functional states of the principle according to the method provided by the invention;
• Figures 4 to 8 show the concrete embodiment, on a weaving machine, of the principle illustrated in Figures 2 and 3, and allowing beam changes without risk of lack of parallelism of the warp son;
• Figures 9 and 10 show the knotting of a new beam;
• Figures 11 to 13 show, step by step, a variant installation using the method provided by the invention.

Figure 1 gives a schematic view of part of a weaving machine and illustrates the process of a conventional weaving, according to which the warp (or ply) yarns 1 are unwound from a beam, pass over a carrier yarns 2 to then be guided in the strips 3 of the chain breaker 4, then by the healds 5 of the frames 6, before being integrated into the fabric 7. The transition between the ply of the warp threads 1 and the fabric 7 is formed by the striking line 8, struck by the comb 9 to strike the weft threads inserted in the shed 10.

As we indicated in the introduction, it sometimes happens that certain warp threads 1 composing the ply between the beam and the chain breaker 4 are not placed parallel to each other and that, more particularly, they affect an arrangement such as that indicated in FIG. 1 over distance A. However, certain applications including in particular the knotting of a new beam require a good parallelism of the warp threads 1 on their path between the chain breaker 4 and the carrier - girl 2.

The invention presented makes it possible to satisfy this requirement by a relative displacement, in a back-and-forth movement, of the warp threads on the one hand and, on the other hand, of the organs of the machine which impose the parallelism of the paths warp threads.

A first application of this principle consists, as already mentioned, in moving only the warp threads 1, the chain breaker 4 and the frames 6 remaining stationary; as shown in Figures 2 and 3 respectively, this movement is achieved by the displacement of the ply 1, and therefore of the striking line 8, on a forward stroke of a length L1 followed by a return stroke of a length L2; this back-and-forth movement of the warp threads 1 placed in front of the striking line 8 drives them through the heddles 5 and strips of the chain breaker 3 (provided that the machine is equipped with a chain breaker), thereby ensuring that they are placed in parallel. It should be noted that the distance L2 can be less than or equal to the distance L1. To prevent the warp threads 1 from crossing during their return stroke, a clamping device 11 of the ply will preferably be applied at the end of the forward stroke, this clamping device, intended to retain the ply 1 during its return stroke, being placed just behind the chain breaker 4.

On the side of the clamping device 11 oriented towards the thread holder 2, the warp threads 1 can be cut using a cutting device 12, after which a new beam can be knotted between the clamping device 11 and the chain breaker 4.

Figure 4 shows schematically a weaving machine implementing the method described above. In the illustrated embodiment, the weaving machine is equipped with a movable guide device 2A, capable of moving over a long stroke. The mobile guide device 2A will preferably be placed at the height of the wire holder 2 or, better still, constituted by the wire holder 2 itself. In addition to the organs already mentioned, the figure also represents the beam 13, the chest 14, the take-up roller 15 and the fabric roll 16. The ply of the isolated warp threads 1 is represented by a broken line, the fabric is represented by a solid line. In addition, the figure schematically represents drive devices such as the motors 17 to 20, respectively controlling the beam 13, the leaf and the comb 9, the take-up roller 15 and the fabric roller 16. The main control members of the assembly include a control unit 21, a measurement unit 22 intended to detect the moment when the beam 13 is almost entirely unwound without being completely unwound, a starting circuit 23 attacking the control unit 21 so as to determine, according to a method described below, the automatic rectification of the paths of the warp son 1 and, optionally, a function programmer 24 making it possible to program the operations to be executed by the control unit 21. The start-up circuit 23 can be controlled automatically or manually by the inputs 25 or 26, respectively.

FIGS. 5 to 8 represent the successive operations which make it possible to condition the warp threads 1 returned to the machine illustrated in FIG. 1 so as to allow the knotting of a new warp without difficulty.

When the measurement unit 22 detects the near exhaustion of the beam 13, the start-up circuit 23 attacks the control unit 21, which launches the automatic execution of the sequence of operations described below. As shown in Figure 5, the guide device 2A is first of all brought back to the race L1 mentioned above; during this movement, the beam 13 unwinds a given length of ply while the winding device, composed of the take-up roller 15 and the fabric roll 16, remains stationary.

In a second phase (illustrated in FIG. 6), the take-up roller 15 and, optionally, the fabric roller 16 are driven in their normal direction of rotation, so that the striking line 8 moves towards the 'before. During this movement, the guide device 2A is driven forward and must overcome, for example, the resistance of an elastic device such as a set of springs. It is clear that the warp threads 1, passing through the strips of the chain breaker 3 and of the stringers 5, will be placed parallel to one another with respect to their portion comprised between the chain breaker 4 and the striking line 8 On weaving machines without chain breaker blades 3, the straightening of the paths of the warp threads will be ensured by the healds 5 alone.

During a third phase (illustrated in FIG. 7), the clamping device 11 placed next to the chain breaker 4 is applied to the warp threads 1. In the absence of the chain breaker, the clamping device 11 will apply to the warp threads 1 next to the frames 6.

During a following phase (illustrated in FIG. 8), the take-up roller 15 and, possibly, the fabric roll 16 will be unwound in the wrong direction while the unwinding of the beam will be interrupted. This will bring back the guide device 2A, the warp threads 2A and the fabric 7; the clamping device 11 accompanying the movement. Finally, the beam 13 can be separated from the warp threads 1 using the cutting device 12, after which a new beam can be tied to the warp threads 1 placed in parallel, at a point between the tightening 11 and the chain breaker 4.

Although the crowd 10 is shown with separate layers on all the sketches mentioned, it is clear that it will be indicated, in some cases, to close the crowd before controlling the back and forth movement of the warp threads 1. On machines without the chain breaker 4 in particular, closing the crowd before the rectification of the ply has the advantage of allowing the positioning of the clamping device 11 in the immediate vicinity of the frames 6 or their heddles 5, at the end of the backward movement (i.e. the forward course) of the striking line 8.

In a particular variant of the method provided by the invention and illustrated in FIGS. 1 to 8, the warp threads 1 reciprocate over relatively long strokes, so that the knotting of a new beam can be produced as illustrated in FIGS. 9 and 10. In this variant, the displacement of the line of striking can be obtained, for example, by unwinding and unwinding the fabric and warp threads over suitably chosen lengths, as described above. During this movement, a new beam 13A can be mounted after cutting the wires remaining on the active beam 13, when the latter is practically empty. The ends of the threads of the new beam 13A, held by means of a tightening device 27, will be placed on a knotter 28. As shown in FIG. 10, the warp threads 1 already retracted will also be led towards the knotter 28 ; they will be pulled through the chain breaker 4 and the stringers 5 by the retraction of the tightening device 11. After the closing of the flanges 29 and 30 of the knotter, the ends 1 and 1A of the warp threads will be connected by a knotting device 31 known elsewhere. It is clear that in this variant, the warp threads 1 must carry out a forward stroke whose length is sufficient to allow them to be brought, subsequently, to the knotter 28 placed next to the weaving machine.

In order to ensure the parallelism of the ends of the threads coming from the new beam 13A at the height of the knotter, it is of course possible to use auxiliary devices such as additional clamping devices 32. Optionally, the clamping devices 27 and 32 may be integrated into the knotter's flanges 29 and 30.

In another variant of application of the invention, already mentioned in the introduction, the reciprocating movement concerns not the warp threads 1 but one or more components of the machine, and more particularly one of the components imposing the parallelism of the warp threads 1. This variant of the invention offers the specific advantage of not requiring complex control of the fabric roll 16 and the beam 13.

In the preferred embodiment variant of the invention, which is also the simplest, the chain breaker 4 will constitute the mobile member mentioned above. In this case, the method provided by the invention can be applied code illustrated in FIGS. 11 to 13. At first, the trajectory of the warp threads will not be corrected over distance A. By moving the chain breaker 4 towards the rear over the distance L1, as indicated in FIG. 12, that is to say by bringing it closer to the beam 13, we will then impose paths parallel to the warp threads 1. At the end of the stroke L1 , a clamping device 11 will be applied to the warp threads 1 near the chain breaker to prevent the threads from crossing again during the return stroke.

During a last phase illustrated in FIG. 13, the chain breaker 4 is brought back into position and the warp threads 1 are cut by the cutting device 12, after which they can be knotted at the ends of the threads coming from 'a new beam.

The above description clearly highlights that the weaving machine specifically intended to implement the method provided by the invention is characterized by the fact that it is equipped with a chain breaker 4 capable of moving in the direction longitudinal chain, and a drive device controlling the movement of the chain breaker 4. For this, the chain breaker 4 can be mounted on a slide 34 or a similar device, the drive device 33 can be consisting of a fixed jack 35 whose rod 36 controls the movement of the slide 34.

It goes without saying that the drive device 33 can be composed of other systems than the jack which has just been mentioned.

Finally, it should be noted, as illustrated for example in FIGS. 2 and 12, that it is possible to provide a guide device 37 intended to maintain the configuration of the shed 38 of the chain during the rectification of the paths of the wires of chain 1. This guiding device is however not essential, since the geometry of the shed 38 can possibly be modified, as indicated by the reference 39 in FIG. 12. The deformation of the shed 38 can moreover be avoided without resorting to the guide device 37, closing the shed during the rectification of the warp thread paths.

Claims (14)

1. Method for rectifying the trajectories of the warp threads between the warp beam and the shed of weaving machines, characterized in that it mainly consists of a to-and-fro movement between the warp threads and at least one of the machine elements (4, 6) which make the trajectories of the warp threads run parallel.
2. Method according to claim 1, characterized in that the relative displacement according to a to-and-fro movement of the warp threads (1) and the machine elements is brought about by, at least, a movement of the warp threads (1) during which they go forward over a distance (L1) and come back over a distance (L2).
3. Method according to claim 1, characterized in that the relative displacement according to a to-and-fro movement of the warp threads (1) and the machine elements is brought about by the displacement, at least, of the warp stop motion (4) of the weaving machine.
4. Method according to claim 1, characterized in that the relative displacement according to a to-and-fro movement of the warp threads (1) and the machine elements is brought about by the displacement of at least one of the harnesses (6) of the weaving machine.
5. Method according to any of the above claims, characterized in that the forward and backward travels (L1, L2) of the relative displacement according to a to-and-fro movement are identical.
6. Method according to any of the above claims, characterized in that in between the forward travel and the backward travel of the to-and-fro movement of the warp threads (1) and the machine elements, the warp threads (1) are gripped by a clamping device (11) such that the warp threads (1), after their trajectories have been rectified, cannot cross again.
7. Method according to claim 2, characterized in that after the forward travel of the warp threads (1) and before their backward travel, they are clamped by means of a clamping device (11) situated next to the warp stop motion (4) or, if the machine is not provided with a warp stop motion (4), next to the harnesses (6), after which said clamping device (11) follows the movement of the warp threads (1) on their backward travel.
8. Method according to claim 2, characterized in that the displacement of the warp threads (1) on their forward and backward travels is achieved by the unwinding of the warp threads (1) whilst the cloth beam is brought to a standstill, followed by the winding of the cloth (7) on the cloth beam whilst the unwinding of the warp beam has been stopped, after which the cloth (7) is unwound in the opposite sense and the warp threads (1) are passed, also in the opposite sense, through the harnesses (6) of the weaving machine, whereby the warp beam is brought to a standstill during the latter movement.
9. Method for realizing a warp beam change with rectification of the trajectories of the warp threads according to claim 7, characterized in that after the backward movement of the warp threads (1) with an accompanying backward movement of the clamping device (11), the warp threads (1) are cut off along the clamping device (11), on the side directed towards the warp beam (13) after which a new warp beam (13A) is put in place and the warp threads (1), which are available on the machine and have been rectified, are connected to the warp threads (1A) of the new warp beam (13A).
10. Method according to claim 9, characterized in that after the warp threads coming from the warp beam (13) have been cut off, the rectified warp threads (1) and their clamping device (11), as well as the warp threads (1A) kept in position by the clamping devices (27, 27A) and coming from the new warp beam (13A), are led to and presented to a tying-in device (28) realizing the connection between the warp threads (1) and (1A).
11. Weaving machine applying the method according to any of claims 1, 2, 5 to 8, characterized in that it is provided, at the height of the back rest (2), with a guiding element (2A) for the warp threads (1) which can be moved backward.
12. Weaving machine according to claim 11, characterized in that the guiding element (2A) is formed by the back rest (2) itself.
13. Weaving machine applying the method according to claim 3, characterized in that it is provided with a warp stop motion (4) which can move according to a to-and-fro movement in the direction of the warp threads (1) and with a drive element (33) which controls the movements of the warp stop motions (4).
14. Weaving machine according to claim 11, 12 or 13, characterized in that it is provided with a clamping device (11) situated between the back rest (2) and the warp stop motion (4) or the harnesses (6), whereby the clamping device (11) can hold back the warp threads (1) over the entire width of the cloth, as well as with a cutting device (12) designed to cut off the warp threads (1) along the clamping device (11) on the side directed towards the warp beam (13).

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