FR2477587A1 - DEVICE FOR INSERTING A WEFT YARN INTO THE CROWD OF A WEAVING MATERIAL - Google Patents

Abstract

The invention relates to an apparatus for inserting a weft thread into the shed of a weaving machine, with a delivery device (1) which delivers threads into a collecting device (4), a weft (3) coming from a weft-thread reserve, and with an insertion device (6) which is arranged between the delivery device and the collecting device and which, in synchronism with the circular movement of the weaving machine, can intermittently insert the weft located in the reserve into the shed formed by the warp threads, characterised in that the introduction of the weft (3) into the insertion device (6) is obtained by means of a device (5) which is moved continuously or intermittently in a single direction or in two directions and which is arranged between the delivery device and the insertion device and is equipped with gripper members (8, 9) for the weft which describe a path, the enveloping curve of which is located outside the path of the movement of the insertion device and intersects the path of movement of the thread between the delivery device and the collecting device, and in that the gripper members, during their displacement, bring the thread into the effective range of the insertion device and continue their movement.

Description

DEVICE FOR INSERTING A WEFT YARN INTO A CROWD
OF A WEAVING.

 The present invention relates to an improvement made to the weaving technique in which the weft thread is inserted into the crowd formed by the warp threads without requiring the use of a shuttle.

The different techniques known to this gour and which allow to insert a weft in the crowd of a loom without using a shuttle can be classified into three main categories namely
- the one in which a fluid vector (air jet, water jet) is used to transport the weft from one side to the other of the crowd,
- the one in which a projectile or a lance system (flexible or rigid) is used which grasps the weft thread and makes it pass through the crowd,
- finally that much more recent, known under the name of "insertion by inertia" and which is described in the French patent nb 1.562.147 (corresponding to the patent of the United States of America 3.543.808) which consists in launching the frame in the form of a loop, one of the strands called "launched strand" of this loop having a free end and being launched at high speed inside the crowd formed by the spacing of the warp threads and the end of the other strand said "subject strand" being held in a clamp outside the crowd.

In all these techniques, the pick to be inserted is prepared, prior to its launch, by forming a reserve of wire of determined length1 in general by using a deliverer calling the weft wire stored on a supply reel and delivering this wire to inside a reserve constituted for example by a depression chamber.

 One of the main problems which arise for the implementation of these techniques is that of the synchronization of the means making it possible to launch the thread inside the crowd and to form the reserve which should constitute the next pick with the cycle of the loom. This problem is all the more difficult to solve when working at high speed.

The present invention relates to a simple, effective device, easily adaptable to practically all types of weaving machines without shuttle which require the preparation of a pick and its reserve prior to its launching through the crowd and which allows, by elsewhere, a perfect syn chronization with the cycle of the loom.

In the following description, the invention will be described more particularly applied to the inertial insertion technique as summarized above, but it is obvious that this is not limiting and that it could also be applied to any other type of loom without shuttle.

As said previously, according to this technique, the weft is launched into the crowd in the form of a loop having a launched strand and a subject strand. In this way, the kinetic energy contained in the launched strand is transformed, in the loop, into a force pulling in the direction of movement of the loop, this force having to be greater than the resistance of the air.

 The propulsion of the launched strand is done either by means of a lever having a lug or pulley at its free end, accelerating the loop at the same time as the wire, or by pinching between two bodies of revolution in rotation and constituted, for example, by cylindrical or frustoconical rollers, having a peripheral speed equal to the desired speed of launching of the wire.

 The invention will be described more particularly for this latter technique in which the launch is obtained by pinching between two bodies of revolution in rotation.

 A solution allowing synchronization of such a launcher with the cycle of the loom as well as with the formation of the reserve of thread intended to be launched is described by VINCENT in the journal Textile Institute and Industry - March 1970. This solution consists in using two throwing rollers which are separated for an instant to introduce the thread to be thrown and then brought together to press the thread and drive it.

This procedure has a number of drawbacks. Indeed, at least one of two rollers must be able to undergo a translational movement perpendicular to its axis in order to move it away from the second roller so as to be able to introduce the wire perpendicular to the common generator.

i thus, as the two rollers must have the same circumferential speed to reduce friction and direct the wire in a well-defined direction, the fact of separating them for an instant requires training them both.

In addition, the loop must be prepared in advance, which requires an additional mechanism which, in general, essentially comprises a crown animated with a movement of rotation in its plane and which carries, on the same side relative to its center, two pliers arranged radially, one near the inner circumference and the other near the outer circumference of the crown. A cutting device cuts the wire between these two pliers and a third fixed plier is located near the launching rollers which can be moved away from one another to receive the wire and then pressed against each other to launch it.

 An enclosure serving as a wire reserve is arranged vertically and concentrically with the crown. The common generator of the rollers when they are in contact is located inside the surface delimited by the crown. The arrangement of the crown and the wire reserve, in particular, makes it difficult to rotate this crown and requires a fairly complicated system; moreover, as said previously, it is necessary to separate the rollers so that the wire is placed between them. The author himself recognizes the complication of his project.

 your present invention aims to remedy these disadvantages vénients and relates to a device which, not only is uti list in association with a launching unit consisting of det = x rotating rollers but which, possibly, can be easily adapted to be associated with other types of members allowing the insertion of a weft in the crowd. of a weaving loom such as for example an air or water nozzle, a projectile or clamp system.

In general, the invention therefore relates to a device for the insertion of a weft thread into the crowd of a weaving loom which comprises
- a deliverer debiting in an accumulation member the pick coming from a weft thread reserve,
an insertion member, arranged between the deliverer and the accumulation member, making it possible to insert intermittently, in synchronism with the cycle of the trade, the pick thus stored, in the crowd formed by the warp threads, this device being characterized by the fact that the introduction of the pick into the insertion member is obtained by means of an assembly driven by a unidirectional or alternating movement, continuous or intermittent, disposed between the deliverer and the inserting member, this assembly being equipped with gripping members of the pick describing an envelope whose surface is external to the path of the inserting member, an envelope which cuts the path of the wire between the deliverer and the accumulation member, said gripping means bringing the wire into the area of action of the insertion members during their movement and continuing their movement.

Preferably, the gripping member catches the strand of thread towards the point of the fabric, said thread being inserted in a loop in the crowd of a loom.

 In the case where the insertion member is constituted by a pair of rollers making it possible to launch the wire in the form of a loop comprising a fixed strand and a launched strand, the rollers will be kept in permanent tangential contact and the means of gripping the wire that comprises the assembly animated by a unidirectional movement, and which allow its introduction between the rollers, will describe an envelope whose surface is external to the generator common to said launching rollers. In the case of an insertion member other, the gripping moles of the wire will describe an envelope whose surface is external to the trajectory of said insertion member (lance, projectile, etc.). In all cases, the envelope cuts the path of the wire between the deliverer and the accumulation member, said gripping means bringing, during their displacement, the wire in the line of contact of the rollers or in intersection with the trajectory of the insertion body.

In this embodiment, the gripping member forms the fixed point of the subject strand of the loop which unwinds inside the crowd, the wire being, after insertion, cut and released by the gripping member and its free end thus formed reintroduced into the reserve member.

 The assembly supporting the gripping means allowing the introduction of the wire into the insertion member is driven in a unidirectional movement which can be either at constant speed or at intermittent variable speed obtained for example using a Maltese Cross system.

Advantageously, the prepared pick is stretched by an air jet along a well-defined path, between the delivery member and the inlet of the accumulation member, this pick being preferably stored in the pick-up member. accumulation in a plane close to the tangent plane common to the two throwing rollers.

the gripping members making it possible to introduce the picks between the launching rollers are constituted for example by these pliers describing a circumference substantially in the tangent plane common to said launching rollers, the opening and closing of these pliers being able to be controlled automatically using fixed cams.

 In general, the unit animated by a unidirectional movement will comprise n clamps fixed at the same angular distance on a circumference of a turntable or disc S at a speed equal to l / n times the speed of the weaving machine. Optionally, if the number of pliers is even, one pliers out of two can title replaced by a knife arranged in such a way that it is possible to insert picks in pairs without cutting between the two, the knives being able to be used as oral gripping the second pick of each pair.

In all cases, all the gripping members may be pliers knives retaining the wire downstream from its cut.

The invention and the advantages which it brings will be better understood thanks to the exemplary embodiments given above, by way of indication but not limiting and which are illustrated by the appended diagrams in which
FIG. 1 shows diagrammatically in perspective, a device according to the invention,
FIG. 2 is a plan view of this same device,
FIG. 3 illustrates the different phases (referenced a, b, c, d, e, f) of its operating cycle of a device according to the invention,
- Figure 4 describes the different phases (a to i) of
operation of a variant of the device according to the invention,
FIG. 5 represents a front view of another embodiment of the invention,
FIG. 6 shows this same embodiment in plan,
FIG. 7 represents a variant of FIG. 5 from the front,
FIG. 8 shows a fabric with a true selvedge obtained by the variant illustrated in FIG. 4,
- Figure 9 shows another mode of system animated with a unidirectional movement allowing the introduction of the pick into the insertion member.

 If reference is made to the appended figures and more particularly to FIG. 1, the device according to the invention comprises a known thread deliverer (unwinder-measurer) 1, driven by a rotational movement which ensures a flow of thread corresponding to the average rate of insertion of the weft thread 3 in the weaving machine.

 The wire thus unwound is sucked into an accumulation enclosure 4 maintained in depression by all known means.

So that the wire 3 remains tight and in a precisely defined position, it is advantageous to guide it by means of a jet of air blown by a nozzle 2 arranged between the unwinder-meter 1 and the enclosure. accumulation 4.

 As a unit driven by a unidirectional movement, a plate 5 is used, the axis of which is substantially orthogonal to the launch axis. The launching member 6 consists, in this embodiment, of two launching rollers 6a-6b and the plate 5 is driven by a uniform rotational movement around its axis. This plate 5 carries two gripping elements constituted by pliers 8, 9 diametrically opposite and its speed of rotation is equal to half the speed of the weaving machine.

 Of course, without departing from the scope of the invention, the plate 5 could include n angularly equidistant clamps; in this case, its speed of rotation must be equal to 1 / n times the speed of the machine. When the plate 5 rotates, the trajectory of the clamps 8, 9 is a circumference situated in the tangent plane common to the two throwing rollers 6-6b.

The opening and closing of the clamps 8, 9 are controlled by a cam (not shown) fixed relative to the weaving machine and mounted under the plate 5.

This cam can be a bell cam if the opening and closing movements of the clamps 8, 9 are perpendicular to the plate 5 or a radial cam if these movements of the clamps are carried out parallel to the plate.

 Figures 3a to 3f illustrate the operation of such a device.

The plate 5 rotating in the counterclockwise direction indicated by the arrow, the clamp 8 arrives open at the level of the wire 3 moving towards the entry of the accumulation member 4, takes this wire 3 and closes (FIG. 3a). The portion of the wire 3 upstream of this clamp will take the path of the accumulation member 4 while the portion of the wire downstream will be entrained between the rollers 6, 7 (FIG. 3b). The plate 5 continuing to rotate, the wire 3 reaches point E in contact with the generator common to the two rollers 6, 7 (FIG. 3c). The loop of thread is then closed and is launched into the crowd of the weaving machine (Figure 3d), the clamp 8 forming the fixed point of the strand subject. When the loop of thread is completely unwound, the strand secured in the pliers 8 comes into contact with the blade of a knife 11 and is cut between the pliers 8 and the edge of the fabric (Figure 3e). 'then opens, the free end of the wire 3 being sucked into the storage member 4 in the direction of the arrow 40 (FIG. 3f). A tie 14, dried only in FIG. 3f, guides the strand of wire released from the clamp 8 to prevent it from being picked up by the launching rollers 6,7. The plate 5 having made a rotation of a half-turn about its axis c 'is the clamp 9 which arrives open at the level of the entry of the reserve 4, takes the wire 3 and completes a cycle identical to that which comes to be described for clamp 8.

Thus, each of the clamps fixed on the plate 5 participates in turn in the insertion of a pick in the crowd of loom.

A variant according to the invention is described using FIGS. 4a to 4i. In this second embodiment, the plate 5 carries an even number of means for gripping the wire, one in two of which is constituted by pliers and the others by a knife, the knife 11 of Figures 3, outside the plate 5, being deleted. . In the device represented in FIGS. 4, the clamp 8 has been replaced by a knife 20.

The first stages of the picking process are identical to those described above. In 4a, the clamp 9 arrives open at the entry orifice of the accumulation member 4, grasps the wire 3 and closes. The plate 5 rotating in the counterclockwise direction indicated by the arrow (FIG. 4b), the wire 3 is introduced between the launching rollers 6, 7. In FIG. 4c, it is located at point E on the generator common to the two rollers 6, 7. In 4d, a wire loop is formed and about to be launched. From this stage, the process is subtly different from the description given from the first realization. The cup comb against the fabric already formed the pick which has just been inserted and is still secured in the clamp 9 (Figure 4e). Then the clamp 9 opens and the released strand is sucked into the accumulator 4. I1 therefore always exists in the accumulation member 4 a loop of wire between the point of shaping 22 and the inlet of the accumulation member (FIG. 4f).

The knife 20 arrived at the entry of the accumulation member 4 cuts the free strand of the wire 3 and the two strands 3a and 3b kept separate are sucked side by side in the accumulation member 4 (Figure 4g ). The knife 20 is arranged in such a way that when the rotation of the plate 5 has brought it from its cutting position (FIG. 4f) to the position shown in FIG. 4g, its back comes into contact with the strand held at the point of shaping 22 , the embarrassment between the point of facade 22 and an embarrassment 15 to insert it between the rollers 6 and 7, form the loop and launch it (figure 4h). The comb cups the pick thus inserted against the fabric already formed so that the edge of the width has on the side of the launching device a real selvedge. During this time, the clamp 9 takes the wire 3 at the entrance to the accumulation member 4 and the cycle begins again.

 This device therefore allows the insertion of picks in pairs 101, 102, into the chain 100 without cuts between the two.

In this way, the fabric obtained comprises, as shown in FIG. 8, a real selvedge on the side of the weft insertion device.

Figures 5 and 6 show another embodiment of a device according to the invention in which the presentation assembly 5 rotates in a unidirectional movement around an axis substantially parallel to the generator common to the launching rollers 6a and 6b. The gripping members 8, 9 are carried by the edge of a plate 5. The wire 3 exiting from the delivery meter (not shown) is sucked by the accumulation member 4 passing through the gripping member 9 which is a knife pliers. This blocks the wire and cuts it.

The free strand continues its path towards the accumulation member 4 and the other strand is driven by the rotation of the plate 5.

A tether 16, animated by a back and forth movement under the action of a mechanism 17 synchronized with the movement of the weaving machine is placed on the path of the thread which is stretched between the dog tail eyelet 18 and said docking 16.

The wire is introduced between the starter rollers 6a, 6b and forms a loop. The tether disappears and the loop is launched in the crowd as above.

 ba FIG. 7 represents an identical device but in which the mobile locking device 16 is replaced by a deflector 19.

This part fixed between the starter rollers 6a, 6b and the turntable 5 guides the wire until it is inserted between the starter rollers.

 Without departing from the scope of the invention, the plate 5 described in the two above-mentioned embodiments can be reduced to a hub provided with a number of arms carrying the gripping members. I1 can be replaced by an endless chain or belt 30 (see FIG. 9) on which the pliers and / or the knives are fixed in the same manner as on the plate 5. This endless conveyor is driven by any means known to a speed equal to lXn times the speed of the weaving machine if it carries n means for introducing the yarn.

 It is obvious that the invention is not limited to the embodiment described above but also covers all the variants thereof. Thus, in certain cases, it may be advantageous to give the plate a rapid movement to facilitate gripping of the wire, for example between positions 3a and 3b while it may be slower during the rest of the race. Such a unidirectional movement can be communicated for example using a Maltese Cross system. Possibly, we could even have a downtime without departing from the scope of the invention.

 Finally, as said previously, such a device can easily be adapted to looms without a shuttle using other types of wire launching devices than launching rollers.

Claims (13)

1 / Device for the insertion of a weft thread into the crowd of a loom which comprises a deliverer 1 debiting in an accumulation member 4 the pick 3 coming from a reserve of weft threads,  - an insertion member 6 arranged between the deliverer 1 and the accumulation member 4 making it possible to intermittently insert, in synchronism with the cycle of the trade, the pick 3 thus stored, in the crowd formed by the wires of chain, characterized in that the introduction of the pick 3 into the insertion member 6 is obtained by means of an assembly 5 animated by a unidirectional or alternating, continuous or intermittent movement, disposed between the deliverer 1 and the insertion member 6, this assembly 5 being equipped with gripping members 8, 9 of the pick 3 describing an envelope the surface of which is external to the path of the insertion member, envelope which cuts the path of the wire between the deliverer 1 and the accumulation member 4, the said gripping means bringing the wire into the zone of action of the insertion members during their movement and continuing their movement.  2 / Device according to claim 1, characterized in that the gripping member 8 or 9 drives the strand of thread towards the fabric stitching point, said thread being inserted in a loop in the crowd of the weaving machine.  3 / Device according to claims 1 and 2, characterized in that the insertion member is constituted by a pair of throwing rollers 6a, 6b for launching the pick 3 in the form of a loop having a strand attached and a strand launched, the gripping means 8, 9 of the pick 3 that comprises the assembly 5 animated with a unidirectional movement allowing the introduction of pick 3 between the rollers 6a, 6b.  4 / Device according to claim 3, characterized in that the wire 3 brought near the point of the fabric is released by cutting with fixed scissors, the strand connected to the accumulator returning there.  5 / Device according to one of claims 1 to 4, characterized in that the prepared pick 3 is stretched by an air jet 2 along a determined path at the entrance of the accumulator.  6 / Device according to claim 5, characterized in that the prepared pick is placed in reserve in a plane close to the tangent plane common to the two throwing rollers 6a, 6b. 7 / Device according to one of claims 3 to 6, characterized in that the gripping means 8, 9 are pliers describing a continuous unidirectional movement a circumference, the opening and closing of these pliers being controlled by a fixed cam.  8 / Device according to claim 7, characterized in that the gripping means 8,9, are pliers describing with a continuous unidirectional movement a circumference substantially in the tangent plane common to the two throwing rollers 6a, 6b.  9 / Device according to claim 7, characterized in that the gripping means 8, 9, are pliers describing a circumference in a plane substantially perpendicular to the tangent plane common to the two throwing rollers 6a, 6b. 10 / Apparatus according to claim 7, characterized in that n clamps 8, 9 are fixed at the same angular distance on the assembly 5 rotating at a speed equal to 1 / n times the speed of the weaving machine.  11 / Device according to claim 7, characterized in that the gripping members 8, 9 are knife pliers retaining the wire downstream of the cut.  12 / Apparatus according to claims 7 and 11, characterized in that if n is even, one pair of pliers is replaced by a knife arranged so that it is possible to insert picks in pairs without cutting between the two , the knives serving as gripping members for the second pick of each pair. 13 / Apparatus according to claim 1, characterized in that the wire gripping means are carried by an endless conveyor (chain, belt).