EP0084471A1 - High-speed shuttleless loom - Google Patents

Abstract

1. Shuttleless weaving-machine, with a weft-carrying device, in which the warp threads (2) unwinding from the beam (4) pass over a rear thread support (6), then through the eyes (8, 8') of the heddles supported by several frames C1 , C2 , etc., then through the teeth of the reed (10) before finally reaching the line (14) where the fabric is formed (16), the said machine being characterised : in that the first frame C1 nearest the reed is placed at a distance a from the line (14) and at a distance b from the rear thread support (6) such that the distance a is not greater than 75 mm, and the ratio b/a is between 12 and 15 ; and in that the thickness of the frames C1 , C2 , etc. is not greater than 7 mm.

Description

The present invention relates to the textile industry and, more particularly, shuttleless weaving machines in which the weft thread is inserted into the shed by means of a weft pass consisting of one or two rigid needles (most often, two needles animated by opposite alternative movements which exchange the thread substantially in the middle of the width), or by a projectile, or by any other device allowing the weft thread to cross the crowd. The invention relates more particularly to weaving machines of large width, weaving at least 140 cm wide.

For several years, manufacturers have sought to manufacture machines of this type beating faster and faster, to increase production.

But we are quickly limited in the increase in rates, because the number of machine stops per hour, especially for wire breakage, increases very quickly when the rate is increased, which can lead, in fact, to a decrease productivity.

The breaks in the warp yarn come partly from the fatigue of the yarn (alternating elongations, number of elongation cycles undergone by each point of the yarn, wear of the yarns by circulation in the smooth, percussion between the threads of the two layers forming the crowd when the layers cross) and, on the other hand, the impact of a moving organ, for example a weft insertion needle, against a chain when the crowd is badly opened and two wires have remained hooked to each other at the cross (formation of Y).

Another cause of incident during high-speed weaving is the poor exchange of the weft thread, towards the middle of the width, between the feed needle and the draw needle.

We will now recall the essential elements of a weaving machine of the aforementioned type.

The warp threads are unwound from the beam, pass over a rear thread-carrying roller, then through the heddle eyelets carried by several frames and then through the comb. The weft thread is inserted into the crowd in front of the comb, by the weft needles activated by their drive mechanism, then the weft thread thus deposited is pressed by the comb against the edge of the already formed fabric.

Until now, all conventional needle looms have a substantially identical arrangement of the chain control members, which is moreover derived from that of the shuttle looms. This is how if we call the distance between the front line and the first frame, and b the distance between this first frame and the rear thread holder (the distance a + b being the total "depth" of the loom) , we note that for all these trades, the ratio 1 is between 5 and 9 approximately, with a depth of the order of 1200 to 1500 mm. Conventionally, the distance a between the facade and the first frame is between 120 and 250 mm, while the total opening angle of the crowd is generally around 25 ° (2 x 12 ° 5) without exceeding 30 ° (2 x 15 °), so as not to impose excessive alternative elongations on the warp threads.

These choices of characteristics and dimensions were considered to be the most advantageous and gave satisfactory results for the usual hitting rates so far, for example around 240 to 300 strokes / minute.

But, as indicated above, attempts to substantially increase the striking rates on such machines led to operational incidents, forcing the machine to stop and reducing or even canceling the expected production advantages.

We will return in more detail, in the following, to the phenomena which can cause wire breaks and, more generally, operational incidents.

The object of the invention is to remedy these drawbacks of conventional weaving machines and to allow them to operate at a much higher rate than hitherto, for example around 400 to 500 strokes / minute, without increasing the average frequency. timetable of stops, this result being obtained, mainly, thanks to a relatively new arrangement of the chain control bodies.

The subject of the invention is a shuttleless weaving machine, in which the warp threads unwinding from the beam pass over a rear thread holder, then through the eyelets of the heddles carried by several frames, then through the teeth. of the comb to finally reach the front line where the fabric is formed, said machine being characterized in that the first frame is arranged at a distance a from the front line and at a distance b from the rear thread holder such that the ratio α is equal to or greater than 10.

Preferably, the abovementioned ratio ^b is of the order of 12 to 15.

The depth (a + b) of the looms without shuttle, with rigid needles, being roughly fixed, by construction requirements, as indicated above, it follows that, on a loom conforming to the Invention, the depth of the crowd between the front line and the first frame (distance a) is approximately 2 to 2.5 times shorter than on a conventional needle loom and does not exceed approximately 75 mm.

The Applicant has arrived at this surprising conclusion that, thanks to this new relative arrangement of chain control members, the fatigue of warp threads has been reduced to a considerable extent at the same time as the other causes of breakage of threads or machine shutdown.

In addition, this new arrangement makes it possible to use a larger crowd opening angle than in the past, for example between 30 ° and 35 ° (2 x 15 to 2 x 17.5).

It will also be seen in what follows that this new arrangement makes it possible to reduce the amplitude of the alternative displacements and the weight of certain control members of the chain compared to conventional trades, thanks to which the mechanisms of the trade can operate without disadvantage at much higher rates than on conventional trades.

All these isolated beneficial results have been found to have a cumulative effect, so it is It has become possible, on a loom in accordance with the invention, to make full use of the performances authorized by improved mechanisms for actuating the needles, in particular so-called "balanced Cardan circle" mechanisms. Such a mechanism has been described in French patent No. 2,477,586 in the name of the applicant. Thanks to this cumulative effect, it was possible to reach striking rates of around 450 to 600 strokes / minute, instead of 240 to 300 with the machines known up to now.

• La figure 1 est une vue schématique montrant les organes principaux de contrôle des fils de chaîne sur un métier à tisser sans navette, à aiguilles.
• La figure 2 montre la disposition relative de ces organes et la géométrie de la chaîne dans un métier conforme à l'invention.
• La figure 3 montre, à la même échelle que la figure 2, la disposition relative de ces organes et la géométrie de la chaîne dans un métier classique.
• La figure 4 est un schéma montrant l'élongation des fils de chaîne lorsque la foule est ouverte.
• La figure 5 montre les courbes du taux d'élongation des fils de chaîne en fonction de l'angle d'ouverture de la foule pour différents rapports â.
• Les figures 6 et 7 illustrent la formation des "Y" respectivement sur un métier classique et sur un métier conforme à l'invention.
• Les figures 8 et 9 montrent la disposition des cadres respectivement sur un métier classique et sur un métier conforme à l'invention.
• La figure 10 est une vue de face d'un mode de réalisation d'un métier suivant l'invention, avec insertion de trame par deux aiguilles rigides.
• La figure 11 est un diagramme d'un cycle de fonctionnement de la machine.
• La figure 12 est une vue schématique de la commande du peigne dans une machine suivant l'invention.
• La figure 13 est une vue partielle schématique d'un métier suivant l'invention, avec insertion de trame par un dispositif passe-trame à inertie.

The invention will be better understood on reading the detailed description which follows and on examining the appended drawings which represent, by way of nonlimiting example, an embodiment of the invention.

• Figure 1 is a schematic view showing the main organs for controlling warp yarns on a shuttleless, needle loom.
• Figure 2 shows the relative arrangement of these members and the geometry of the chain in a loom according to the invention.
• Figure 3 shows, on the same scale as Figure 2, the relative arrangement of these members and the geometry of the chain in a conventional trade.
• FIG. 4 is a diagram showing the elongation of the warp threads when the crowd is open.
• FIG. 5 shows the curves of the rate of elongation of the warp threads as a function of the opening angle of the crowd for different ratios â.
• Figures 6 and 7 illustrate the formation of "Y" respectively on a conventional loom and on a loom according to the invention.
• Figures 8 and 9 show the arrangement of the frames respectively on a conventional loom and on a loom according to the invention.
• Figure 10 is a front view of an embodiment of a loom according to the invention, with weft insertion by two rigid needles.
• Figure 11 is a diagram of an operating cycle of the machine.
• Figure 12 is a schematic view of the control of the comb in a machine according to the invention.
• FIG. 13 is a partial schematic view of a loom according to the invention, with weft insertion by a weft pass-through device.

In the schematic representation of FIG. 1, we see the chain 2 which unwinds from beam 4, passes over the rear wire holder 6, passes through the eyelets 8-8 ′ carried by the frames C ₁ -C ₂ , then through the teeth of the comb 10. The weft thread 12 is deposited in the shed F by a needle 13 and is then compacted by the comb against the edge line 14 from which the formed fabric 16 is wound on a roll fabric holder 18.

It should be noted that, for the sake of clarity, Figure 1 is not to scale in the horizontal and vertical directions and that only the first frame C ₁ and the second frame C _{2 have been shown} which divide the chain in two layers 20-20 ', while the number of frames is generally much greater.

The distance a is that measured between the facade line 14 and the first frame C ₁ , while the distance b is that measured between this first frame C ₁ and the rear thread holder 6.

There is shown in Figure 2, to scale, in the vertical and horizontal directions, the relative arrangement of the chain control members in a loom according to the invention in which the report 1 is greater than 10 (ratio 1 = 15, in FIG. 2) and in which the opening angle 2a of the crowd is approximately 35 °.

est compris entre 5 et 9 (rap- port

= 6 sur la figure 3), l'angle d'ouverture 2a de la foule étant d'environ 25°. Sur les deux figures, la profondeur a + b ou a' + b' du métier est identique.FIG. 3 shows, by comparison, on the same scale, the arrangement of the same members in a profession known hitherto in which the ratio

is between 5 and 9 (ratio

= 6 in Figure 3), the opening angle 2a of the crowd being about 25 °. In the two figures, the depth a + b or a '+ b' of the loom is identical.

By simply examining these two figures, we can see how different the "geometry" of the crowd is, despite neighboring crowd opening angles, and even larger in the case of Figure 2. This is particularly true if we consider the part of the crowd (indicated in hatched) between the facade and the first frame which is much more "reduced" in Figure 2 than in Figure 3. This is why, in what follows, we will use the name "reduced crowd" to designate the particular crowd planned on a loom according to the invention and the name "classic crowd" for the looms used until now.

We will now examine the advantages brought by this reduced crowd.

One of the causes of breakage of a chain wire is the fatigue of the wire caused by the alternating elongations which it undergoes because of the movement of raising and lowering of the frames.

.If we call elongation rate E the ratio between the length AB of the wire (Figure 4) in the middle position (at the crossroads) and the length AC + CB when the crowd is at full opening, it is obvious that E depends on a and report

.

de 5, 7 et 9. Les courbes 4-5-6- 7 concernent des métiers suivant l'invention ayant respectivement des rapports

de 11, 13, 15 et 17. FIG. 5 shows the variation in the elongation rates at the first frame as a function of the opening angle a of the crowd. Curves 1-2-3 relate to traditional trades with respective ratios

of 5, 7 and 9. Curves 4-5-6- 7 relate to trades according to the invention having respectively ratios

from 11, 13, 15 and 17.

= 9 et a a = 15°) .Up to now, on conventional trades, we have accepted elongation rates of around 0.40% in the first frame (for example 0.39% with

= 9 and aa = 15 °).

= 15), soit 41 % de réduction du taux d'élongation. On réalise ainsi une réduction considérable de la fatigue des fils de chaîne. Avec un angle a porté à 17°5, le taux de fatigue devient 0,32, soit enccre une réduction de 18 % malgré une augmentation appréciable de l'angle d'ouverture de la foule, augmentation qui est très favorable, comme on le verra plus loin, dans le cas de fils qui décroisent mal, mais qui, dans les métiers classiques ne peut pas être appliquée puisqu'elle augmente le taux d'élongation (voir figure 4).Thanks to the invention, the elongation rate is reduced to between approximately 0.20 and 0.30 for the same angle a (for example 0.23 with

= 15), i.e. 41% reduction in the elongation rate. This results in a considerable reduction in the fatigue of the warp threads. With an angle increased to 17 ° 5, the fatigue rate becomes 0.32, i.e. an 18% reduction despite an appreciable increase in the opening angle of the crowd, an increase which is very favorable, as we will see later, in the case of threads which do not uncross well, but which, in conventional trades cannot be applied since it increases the rate of elongation (see FIG. 4).

Another cause of fatigue is the wear caused by the circulation of the wire 20 in the heald eyelet 8-8 'with each movement of the frames C ₁ , C ₂ ... In fact, when the wire undergoes elongation in position open from the crowd, part of this elongation can be compensated by a lateral flexion of the healds, but if the elongation is significant it is the wire which ends up moving in the heald eyelet and this friction produces wear of the wire, source of breakage.

The elongation, therefore fatigue, of the chain being reduced thanks to the invention, it also reduces wear by circulation of the wire, especially since the point of friction on the eyelets is closer to a fixed point (the line of facade), so that a point of the wire in contact with a heald eyelet moves less than in a conventional loom.

These two advantageous results (reduction in the rate of elongation and reduction of wear by circulation of the wire) have a cumulative effect, and not only additional, since the wire works in conditions more distant from its critical fatigue conditions.

As indicated in the introduction to the present application, another cause of breakage of a warp thread or of incomplete insertion of a weft thread is the impact of one of the needles against a thread when the crowd is not "clean", that is to say when certain threads do not separate, and remain attached to each other, when the crowd opens. There is then formation of "Y", as illustrated by FIGS. 6 and 7. This phenomenon of formation of Y is accentuated by the presence of several wires in a tooth of the comb and by the use of irregular wires which decrease. wrong.

FIG. 6 shows the two plies of warp threads 20-20 ′, the front line 14, the eyelets 8-8 ′ of the heddles carried by the first two frames C ₁ -C ₂ and the bisector AB of the fcu- le. If two warp threads 21-21 'remain hooked together, during the crossing, at point D, distant from Y' of the facade, they form a "Y" (ADC) of maximum angle 6. The crowd is not not completely cleared and the insertion of the weft thread may not be normal, especially if it is done in the DA zone of the crowd, or in the vicinity of it.

We will consider that FIG. 6 represents the formation of a "Y" of maximum angle e on a conventional loom, with normal crowd (for example where a ′ is of the order of 130 mm) and we have represented, at the same scale, in FIG. 7, the formation of a "y" of the same maximum angle θ on a "reduced crowd" loom in accordance with the invention (for example where a is of the order of 65 mm) with opening from the crowd 2a. It is understood that, in both cases, Y of angle less than 8 can also form, closer to the facade, in the area DA, but these Y are less harmful since they are further from the line where is filed the frame.

The two figures 6 and 7 being homothetic (in the ratio 2 to 1) all the triangles are similar in the two figures and we will have:

These theoretical diagrams would therefore tend to show that, for the same opening angle 2a of the crowd, the phenomenon of the formation of Y, their maximum opening angle and their number would be identical with a reduced crowd (Figure 7) and with a normal crowd (Figure 6).

était plus petit que le rapport

, c'est-à-dire qu'avec a une foule réduite la formation des Y est moins fréquente qu'avec une foule normale et que l'angle maximum 6 des Y était moins grand.The plaintiff was able to observe this surprising result that, in practice, the report

was smaller than the ratio

, that is to say that with a reduced crowd the formation of Y is less frequent than with a normal crowd and that the maximum angle 6 of Y was less great.

This surprising observation can come from the fact that the homothety in the ratio 2 to 1 of FIGS. 6 and 7 indicated above is not perfect, because the same thread was considered in both cases, whereas the wire in FIG. 6 should have a diameter twice that of FIG. 7 and would therefore hang more with its neighbor, since the spacing of the warp threads is the same in both cases.

The plaintiff has made yet another observation which may provide an explanation for this surprising result. Indeed, if one lengthens by pulling a length 1 of a given wire, it starts to turn, part in one direction, part in the other, if it is irregular; if we reduce this length, it turns much less. From a certain moment, it does not rotate any more. When the wires rotate when they are stretched during the movement of the frames, this rotation is all the more important as the crowd is longer. It is during this rotation that the wires hang on and form Y. This is another reason which proves that a reduced crowd according to the invention (not exceeding approximately 75 mm for dimension a), will be more "clean" and will give birth less to Y, than a traditional crowd (for example from 120 to 200 mm).

Again, this advantageous result has a cumulative effect with the advantageous results previously reported. In fact, the phenomenon of "Y" formation has been described above, assuming that the crowd opening angles were identical in both cases (Figures 6 and 7).

However, we have seen that it was possible, thanks to the reduced crowd, to increase the opening angle of the crowd, while maintaining a rate of elongation of the wire much lower than that which is applied to a loom. classic. It is obvious that increasing the opening angle of the crowd will make the formation. of the Y more difficult and will therefore further reduce their number.

Hitherto, reference has only been made to the first heddle frame and, in the figures, only the first two frames C ₁ , C _{2 have been shown} for clarity. But, as we know, for the realization of the greatest number of contexts, we need more frames, generally a dozen frames, sometimes 12 to 16.

On conventional looms, the frames, which are subject to alternating displacements of fairly large amplitude, have fairly large heights, so that to be sufficiently rigid, they always have a thickness of between 10 and 16 mm, the thickness the most common being 12 mm. A classic loom, with normal crowd (for example a '= 150 mm) equipped with a harness with ten 12 mm frames C ₁ -C ₂ - ^C ₃ ... ^C ₉ ^-C is shown diagrammatically in FIG. 8 ₁₀ .

The total center distance h of the stacking of the ten frames is therefore 108 mm. If we consider the elongation applied to the warp yarn 20 ₁₀ by the tenth frame C ₁₀ (and no longer the elongation applied to the warp yarn 20 ₁ by the first frame C ₁ , as so far), we see that for a same angle 2a of opening of the crowd, the rate of elongation is more important, since the distance a '= 150 mm has become a "= a' + h = 258 mm, because of the thickness of the harness .

There is shown schematically in Figure 9, on the same scale as Figure 8, a loom according to the invention with 10 frames also, whose reduced crowd has measured for example 65 mm.

The amplitude of movement of the frames and the height of the frames being reduced on a loom in accordance with the invention, the thickness of the frames can be reduced without inconvenience. According to a characteristic of the invention, the frames have a thickness e which does not exceed 7 mm.

In the case of FIG. 9, the total center distance h of the stacking of the ten frames is only 63 mm, so that the distance between the front line 14 and the tenth frame C ₁₀ is only: a "= a + h = 65 = 63 = 128 mm, instead of 258 mm for the classic loom shown in Figure 8.

Referring to the curves in FIG. 5, for the same loom depth (a + b), and for the same angle 2a, the rate of elongation of the warp thread in the tenth frame is reduced by approximately 40% compared to to a classic trade.

Another cause of fatigue and breakage of the warp threads is the number of alternating cycles of elongation that each point of the thread undergoes, from the moment it leaves the beam to the moment it reaches the front line. To reduce this fatigue, it is therefore desirable to reduce this number of cycles.

In the foregoing, to simplify the comparisons between a conventional trade and a reduced crowd trade according to the invention, it has always been assumed that the depth (a + b) of the trade was the same (see Figures 2 and 3). If we take as an example a conventional loom, illustrated by Figures 3 and 8, in which a = 150 mm and - = 9, the depth a a + b of the loom is 1500 mm.

In a loom according to the invention, it has been seen that the distance a is less than 75 mm (an advantageous dimension being 70 mm) and that the ratio - is advantageously 15. a

In this case the depth a + b of the loom in accordance with the invention would be 1120 mm, a reduction of 25.3%. As a result, the number of alternating cycles of elongation undergone by one point of the thread before being woven is reduced in the case indicated above. also 25.3% compared to what happens on a traditional job, which further distances the thread from its critical rate of fatigue and reduces the number of breaks. Here again there is an accumulation of advantageous results and, preferably, the depth is chosen between 900 and 1200 mm, so as to obtain the best compromise between the advantages obtained.

You could say that, on a traditional trade, it would be enough to reduce the depth to obtain the same result. But this is not the case because, in this case, the rate of elongation undergone by the warp threads would be increased and the phenomenon of Y formation would not be reduced in any way. The advantageous results obtained by the 'invention.

In a loom according to the invention, the opposite reciprocating movement of the two weft-passing needles can be produced by any known mechanism, for example by a conventional mechanism called "diamond", but according to a preferred embodiment, which will be described in About FIG. 11, a so-called "balanced Cardan circle" mechanism is used, such as that described in French patent No. 2,477,586.

The large width machine (for example equal to or greater than 1 meter 40) shown diagrammatically in FIG. 10 comprises a frame 31 which supports a beam 4 from which the warp threads 2 unfold in any known manner. The beam is shown in the upper part of the machine, but it can occupy any other position well known to those skilled in the art.

The weft threads 12 are unwound from one or more reels such as 32 placed outside the machine. The weft threads are inserted, in a known manner, using two needles 13-13 'each performing an alternating movement, the elongated maximum tion leads the pliers 33-33 'substantially in the middle of the width. The weft thread brought by the needle 13 is then taken by the needle 13 'which makes it travel the second half of the crowd. When the two needles 13 and 13 ′ have emerged outside the crowd, the comb 10 driven by the leaf 34 cups the newly inserted pick against the front line of the fabric 16 which is wound on the roller 18.

The movement of each of the needles 13-13 'is controlled by a mechanism 35-35' describing a Cardan circle and communicating to the corresponding needle a sinusoidal movement.

Such a mechanism, when produced according to the aforementioned patent makes it possible to actuate the needles, with safe exchange of the weft thread, at a rate of approximately 450 to 600 strokes / minute. However, in conventional trades, the mass and the amplitude of movement of the parts in reciprocating motion (in particular the comb, the leaf and the frames) prevent correct operation at such rates.

On the contrary, in a weaving loom according to the invention, as seen above, the frames have a stroke reduced by about half (see Figures 8 and 9) and their weight is much lower, since their thickness does not exceed 7 mm instead of 12 mm on average on a conventional loom. In addition, it is possible to use shorter beams, therefore less heavy.

The height of the comb, therefore its weight, is also reduced by about half and its stroke, at the level of the bisector of the crowd, does not exceed approximately 50 mm (44 mm for a distance a of 65 mm) instead of 100 mm approximately on a conventional loom.

It is therefore clear that all of the pieces in reciprocating motion the machine can operate at a much higher rate than conventional machines.

FIG. 11 shows the different phases of a weaving cycle during which the mechanism 35-35 ′ for actuating the needles describes the circumference y.

As is known in E, the pliers 33-33 'of the needles 13-13' exchange the weft in the middle of the width. Between E and F, the needles 13-13 'stand out in such a way that at F the pliers 33-33' have reached the edges of the width, then continue to move back to G. Then they start in the opposite direction and the needle 13 grasps the thread 12 around H, just before entering the crowd, and transports it to the middle of the width where the clamp 33 reaches E.

In the FGH sector, the needles are completely pulled out of the crowd and it is during this period that the comb is struck and at least part of the movement of the frames to change the crowd, so that the crowd is completely open when the needles re-enter the crowd (point H).

On conventional needle looms, the FGH arc measures approximately 120 ° (1/3 of the cycle) because the inertia of the entire comb and leaf, as well as that of the frames, prevents the duration of the strike from being reduced . We can therefore devote to the useful stroke of the needles, inside the crowd, only 2/3 of the cycle (240 °).

However, in a trade according to the invention, the inertia of the organs driven by an alternating movement (comb, leaf, frames) is much lower and it is possible to actuate these organs on a much reduced arc of the machine cycle, for example 90 ° or 100 ° only for the movement of the leaf.

This reduction provides many additional advantages to a trade according to the invention. Indeed, if we assume, as shown in Figure 11, that the duration of the strike is reduced to the arc F'GH '(90 ° approximately), the pliers 33-33' can reach the edges of the width in F 'and the retraction of the needles will only continue during the arc F'G. Thus the needles will stop to turn back at a shorter distance from the edge of the width, which will reduce the overall width of the machine (the segment IG is reduced to the G).

In addition, the speed of the clamp 33 animated by a sinusoidal movement is proportional to the sine of the angle. This speed is therefore greater in H than in H '. If the weft thread 12 is gripped by the clamp 33 takes place at H ′, the shock absorbed by the thread 12 will be less, therefore the risk of breakage will be reduced.

Finally, the hands 13-13 'will benefit from an increased cycle time (260 to 270 ° instead of 240 °) for the useful portion of their stroke in the crowd.

Of course, such a modification of the weaving cycle results in a modification of the control of the movements of the leaf. If this command is carried out by cam (and cam follower), as illustrated diagrammatically by FIG. 12, the boss 38 of the cam 40 for controlling the comb 10 must extend over an arc e less than or equal to 100 °, by example 90 °.

Above all, mention has been made of weaving machines in which the weft passing device consists of needles rigid, reciprocating.

But the invention also applies to machines in which the frame is inserted by other types of devices, for example projectile or "inertia".

A part of a loom according to the invention is shown diagrammatically in FIG. 13 in which the weft is inserted by means of a system called "inertia", for example of the kind described in French patent No. 2,477. 587.

It suffices to recall that, in such a system, the pick to be inserted forms a loop of which one strand is held and the other free. The latter is accelerated to a given speed which gives the wire kinetic energy proportional to its mass. This kinetic energy is used to propel the loop through the crowd; the loop moves gradually until the end of the free strand has reached the edge opposite the side of the launch.

In FIG. 13, only the two layers of warp threads 20-20 ′ have been shown, the shed F, the front line 14 and the fabric produced 16. The launching system with inertia can essentially comprise: a deliverer 41 delivering the pick 12 into an accumulation member 42; insertion rollers 43; a turntable 44 provided with clamps 45-46; and a knife 47.

The pick is launched, in a loop, in crowd F, by the launching rollers 43.

Claims (6)

1. Non-shuttle weaving machine, with weft pass device, in which the warp threads (2) unwinding from the beam (4) pass over a rear thread holder (6), then through the eyelets (8 , 8 ') of the beams carried by several frames C ₁ , C ₂ ... then through the teeth of the comb (10) to finally reach the line of facade (14) where the fabric (16) is formed, said machine being characterized: in that the first frame C ₁ is arranged at a distance a from the front line (14) and at a distance b from the rear wire holder (6) such that the distance a is equal to or less than 75 mm , and the ratio b / a is between 12 and 15; and in that the thickness of the frames C ₁ , C ₂ ... is equal to or less than 7 mm. 2. Machine according to claim 1, characterized in that the width of the width is at least 140 cm. 3. Machine according to one of claims 1 or 2, characterized in that the weft passing device comprises two needles (13-13 ') each of which is actuated, according to a sinusoidal reciprocating movement, by a mechanism (35-35' ) with a balanced Cardan circle. 4. Machine according to one of claims 1 to 3, characterized in that the depth a + b of the machine is between 900 and 1200 mm. 5. Machine according to one of claims 1 to 4, characterized in that the cams (40) which control the movements of the leaf of the comb (10) have a profile such that their boss (38) extends over a lower angle or equal to 100 °. 6. Machine according to one of claims 1 or 2, characterized in that the weft pass device is a system called "inertia" (41-42-43-44-45-46).

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