EP0385893A1 - Device for selectively maintaining the tension of weft threads in weaving machines - Google Patents

Abstract

The invention provides for arranging on each of the sides of the weaving machines, between the selvedge of the fabric (6) being produced and the corresponding shuttle box (1), a device (8) equipped with a number of movable grippers (24) equal to that of the shuttles, these grippers offset in a vertical plane being controlled in such a way that the thread of each shuttle (9) is grasped at its exit from the weft threads (4) in order to be maintained under tension, thus preventing any risk of entanglement. …<IMAGE>…

Description

The present invention relates to weaving looms with one or more shuttles and it relates more particularly to large width machines of the kind used for the production of tubular fabrics intended for the paper industry.

We know that in weaving machines of this kind, the use of traditional shuttles equipped with bobbins harms the regularity of the tension of picks. In addition, as most often the width of the fabric to be produced is significantly less than the width of the loom, the lengths of the weft threads which extend laterally between each edge of the fabric in progress and the corresponding shuttle box tend to become tangled, causing serious weaving defects or untimely machine stops.

It is to these drawbacks that the present invention mainly intends to remedy, and this by means of two selector devices arranged on the loom in front of the leaf and suitable for ensuring the gripping and keeping under tension of each of the weft threads. at the exit of the crowd, before tightening each pick.

The object of the invention is defined in claim 1. In fact each of the two devices concerned comprises a number of clamps equal to that of the shuttles of the trade, each of said clamps being carried by a movable member which is controlled so as to affect either an extension position for which said clamp, bearing against a bearing provided on the leaf, is capable of gripping the weft thread under tension, or a retracted position for which this clamp is on standby outside the movement of va -and coming from the wing, that is to say still a medium position for which the clamp is located a short distance from the abovementioned stop to allow the release of the weft thread when the shuttle enters the crowd again, the movable members holding the clamp being arranged at different levels corresponding to those of each shuttle box and being controlled in height so that the clamp of one comes to cooperate at the time appropriate with the aforementioned scope of the leaf.

It is understood that keeping the weft threads under tension as they exit the crowd, joined to the difference in inclination of the clamps in the vertical direction, radically oppose any risk of tangling of the threads. frame.

• Fig. 1 est une vue en plan montrant très schématiquement le montage des deux dispositifs sélecteurs suivant l'invention sur la partie avant d'un métier à tisser.
• Fig. 2 est une vue en plan à plus grande échelle illustrant l'agen­cement de l'un des deux dispositifs (celui de gauche sur la fig. 1).
• Fig. 3 est une coupe transversale du métier, représentant le dis­positif sélecteur de fig. 2 en coupe longitudinale.
• Fig. 4 montre en plan à plus grande échelle l'une des trois pinces de ce dispositif.
• Fig. 5 est une vue de côté de la pince suivant fig. 4.
• Fig. 6 est une coupe de détail de l'extrémité de la pince suivant le plan de coupe indiqué en VI-VI (fig. 4).
• Fig. 7 est une vue en plan partielle montrant l'agencement du méca­nisme pour la commande de l'un des organes porte-pince.
• Fig. 8 et 9 sont des vues de côté illustrant le fonctionnement du mécanisme de fig. 7.

The appended drawing, given by way of example, will allow a better understanding of the invention and the advantages which it is likely to provide:

• Fig. 1 is a plan view very schematically showing the mounting of the two selector devices according to the invention on the front part of a loom.
• Fig. 2 is a plan view on a larger scale illustrating the arrangement of one of the two devices (the one on the left in FIG. 1).
• Fig. 3 is a cross section of the loom, representing the selector device of FIG. 2 in longitudinal section.
• Fig. 4 shows in plan on a larger scale one of the three clamps of this device.
• Fig. 5 is a side view of the clamp according to FIG. 4.
• Fig. 6 is a detail section of the end of the pliers along the cutting plane indicated in VI-VI (fig. 4).
• Fig. 7 is a partial plan view showing the arrangement of the mechanism for controlling one of the clamp holder members.
• Fig. 8 and 9 are side views illustrating the operation of the mechanism of FIG. 7.

In the description which follows, it has been assumed that the invention was implemented in the case of a weaving loom equipped with two shuttle boxes 1 provided on either side of the usual leaf 2 which is allocated a movement transverse alternative after the placement of each pick. Each shuttle box 1 has three superimposed stages to receive three shuttles and is moved vertically so that each stage is likely to come at the appropriate time to be placed at the corresponding end of the leaf 2, which carries comb 3. Reference 4 designates all of the warp threads prior to the laying of the weft threads 5, the fabric obtained 6 is wound on a conventional beam placed below the slides 7 forming supports for the templets (not shown) which keep the said fabric 6 wide.

According to the invention, two devices 8 have been fixed on the runners 7 intended to keep the weft threads 5 under tension immediately after their installation by one of the three shuttles 9 in the trade. Each device 8 is located substantially midway between the edge of the fabric 6 and the corresponding shuttle box 1. These two devices 8 are symmetrically identical to each other, so that the explanations given for one of them (the one on the left in this case), will be valid, mutatis mutandis, for the other .

As shown in fig. 2, each device 8 comprises a housing 10 with a rectangular profile. In the vicinity of the wall of this housing 10 which is oriented parallel to the leaf 2 and opposite to it, there is provided an axis 11 on which the movable rod 12 of a pneumatic cylinder is articulated, the cylinder 13 of which is secured to the cylinder 14 of a second pneumatic cylinder. The movable rod 15 of the latter carries at the end a transverse axis 16 on the ends of which are articulated two bent levers 17. As shown in fig. 3, each angle lever 17 pivots freely 17a on the corresponding wall of the housing 10, while its free end is profiled in the manner of a fork embracing a roller 18. the axis which supports each roller 18 is fixed laterally against a cross member 19 which is free to move vertically in the part of the housing 10 which opens in the direction of the leaf 2.

It is understood that the two pneumatic cylinders 12-13 and 14-15 are capable of being controlled in succession to vertically move the crosspiece 19 and give it either a high position for which it comes to bear against an upper stop 20 fixed against the housing 10 , either a low position for which it bears against a lower stop 21 of said housing, or even an average position provided midway between the two extreme positions indicated above.

The cross member 19 forms a common support for the end of the cylinder 22 of three pneumatic cylinders oriented parallel to each other, but arranged on said cross member 19 at three different heights, of so as to form a sort of fan in a vertical plane. the opposite end of each cylinder 22 articulates freely on the axis 11 carried by the housing 10, while the movable member or rod 23 of each cylinder extends in the direction of the leaf 2 to form a support for a clamp 24 .

The arrangement of each of the three clamps 24 of each device 8 appears clearly in FIG. 4, 5 and 6.

Each clamp comprises a main body 25 provided with a split flange 25 a which ensures its fixing at the end of the movable member 23. This body 25 is integral with a lateral crosspiece 25 b on which two double links 26 are freely articulated , the free ends of these enclosing two supports 27. As more particularly shown in FIG. 6, these two supports 27 hold between them a blade 28 against which two jaws 29 are resiliently applied under the effect of return systems, three in number in the example considered. Each system comprises two opposite springs 30 compressed between one of the jaws 29 and a stop 31; the two stops 31 are screwed onto the threaded ends of the same stud 32 which crosses the jaws 29 with play and the guidance of which is ensured by said stops 31, engaged practically without play in openings made in the supports 27.

As shown in fig. 4, one of the double links 26 is provided with an actuating stub 26 a and it is understood that if one exerts a pressure on said heel directed towards the inside of the clamp, the two links 26 rock around their pivots 33, which has the effect of moving laterally the assembly formed by the supports 27, the blade 28 and the jaws 29, as illustrated in broken lines. This lateral movement takes place against elastic return means constituted by a spring 34 housed in a cavity of the main body 25 and held between the annular bottom of said cavity and the head of a screw 35 which is screwed in a cylindrical die 36, which is retained in holes made in one and the other jaws 29.

It should be observed that the free end of each jaw 29 is shaped so as to constitute a jaw 29 a whose profile emerges well from the examination of FIG. 4 and 6. It is intended that these jaws 29 a , normally maintained applied one against the other by the springs 30, must open automatically when the assembly formed by the supports 27, the central blade 28 and the jaws 29 moves laterally under the effect of a pressure exerted on the heel 26 a ; for this purpose, the body 25 is integral with a rod 37 which is oriented parallel to the screw 35 to engage between the jaws 29 and which carries at the end a stop 38, profiled to cooperate with bearings 29 b provided on said said jaws.

It will be understood that at the end of the abovementioned lateral movement, the bearing surfaces 29 b come to bear against the stop 38 which operates their separation against the springs 30, causing the jaws 29 a to open .

The movable member 23 of each clamp holder cylinder 22-23 is assembled by a transverse flange 39 (FIG. 4) to a tubular rod 40 oriented parallel to said member. Inside of the rod 40 axially slides a plunger 41 associated with a return spring 42 and for the actuation of the bead 26 has the above-mentioned.

As illustrated in fig. 2, the rod 40 associated with each cylinder 22-23 freely crosses the crosspiece 19 to come to cooperate with a stroke limitation mechanism. This mechanism comprises a small plate 43 (FIGS. 7 to 9) which flanges 44 make integral with the cylinder 22 of the envisaged jack and which is equipped with a tilting pallet 45 oriented parallel to the axis of said jack. The end of this pallet 45 which is turned in the direction of the axis 11 is subjected to the action of an electromagnetic jack 46 which, when excited, causes said end to tilt downwards against elastic return means 47 associated with the opposite end of the pallet and housed inside a small cover 48 secured to the plate 43.

The tipping platform 45 is intended to cooperate with a dog 49 hinged 49 has a vertical leg 50 which is fixed at the end of the free end of the tubular shaft 40 and which freely slides along a guide bar 51 disposed au below said rod, as illustrated in fig. 8 and 9. Things are arranged so that when the pallet 45 is not actuated by the jack 46, the upper end of the dog 49 has the very slight clearance indicated in J in fig. 8 to pass freely below the plate 43. On the other hand, when this pallet 45 is lowered by the aforementioned jack, the dog 49 comes into contact with the end of said pallet (see fig. 9) and therefore rocks around its pivot 49 a , then actuate the pusher 41, the end of which protrudes beyond the end of the tubular rod 40.

• 1 - une position d'extension maximale pour laquelle la pince 24 (cas de celle la plus à gauche en fig. 2 et la plus basse en fig. 3) vient se présenter au niveau du battant 2 supposé en posi­tion arrière ;
• 2 - une position de rétraction maximale (cas des deux autres pinces de fig. 2 et 3) pour laquelle chaque pince 24 se trouve disposée contre la traverse 19 du boîtier 10 ;
• 3 - et une position moyenne (cas représenté en tracé interrompu pour la pince centrale) pour laquelle chaque pince 24 se trouve située à mi-distance entre les deux positions extrêmes.

This pusher 41 is thus moved axially against its return spring 42, which has the effect of actuating the clamp 24. It should be observed that the tilting of the dog 49 is limited by bearing against a stop 50 a of the lug 50, so that the longitudinal displacement of the movable member 23 of the jack 22-23 considered cannot continue. It is understood that this stroke limitation system is suitable for making it possible to give each mobile member 23 and the corresponding clamp 24 three different axial positions, namely:

• 1 - a position of maximum extension for which the clamp 24 (case of the leftmost in fig. 2 and the lowest in fig. 3) comes to be at the leaf 2 assumed in the rear position;
• 2 - a position of maximum retraction (case of the other two clamps of FIGS. 2 and 3) for which each clamp 24 is placed against the crosspiece 19 of the housing 10;
• 3 - and a middle position (case shown in broken line for the central clamp) for which each clamp 24 is located midway between the two extreme positions.

It should be noted here that the main body 25 of each clamp 24 is provided with a projection or stop 25 c (see fig. 3, 5 and 6) provided on the underside of said body in order to cooperate with a corresponding bearing 52 fixed laterally against the anterior face of the leaf 2, at each device 8 according to the invention. The cooperation of this projection or stop 25 c and one or other of the spans 52 of the leaf 2 ensures the perfectly precise positioning of each of the clamps 24 relative to the shuttles 9 when these clamps are in the extended position maximum.

Before explaining the operation of each of the two devices 8, it will be observed that the valves which supply the various pneumatic cylinders 12-13, 14-15 and 22-23 of each of them, as well as the contactors which control the electromagnetic cylinders 46, are placed under the dependence of an automaton 53 which operates the management of the various movements of the assembly formed by the two devices 8 and the loom.

This being said, it is understood that this automaton 53 is capable of being programmed so that when the shuttle 9 which has just passed through the crowd by depositing a pick between the warp threads 4 comes out of these, one of the pneumatic cylinders 22-23 is actuated to bring its clamp 24 to the maximum extension position, at the same time as the cylinders 12-13 and 14-15 are themselves powered to vertically move the cross member 19 and ensure that the stop 25 c of the clamp 24 considered comes, at the end of travel of the corresponding movable member 23, to be positioned properly against the bearing 52 of the leaf 2, then in the retracted position.

At this time, the jaws 29 has jaws 29 of this clamp 24 are applied one against the other. Each shuttle 9 of the loom being provided with a lateral lug 9 a (fig. 2 and 4) pierced with an opening traversed by the corresponding warp thread 5, it is understood that said lug 9 a will penetrate between the jaws 29 a qu 'it opens by force against the springs 30; as the latter return the jaws 29 to the closed position as soon as the ear 9 a has come out of the clamp 24, these jaws 29 a close on the wire 5 which is clamped firmly. The pick which has just been deposited is thus kept under tension.

While the shuttle in question finishes its race as far as the interior of the box 1, the machine 53 returns the clamp 24 to the maximum retraction position, so that the leaf 2 can carry out its usual tightening movement without being hampered by said clamp 24. When this same shuttle 9 will be projected out of the box 1 to deposit a new pick, the machine 53 actuates the jack 22-23 and the corresponding jack 46 so that the clamp 24 envisaged comes affect the middle position. When the pusher 41 is moved axially by the dog 49, the jaws 29 open and the jaws 29 a release the weft thread 5 which has been previously relaxed as a result of the lateral movement of the aforementioned jaws. The shuttle 9 is thus capable of depositing the pick in the crowd, without any risk of default.

As soon as the wire 5 has thus been released, the automatic device 53 brings the clamp 24 against the cross-member 19 and the device 8 is then ready for a new operation. It is the opposite device 8 which will take hold of the weft thread 5 for keeping it under tension.

It is finally understood that if care is taken to provide the devices 8 with a number of clamps 24 and clamp holder 22-23 equal to that of the shuttles 9 in the trade, the tension is maintained on all the wires of frame 5. Since the clamps 24 of the same device 8 are located at different heights, we systematically avoid any risk of tangling and defect, regardless of the rebounds of the shuttles when they arrive at the end of stroke in boxes 1 and whatever the distance separating the selvedges of the fabric being produced and said boxes 1.

It is understood that it may be advantageous to implement the invention even when the profession comprises only one shuttle.

Claims (10)

1. Device intended to be mounted on either side of a weaving loom with one or more shuttles, between the edge of the fabric being formed and the corresponding shuttle box, in order to ensure the keeping each of the weft threads under tension as it leaves the crowd, characterized in that it comprises in combination:
- A series of movable members (23) equal in number to that of the shuttles (9) of the trade, which movable members extend parallel to the warp son (4) being offset relative to each other in the vertical direction ;
- a clamp (24) provided at the end of each of the movable members (23) and arranged so as to grip the weft thread (5) which has just been deposited by the shuttle (9) and to release it when the same shuttle leaves the corresponding box (1);
- Means (12-13-14-15) for controlling all the movable members (23) in a vertical plane in order to selectively bring one of the clamps (24) to the leaf (2 ) of career ;
- Means (22) associated with the movable members (23) in order to selectively give each of the clamps (24) either an extension position for which the clamp concerned is arranged at the leaf (2) to be able to grasp the weft thread (5) which has just been deposited, either a retracted position for which this clamp is on standby apart from the reciprocating movement of the leaf, or again a medium position for which the clamp is located at a short distance from this leaf to allow the weft thread (5) to be released when the shuttle enters the crowd again;
- And an automaton (53) arranged so as to actuate the aforementioned means in synchronism with the control of the wing (2) and the shuttle boxes (1). 2. Device according to claim 1, characterized in that each movable clamp-holder member is constituted by the rod of a pneumatic cylinder (22-23) whose cylinder (22) is articulated on a fixed housing (10) and is supported, at different heights according to the different cylinders, by a cross member (19) subjected to the means (12-13-14-15) ensuring the vertical control of said cylinders. 3. Device according to claim 2, characterized in that the crosspiece (19) is coupled to the movable rod (15) of a pneumatic cylinder (12-13-14-15). 4. Device according to any one of claims 1 to 3, characterized in that each clamp (24) has a stop (25 c ) which is adapted, in the extended position, to come to bear against a bearing (52 ) provided in correspondence on the leaf (2). 5. Device according to any one of claims 1 to 4, characterized in that each clamp (24) comprises two jaws (29) which are resiliently applied one against the other and which carry jaws (29 a ) for pinching the weft thread (5), which jaws are capable of being separated from each other by an ear (9 a ) provided laterally on each shuttle (9) and perforated to be crossed by said thread (5 ). 6. Device according to any one of claims 1 to 5, characterized in that each clamp (24) is actuated so as to move transversely to the warp threads (5) and thus to relax the weft thread (5) when the movable member (23) which carries it arrives at the middle position, and this prior to the opening of said clamp. 7. Device according to claims 5 and 6 envisaged in combination, characterized in that the two jaws (29) of each clamp (24) are coupled to the main body (25) thereof by rods (26) including at least one comprises an actuation heel (26 a) capable, under the effect of the opening means (41-46) to provide the transverse movement of the jaws against elastic return means (34). 8. Device according to claim 7, characterized in that the main body (25) of each clamp (24) has a fixed stop (38) arranged to cooperate with bearing surfaces (29 b ) provided on the jaws (29) in view to remove them and open their jaws (29 a ) when these chews res complete their transverse movement. 9. Device according to any one of claims 6 to 8, characterized in that each pneumatic cylinder (22-23) is associated with a tilting pallet (45) subjected to the action of a cylinder (46) and clean to come to dispose on the path of a lug (50) which moves at the same time as the corresponding movable member (23), in order to limit the displacement of the latter and thus to give it the average position by simultaneously causing the transverse movement of the corresponding clamp (24) and the opening thereof. 10. Device according to claim 9, characterized in that between the tilting pallet (45) and the tab (50) is interposed a dog (49) whose tilting actuates a pusher (41) with elastic return, suitable for controlling the actuation heel (26 a) of the clip (24) correspondingly.

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