EP1413657B1 - Shedding mechanism and loom with such a mechanism - Google Patents

Abstract

The shed-forming mechanism for a Jacquard loom consists of a series of hooks (13) moved by a blade between a top position in which it can be stopped by a selector and a bottom position. Each hook comprises a body (20) and a projecting tip (202) that interacts with the blade, and is additionally equipped with a metal strip (21) that interacts with the selector (16). The strip is attached to the body of the hook and capable of a relative displacement (F3) in the selector zone, the body being made from a synthetic material that is overmoulded onto part (211) of the strip and is supple enough to adapt to faults in the trajectories of the body and blade. The strip is able to slide in a housing and has an aperture that engages with a projection on the selector.

Description

The invention relates to a shedding mechanism and to a loom equipped with such a mechanism.

In a Jacquard loom, a shedding mechanism selectively raises heddles, each comprising an eyelet through which a warp thread passes, which yarn is located, depending on the position of a hook to which the yarn is attached. upper end of the bar, above or below a weft yarn moved by the loom. Such a known mechanism, for example of EP-A-0 219 437 comprises, in addition, movable hooks each provided with a lateral nose capable of cooperating with knives animated vertical reciprocating movements in opposition of phase. Each movable hook is provided with a curved end to allow its immobilization by cooperation of forms with a retaining lever.

Each movable hook is also provided with a one-piece elastic tongue with the hook and intended to control the movement of the retaining lever. Such a tongue is subjected to relatively intense repeated forces, likely to induce its permanent deformation by creep, or even rupture. In this case, the crowd obtained has "faults".

It is these drawbacks that the invention intends to remedy more particularly by proposing a shedding mechanism whose mobile hooks are robust and dimensioned in a precise manner, which ensures reliable operation of the loom, while they are compact in height, that is to say parallel to their direction of travel. This creates a compact mechanism, resulting in space saving and better economic performance.

In this spirit, the invention relates to a shedding mechanism on a loom Jacquard type, this mechanism comprising movable hooks each displaced by a knife, between a top dead center position, in or near which each hook can be immobilized by a selection device, and a bottom dead center position, each movable hook comprising a body provided with a spout , intended to bear on the aforementioned knife. This mechanism is characterized in that each hook comprises, in addition, a metal blade intended to interact with the selection device and fixed on the aforementioned body, with possibility of relative movement relative to the body, in an area of this body opposite to the selection device with respect to the area of the body from which the spout extends.

Thanks to the invention, the bipartite nature of the mobile hooks, whose body is advantageously made of synthetic material, makes it possible to benefit from the robustness of the body for the mechanical connection between the hook and the knife, while the geometry of the metal blade is defined with great precision, which induces a great reliability of the interactions between the mobile hook and the selection device. As the metal blade is fixed on the body at the bottom when the hook is in the operating configuration of the mechanism, the flexibility of the blade, over substantially its entire height, can be used for the transverse displacement of its part more particularly intended to come in engagement with a corresponding part of the selection device. The fact that a relative movement is possible between the blade and the body of the hook can come from the flexibility of the blade and / or that of the body.

According to advantageous but not obligatory aspects of the invention, this mechanism incorporates one or more of the features of the dependent claims.

In particular, the electromagnet of the selection device may be overmoulded in one of the sides of a housing for receiving and guiding the mobile hook in translation. This overmolding induces a precise positioning of the electromagnet relative to the other functional parts of the device, such as the axes of the retaining levers, the stops and the supports of these levers as well as the guide grooves of the movable hooks. Because of this high accuracy, the amplitudes of the movements of the moving parts can be reduced, in particular as regards the oscillation of the retaining levers and the bending of the blade of the movable hooks. This also contributes to the compactness of the mechanism.

The invention also relates to a loom equipped with a mechanism for forming the crowd as previously described.

• la figure 1 est une représentation schématique de principe illustrant un métier à tisser de type Jacquard incorporant l'invention ;
• la figure 2 est une coupe longitudinale à plus grande échelle du mécanisme de formation de la foule du métier de la figure 1 ;
• les figures 2A et 2B sont des sections partielles respectivement selon les lignes A-A et B-B à la figure 2 ;
• la figure 3 est une vue à plus grande échelle d'un crochet mobile et d'une partie d'un levier de retenue du mécanisme de la figure 2 ;
• la figure 4 est une vue dans le sens de la flèche IV à la figure 3 ;
• la figure 5 est une vue analogue à la figure 2 pour un mécanisme conforme à un second mode de réalisation de l'invention ;
• la figure 6 est une coupe longitudinale partielle de principe d'un mécanisme conforme à un troisième mode de réalisation et
• la figure 6A est une section partielle selon la ligne A-A à la figure 6.

The invention will be better understood and other advantages thereof will appear more clearly in the light of the following description of three embodiments of a crowd-forming mechanism according to its principle, given solely for example and with reference to the accompanying drawings, in which:

• the figure 1 is a schematic representation of principle illustrating a loom Jacquard type incorporating the invention;
• the figure 2 is a longitudinal section on a larger scale of the crowd forming mechanism of the craft of the figure 1 ;
• the Figures 2A and 2B are partial sections respectively along the lines AA and BB at the figure 2 ;
• the figure 3 is a view on a larger scale of a movable hook and a part of a lever of the mechanism of the figure 2 ;
• the figure 4 is a view in the direction of arrow IV to the figure 3 ;
• the figure 5 is a view similar to the figure 2 for a mechanism according to a second embodiment of the invention;
• the figure 6 is a partial longitudinal sectional view of a mechanism according to a third embodiment and
• the Figure 6A is a partial section along line AA at the figure 6 .

In the loom M represented at figure 1 a warp of warp threads 1 comes from a warp beam 2. Each warp thread 1 passes into eyelet 3 a of a rail 3 intended to open the step to allow the passage of a pick to constitute the fabric that wraps on a spool 4. Only two smooth 3 and 3 'are shown at figure 1 , the arm 3 being in the high position, while the arm 3 'is in the low position. The lower end of each rail is connected to the frame of the loom by a tension spring 5, while its upper end is secured to an arch 6.

A shedding mechanism 7 associated with an electronic control unit 8 makes it possible to lift the arches 6 more or less against a return force exerted by the springs 5. As shown only for the arcade associated with the rail 3, each arch has one end 6a fixed to a housing 10 of the mechanism 7, the arcade passing inside an 11-suspended muffle a cord 12 whose both ends are respectively integral with two movable hooks 13 to be selectively raised by knives 14 animated by a movement of vertical oscillations in opposition of phase, as represented by the arrows F ₂ .

Only a part of the constituent elements of the crowd-forming mechanism is represented in the figure 1 for the clarity of the drawing.

As is clear from the Figures 2 to 4 Each hook 13 is formed of a plastic body 20 in the lower end 201 which is molded an end 12 a of the cord 12.

The body 20 forms a single spout 202 that extends laterally with respect to a main longitudinal axis XX 'of the body 20. This nozzle 202 is intended to bear against the upper surface 14 has a knife 14. The hook 13 can be regularly raised by a single knife 14.

Given its constituent material, the body 20 has a flexibility to adapt to a possible defect position or parallelism of the respective paths of the body and the associated knife 14. This possibility of elastic deformation of the body 20 is represented by the double arrow F ₂₀ at the figure 2 . In practice, the flexibility of the body 20 makes it possible to obtain self-positioning of the spout 202 on the knife 14.

The hook 13 also comprises a metal blade 21 partially overmolded in the body 20. In practice, the blade 21 comprises a portion 211 overmolded in a zone 203 of the body 20, located near its lower end 201, that is to say say below the portion 204 of the body 20 from which extends laterally the spout 202.

Part 211 is downwardly open, which allows the passage of the end 12 a of the cord 12 which may be molded into the body 20 over a length L ₁₂ relatively large.

The blade 21 extends over a length L ₂₁ above its portion 211, this length being relatively large compared to the total length L _'21 of the blade 21

The blade 21 comprises two lateral uprights 212 and 212 'defining between them a window 213 in which is housed most of the body 20.

The posts 212 and 212 'extend beyond the window 213 to a bent end 214. The posts 212 and 212' are connected by a cross member 215 which separates the window 213 from an opening 216 formed between the parts 212, 212 ', 214 and 215 of the blade 21.

Given their respective fastening mode, the elements 20 and 21 are integral at the bottom of the hook 13, while the portion of the blade 21 which extends along the length L ₂₁ above the zone 203 of the body 20 , is capable of lateral deflections, as represented by the double arrow F ₃ at the figure 3 . These lateral deflections F ₃ correspond, in fact, to a relative movement of the blade 21 relative to the body 20.

The mechanism 7 also comprises an electromagnet 15 overmolded in a portion of the housing 10. This overmolding ensures precise positioning of the electromagnet 15 relative to the housing 10 and to the elements that it supports or guides.

The housing 10 comprises two fixed axes 10a on which are pivotally mounted two retaining levers 16 designed to cooperate respectively with the two movable hooks 13 connected to both ends of the same cord 12.

Each lever 16 comprises a metal frame 30 provided with a cylindrical bore 301 of circular cross section adapted to the outer diameter of a shaft 10a, so that the armature 30 may be mounted about an axis 10 with a possibility of pivoting, as represented by the duplicates arrows F ₄ at the figure 2 . The bore 301 of each armature 30 is formed in an end 302 of this armature.

At its opposite end 303, the armature 30 is overmolded in a body 31 made of a non-magnetic material, such as a synthetic material and, more specifically, a plastic material. The body 31 forms a spout 311 for retaining a movable hook 13 close to its top dead center position. The body 31 is also provided with a heel 312 of centering with respect to a spring 32 exerting on the body 31 a force F ₅ tending to pivot the lever 16 towards the outside of the housing 6. This effort tends to penetrate the beak 311 in the opening 216 of the blade 21 of a neighboring mobile hook, which allows to retain such a movable hook in the upper position.

The metal armature 30 of a lever 16 makes it possible to control its pivoting thanks to the electromagnet 15, a lever 16 that can be displaced by the curved end 214 of a blade 21, and, optionally, held in position at against the force F ₅ , when the electromagnet 15 is excited.

The body 31 allows effective interaction without metal / metal contact of a retaining lever 16 with a movable hook 13.

The levers 16 are each provided with a deflector 161 projecting with respect to their main part 16a in direction of the central axis X ₁₀ -X _'10 of the housing 10 between its pivot axis 10 and has a zone Z ₁ in which the armature 30 can bear against the electromagnet 15. A second deflector 162 is provided between the zone Z ₁ and the hook 13 adjacent. The deflectors 161 and 162 are movable with the lever 16, inside grooves 101 and 102 formed in the body 10, which allows them to isolate the zone Z ₁ which thus forms a protected closed chamber against pollution, in particular fluff likely to be carried by a hook 13.

Given the positioning of the pins 10 has on the housing 10 and the geometry of the levers 16, said levers only extend downwardly from the fixed axes, which gives the mechanism 7 improved compactness relative to the mechanisms which the lever extends on either side of its hinge axis, as described for example in EP-A-0 219 437 .

Furthermore, the amounts 212 and 212 'of the blade 21 of a hook 13 slide in grooves 10 b arranged on the height of the housing 10, as shown in FIG. figure 2 where the cords 12 have been partially shown so that the grooves 10b are visible. Thus, the guide of a lever 13 relative to the housing 10 is performed accurately and with minimal wear. As is apparent from Figures 2A and 2B , each groove 10b of the housing 10 is delimited by two ribs 10f and 10f 'between which it extends, which allows effective guidance of the amount 212 or 212' it receives. Each rib has this shape from the bottom of the housing 10 to approximately the location of the upper curved portion of the nozzle 202 on the right of the figure 2 where the rib 10 f 'is removed, while the rib 10 f extends upwards. The removal of the outer edge 10 f 'of the groove, that is to say the fact that it is open towards the outside of the housing near the retaining lever 16, allows the outward movement of the blade 21, in the direction of arrow F ₇ to Figure 2B when the blade 21 bears against the lever 16 next to it, as shown on the left of the figure 2 to exert a leveling effort F ₆ .

In practice, most of the bending of the blade 21 takes place at the part of the housing 10 where the groove 10b is devoid of an external edge, this part extending over a height H, between the position of the top of the spout 202 on the right of the figure 2 and the zone of interaction between the blade 21 and the lever 16 during leveling.

According to a variant not shown of the invention, the rib 10 f 'which forms the outer edge of the groove 10b may not be removed on the height H but deviate from the rib 10 f to leave the blade 21 a sufficient clearance space.

In the embodiment shown and in the variant mentioned above, the widening or the opening of the groove 10b towards the outside near the elements 15 and 16 is intended to allow the bending of the blade 21 in this zone .

In accordance with the technical teaching of FR-A-2,752,246 , a stop 40 loaded elastically by a spring 41 is mounted between the sliding paths of two movable hooks 13, bearing on tabs 10c of the housing 10. This elastic stop 40 is intended to cooperate with a heel 205 formed close of the end 201 of each body 20. Given the respective positioning of the elements 205 and 40, this interaction takes place when each movable hook 13 reaches the vicinity of its top dead center position. This arrangement makes it possible to overcome most of the forces of inertia and friction of the movable hooks, which facilitates the reversal of movement and makes it possible to optimize the dimensioning of the harness and the mechanical drive parts, such as the knives 14. , or elastic return, such as the springs 5.

The bent end 214 of the blade 21 is also dimensioned so that it can come into abutment and exert a force F ₆ against a ramp 313 formed by the body 31 of each lever 16. This momentary support of a hook 13 on a lever 16 makes it possible to proceed to the leveling of the lever 16, that is to say its bearing on the electromagnet 15, with elastic preload due to the bending of the blade 21 which ensures the function of the elastic tongue described in EP-A-0 219 437 . The blade 21 thus provides a leveling function.

In the second embodiment of the invention shown in figure 5 elements similar to those of the first embodiment bear identical references. As before, knives 14 make it possible to move mobile hooks 13 selectively, each comprising a body 20 made of synthetic material and an elastic metal blade 21 which extends, essentially, above the zone where it is fixed at this point. body. Holding levers 16 are associated with an electromagnet 15.

In this embodiment, the levers 16 are pivotally mounted around axes 10a fixed relative to a housing 10. It is here applied to the technical teaching of EP-A-0 577 524 insofar as the housing 10 comprises partitions 10 d for isolating the electromagnet 15 from the ambient atmosphere. Each lever 16 is pivotally mounted on the axle 10 has corresponding, as represented by double-F ₄ and comprises a frame 30 which extends on either side of the axis 10 a on which it is mounted. More specifically, each frame 30 comprises a first branch 304 which extends upwardly from a central portion 305 in which is provided a circular bore 301 for receiving the axle 10 a. The branch 304 is intended to interact with the electromagnet 15 as a function of its activation. The armature 30 also comprises a branch 306 which extends opposite the arm 304 with respect to the portion 305. This arm 306 is overmolded in a plastic body 31 which forms a spout 311 intended for interacting with an opening 216 of the blade 21 of a hook 13. The body 31 also forms a ramp 313 for leveling the position of the lever 16 used during an interaction with the curved upper end 214 of a blade 21. The blade 21 then exerts on the lever 16 a force F ₆ for moving the armature 30 towards the electromagnet 15.

To effectively isolate the electromagnet 15, the walls 10 of the housing 10 are provided with seals 10 e disposed near the cylindrical outer surface with a circular base 305 a of the part 305. Thus, regardless of the orientation of a lever 16 about the axis 10a, satisfactory sealing can be ensured.

Alternatively, the walls 10 d may be provided at reduced play relative to the surface 305 a, the 10th seals may then be removed since the ends of the walls 10 d then constitute dustproof means.

In the third embodiment shown at figure 6 elements similar to those of the first embodiment bear identical references. As before, hooks 13 each comprise a body 20 made of plastic material and a metal blade 21, these elements being overmolded one inside the other in the lower part of the body 20. A relative movement F ₃ is possible between the body 20 and the blade 21 of each hook. The blade 21 of each hook can be retained in position by a nose 311 formed by a body 31 of a locking lever 16 pivotally mounted about an axis 10 formed by a housing 10.

Each lever 16 comprises a metal armature 30 intended to interact with an electromagnet 15 at a zone Z ₁ in which the armature 30 can bear against the electromagnet 15 against an effort elastic spring exerted 32 centered on a heel 312 of the body 31.

As in the first embodiment, a deflector 161 is provided on each lever 16, between the armature 30 and the axis 10a while a second baffle 162 is provided between the armature 30 and the body part 31 for interacting with the blade 21 of a hook 13. The deflector 162 of this second embodiment can move inside a groove 102 formed in the housing 10 between the positions respectively represented on the left and on the right of the figure 6 . This deflector 162 protrudes with respect to the main portion 16a of the lever 16 both in the direction of the center line X ₁₀ - X _'10 of the housing 10 and both opposite thereof, such so that the flow of fluff or dust is prevented both between the lever 16 and the electromagnet 15 and between the lever 16 and the outer web 10 g of the housing 10.

Moreover, and as is clear from the Figure 6A the deflector 162 also protrudes perpendicular to the plane of the figure 6 relative to the main portion 16a of the lever 16, which also avoids the pollution of ascent towards the armature 30.

Whatever the embodiment considered, the elastic blade 21 effectively performs the functions of selection and leveling, while it is not in contact with the knife 14 neighbor, the function of direct interaction with the knife being devolved at the nozzle 202 of the body 20. In the same way, the body 20, through which the tensile force exerted by the knife 14 passes, does not come into direct contact with the selection device which comprises the elements 15 and 16.

The characteristics of the various embodiments described can be combined in the context of the present invention.

The invention relates to two-position shedding mechanisms used for weaving so-called "flat" fabrics, unlike the three-position mechanisms used for carpets and velvets. However, the invention can be used in the context of combining two-position mechanisms making it possible to obtain a three or four-position crowd, as described, for example, in EP-B-0 399 930 or FR-B-2,715,666 .

Claims (16)

1. Shed forming mechanism on a weaving loom of Jacquard type, said mechanism comprising mobile hooks (13), each displaced by a knife (14), between a position of top dead centre, in or near which each hook may be immobilized by a selection device (15, 16), and a position of bottom dead centre, each mobile hook comprising a body (20) provided with a catch (202) intended to come into abutment on said knife, characterized in that each hook (13) further comprises a metal blade (21) intended to interact with said selection device (15, 16) and fixed on said body (20), with the possibility of relative clearance (F₃) with respect to said body, in a zone (203) of said body opposite said selection device with respect to a zone (204) of said body from which said catch (202) extends.
2. Mechanism according to Claim 1, characterized in that said body (20) is made of synthetic material and moulded on a part (211) of said blade.
3. Mechanism according to one of the preceding Claims, characterized in that said body (20) is supple to the point of adapting itself to a possible defect of relative position or of parallelism of the respective paths of said body and of the knife (14) on which its catch (202) is in abutment.
4. Mechanism according to one of the preceding Claims, characterized in that said blade (21) is adapted to exert on a mobile lever (16) of the selection device an effort (F₆) of abutment on an electromagnet (15) for controlling pivoting of said lever.
5. Mechanism according to one of the preceding Claims, characterized in that said blade (21) is provided with a window (213) for receiving at least a part of said body (20).
6. Mechanism according to one of the preceding Claims, characterized in that said blade (21) is provided with at least one opening (216) for engagement of a selection catch (311) belonging to said selection device (15, 16).
7. Mechanism according to one of the preceding Claims, characterized in that said blade (21) comprises two sides (212, 212') adapted to slide in grooves (10b) of a box (10) for receiving and guiding in translation said mobile hook (13), said body (20) thus being positioned with respect to said box.
8. Mechanism according to Claim 7, characterized in that said groove (10b) widens or opens out towards the outside of said box (10) in the vicinity of said selection device (15, 16).
9. Mechanism according to one of the preceding Claims, in which said selection device comprises at least one retaining lever (16), characterized in that said lever comprises a metal armature (30), adapted to interact with an electromagnet (15) for controlling the position of said lever, and an amagnetic part (31) forming element in relief (311) adapted to cooperate with said metal blade (21) and fixed on said armature.
10. Mechanism according to Claim 9, characterized in that said retaining lever (16) is mounted to pivot about a fixed pin (10a) from which it extends substantially downwardly when said mechanism is in configuration of operation.
11. Mechanism according to one of Claims 9 or 10, characterized in that said retaining lever (16) is provided with at least one deflector (161, 162) adapted to isolate from the outside a chamber in which is located the zone (Z₁) of interaction between said armature (30) and said electromagnet (15).
12. Mechanism according to Claim 11, characterized in that said or one of said deflectors (162) extends on either side of a principal part (16a) of said lever (16).
13. Mechanism according to one of Claims 11 or 12, characterized in that said or one of said deflectors (162) is arranged between said chamber (Z₁) and the hook (13) adjacent to said lever (16).
14. Mechanism according to Claim 9, characterized in that said retaining lever (16) is mounted to pivot about a pin (10a) fixed with respect to a box (10) isolating said electromagnet (15) from the ambient atmosphere, said retaining lever extending both inside and outside said box, while sealing means (10e) are provided between said box and a circular part (305) of said retaining lever substantially centred on said axis.
15. Mechanism according to one of the preceding Claims, in which said selection device comprises an electromagnet, characterized in that said electromagnet (15) is moulded in one of the sides of a box (10) for separating and guiding said retaining hook (13).
16. Weaving loom (M) equipped with a shed forming mechanism (7-306) according to one of the preceding Claims.

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