EP0108700B1 - Dobby with selection of the hooks - Google Patents

Description

The present invention relates to improvements made to the system for selecting the hooks of a weave mechanism in order to allow the production of shaped fabrics, that is to say requiring a very large number of warp threads to be raised or lowered. Such fabrics constitute paintings, tapestries or other engravings for which manual looms have been used until now.

In patent FR-A-80 04 281 (2 476 694), it has been proposed to produce a control device for warp threads in order to operate the opening of the pitch by dividing this device into separable modules each comprising blades which pass through a first plate provided with bars and a second plate provided with perforations. The blades each carry a shoe and a hook. When electromagnets attract the blades, the hooks of those called are moved by the first plate, while those not called follow the translation of the second plate. Thus, the step is opened by the translation of the two plates.

Such an armor mechanism is very complex and requires significant precision in the production of all of its elements in order to guarantee the relative position of each blade relative to its electromagnet and to the lifting plate. It is provided with a large number of mobile elements so that to avoid any premature wear and in order to obtain the precision essential for the realization of all the elements, one arrives at a very high cost of such a mechanical .

In patent FR-A-1 380 967, an electromagnetic individually controlled armor mechanism has also been described in which the selection of the hooks is carried out by levers actuated by electromagnets and in which each knife is produced under the shape of a blade elastically deformed by a ramp of the hook so that it comes to bear against a pole piece of a permanent magnetic circuit which retains it when the hooks must descend with the slide. The flow of said magnetic circuit is canceled when a coil associated with the pole piece is excited to the right of each blade. This arrangement, which is particularly suitable for loom ribbons with small widths or selvedge threads, is unfortunately not possible for armor threads with high density threads, with large widths, such as for example one hundred threads per centimeter in one hundred and forty centimeters wide, as is currently sought in silk, because the various mechanical parts necessary for the operation of this device cannot be miniaturized. In this way, the mechanics would be disproportionately bulky for such an application.

The invention overcomes these drawbacks. It is aimed at armor mechanics with a very large number of hooks, of the type in question which is economical compared to the devices proposed until then, requires low consumption of electrical energy during operation and is particularly suitable for armor wires high density yarn, that is to say of the order of one hundred yarns per centimeter in large width.

• - dans laquelle la sélection des crochets s'effectue par des lames actionnées par des électro-aimants ;
• - et dans laquelle chaque couteau du plateau supérieur est réalisé sous la forme d'une lame métallique, qui est déformée élastiquement par une rampe ménagée soit sur le crochet lui-même. soit sur le plateau inférieur, afin que cette lame vienne en appui contre une pièce polaire d'un -circuit magnétique permanent qui la retient lorsque les crochets doivent descendre avec le plateau inférieur, le flux dudit circuit magnétique étant annulé quand on excite une bobine associée à la pièce polaire au droit de chaque lame ;
• - et dans laquelle le circuit magnétique comprend :
  • un bloc support amagnétique,
  • une pièce polaire pourvue de dents entourées chacune d'une bobine ;
  • un aimant permanent plaqué contre la pièce polaire ;
  • - et dans laquelle les lames passent à proximité de l'extrémité des dents ; est caractérisée en ce que la pièce polaire du circuit magnétique est réalisée sous la forme d'une plaque plane prolongée par des languettes verticales recourbées à 90° par rapport au plan général de la plaque et qui forment des dents décalées longitudinalement.

To this end, the armor mechanics according to the invention:

• - in which the selection of the hooks is carried out by blades actuated by electromagnets;
• - And in which each knife of the upper plate is produced in the form of a metal blade, which is elastically deformed by a ramp provided either on the hook itself. either on the lower plate, so that this blade comes to bear against a pole piece of a permanent magnetic circuit which retains it when the hooks must descend with the lower plate, the flow of said magnetic circuit being canceled when an associated coil is excited to the pole piece to the right of each blade;
• - and in which the magnetic circuit comprises:
  • a non-magnetic support block,
  • a pole piece provided with teeth each surrounded by a coil;
  • a permanent magnet pressed against the pole piece;
  • - And in which the blades pass near the end of the teeth; is characterized in that the pole piece of the magnetic circuit is produced in the form of a flat plate extended by vertical tongues curved at 90 ° relative to the general plane of the plate and which form teeth offset longitudinally.

Other provisions of the invention will emerge more clearly from the description and the claims.

The appended drawing, given by way of example, will allow a better understanding of the invention, the characteristics which it presents and the advantages which it is capable of providing.

Figures 1 and 2 schematically show an armor mechanism established in accordance with the invention in the closed crowd and open oblique crowd positions, respectively.

Figure 3 is a large-scale vertical section of the hook selection system.

Figure 4 is an exploded view.

Figures 5 to 8 are views similar to that of Figure 3 but illustrating the selection system at its different positions.

Figure 9 is an alternative embodiment of the ramp intended to offset the blades.

Figure 10 is a view similar to that of Figure 3, but showing another way to perform the retention of the blades.

FIG. 11 is a diagram of the electrical circuit intended for the operation of a module of the selection system.

There is illustrated very schematically in FIG. 1 and 2, an armor mechanism comprising application of the improvements according to the invention. This mechanism essentially comprises two mobile plates 1 and 2, one lower carrying the hooks, the other upper supporting the selection system. Each of the plates is connected by a link 3, 4 to a bent pendulum 5, 6 articulated around a fixed axis 7, 8. The bent part of the pendulums assumes the shape of a fork 7a, 8a whose ends of the branches are associated with free rollers 7b, 7c respectively 8b, 8c which cooperate with cams and cams 9. The rotation of the latter which are wedged on a rotating shaft 10 causes the rockers 5 and 6 to tilt and the platens to move vertically 1 and 2. For this purpose, each of these has an external finger 1a, 2a which moves in opposite slides 11a, 11b of a vertical slide 11.

Each plate has a roller 12, respectively 13, mounted freely at the end of a bracket 1b, 2b and which is located inside a slot 14, respectively 15, of a fixed plate 16. Each slot 14, 15 comprises a vertical part 14a, 15a which ensures a displacement of the two plates parallel to themselves, then each lumen is rounded so that after having carried out their course parallel to themselves corresponding to the selection phase, the two plates come in oblique position as illustrated in fig. 2.

Thanks to this arrangement, a mechanical lift and fall is carried out comprising an oblique crowd.

As illustrated in fig. 3 the plate 1 is provided with holes 1c intended for the passage of the hooks 17 of the armor mechanism according to the invention. We will not describe the lower part of the hook 17 which is associated with a heddle as is well known in practice. The upper part of the hook has a spout 17a below which there is a bulge or heel 17b which comes to rest in a housing 18a of a guide 18 associated above the plate 1 by means of an assembly bolt 19. On observes that the housing 18a is at the upper end of a vertical conical bore 18b formed in the guide 18 in correspondence with the hole 1c of the plate 1.

The upper plate 2 supports the modules 20 of the selection system, each module being intended for the control of twenty four hooks. Each module 20 comprises a support 21 made of non-magnetic material such as a thermoplastic resin, which comprises centering pins 21a engaging in corresponding holes 2c of the plate 2. The support 21 is first of all associated with a single pole piece 22 produced in the form of a flat plate extended by tongues 22a bent at 90 ° relative to the general plane of said plate to form teeth 22b, 22c offset longitudinally. This pole piece 22 is shown in detail in FIG. 4, on which we can clearly see the offset of the teeth 22b and 22c in the height direction. It is also observed that the teeth 22b are shorter than those 22c. The pole piece 22 is assembled to the support 21 by means of bolts 23 which also hold a comb 24 whose blades 25 oriented downwards, cross the plate 2 in openings 2d. The end of each blade 25 is bent upwards to form a lug 25a intended to cooperate with the spout 17a of the corresponding hook 17.

The bolts 23 also hold a panel 26 in which is printed the control circuit of the coils 27 engaged around the teeth 22b and 22c of the pole piece.

A permanent magnet 28 is disposed parallel to the underside of the plate 2 in a cavity 21b of the support 21. The different supports 21 are assembled together by means of centering devices not shown, the supports being fixed to the plate 2 to the hub of clamping screws 29 engaged in tapped holes formed in a fixed bracket 30.

Finally, there is the presence of a plate 31 kept pressed against the comb 24 and its blades 25, this plate being assembled with the other elements of the module 20 by the bolts 23. This plate is intended to dampen the vibrations of the blades.

• Lorsque les deux plateaux se rapprochent l'un de l'autre (Fig. 5) l'ergot 25a de la lame 25 correspondant à chaque crochet 17 vient en contact avec une rampe oblique 18c ménagée dans le guide 18 de telle manière que la lame est déformée en direction de la pièce polaire comme illustré en fig. 6. Au point mort bas du plateau supérieur 2, la lame considérée 25 vient en contact avec l'une des dents de la pièce polaire de telle sorte qu'elle est retenue dans cette position du fait de l'existence d'un circuit magnétique constitué par l'aimant permanent 28, la pièce polaire 22, la lame 25 et un entrefer situé entre celle-ci et l'aimant 28.

The operation follows from the above explanations:

• When the two plates approach each other (Fig. 5) the lug 25a of the blade 25 corresponding to each hook 17 comes into contact with an oblique ramp 18c formed in the guide 18 so that the blade is deformed in the direction of the pole piece as illustrated in fig. 6. At the bottom dead center of the upper plate 2, the blade considered comes into contact with one of the teeth of the pole piece so that it is retained in this position due to the existence of a magnetic circuit. constituted by the permanent magnet 28, the pole piece 22, the blade 25 and an air gap situated between the latter and the magnet 28.

When the two plates 1 and 2 again move away from each other, the lug 25a cannot grasp the spout 17a of the hook (fig. 7) due to the distance d existing between these two elements of so that the hook 17 descends with the plate 1. In this case the considered hook is not selected.

On the contrary if the permanent magnetic circuit is interrupted for example by feeding the coil 27 arranged around the tooth with which the blade is in contact, as soon as the two plates move away from the lug 25a of the blade 25 will cooperate with the ramp 18c to enter the spout-17a of the hook 17 (fig. 8); under these conditions the hook considered will be selected, that is to say that the warp thread with which it is joined will be raised.

Illustrated in fig. 9 a variant in which it is the hook 17 itself which carries the deformation ramp of the blade 25. To do this its heel 17b is extended so as to constitute said ramp. The underside of the heel then comes to rest against a flat 18d of the guide 18. In order to excite the coils, provision has been made to form a printed circuit embedded in the panel 26. As it is a question of ordering a very large number of coils referenced 27 ₁ to 27n independently of each other, the printed circuit has been installed very close to the coils to reduce the length of the conductors. The control information from the selection reader is sent by a single wire 32 (fig. 11). This information results in a shift register 33 of known type. The register command introduces the first information into its first box 33a. The information for the second coil is then presented at the entry of the register 33. The shift command then places the content of box 33a in box 33b and places the information for coil 27 ₂ at 33a. The information for the coil 27 ₃ is then presented, then the shift command passes the contents of boxes 33a and 33b into those 33b and 33c, while the information for the third coil is entered in box 33a. The information arriving as the shift register operates is carried out in the same manner until the information for the last coil 27n is introduced. There are therefore only two wires for controlling all the coils which are preferably 24 in number. It then remains to excite the latter from the information contained in the register 33. It goes without saying that the simultaneous supply of all the coils would cause a very high current (around 2000 amperes) but very brief (of the order of a millisecond). Each module therefore includes a power supply with two circuits. The first which is produced by means of the conductors 34 which can have significant lengths brings the current to the terminals of a capacitor 35, thus placed in bypass with respect to the supply of the circuit 34. The supply of the capacitor can therefore be carry out under a permanent current of very low intensity (close to ten milliamps), which allows a significant reduction in the diameter of the supply wires 34, while the overall permanent current remains low (of the order of 5 amps). The second circuit is intended for supplying the coils from capacitor 35.

It is observed that each of the boxes of the shift register 33 is connected to the coils 27 ₁ to 27n by means of a switch i which receives the information from said register 27n by a conductor 36. When the information is stabilized, the circuit d is closed. 'supply of said switches by means of a power switch 37 provided with a protection 38. The switch 37. is preferably a power transistor capable of withstanding the overvoltage caused by the self induction of the coils at the time of the power cut . It is only after the total extinction of this current that the switches i can be operated. The shift registers are then reset to zero so as to stop the current consumption for controlling the switches i. This saves energy and considerably reduces the temperature rise at the level of the printed circuits while increasing reliability.

It is however necessary to avoid any interaction between the coils because the fluxes created by them are opposed and the resulting flux in each coil is weaker than when they are fed separately. When they are all supplied, the phenomenon increases and it can result in selection errors.

According to the invention, the coils have been separated into two groups, that is to say those associated with the teeth 22b and those which are mounted around the teeth 22c. The coils of the first row are fed first, then that of the second. As the distance between the neighboring coils supplied at the same time is increased the interaction between their flux decreases. The time separating the two power supplies being very small (less than a millisecond) the selections can be considered to be confused from the mechanical point of view, the corresponding difference in positioning of the plates being less than 0.5 millimeter.

Armor mechanics have thus been produced intended for controlling a very large number of hooks, the selection system of which is made up of separate modules is arranged very precisely relative to the upper plate. In addition, the arrangement of the magnetic circuit eliminates any air gap adjustment between the elastic blade and the pole piece and any distance adjustment between said blade and the hook. Finally, the disassembly or the installation of the modules is very easy because of their extremely simple assembly.

Claims (8)

1. Weaving mechanism, in which the selection of the hooks (17) is effected by blades (25) actuated by electro-magnets :

- and in which each cutter of the upper plate (2) is in the form of a metallic blade (25), which is elastically deformed by a ramp provided either on the hook itself (17b), or (18c) on the lower plate (1), so that said blade (25) rests against a pole piece (22) of a permanent magnetic circuit retaining the blade when the hooks (17) have to go down with the lower plate (1), the flux of said magnetic circuit being cancelled when a coil (27) is energized, said coil being associated with the pole piece (22) at right angle to each blade (25) :

- and in which the magnetic circuit comprises :

a non-magnetic supporting block (21),

a pole piece (22) provided with teeth (22b, 22c), each surrounded by a coil (27) ;

a permanent magnet (28) applied against the pole piece (22) ;

- and in which the blades (25) pass close to the end of the teeth (22b, 22c), characterized in that the pole piece (22) of the magnetic circuit is in the form of a plane plate extented by vertical tongues (22a) bent to form an angle of 90° with the longitudinally offset teeth (22b, 22c).

2. Weaving mechanism according to claim 1, characterized in that the elastic blades (25) issue from a joint heel piece (24).

3. Weaving mechanism according to claim 2, characterized in that the pole piece (22) is associated with a panel (26) comprising a printed circuit for the supply of the coils (27) engaged around the teeth (22b, 22c) of said piece (22).

4. Weaving mechanism according to claim 2, characterized in that the non-magnetic supporting block (21) is centered by pins (21a) on the upper plate (2) and in that a plurality of magnetic circuits are placed thereon, the blocks placed side by side being centered one with respect to the others by means of lateral fingers and held in place by fixing screw means (29).

5. Weaving mechanism according to claim 1, characterized :

- in that the means controlling the supply of the coils (27) mounted around the teeth (22b, 22c) is achieved by means of a shift register stage (33), the programmed information being transmitted by a single conductor (32) successively to the different compartments (33a, 33b, 33c) of the register, which each store the information at the end of shift and communicate said information to a switch placed at the level of each coil (27) ;

- and in that the individual switches of the coils (27) are connected to a current supply circuit (34) which energizes the coils selected by a programmator.

6. Mechanism according to claim 5, characterised in that the selection applies successively to the two transverse rows of coils (27).

7. Mechanism according to claim 5, characterized in that the supply of individual switches of a series of coils (27) is achieved through a power switch (37), from a capacitor (35) mounted in parallel with respect to the source of current.

Images