EP0108700A1 - Dobby with selection of the hooks - Google Patents

Abstract

The selection is made by means of elastic blades (25) of the upper plate (2) which are deformed by ramps (18c) of the lower plate (1) so that they bear against a pole piece (22) of a magnetic circuit which retains them if the hook has to come back down or releases them if the hook has to be selected. The flow of the magnetic circuit is canceled when a coil (27) associated with the magnetic circuit is excited to the right of the blades (25). Armor mechanics.

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 an earlier patent FR.B. 80 04281 it has been proposed to produce a device for controlling the warp threads in order to open 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 addition, it requires long and tedious adjustments to guarantee the simultaneous operation of approximately ten thousand blades. It should be noted for this purpose that it must be taken into account that the metal blades must be brought into contact with the electromagnets and that the slightest air gap does not guarantee the retention of the blades, knowing that the force of attraction of an electromagnet decreases inversely proportional to the size of the air gap.

In addition, in the event of failure of a metal blade, it is necessary to replace it by making it cross the plates which are actually four in number.

If an electromagnet fails, it must be removed from its support through the guide plate or from the side. It is easily understood that due to the very high density of the components, the electromagnets are difficult to access.

The improvements which are the subject of the present invention aim to remedy these drawbacks and to allow the production of an armor mechanism with a very large number of hooks and which can allow the replacement of all of its components quickly and simply while ensuring a considerable reduction in its price. returns compared to that of the devices manufactured previously. By the general arrangement and the control mode, it is possible, thanks to the invention, to considerably reduce the consumption of electrical energy necessary for the operation of the mechanics.

To this end, the armor mechanics according to the invention now only comprises two movable plates, the first of which, which is used to lower the warp threads, supports the unselected hooks making it possible to form the lower layer of the crowd while guiding selected hooks which generate the upper ply, the latter being brought into the upper position by a second plate. This comprises flexible blades provided with a spout intended to cooperate with the hooks selected in order to raise them.

This action is first obtained by pushing the flexible blade by a ramp of the lower plate so as to bring it into contact with a pole of a magnetic circuit of which it is itself part. If you want the hook to be lifted, the blade restraint is eliminated by canceling the action of the magnetic circuit. The whole formed by the blades and their magnetic circuits is divided into modules of twenty-four elements, each module having its own power supply means.

According to the invention each knife of the upper plate is produced in the form of a blade which is elastically deformed by a ramp of the lower plate 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 lower plate, the flow of said magnetic circuit being canceled when a coil associated with the pole piece is excited to the right of each blade.

• Fig. 1 et 2 représentent schématiquement une mécanique d'armure établie conformément à l'invention en position respectivement de foule fermée et de foule oblique ouverte.
• Fig. 3 est une coupe verticale à grande échelle du système de sélection des crochets.
• Fig. 4 en est une vue éclatée.
• Fig. 5 à 8 sont des vues semblables à celle de fig. 3 mais illustrant le système de sélection à ses différentes positions.
• Fig. 9 est une variante d'exécution de la rampe destinée à déporter les lames.
• Fig. 10 est une vue semblable à celle de fig. 3 mais montrant une autre manière d'effectuer la retenue des lames.
• Fig. 11 est un schéma du circuit électrique destiné au fonctionnement d'un module du système de sélection.

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:

• Fig. 1 and 2 schematically represent an armor mechanism established in accordance with the invention in the closed crowd and open oblique crowd positions, respectively.
• Fig. 3 is a large-scale vertical section of the hook selection system.
• Fig. 4 is an exploded view thereof.
• Fig. 5 to 8 are views similar to that of FIG. 3 but illustrating the selection system at its different positions.
• Fig. 9 is an alternative embodiment of the ramp intended to offset the blades.
• Fig. 10 is a view similar to that of FIG. 3 but showing another way of carrying out 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 comprises an external finger la, 2a which moves in opposite slides lla, llb of a vertical slide 11.

Each plate has a roller 12, respectively 13, mounted free at the end of a bracket 1b, 2b and which is 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 lift and drop mechanism is produced comprising an oblique crowd.

As illustrated in fig. 3 the plate 1 is provided with holes 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 stringer as this 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. We observe 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 lc 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 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 arranged parallel to the underside of the plate 2 in a cavity 21b of the support 21.

The various supports 21 are assembled together by means of centering devices not shown, the supports being fixed to the plate 2 by means 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.
• Lorsque les deux plateaux 1 et 2 vont à nouveau s'éloigner l'un de l'autre, l'ergot 25a ne pourra saisir le bec 17a du crochet (fig. 7) du fait de la distance d existant entre ces deux éléments de sorte que le crochet 17 redescend avec le plateau 1. Dans ce cas le crochet considéré n'est pas sélectionné.

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 come and grab 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.

According to another variant, the magnet 28 could be eliminated and the blade 25 retained, when it bears against one of the teeth 22b, 22c of the pole piece 22, by supplying the corresponding coil 27 (fig. 10) to constitute an electromagnet retaining the blade in the deformed position. Contrary to what has been described above, it is by removing the supply from the coil that the blade 25 is released so that it is gripped by the hook.

In order to excite the coils, it is planned to constitute 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 reel 27 ₃ is then presented then the shift command passes the contents of the boxes 33a and 33b into those 33b and 33c, while the information for the third reel is entered in the box 33a. Information arriving as you go the shift register operates in the same way until the information for the last coil 27n is entered. There are therefore only two wires to control 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 (about 2000 amperes) but very brief (of the order of 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 perform under a permanent current of very low intensity (close to ten milliamps) therefore allowing 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 heating at the level of 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 (11)

1. Armor mechanics whose selection of hooks (17) is effected by levers (25) actuated by electromagnets, characterized in that each knife of the upper plate (2) is produced in the form of a blade (25), which is elastically deformed by a ramp (18c) of the lower plate (1) so that it comes to bear against a pole piece (22) of a permanent magnetic circuit which retains it when the hooks have to descend with the lower plate (1), the flow of said magnetic circuit being canceled when a coil (27) associated with the pole piece (22) is excited in line with each blade (25). 2. armor mechanism according to claim 1, characterized in that the magnetic circuit comprises a non-magnetic support block (21), a pole piece (22) provided with teeth (22b, 22c) each surrounded by a coil (27) , a permanent magnet (28) pressed against the pole piece (22) and blades (25) which pass near the end of the teeth (22b, 22c). 3. armor mechanism according to claim 2, characterized in that the pole piece (22) is produced in the form of a flat plate extended by vertical tongues (22a) bent at 90? relative to the general plane of the plate and which form teeth (22b, 22c) offset longitudinally. 4. Armor mechanics according to claim 2, characterized in that the elastic blades (25) come from a common heel (24). 5. armor mechanics according to claim 2, characterized in that the pole piece (22) is associated with a panel (26) comprising a printed circuit intended for supplying the coils (27). Engaged around the teeth (22b , 22c) of said part (22). 6. armor mechanism according to claim 2, characterized in that the magnetic support block (21) is centered by pins (21a) on the upper plate (2) and in that there are several magnetic circuits on the latter , the blocks placed side by side being centered with respect to each other by means of lateral fingers and held in place by fixing screws (29). 7. armor mechanism according to claim 1, characterized in that the control of the supply of the coils (27) mounted around the teeth (22b, 22c) is effected by means of a shift register (33 ), the programmed information being transmitted by a single conductor (32) successively to the different boxes (33a, 33b, 33c ...) of the register which each store the information at the end of the shift and communicate it to a switch placed at each coil (27). 8. Armor mechanics according to claim 7, characterized in that the individual switches of the coils (27) are connected to a current supply circuit (34) which excites the coils selected by the programmer. 9. Mechanics according to claim 3, characterized in that the selection is applied successively to the two transverse rows of coils (27). 10. Mechanics according to claim 8, characterized in that the supply of the individual switches of a series of coils (27) is carried out through a power switch (37), from a capacitor (35) mounted in parallel with the current source. 11. Mechanics according to claim 1, characterized in that each plate (1,2) comprises a roller (12, 13) cooperating with a light (14, 15) comprising a vertical part (14a, 15a) extended by a rounding so that these trays move while remaining perfectly parallel during the selection and then arrange themselves obliquely.

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