EP0837957B1 - Hook selection device for a weaving loom dobby head - Google Patents

Description

The present invention relates to a device for selection hooks in a weaving loom mechanic.

Such a device is used in the textile industry for the purpose of allow the production of shaped fabrics, that is to say requiring a very large number of chain son to be raised or lowered. Such fabrics constitute, for example, paintings, tapestries or other engravings for which looms are still often used manuals.

In document FR 2 476 694, it has been proposed to produce a chain son control device to operate the opening of the not by dividing this device into separable modules each comprising blades which pass through a first plate provided with bars and a second tray with perforations. The blades each carry a hoof and a hook. When electromagnets attract blades, the hooks of those called are moved by the first board, while those called not called follow the translation of the second plate. So we open the not by the translation of the two plates.

Such armor mechanics are very complex and requires an important precision in the realization of all its elements in view of ensuring the relative position of each blade relative to its electromagnet and lift plate. It has a large number moving parts, so that to avoid premature wear and in order to obtain the precision essential to the realization of all elements, we arrive at a very high cost of such a mechanical.

Document EP-0 108 700 discloses a device for the selection of hooks in an armor mechanism which includes a lower plate carrying the hooks and an upper part supporting the selection device and movable relative to the lower plate, this device comprising parts provided with a lug, each of these parts corresponding to a hook on the lower plate and the position of the lug relative to the hook being controlled by a device electromagnetic having at least one coil, so that, when the lower plate moves away from the upper part, the lug, according to its position, or not the hook with it.

In this device, the parts provided with a lug are blades elastic. These are elastically deformed when the plate lower approaches the upper part. The blades then come in support against a pole piece of a permanent magnetic circuit. The blades are held in this position which does not allow to retain hooks on the lower plate. Each blade then corresponds to a coil which is excited when the blade must retain a hook of the plate lower, allowing the blade to return to its undistorted position.

When magnetic dust sticks to a pole piece of the permanent magnetic circuit, it may happen that the blade is no longer held in its deformed position and so this blade holds the corresponding hook of the plate each time inferior. This then causes a defect in the weaving of the fabric.

In addition, to deform the elastic blade, an inclined ramp is provided at each hook of the lower plate. To avoid a shock when the lower plate approaches the upper part, the slope of this ramp is low. To obtain sufficient deformation of the blade, the relative stroke between the lower plate and the part upper must be relatively large. The race being important, the time to cover it is also important and, therefore, the time to inserting the frame is limited.

The object of the invention is therefore to provide a device for selection to overcome these drawbacks, that is to say reliable and requiring only a reduced stroke to be able to retain the hooks selected from the lower shelf, and increasing the time available for the insertion of the frame.

This object is achieved by the invention thanks to a device for the selection of hooks in an armor mechanism which includes a plate lower carrying the hooks and an upper part supporting the device selection and movable relative to the lower plate, this device comprising parts provided with a lug and means for creating a magnetic field permanent, each of these pieces corresponding to a hook on the lower plate and the position of the lug relative to the hook being controlled by a device electromagnetic having at least one coil, so that when the lower plate moves away from the upper part, the lug, according to its position, or not the hook with it, device characterized in that each piece provided with a lug is a rigid blade comprising at least one part made of magnetic material and pivotally mounted about an axis, in that the means to create a permanent magnetic field act on the part produced in magnetic material of the blade, and in that the coil makes it possible to act on the piece of the blade made of magnetic material, so that, according to the polarities of the coil and the permanent magnetic field, the blade pivots around of its axis is in a first position to drive the hook lower corresponding when the lower plate moves away from the part upper, or in a second position does not allow such training.

By these arrangements, the rigid blade then pivots between two stable positions around an axis which can be real or virtual. These positions depend on polarities of the permanent magnetic field and the coil. The polarity of permanent magnetic field is constant, while that of the coil depends on the direction of the current flowing through it. When the current supplying the coil is cut, regardless of the position of the rigid blade, this the latter remains in its position. Compared to known devices, the device according to the invention is therefore more reliable.

In addition, the relative travel between the lower plate and the part upper is limited. It suffices that the lug of the pivoting blade come next to the hook of the lower plate to be able to select or not the hook.

Advantageously, the blade provided with a lug is produced in a material without magnetic property on the side of the lug and in a magnetic material on the side opposite the lug. In this way, the elements for controlling the position of the rigid blade are away from the lug and thereby less exposed to dust and the like foreign bodies which may disturb the functioning of the selection.

There are several ways to arrange the coil and create the permanent magnetic field necessary for the device for selecting hooks. The invention therefore proposes several embodiments.

According to a first embodiment, the device for electromagnetic control has two pole pieces between which is a permanent magnet and between which part of the part of the blade made of magnetic material can move, and the coil surrounds part of the blade part made of material magnetic. In this case, the permanent magnet creates the magnetic field. permanent and the coil polarizes the part of the blade produced by magnetic material.

According to a second embodiment proposed by the invention, the electromagnetic control device has two pole pieces between which is a second coil and between which a part of the blade part made of magnetic material can be move, as well as the coil surrounding part of the blade piece made of magnetic material. Here, the second coil replaces the magnet of the first embodiment.

In these two embodiments, the pole pieces may be common to several rooms fitted with a lug. this is advantageous from a cost point of view of the device, because the number of parts is limited. However, when the mechanical hooks of armor are very close to each other, interference magnetic may appear.

In a third embodiment, the piece of the blade made of magnetic material is a permanent magnet and the electromagnetic control device has two pole pieces between which is the coil and between which part of the permanent magnet can move. Unlike fashions of previous execution, the polarity of the part of the blade produced in magnetic material has a constant polarity and the polarity of pole pieces varies depending on the direction of the current flowing in the coil. In addition, the selection devices for each hook are independent of each other.

In these three embodiments, the two pole pieces advantageously serve as a mechanical stop for the rigid pivoting blade and thus define the two positions that the latter can take. So, the number of parts of the device is limited.

To ensure better guidance of the pivoting blades, the invention proposes two other embodiments in which when the blade pivots, it is not only attracted to its new position, but it is also pushed back from its initial position.

In this first embodiment, each blade has on the side opposite the lug a housing receiving a permanent magnet placed between two pole pieces projecting from the housing, and the device electromagnetic control has an E-shaped armature, as well as the coil surrounding the middle branch of the E, the end of each pole piece projecting from the housing between two branches of E.

In the other embodiment, each blade has the side opposite the lug a housing receiving an E-shaped frame, the coil surrounding the middle branch of E, and a permanent magnet placed between two pole pieces faces this armature so that a end of each pole piece is between two branches of the E.

In these last two embodiments, the device is, like all the devices according to the invention, bi-stable but also double effect. In addition, the blade has two stop points in each of its two stable positions, which is favorable from a mechanical point of view.

In order to adjust the force of attraction between the pole pieces and the frame, an air gap made of a non-magnetic material is placed between each end of a pole piece and the neighboring branches of E-shaped frame

Advantageously, the management of the selection of the hooks is done electronically. In this case then, the control device electromagnetic is equipped with an electronic card comprising a printed circuit to control the flow of current through the coil to select the position of the blade. The selection of hooks can be very fast as well.

Figure 1 est une vue en perspective éclatée d'un dispositif pour la sélection de crochets selon l'invention,

Figure 2 est une vue en coupe transversale selon la ligne II-II de la figure 1,

Figures 3 et 4 sont des vues simplifiées correspondant à la figure 2 et montrant des variantes d'exécution,

Figure 5 est une vue en perspective éclatée correspondant à la figure 1 d'un autre dispositif de sélection de crochets selon l'invention,

Figure 6 est une vue en coupe simplifiée, à échelle agrandie, selon la ligne VI-VI de la figure 5, et

Figure 7 est une vue simplifiée correspondant à la figure 6 d'une autre forme d'exécution.

In any case, the invention will be clearly understood with the aid of the description which follows, with reference to the appended schematic drawing, representing by way of nonlimiting examples a device for selecting hooks according to the invention and two alternative embodiments.

FIG. 1 is an exploded perspective view of a device for the selection of hooks according to the invention,

FIG. 2 is a cross-section view along line II-II of FIG. 1,

Figures 3 and 4 are simplified views corresponding to Figure 2 and showing alternative embodiments,

FIG. 5 is an exploded perspective view corresponding to FIG. 1 of another hook selection device according to the invention,

FIG. 6 is a simplified sectional view, on an enlarged scale, along the line VI-VI of FIG. 5, and

Figure 7 is a simplified view corresponding to Figure 6 of another embodiment.

The hook selection device shown in the drawing is intended to equip an armor mechanic used in the textile industry for weaving. This armor mechanism has a lower plate 1 bearing hooks 2 and an upper part supporting the device selection of hooks 2. The lower plate 1 and the upper part are movable relative to each other, these two elements can be move towards or away from each other. When they move away, the hooks 2 selected are retained by the selection device, while the hooks 2 not selected follow the movement of the lower plate 1.

The hook selection device comprises blades 3. Each of these corresponds to a hook 2. It is provided at its end facing the hook 2 of a lug 4 intended to cooperate with the hook 2 when the latter must be selected.

The blades 3 are pivotally mounted in a housing 5 provided a cover 6. Each blade 3 is equipped with a transverse axis 7, mounted on bearings 8 provided on a wall of the housing 5.

Each blade is made of two separate materials. From a side, the blade is made of synthetic material and on the other side, it is made a magnetic material, such as soft iron; the part of blade 9 produced in soft iron used to control the position of the blade 3. The other part 10 has the lug 4 and faces the hook 2. This part 10 is by example overmolded at one end of part 9 in soft iron. Axis 7 is found substantially at the junction between part 9 in soft iron and that 10 in synthetic material.

In the embodiment shown in Figures 1 and 2, the part 9 of the soft iron blade is placed in a coil 11. The end of the blade opposite the lug 4 protrudes from the coil 11. It is placed between two pole pieces 12. These serve as stops for the blade 3 when it pivots around the axis 7. Two notches 13 are provided on the blade 3 to accommodate the end of the pole pieces 12. Between these pieces polar 12 is placed a permanent magnet 14 which polarizes these parts 12.

The coil 11 can be crossed by an electric current continued. An electronic card 15 comprising a printed circuit manages the passage of current through the coil 11. Depending on the direction of circulation of the current in coil 11, part 9 of blade 3 made of soft iron will be polarized and its end placed between the pole pieces 12 is then either a magnetic north pole, or a south pole. According to the polarization of this part 9 in soft iron, the blade 3 takes one or the other of the positions shown in Figure 2. In the position shown in solid lines, the lug 4 of the blade does not catch the hook 2 when the part upper moves away from the lower plate 1, while in the position shown in phantom, the lug 4 remains hooked and the hook 2 is then driven by the upper part.

As can be seen in FIG. 2, it suffices that the lug 4 go under the hooked part of hook 2 to select or not this hook. The stroke of the upper part relative to the lower plate 1 can therefore be reduced to the minimum necessary.

In Figures 3 and 4 illustrating alternative embodiments, only blade 3 and the device for controlling the position of this blade have been represented.

In FIG. 3, the magnetic part 9 of the blade is a magnet permanent. As before, this part 9 of the blade is placed between two pole pieces 12. The coil 11 is itself placed between the pole pieces 12.

In this case, the polarity of part 9 of the blade made in magnetic material is constant and the polarity of the pole pieces 12 varied.

In the variant shown in FIG. 4, by compared to the device of FIGS. 1 and 2, only the permanent magnet 14 is replaced by a second coil 16. The latter plays the same role as the permanent magnet.

Figures 5 and 6 show a fourth form of execution. Compared to Figure 1, the main difference is the fact, on the one hand that two successive hook selection devices are magnetically independent of each other and on the other hand that the devices shown are double-acting.

Here, the blades 3 have a housing 17 on the side opposite to lug 4. A permanent magnet 18 is placed between two pole pieces 19 inside this housing 17. The magnet does not protrude from the housing 17, but one end of each pole piece 19 protrudes out of this housing.

Facing blade 3, on the side of magnet 18 and the pole pieces 19, there is an armature 20 and the coil 11.

The frame 20 has the shape of an E whose teeth are oriented towards blade 3. Between two branches of the E, is located at each times one end of a pole piece 19. The central branch of E carries coil 11.

An air gap 21, made of a non-magnetic material, is placed on each side of a branch of the E facing a pole piece 19.

FIG. 7 represents a variant of the embodiment of the Figures 5 and 6. In this variant, the armature 20 and the coil 11 are placed in the housing 17, while the permanent magnet 18 and the pole pieces 19 face the blade 3.

The operating principle of these devices (Fig. 5 to 7) is close to the principle described above with reference to Figures 1 to 4.

The polarity of the middle arm of the armature depends on the direction of the current in the coil 11. The polarities of the two lateral branches of the armature are opposite to the polarity of the middle branch. The polarities of the two pole pieces do not vary and they are opposite.

At equilibrium, whether current flows through the coil 11 or not, each pole piece 19 abuts against the end of a branch of the armature 20. If current flows through the coil 11, in the opposite direction at the last current flow, the polarity of the central branch of the frame varies, as does that of the lateral branches. The pole piece 19 in abutment against the middle branch of the armature is then pushed back by the middle branch of the frame, but also attracted by a branch lateral. The same goes for the other pole piece, which is repelled by the side branch against which it rested and which is attracted by the central branch.

The air gaps 21, made of non-magnetic material, allow to adjust the force of attraction between the pole pieces 19 and the branches of the frame 20.

Whatever the variant of execution described above, the blade 3 of the hook selection device can take two positions stable: one corresponds to the selection of the corresponding hook 2, the other to the non-selection of it.

In the absence of current in the coil 11, the blade 3 remains in the position in which it is, both in the position of selection than non-selection. As long as a new field electromagnetic generated by a reverse current in the coil 11 does not change the polarity of part 9 of the blade (Fig. 1, 2 and 4), or pole pieces 12 (Fig. 3), or branches of the frame 20 (Fig. 5 to 7), the blade 3 remains in a stable position.

In these devices, a few milliseconds are enough to cause tilting of the blade 3 from one position to the other. The selection of the hooks 2 can therefore be carried out quickly. Therefore, the energy consumption is minimized.

It goes without saying that the invention is not limited to forms of execution described above by way of nonlimiting examples, it on the contrary embraces all variants.

Thus, for example, Figures 1 and 5 show a housing does containing only two blades. This can contain as many slides as longed for.

The blades are made of two different materials. However, they could be made only of a material magnetic.

The relative position of the blade axis, the spool and the lug is not frozen. The coil could be for example between the axis and the lug.

In the variants, the pole pieces or the armature branches serve as stops. The case could integrate such mechanical stops. The solution adopted in the description above is a preferred but not mandatory solution.

Claims (10)

1. Device for selecting hooks in a weave pattern mechanism which comprises a lower plate (1) carrying hooks (2) and an upper section supporting the selecting device and which is movable with respect to the lower plate (1), this device including parts (3) provided with a catch (4) and means (14, 16) for creating a permanent magnetic field, each of these parts (3) corresponding to a hook (2) of the lower plate and the position of the catch (4) with respect to the hook (2) being controlled by an electromagnetic device having at least one coil (11) so that, when the lower plate (1) moves away from the upper section, the catch (4), according to its position, entrains or does not entrain the hook (2) with it, characterized in that each part (3) provided with a catch (4) is a rigid blade including at least one part (9) made of a magnetic material, mounted pivotingly about an axle pin (7), in that the means (14, 16) for creating a permanent magnetic field act in the region of the part (9) of the blade made of magnetic material, and in that the coil (11) makes it possible to act on the part (9) of the blade made of magnetic material so that, according to the polarities of the coil and of the permanent magnetic field, the blade (3) pivots about its axle pin (7) either in a first position enabling the corresponding lower hook (2) to be entrained when the lower plate (1) moves away from the upper section, or in a second position not permitting such entrainment.
2. Device according to claim 1, characterized in that the blade (3) provided with a catch (4) is made of a material without a magnetic property on the side of the catch and of a magnetic material on the side opposite the catch.
3. Device according to claim 2, characterized in that the electromagnetic control device comprises two polar parts (12) between which a permanent magnet (14) is situated and between which a portion of the part (9) of the blade made of magnetic material can move, and in that the coil (11) surrounds a portion of the part (9) of the blade made of magnetic material.
4. Device according to claim 2, characterized in that the electromagnetic control device comprises two polar parts (12) between which a second coil (16) is situated and between which a portion of the part (9) of the blade made of magnetic material can move, as well as the coil (11) surrounding a portion of the part of the blade (9) made of a magnetic material.
5. Device according to claim 2, characterized in that the part (9) of the blade made of magnetic material is a permanent magnet and in that the electromagnetic control device includes two polar parts (12) between which the coil (11) is situated and between which a portion of the permanent magnet can move.
6. Device according to one of claims 3 to 5, characterized in that the two polar parts (12) serve as a mechanical stop for the rigid pivoting blade (3) and define in this way the two positions which the latter may assume.
7. Device according to claim 1, characterized in that each blade has, on the side opposite the catch (4), a housing accommodating a permanent magnet placed between two polar parts which project out of the housing, and in that the electromagnetic control device includes an E-shaped armature, as well as the coil (11) surrounding the central arm of the E, the end of each polar part projecting outside the housing being situated between two arms of the E.
8. Device according to claim 1, characterized in that each blade has, on the side opposite the catch (4), a housing accommodating an E-shaped armature, the coil (11) surrounding the middle arm of the E, and in that a permanent magnet placed between two polar parts faces this armature so that one end of each polar part is situated between two arms of the E.
9. Device according to claim 7 or 8, characterized in that an air gap made of a non-magnetic material is placed between each end of a polar part and the adjacent arms of the E-shaped armature.
10. Device according to one of claims 1 to 9, characterized in that the electromagnetic control device is equipped with an electronic card (15) bearing a printed circuit for controlling the passage of current in the coil (11) enabling the position of the blade (3) to be selected.

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