EP0849384B1 - Shedding mechanism, method of assembly thereof and Jacuard loom with such a mechanism - Google Patents

Description

The invention relates to a crowd forming device for a Jacquard type weaving loom, to a method of mounting such a device and to a weaving loom equipped with such a crowd forming device or mounted according to such a method. The invention is more particularly centered on the vertical actuation, in phase opposition, of the two series of blades or knives which ensure the control of the hooks of an armor mechanism.

In a crowd formation device, hooks are arranged in parallel rows separated from each other by spaces in each of which a knife moves vertically. This knife is most often supported by one of two claw frames. Each frame is suspended from levers animated by an oscillating movement so as to lower and raise alternately, it being observed that the vertical movements of the knives take place simultaneously, in opposite directions to each other, in order to operate the opening of the pitch for the insertion of the weft thread.

In traditional mechanics such as, in particular, known from patent application FR-A-2,669,650, a single shaft is provided which is linked to the main shaft of the loom and which extends over the entire width. of the mechanical frame. In the vicinity of each of its ends, this shaft, which is driven by a continuous rotation movement, is equipped with two adjacent cam or eccentric systems capable of transforming this continuous rotation into an alternative rotation in order to give the lever which carries the claw frames the desired lowering and lifting movement. These traditional mechanics have a number of drawbacks. The presence of the mechanisms for transforming the continuous movement into reciprocating movement substantially increases the cost of the assembly at the same time as it increases the size of the actuation mechanism and hinders accessibility to the hooks of the mechanism. In addition, these transformation mechanisms complicate the general structure of the building.

In addition, the output shaft of the loom on which the shedding device is to be installed can be located on the left or right side of this loom. It is it is customary to provide that the crowd training device can be adapted to trades with an output shaft on the left or on the right. However, it sometimes happens that the weaver who will use the loom decides to change the type or supplier of loom while he maintains his choice with regard to the crowd training device, so that it is sometimes necessary to change the entry side of the movement into the crowd formation device. With known devices, this modification is long and complex. In particular, it induces significant interventions on the peripheral mechanical parts such as the chassis and the transmission elements.

It is to these drawbacks that the present invention mainly intends to remedy, which essentially consists in providing two longitudinal shafts arranged co-axially inside a rigid tube integral with two support plates for said shafts and a mechanism for cams transmitting an alternating rotational movement from an input shaft of the shedding device to the longitudinal shafts.

Thanks to the invention, the coaxial longitudinal shafts constitute an efficient and not very complex device making it possible to transform, with the cam mechanism, the movement of the input shaft into the movement for controlling the claw frames. Thanks to the rigid tube, the plates and the longitudinal co-axial shafts constitute a solid assembly which can be manipulated in a unitary manner, for example by means of a hoist, in order to be placed on the structure of the crowd forming device. . This gives great flexibility in the manufacture of crowd forming devices according to the invention, insofar as the assembly formed by the longitudinal shafts, the tube, the plates and the cam mechanism can be mounted on the structure of the device when the side by which the movement enters the crowd-forming device is known with certainty.

According to a first advantageous aspect of the invention, the plates are removably mounted on the structure of the device. This aspect of the invention facilitates maintenance operations because, when it is necessary to access, by For example, with the selection modules for the hooks of the crowd formation device, the plates can be separated from the structure and the drive assembly formed by the plates, the shafts, the tube and the cam mechanism can be removed.

According to another advantageous aspect of the invention, the plates are capable of being mounted on the structure in two positions corresponding respectively to the positioning of the input shaft on one side or the other of the device. This aspect of the invention therefore makes it possible to produce, with the same drive assembly, a crowd training device with movement input on the right or on the left.

According to a first advantageous embodiment of the invention, the plates are asymmetrical, that is to say the axis common to the longitudinal shafts and to the tube is offset with respect to the median axis of the plates. This variant of the invention makes it possible to obtain an oblique crowd in a simple manner.

According to another advantageous variant of the invention, the plates are symmetrical, that is to say the axis common to the longitudinal shafts and to the tube is intersecting with the median axis of said plate. This aspect of the invention makes it possible to use the same plates for their mounting in the two positions corresponding to an entry of the movement on the right and an entry of the movement on the left.

According to another particularly advantageous aspect of the invention, usable with all types of plates, when the crowd formation device comprises electromagnetic modules for selecting the hooks resting on the knives, these modules are distributed in baskets able to be put in place in the device once the modules are in place in the baskets. This aspect of the invention makes it possible to prepare the modules outside the crowd training device, that is to say in particular on a workbench allowing comfortable work for an operator and of good quality and to install them. then by groups in the device of the invention.

The invention also relates to a method of mounting a crowd training device, in particular as described above. This process is characterized in that it consists in pre-mounting on the one hand a structure equipped with selection modules and on the other hand in a rigid drive assembly comprising two longitudinal shafts arranged co-axially inside a rigid tube integral with two plates and a cam mechanism and mounting said drive assembly on said structure equipped with modules. This two-stage assembly makes it possible to obtain both good flexibility in the manufacture of the device, in particular with regard to the input side of the drive movement, and an improvement in the working conditions of the operators who can perform their tasks. under conditions adapted to the assembly of each sub-assembly considered. In particular, the drive assembly can, if necessary, be pre-mounted in a clean room and moved to the structure of the crowd training device when all of its protective covers are in place.

According to an advantageous variant of the invention, the method also consists in equipping the structure with modules distributed in pre-assembled baskets. This further facilitates the work of operators.

According to another advantageous aspect of the method of the invention, the mounting of the drive assembly on the structure equipped with modules is carried out in a removable manner. This removable nature makes it possible to separate these assemblies, in particular in the event of modification of the customer's order or for maintenance operations.

The invention finally relates to a Jacquard type loom equipped with a crowd training device as previously described.

• la figure 1 est une vue en perspective des éléments cinématiques d'un dispositif de formation de la foule conforme à l'invention ;
• la figure 2 est une vue en perspective éclatée d'un dispositif de formation de la foule conforme à l'invention en cours de montage et
• la figure 3 est une coupe axiale schématique partielle d'un dispositif conforme à l'invention.

The invention will be better understood and other advantages thereof will appear more clearly in the light of the following description of an embodiment of a crowd training device for a loom in accordance with its principle. , given solely by way of example and made with reference to the appended drawings in which:

• Figure 1 is a perspective view of the kinematic elements of a crowd forming device according to the invention;
• FIG. 2 is an exploded perspective view of a crowd formation device according to the invention during assembly and
• Figure 3 is a partial schematic axial section of a device according to the invention.

In FIG. 1, the knives or blades of a crowd-forming mechanism are divided into two groups 1 and 1 ′ each suspended from a frame of claws animated by vertical reciprocating movements in phase opposition. The claw frames are formed by bars 2 and 3. The ends of bars 2 and 3 are engaged in slides 4 rigidly fixed to the frame of the device which is not shown in FIG. 1, but which appears in FIG. 2 in the form of two beams 5 and 6 with a C section.

In order to improve the guidance of its alternating vertical movement, each bar belonging to the claw frame is associated with a substantially horizontal lever. These levers bear the references 7 and 8 and are respectively associated with bars 2 and 3. One end of each lever is coupled to the corresponding bar while the opposite end pivots on the fixed frame around an axis X ₁ -X ₁ 'fixed. In the case where the depth of the machine, sometimes called the packing depth, is relatively small, for example less than 800 mm, the slides 4 can be omitted because the bars 2 and 3 have a length which does not require very precise guidance.

Above the knives 1 and 1 ′ is mounted a shaft 10 for inputting the movement of the crowd-forming device. This shaft 10 is connected by means of a coupling 11 to a second shaft 12 driven in continuous rotation by the shaft of the loom with which the shedding device is associated.

On the part of the shaft 10 which is disposed opposite the coupling 11 are wedged two conjugate cams 13 and 14 which appear more clearly in fig 3. In a manner known per se, each cam 13 or 14 is constituted by two eccentric discs, fixed side by side on the same hub, the eccentricities being oriented one opposite the other in each cam. The periphery of the discs of the two cams 13 and 14 form raceway for rollers 15, shown in the form of arrows, which are carried by radial arms 16 a , 16 b , 17 a and 17 b , oriented opposite each other and axially offset l one over the other. These arms form two rockers 16 and 17. The rocker 16 is fixed at the end of a shaft 20, mounted coaxially inside a shaft 21 of length slightly shorter than that of the shaft 20. The rocker 17 is fixed at the end of the shaft 21.

According to the invention, the two shafts 20 and 21 are arranged co-axially inside a rigid tube 22 secured to two plates 23 and 24 capable of being assembled on the beams 5 and 6, for example by means of screws represented by their center lines 25 and 26 in FIG. 2. The two co-axial shafts 20 and 21 are suitably rotatably supported in bearings added in the plates 23 and 24 and they are oriented along the longitudinal axis median of the mechanical frame in the upper part of it. The cam mechanism constituted by the elements 13 to 17 ensures the transformation of the continuous rotational movement of the input shaft 10 into an oscillating movement, while the two co-axial shafts 20 and 21 are driven by an alternating movement , in synchronism and in phase opposition, one with respect to the other.

In the immediate vicinity of the inner face of each of the two plates 23 and 24, the outer shaft 21 is cut out from two openings 21 a offset axially from one another and oriented opposite one of the 'other. Each of these lights 21a is traversed by a lever 28 fixed radially to the inner shaft 20. At the opposite of each lever 28, a lever 29 is fixed radially to the outer shaft 21 along the axis of the lever 28 corresponding . Each of the pairs of opposite levers 28 and 29 therefore constitutes a sort of plague which the two concentric shafts 20 and 21 animate with an oscillating movement.

As shown in FIG. 2, the tube 22 makes it possible to constitute a rigid assembly which can be qualified as a "drive assembly" with the shafts 10, 20 and 21 and the plates 23 and 24, this assembly being able to be mounted in one operation, on a structure which includes hook selection modules belonging to the crowd training device.

The tube 22 is connected to the plates 23 and 24 by means of upper extensions 23 a and 24 a and lower 23 b and 24 b disposed respectively above and below the pairs of levers 28 and 29 at the two ends of the tube 22.

Each lever 28 and 29 is pierced by an arcuate slot 28a, respectively 29a for the adjustable fastening of a vertical rod 30 shown in axis lines in Figure 1. The links 30 allow to alternately raise the bars 2 and 3. Thus, the movement of the costers 1 and 1 ′ is obtained from the rotation of the shaft 10 thanks to the transformation of the continuous rotation movement into a reciprocating oscillation movement inside the tube 22.

According to a particularly advantageous aspect of the invention, baskets 31 are provided in which are installed selection modules 31 ′, for example electromagnetic, intended to immobilize the hooks connected to the heddles of the harness of the Jacquard mechanism at a given point of their trajectory. These modules can be of any known type. The use of baskets 31, which are shown empty in FIG. 2 with the exception of a module 31 ′ in order to simplify the diagram, allows the baskets to be filled with modules according to a chosen configuration, then the installation of these modules 31 ', in groups each corresponding to a basket 31, between the beams 5 and 6. This procedure makes it easier to assemble in the sense that each basket can be equipped with a chosen number of modules which can be tested at by means of a device of suitable capacity.

Then, the baskets 31 are easily put in place between the beams 5 and 6 because access to the volume located between these beams is free because the device for driving the bars 2 and 3, visible in FIG. 1, doesn’t is not yet installed. Another operator can proceed, in a specially dedicated workshop, and in particular in a clean room, with the assembly of the rigid drive assembly which comprises the input shaft 10, the two longitudinal shafts 20 and 21, the tube 22 , the plates 23 and 24 and the cam mechanism 13 to 17 which appears when mounted in the upper part of FIG. 2. It is noted that this drive assembly is provided with a cover 33 which protects the cam mechanism while a sleeve 34 surrounds the shaft 10 while being fixed on the cover 33. Thus, the drive assembly is a rigid and robust device which can be manipulated, for example by means of a hoist, in order to be put in place on the structure, represented by beams 5 and 6, fitted with modules, after the baskets 31 have been put in place.

According to an advantageous aspect of the invention, the assembly of the drive assembly on the beams 5 and 6 is carried out in a removable manner, so that, during a maintenance operation, it is possible to separate the drive assembly for the rest of the structure of the crowd formation device in order to intervene on the modules by removing the baskets 31.

In view of Figure 2 in particular, it is understood that the drive assembly formed by the shafts 20 and 21, the tube 22, the plates 24 and 25 and the input shaft 10, the cover 33 and the sleeve 34 can be mounted on the beams 5 and 6 in two positions corresponding respectively to the positioning of the input shaft 10 on one side or the other of the device. This therefore makes it possible to adapt a crowd training device according to the invention to the wishes of the client, including when the latter must be satisfied as soon as possible. It suffices to keep, in the inventory of the manufacturer of crowd training devices, an adequate number of drive assemblies and an adequate number of structures of crowd training device.

We denote YY 'the middle axis of the plates 23 and 24. As it appears in FIG. 2, this axis is offset with respect to the axis XX' common to the shafts 20 and 21 and to the tube 22. This corresponds to a construction more rational of the drive assembly in which the inclination of the connecting rods 30 is limited while the forces on the levers 7 and 8 are kept at a low level. One can in particular adjust the obliquity of the crowd by means of the arched lights 28 a and 29 a . The non-symmetrical construction of the plates 23 and 24 also makes it possible to limit the dimensions of the arcuate openings 28 a and 29 a .

However, according to a variant not shown of the invention, it can be provided that the plates 23 and 24 are symmetrical, that is to say that the axis XX 'is intersecting with the median axis YY' of these plates, so that the same drive assembly can be indifferently mounted with the input shaft oriented on one side or the other of the crowd-forming device. This device is also capable of producing an oblique crowd, even if the mechanical stresses are greater than in the case where the plates are asymmetrical.

According to an advantageous aspect of the invention, the rigid structure formed essentially by the tube 22 and the plates 23 and 24 makes it possible to support the shaft 10 in overhang, which avoids having to provide a force recovery tab. on the beams 5 and 6 for the support of the shaft 10. The lower structure of the device of the invention is thus simplified.

Claims (10)

1. A shed-forming device for a weaving loom of the Jacquard type, in which alternating vertical actuation of two series of blades (1, 1') is operated from an input shaft (10) to which a continuous rotary motion is imparted,
   characterised in that it comprises two longitudinal shafts (20, 21) disposed coaxially inside a rigid tube (22) integral with two support plates (23, 24) for said shafts and a cam mechanism (13-17) transmitting an alternating rotary motion from said input shaft to said longitudinal shafts.
2. A shed-forming device according to claim 1,
   characterised in that said plates (23, 24) are mounted in removable manner on a framework (5, 6) of said device.
3. A shed-forming device according to claim 2,
   characterised in that said plates (23, 24) are capable of being mounted on said framework (5, 6) in two positions corresponding respectively to the positioning of said input shaft (10) on one or other side of said device.
4. A shed-forming device according to any one of the preceding claims, characterised in that said plates (23, 24) are asymmetrical, that is to say the axis (XX') common to said longitudinal shafts (20, 21) is offset with respect to the median axis (YY') of said plates.
5. A shed-forming device according to any one of claims 1 to 3, characterised in that said plates are symmetrical, that is to say the axis common to said longitudinal shafts intersects the median axis of said plates.
6. A shed-forming device according to any one of the preceding claims, comprising electromagnetic modules for selecting the hooks supported on said blades, characterised in that said modules (31') are distributed in magazines (31) capable of being positioned in said device once said modules are in place in said magazines.
7. A process for assembling a shed-forming device,
   characterised in that it comprises preassembling a framework (5, 6) equipped with selection modules (31'), on the one hand, and a rigid drive unit comprising two longitudinal shafts (20, 21) disposed coaxially inside a rigid tube (22) integral with two plates (23, 24) and a cam mechanism (13-17), on the other hand, and mounting said drive unit on said framework equipped with modules.
8. An assembly process according to claim 7,
   characterised in that it comprises equipping said framework with modules (31') distributed in preassembled magazines (31).
9. An assembly process according to claim 7,
   characterised in that mounting of said drive unit (13-17, 20-24) on said framework (5, 6) equipped with modules (31') is effected in removable manner.
10. A weaving loom of the Jacquard type, equipped with a shed-forming device according to any one of claims 1 to 6.