Shedding device and Jacquard weaving machine with such a device

Description

[0001] The present invention relates to a shedding device for a Jacquard type loom.

[0002] In the field of Jacquard type looms, it is known to use a shed forming device, sometimes called "Jacquard mechanics" comprising two series of longitudinal blades or knives driven by an alternating vertical movement in phase opposition, on which the hooks of the collar movement selection devices constituting the upper ends of a Jacquard harness can rest.

[0003] EP-A-3719187 discloses such a Jacquard mechanism which comprises two oscillating shafts arranged one above the other and articulated in two frame plates, between which extend two series of knives or blades, as well as the two oscillating shafts. Each oscillating shaft is equipped with a crank driven by a connecting rod which is driven by an eccentric mounted on an input shaft of the Jacquard mechanism. This Jacquard mechanism gives overall satisfaction and has the advantage of a well-controlled cost price and good compactness, which facilitates its integration within a weaving.

[0004] Such a Jacquard mechanism allows for knife movement profiles to be obtained that are sinusoidal in a time representation and very close to a pure sine function. Such a mechanism does not allow for more elaborate knife movements. With this type of shed forming device, the weaver has no other resource than to increase the stroke of the knives; the shed does not allow the insertion of the weft because it clings to the warp threads.

[0005] It is also known from CN-A-105483895 to mount, at each end of two superimposed oscillating shafts of a Jacquard mechanism, a rocker equipped with two follower rollers. These follower rollers each cooperate with a cam mounted on an input shaft of the mechanism, driven by a uniform rotational movement. This construction makes it possible to obtain knife movement profiles other than a pure sine function by adding, for example, harmonics so as to increase the insertion time available for the same weaving speed of the loom and for the same knife stroke. This construction is relatively compact in the warp direction and in a vertical direction. However, it is bulky in a direction parallel to the weft, in particular because it requires the use of four juxtaposed cams.Furthermore, the positioning of the camshaft, mid-height between the oscillating shafts, makes it difficult to lubricate the contact areas between the rollers and the cams by oil bath, particularly for the rollers associated with the upper oscillating shaft.

[0006] It is these drawbacks that the invention more particularly intends to remedy by proposing a new device for forming the shed for a Jacquard type loom which has a simple and compact structure, including in a direction parallel to the weft direction, which makes it possible to obtain knife movement profiles other than a pure sinus and in which the lubrication of the rollers is not problematic.

[0007] To this end, the invention relates to a shedding device for a Jacquard type weaving loom, this shedding device comprising two series of knives extending parallel to a longitudinal axis of the shed forming device, driven by an alternating vertical movement in phase opposition and connected at each of their ends to a drive bar; an upper oscillating shaft and a lower oscillating shaft which extend one above the other, which are respectively oscillating about an upper oscillation axis and a lower oscillation axis and which are respectively provided, at each of their ends, with two tilting levers each connected to a drive bar by a connecting rod; two chassis plates, between which the two series of knives and the oscillating shafts extend;an input shaft driven by a continuous rotational movement around an axis of rotation and equipped with a first cam and a second complementary cam, the second cam being further from the chassis plates, along the longitudinal axis, than the first cam; a roller rocker pivotally mounted around a pivot axis parallel to the axis of rotation of the input shaft, this roller rocker comprising a first roller cooperating with the first cam, a first follower arm, at one end of which the first roller is pivotally mounted, around a first roller axis, a second roller cooperating with the second cam, a second follower arm, at one end of which the second roller is pivotally mounted, around a second roller axis, an upper connecting rod arm, and a lower connecting rod arm. ;

[0008] According to the invention, the crowd forming device is such that: the upper connecting rod arm is coupled to an upper control connecting rod of the upper swinging shaft, the upper control connecting rod being coupled to an upper crank belonging to the upper swinging shaft; the lower connecting rod arm is coupled to a lower control connecting rod of the lower swinging shaft, the lower control connecting rod being coupled to a lower crank belonging to the lower swinging shaft; in a plane perpendicular to the longitudinal axis, the pivot axis of the roller rocker is arranged horizontally between the axis of rotation of the input shaft and the upper and lower swing axes; a hinge axis between the upper crank and the upper control connecting rod is located, relative to a vertical plane passing through the upper swing axis, on the same side as the axis of rotation of the input shaft;a hinge axis between the lower crank and the lower control rod is located, relative to a vertical plane passing through the lower oscillation axis, on the side opposite the axis of rotation of the input shaft; a hinge axis between the upper connecting rod arm and the upper control rod is located, relative to a plane containing the pivot axis of the roller rocker and the upper oscillation axis, on the side opposite the axis of rotation of the input shaft; and a hinge axis between the lower connecting rod arm and the lower control rod is located, relative to a plane containing the pivot axis of the roller rocker and the lower oscillation axis, on the side opposite the axis of rotation of the input shaft. ;

[0009] Thanks to the invention, the combination of the roller rocker and the first and second cams allows the use of relatively sophisticated laws of motion of the knives, while the device remains compact, in particular in a direction parallel to the weft direction of the loom on which the shedding device is mounted. Indeed, the kinematic chain for transmitting movement between the two cams and the two oscillating shafts is optimized to minimize its size, by concentrating most of the moving parts between the input shaft and the oscillating shafts, in a horizontal direction. In addition, the cost price and reliability of the shedding device are improved compared to the prior art because only two cams and two rollers are necessary, compared to the four cams and four rollers of CN-U-105483895. Finally, the structure envisaged does not cause any problems in terms of oil bath lubrication.

[0010] According to advantageous but not mandatory aspects of the invention, such a device may incorporate one or more of the following characteristics taken in any technically admissible combination: The first roller axis is located below a plane containing the pivot axis of the roller rocker and the rotation axis of the input shaft and the second roller axis is located above the plane containing the pivot axis of the roller rocker and the rotation axis of the input shaft. The first roller axis is located above a plane containing the pivot axis of the roller rocker and the rotation axis of the input shaft and the second roller axis is located below the plane containing the pivot axis of the roller rocker and the rotation axis of the input shaft.A median plane of the first cam, a median plane of the first roller, a median plane of the first follower arm, a median plane of the upper connecting rod arm, a median plane of the upper control connecting rod and a median plane of the upper crank are merged and included in a first main median plane, while a median plane of the second cam, a median plane of the second roller, a median plane of the second follower arm, a median plane of the lower connecting rod arm, a median plane of the lower control connecting rod and a median plane of the lower crank are merged and included in a second main median plane.A median plane of the first cam, a median plane of the first roller, a median plane of the first follower arm, a median plane of the lower connecting rod arm, a median plane of the lower control rod and a median plane of the lower crank are merged and included in a first main median plane, while a median plane of the second cam, a median plane of the second roller, a median plane of the second follower arm, a median plane of the upper connecting rod arm, a median plane of the upper control rod and a median plane of the upper crank are merged and included in a second main median plane. The first and second main median planes are offset along the longitudinal axis and perpendicular to this axis. The first main median plane is closer to the chassis plates than the second main median plane.The upper connecting rod arm, the upper control rod and the upper crank together define a generally Z-shaped or inverted Z-shaped articulated structure. The lower connecting rod arm, the lower control rod and the lower crank together define a generally U-shaped articulated structure. The first and second cams, the roller rocker, the upper and lower control rods and the upper and lower cranks are removable and replaceable to change the shedding device from a first configuration, with a cam-driven assembly of the upper and lower oscillating shafts, to a second configuration with a crank-driven assembly of the upper and lower oscillating shafts, and vice versa, without disassembling the upper and lower oscillating shafts from the chassis plate which supports the input shaft.

[0011] According to a second aspect, the invention relates to a Jacquard type loom which comprises, among other things, a shed forming device as mentioned above.

[0012] Such a loom can operate at high speeds, reliably, while remaining compact and inexpensive to manufacture and operate.

[0013] 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 shed forming device and of a weaving loom in accordance with its principle, given solely by way of example and with reference to the appended drawings in which: [ Fig.1 ] There figure 1 is a partial perspective view of a loom according to the invention incorporating a shed forming device according to the invention; [ Fig 2 ] there figure 2 is a perspective view, from another angle, of the crowd forming device according to the invention shown in figure 1 , certain parts of this device being omitted for clarity of the drawing; [ Fig.3 ] There figure 3 is an end view in the direction of arrow F3 at figure 2 ; [ Fig.4 ] There figure 4 is a view taken under the same conditions as the figure 3 when the loom is in another configuration; [ Fig.5 ] There figure 5 represents, on two inserts A and B, a part of a crowd-forming device according to a second embodiment of the invention, seen in perspective from two different angles and; [ Fig.6 ] There figure 6 is a perspective view of a portion of a crowd forming device according to a third embodiment.

[0014] The loom M represented very schematically in the figure 1 is of the Jacquard loom type and comprises a shed forming device, 2, also called “Jacquard mechanics”, intended to move alternately, with a vertical movement represented by the double arrow F1 at the figure 1 , 4 rails provided with eyelets 42 for passing warp threads 6.

[0015] The different rails are supported by the cords of a Jacquard harness 8 whose upper ends are connected to the collars of selection devices provided with hooks 10 resting on two series of knives 12 and 14 driven by an alternating vertical movement in phase opposition represented by the double arrow F2 at the figure 1 The two sets of knives 12 and 14 are nested within each other, in the sense that, except at the longitudinal edges of the shed-forming device 2, a knife 12 is arranged between two knives 14 and vice versa.

[0016] The shedding device 2 comprises a frame 16 which includes two longitudinal cross members 18 and 20 extending parallel to a longitudinal axis X2 of the shedding device 2. For clarity of the drawing, the longitudinal cross member 20 is omitted in the figure 1 , while the longitudinal crosspiece 18 is omitted at the figure 2 .

[0017] We define an orthogonal reference XYZ associated with the loom M and the shed forming device 2, whose X axis is horizontal and parallel to the X2 axis, whose Y axis is horizontal and perpendicular to the X axis and whose Z axis is vertical and directed upwards. In particular, the YZ plane is perpendicular to the X axis, therefore to the X2 axis. figures 3 And 4are taken parallel to the YZ plane. The X axis defines a longitudinal direction of the shedding device, while the Y axis defines a transverse direction of this shedding device and the Z axis defines a height direction of this shedding device.

[0018] In the present description, an axis or a plane is said to be horizontal when it forms, in the assembled and installed configuration of the crowd forming device 2 on the loom M, an angle of less than 5° with a horizontal plane. Furthermore, an axis or a plane is said to be vertical when it forms, in the assembled and installed configuration of the crowd forming device 2 on the loom M, an angle of less than 5° with a vertical plane.

[0019] The two sets of knives 12 and 14 extend between the longitudinal crosspieces 18 and 20, parallel to the axis X2.

[0020] The chassis 16 also comprises a first chassis plate 22 and a second chassis plate 24 arranged between the longitudinal crosspieces 18 and 20 and which each extend perpendicular to the axis X2. The two series of knives 12 and 14 are arranged, along the axis X2, in a volume V2 of the shed-forming device 2 located between the plates 22 and 24.

[0021] Each chassis plate 22 or 24 is made by casting and machining metal, preferably cast iron, and includes stiffening ribs, some of which are visible on the figures 1 And 2 with the reference 241 for the plate 24. The stiffening ribs of the plate 22 are hidden at the figure 1 . For clarity of drawing, plate 22 is omitted in the figure 2 .

[0022] Each knife 12 or 14 of a series of knives is guided linearly in its vertical movement according to the double arrow F2 and connected, at each of its ends, to a connecting rod 26 suspended from a drive bar, also called an “oblique bar”. More precisely, each knife of a series of knives 12 or 14 is suspended by two connecting rods 26 from two drive bars, namely a first drive bar arranged in the vicinity of the plate 22 and a second drive bar arranged in the vicinity of the plate 24.

[0023] The four training bars are visible at the figure 2 and comprise a first drive bar 30 and a second drive bar 32 arranged in the vicinity of the plate 22, as well as a third drive bar 34 and a fourth drive bar 36 arranged in the vicinity of the plate 24. The four drive bars 30 to 36 are each respectively articulated on a guide arm, itself articulated on the chassis 16, at or in the vicinity of the longitudinal cross member 18. A single guide arm is visible at the figure 1 , with reference 31, the guide arms being omitted on the figure 2 , for clarity of drawing.

[0024] Each drive bar consists of two flanges, as seen in particular for drive bar 30, the flanges of which are designated 302 and 304.

[0025] The shedding device 2 also comprises an upper oscillating shaft 40 and a lower oscillating shaft 42 arranged one above the other and extending parallel to the axis X2. X40 denotes an oscillation axis of the upper oscillating shaft 40, in other words an upper oscillation axis, and X42 denotes an oscillation axis of the lower oscillating shaft 40, in other words a lower oscillation axis. The axes X40 and X42 are longitudinal axes of the oscillating shafts 40 and 42.

[0026] In this example, the X2, X40 and X42 axes are parallel.

[0027] The upper oscillating shaft 40 comprises a tube 402 whose diameter is, in the example, equal to 120 mm. In practice, the diameter of the tube 402 is between 80 and 160 mm, preferably between 100 and 140 mm, more preferably of the order of 120 mm, which gives it good torsional rigidity.

[0028] At each of its ends, the tube 402 is fixed to a rocker 404 which also belongs to the shaft 40 and which defines two rocking levers 405 and 406.

[0029] Similarly, the lower swing shaft 42 comprises a central tube and two rockers which each define two rocking levers.

[0030] In the example, the diameter of the central tube of the lower swing shaft 42 is the same as that of the tube 402. This is not mandatory and, alternatively, the diameters of the swing shafts may be different.

[0031] The rockers 404 and equivalent are respectively secured to the tubes 402 and equivalent by screws parallel to the axes X40 and X42.

[0032] In the vicinity of the plate 22, the tilting levers 405 and 406 of the rocker 404 are respectively connected to the drive bars 30 and 32 by means of connecting rods 50. In the same way, in the vicinity of the plate 24, the tilting levers 405 and 406 of the rocker 404 are respectively connected to the drive bars 34 and 36 by means of connecting rods 50.

[0033] In the vicinity of the plate 22, the rocking levers of the first rocker of the lower oscillating shaft 42 are respectively connected to the drive bars 30 and 32 by means of connecting rods 52. In the same way, in the vicinity of the plate 24, the rocking levers of the second rocker of the lower oscillating shaft 42 are respectively connected to the drive bars 34 and 36 by means of connecting rods 52.

[0034] The position of the articulation points of the connecting rods 50 and 52 on the rocking levers 405, 406 and equivalents is adjustable, in arc-shaped notches provided on these rocking levers.

[0035] The two oscillating shafts 40 and 42 are driven in rotation, respectively around the axes X40 and X42 by a drive assembly 70 arranged on the side of the plate 22 opposite the knives 12 and 14, that is to say the outside of the volume V2. The movement or control of the oscillating shafts 40 and 42 thus comes from the side of the plate 22 which can be called the “control plate”.

[0036] The drive assembly 70 comprises an input shaft 72 driven by a continuous rotational movement around an axis X72, this movement being represented by the arrows F4 at figures 1 And 2 .

[0037] The input shaft 72 carries a first cam 74 and a second cam 76 which are complementary and angularly offset around the axis X72.

[0038] In a direction parallel to the X axis, the first cam 74 is closer to the control plate 22 than the second cam 76. In other words, along the X and X2 axes, the second cam 76 is further from the chassis plates 22 and 24 than the first cam 74.

[0039] The drive assembly 70 also includes a roller rocker 80 which is pivotally mounted about a pivot axis X80 parallel to the axis X72.

[0040] The roller rocker 80 is a mechanical organ formed of several parts and designed to rock, in other words to pivot, with back and forth movements around the axis X80.

[0041] The roller rocker 80 comprises a first roller 84 bearing on an external peripheral track of the first cam 74, as well as a second roller 86 bearing on an external peripheral track of the second cam 76.

[0042] The roller 84 is rotatably mounted, around a roller axis X84 parallel to the X axis, at a distal end 942 of a first follower arm 94. The second roller 86 is rotatably mounted, around a roller axis X86 parallel to the X axis, at a distal end 962 of a second follower arm 96. The follower arms 94 and 96 belong to the roller rocker 80.

[0043] The two follower arms 94 and 96 extend from a central shaft 82 of the roller rocker 80. The distal ends 942 and 962 of the two follower arms 94 and 96 are the ends of these arms which are furthest from this central shaft 82.

[0044] The roller rocker also comprises an upper connecting rod arm 104 and a lower connecting rod arm 106, the distal ends of which, opposite the central shaft 82, are denoted 1042 and 1062 respectively.

[0045] In summary, the roller rocker 80 comprises the elements 82, 84, 86, 94, 96, 104 and 106. The arms 94, 96, 104 and 106 of the roller rocker 80 are integral with the central shaft 82, pivoting around the axis X80.

[0046] At its distal end 1042, the upper connecting rod arm 104 is articulated, around an axis X104, on an upper control connecting rod 114. In the same way, at its distal end 1062, the lower connecting rod arm 106 is articulated, around an axis X106, on a lower control connecting rod 116. The axes X104 and X106 are parallel to the axis X.

[0047] At its end opposite the upper connecting rod arm 104, the upper control connecting rod 114 is articulated, around an axis X114, on an upper crank 408 which belongs to the upper oscillating shaft 40. In the same way, at its end opposite the lower connecting rod arm 106, the lower control connecting rod 116 is articulated, around an axis X116, on a lower crank 428 which belongs to the lower oscillating shaft 42. The axes X114 and X116 are parallel to the axis X.

[0048] The cranks 408 and 428 are respectively mounted on the rockers 404 and equivalents which pass through the plate 22, on the side of these rockers opposite the tubes 402 and 422. Screws parallel to the axes X40 and X42 are used to secure the rockers and the cranks together.

[0049] The articulations made at the axes X104, X106, X114 and X116 have the effect that the upper and lower connecting rod arms 104 and 106 are respectively coupled to the upper and lower control connecting rods 114 and 116 and that these connecting rods are respectively coupled to the upper and lower cranks 408 and 428.

[0050] Thus, a movement originating from the cam 74 is transmitted to the upper oscillating shaft 40 by the kinematic chain formed by the elements 84, 94, 104, 114 and 408, while a movement originating from the cam 76 is transmitted to the lower oscillating shaft 42 by the kinematic chain formed by the elements 86, 96, 106, 116 and 428.

[0051] As is more particularly evident from the figure 3 , the pivot axis X80 of the roller rocker 80 is arranged horizontally, i.e. here in a direction parallel to the Y axis, between the rotation axis X72 of the shaft 72 and the upper X40 and lower X42 oscillation axes. This makes it possible to arrange the roller rocker 80 between the input shaft 72 and the oscillating shafts 40 and 42, in the transverse direction of the shed-forming device 2. It is therefore not necessary to offset the roller rocker 80 relative to the shafts 40, 42 and 72 in the longitudinal direction X of the shed-forming device, which allows this device to be compact in the warp direction of the loom M, which is parallel to the longitudinal direction of the shed-forming device.

[0052] We denote P40 a vertical plane containing the upper oscillation axis X40. We denote P42 a vertical plane containing the lower oscillation axis P42. The planes P40 and P42 are parallel to the X and Z axes.

[0053] In the example in the figures, planes P40 and P42 are merged. However, this is not mandatory.

[0054] As is evident from the figure 3 , the axis X114 is located, relative to the plane P40, on the same side as the axis X72. On the other hand, the axis X116 is located, relative to the plane P42, on the side opposite the axis X72. This contributes to the compactness of the drive assembly 70.

[0055] We denote by π40 a plane containing the axes X80 and X40. We denote by π42 a plane containing the axes X80 and X42. The axis X104 is located, with respect to the plane π40, on the side opposite to the axis X72. On the other hand, the axis X106 is located, with respect to the plane π42, on the side opposite to the axis X72. This also contributes to the compactness of the drive assembly 70.

[0056] Consider the articulated structure formed by the upper connecting rod arm 104, the upper control rod 114 and the crank 408. This articulated structure is generally in the shape of an inverted Z. Alternatively, this articulated structure may be Z-shaped. Also consider the articulated structure formed by the lower connecting rod arm 106, the control rod 116 and the crank 428. This second articulated structure is generally U-shaped. The shapes of these first and second articulated structures also contribute to the compactness of the drive assembly 70. They allow the upper and lower oscillating shafts 40 and 42 to rotate in opposite directions to each other to drive the two sets of knives 12 and 14 in phase opposition.

[0057] Thanks to this spatial arrangement of the constituent parts of the drive assembly 70, in particular thanks to the combination of the distributions of the axes X40 to X116, of the planes P40, P42, π40 and π42, this drive assembly can be particularly compact, including in the longitudinal direction of the shed forming device 2, that is to say in the weft direction of the loom M.

[0058] The median plane of a constituent element of the drive assembly 70 is defined as a plane located midway, along the X axis, between the ends of this element.

[0059] In the first embodiment of the invention, a median plane of the first cam 74, a median plane of the first roller 84, a median plane of the first follower arm 94, a median plane of the upper connecting rod arm 104, a median plane of the upper control connecting rod 114 and a median plane of the upper crank 408 are merged and included in a first main median P1.

[0060] On the other hand, a median plane of the second cam 76, a median plane of the second roller 86, a median plane of the second follower arm 96, a median plane of the lower connecting rod arm 106 and a median plane of the lower control connecting rod 116 and a median plane of the lower crank 428 are merged and included in a second main median plane P2.

[0061] The first and second principal median planes P1 and P2 are parallel to the YZ plane of the XYZ reference frame, therefore perpendicular to the X axis.

[0062] The first and second principal midplanes P1 and P2 are offset along the X axis, hence along the X2 axis. Here, the first principal plane P1 is closer to the chassis plates 22 and 24 than the second principal plane P2.

[0063] The drive assembly 70 is covered by a cover 120 outside of which the input shaft 72 protrudes so that it can be connected to a drive shaft not shown. The cover 120 can be equipped with force-recovery bearings at the end of the shafts 40 and 42 and the central shaft 82 of the roller rocker 80. These bearings are respectively closed by plugs 122, 124 and 126. This is why they are not visible at the figure 1 .

[0064] Advantageously, the rotation axis X72 of the input shaft 72 is located, along the Z axis, lower than the pivot axis X80 of the roller rocker 80.

[0065] As is evident from the figure 3 , the good compactness of the drive assembly 70 and the relative positioning of the axes X72 and X80 allows effective oil bath lubrication of the elements 74 to 116, particularly of the elements 74, 76, 84 and 86, when the cover 120 is in place.

[0066] The compactness of the drive assembly 70 allows it to be installed in the space required by a connecting rod-crank type drive system 70' in which two eccentrics 174 and 176 are mounted on the input shaft 70. Such a connecting rod-crank system is shown in FIG. figure 4 The first eccentric 174 drives a first control rod 184 which is coupled to the upper crank 408. The second eccentric 176 drives a second control rod 186 which is coupled to the lower crank 428. This drive system 70' may be in accordance with the technical teaching of EP-A-3719187. Alternatively, this drive system 70' is of a different type.

[0067] It is therefore possible to change the loom M from the configuration shown in figures 1 à 3 , with a 70 cam and follower roller drive device, in the configuration shown in figure 4 , with a 70' connecting rod-crank drive device.

[0068] To this end, the first and second cams 74 and 76, the roller rocker 80, the upper and lower control rods 114 and 116 and the upper and lower cranks 408 and 428 are provided removably in the device 70, so that they can be replaced to install the eccentrics 174 and 176, the control rods 184 and 186 and new upper and lower cranks 408 and 428 on the upper and lower oscillating shafts 40 and 42.

[0069] Advantageously, the upper and lower cranks 408 and 428 can be common to the two drive devices 70 and 70' but secured to the upper and lower oscillating shafts 40 and 42 in different orientations.

[0070] Conversely, the eccentrics 174 and 176, the control rods 184 and 186 and the upper and lower cranks 408 and 428 of the drive device 70' are removably mounted and can be replaced by the first and second cams 74 and 76, the roller rocker 80, the upper and lower control rods 114 and 116 and new upper and lower cranks 408 and 428, when it is necessary to change the loom M from the configuration of the figure 4 to the configuration of the figures 1 à 3 .

[0071] The size of the drive device 70 is not greater than the size of the drive device 70'.

[0072] In the second and third embodiments of the invention shown in figures 5 And 6 , elements similar to those of the first embodiment bear the same references. If a reference is given in one of these figures without being mentioned in the description, it corresponds to the same element in the first embodiment. Furthermore, if a reference is mentioned in the description without being shown in the figures, it corresponds to the same element in the first embodiment. In the following, we mainly describe what distinguishes these second and third embodiments from the first embodiment.

[0073] In the second embodiment, the first main median plane P1 includes the median plane of the first cam 74, the median plane of the first roller 84, the median plane of the first follower arm 94, the median plane of the lower connecting rod arm 106, the median plane of the lower control rod 116 and the median plane of the lower crank 428. On the other hand, the second main median plane P2 includes the median plane of the second cam 76, the median plane of the second roller 86, the median plane of the second follower arm 96, the median plane of the upper connecting rod arm 104, the median plane of the upper control rod 114 and the median plane of the upper crank 408.

[0074] In other words, the distribution of the median planes of the constituent elements of the drive assembly 70, between the main median planes P1 and P2 is modified compared to the first embodiment, while maintaining good compactness in the longitudinal direction of the crowd forming device 2.

[0075] In this embodiment also, the first and second main midplanes are offset along the X axis, thus along the X2 axis. Here, the first main plane P1 is closer to the chassis plates 22 and 24 than the second main plane P2.

[0076] In the third embodiment, the first roller axis X84 is located above the plane π72 defined as in the first embodiment, while the second roller axis X86 is located below this plane.

[0077] For the rest, the distribution of the median planes of the constituent elements of the drive device 70 of the third embodiment is comparable to that of the first embodiment.

[0078] In the second and third embodiments, as in the first embodiment, the pivot axis X80 of the roller rocker 80 is arranged horizontally between the rotation axis X72 of the input shaft 72 and the oscillation axes X40 and X42 of the oscillating shafts 40 and 42. On the other hand, the axis X114 is located, relative to the plane P40 defined as in the first embodiment, on the same side as the rotation axis X72, while the axis X116 is located, relative to a vertical plane P42 defined as in the first embodiment, on the side opposite the axis X72. Furthermore, the X104 axis is located, relative to a π40 plane containing the X80 and X40 axes, on the side opposite the X72 axis, while the X116 axis is located, relative to a π42 plane containing the X80 and X42 axes, on the side opposite the X72 axis.

[0079] The drive assemblies 70 of the second and third embodiments are also removable, as explained with reference to the first embodiment, which allows them to be replaced by connecting rod-crank type drive assemblies, such as the assembly 70'.

[0080] Thus, whatever the embodiment, the shedding device 2 and the loom M of the invention have a high adaptability since it allows to switch from a configuration with cam and follower roller drive assembly to a configuration with connecting rod-crank type drive assembly, and vice versa. This allows to adapt the weaving loom M to its conditions of use, which can vary during the lifetime of the weaving loom and the shedding device 2. The switch from one configuration to the other is reversible. For example, a weaving loom can be used for a few years with a connecting rod-crank type drive system to weave fabrics whose warp threads uncross easily and allow the use of a knife movement profile close to a pure sine function.This allows the cost of the drive device 2 to be well controlled when it is purchased, because it is not necessary to machine cams, which is a relatively complex operation. If the loom M is then to be used to manufacture fabrics whose warp threads catch together when the shed opens, it is possible to retrofit the shed-forming device 2 with a drive assembly 70 as shown in . figures 2 , 3 , 5 And 6 to allow a movement profile of the knives 12 and 14 for which the speed of the warp threads at the crossing is higher than for a movement profile close to a pure sine function. This is possible thanks to the compactness of the drive assembly 70 of the shed forming device 2 of the present invention which can fit into the size of a connecting rod-crank type drive system 70'.

[0081] The embodiments and variations mentioned above can be combined to generate new embodiments of the invention.

[0082] The invention has been described for a kinematic system comprising two series of knives 12 and 14 connected at each of their ends to a drive bar 30, 32, 34 or 36 by means of connecting rods 26. It also applies to a kinematic system in which each series of knives constitutes a rigid assembly secured to two drive bars located on each side of the machine, thus forming a frame of claws.

Claims

1. A shed-forming device (2) for a Jacquard loom (M), comprising - two sets of knives (12, 14) extending parallel to a longitudinal axis (X2) of the shed-forming device, animated by an alternating vertical movement (F2) in phase opposition and connected at each of their ends to a drive bar (30, 32, 34, 36); - an upper oscillating shaft (40) and a lower oscillating shaft (42) which extend one above the other, which are respectively oscillating about an upper oscillation axis (X40) and a lower oscillation axis (X42) and which are respectively provided, at each of their ends, with two tilting levers (405, 406) each connected to a drive bar (30, 32, 34, 36) by a connecting rod (50, 52); - two frame plates (22, 24), between which extend the two sets of knives and the oscillating shafts; - an input shaft (72) driven in a continuous rotary motion (F4) about an axis of rotation (X72) and equipped with a first cam (74) and a second complementary cam (76), the second cam (76) being further away from the frame plates along the longitudinal axis than the first cam; - a roller rocker (80) mounted to pivot about a pivot axis (X80) parallel to the axis of rotation (X72) of the input shaft, this roller rocker comprising • a first roller (84) cooperating with the first cam (74), • a first follower arm (94), at one end (942) of which the first roller is pivotally mounted about a first roller axis (X84), • a second roller (86) cooperating with the second cam (76), • a second follower arm (96), at one end (962) of which the second roller is pivotally mounted about a second roller axis (X86), • an upper connecting rod arm (104), and • a lower connecting rod arm (106), characterized in that - the upper connecting rod arm (104) is coupled to an upper control rod (114) of the upper oscillating shaft (40), the upper control rod being coupled to an upper crank (408) belonging to the upper oscillating shaft; - the lower connecting rod arm (106) is coupled to a lower control rod (116) of the lower oscillating shaft (42), the lower control rod being coupled to a lower crank (428) belonging to the lower oscillating shaft; - in a plane (YZ) perpendicular to the longitudinal axis (X2), the pivot axis (X80) of the roller rocker (80) is located horizontally between the axis of rotation (X72) of the input shaft (72) and the upper and lower axes of oscillation (X40, X42); - an articulation axis (X114) between the upper crank (408) and the upper control rod (114) is located, relative to a vertical plane (P40) passing through the upper axis of oscillation (X40), on the same side as the axis of rotation (X72) of the input shaft (72); - an axis of articulation (X116) between the lower crank (428) and the lower control rod (116) is located, relative to a vertical plane (P42) passing through the lower axis of oscillation (X42), on the opposite side to the axis of rotation (X72) of the input shaft (72); - an articulation axis (X104) between the upper connecting rod arm (104) and the upper control rod (114) is located, relative to a plane (π40) containing the pivot axis (X80) of the roller rocker (80) and the upper oscillation axis (X40), on the opposite side to the axis of rotation (X72) of the input shaft (72); and - an articulation axis (X106) between the lower connecting rod arm (106) and the lower control rod (116) is located, relative to a plane (rr42) containing the pivot axis (X80) of the roller rocker (80) and the lower oscillation axis (X42), on the opposite side to the axis of rotation (X72) of the input shaft (72).

2. The shed-forming device according to claim 1, characterized in that - the first roller axis (X84) is located below a plane (π72) containing the pivot axis (X80) of the roller rocker (80) and the axis of rotation (X72) of the input shaft (72); and - the second roller axis (X86) is located above the plane (π72) containing the pivot axis (X80) of the roller rocker (80) and the axis of rotation (X72) of the input shaft (72).

3. The shed-forming device according to claim 1, characterized in that - the first roller axis (X84) is located above a plane (π72) containing the pivot axis (X80) of the roller rocker (80) and the axis of rotation (X72) of the input shaft (72); and - the second roller axis (X86) is located below the plane (π72) containing the pivot axis of the roller rocker (80) and the axis of rotation (X72) of the input shaft (72).

4. The shed-forming device according to one of the preceding claims, characterized in that - a median plane of the first cam (74), a median plane of the first roller (84), a median plane of the first follower arm (94), a median plane of the upper connecting rod arm (104), a median plane of the upper control rod (114) and a median plane of the upper crank (408) are coincident and included in a first main median plane (P1); - a median plane of the second cam (76), a median plane of the second roller (86), a median plane of the second follower arm (96), a median plane of the lower connecting rod arm (106), a median plane of the lower control rod (116) and a median plane of the lower crank (428) are coincident and included in a second main median plane (P2).

5. The shed-forming device according to one of claims 1 to 3, characterized in that - a median plane of the first cam (74), a median plane of the first roller (84), a median plane of the first follower arm (94), a median plane of the lower connecting rod arm (106), a median plane of the lower control rod (116) and a median plane of the lower crank (428) are coincident and included in a first main median plane (P1); - a median plane of the second cam (76), a median plane of the second roller (86), a median plane of the second follower arm (96), a median plane of the upper connecting rod arm (104), a median plane of the upper control rod (114) and a median plane of the upper crank (408) are coincident and included in a second main median plane (P2).

6. The shed-forming device according to one of claims 4 and 5, characterized in that the first and second main median planes (P1, P2) are offset along the longitudinal axis (X2) and perpendicular to this axis.

7. The shed-forming device according to claim 6, characterized in that the first main median plane (P1) is closer to the frame plates (22, 24) than the second main median plane (P2).

8. The shed-forming device according to one of the preceding claims, characterized in that - the upper connecting rod arm (104), the upper control rod (114) and the upper crank (408) together define a generally Z-shaped or inverted-Z-shaped articulated structure; and - the lower connecting rod arm (106), the lower control rod (116) and the lower crank (428) together define a generally U-shaped articulated structure.

9. The shed-forming device according to one of the preceding claims, characterized in that the first and second cams (74, 76), the roller rocker (80), the upper and lower control rods (114, 116) and the upper and lower cranks (408, 428) are able to be removed and replaced to change the shed-forming device from a first configuration, with the cam-operated drive assembly (70) for the upper and lower oscillating shafts (40, 42), to a second configuration with the crank-operated drive assembly (70') for the upper and lower oscillating shafts, and vice versa, without dismantling the upper and lower oscillating shafts (40, 42) relative to the frame plate (22) supporting the input shaft.

10. A Jacquard loom (M) comprising a shedding device (2) according to one of the preceding claims.