FR2857380A1 - Rectilinear textile combing procedure and machine uses regulation of fibre head length while retaining pulling capacity - Google Patents

Abstract

The procedure, for use on a rectilinear combing machine with a feeder, puller and fibre (14) head cleaner, employs a clamp (3) with upper (4) and lower (5) jaws and a metal sheet (6) between them. It consists of regulating the grading basis and withdrawing the fibres to reduce their length projecting beyond the clamp before it is closed, while retaining a good pulling capacity and a high mechanical spacing value. The withdrawal of the fibres is carried out by holding the fibre heads by the feeder and pulling it back before the clamp is closed, using a cam and lever system connected to the feed grid (1) and comb (2), with the latter in its lowered position. In a variant the feeder can be in the form of a continuous chain moving bars equipped with needles or points like a plain gill system.

Description

1 DESCRIPTION

  The present invention relates to the field of the textile industry, in particular the rectilinear combers, and relates to a combing process consisting in adjusting the sorting base at constant spacing of a rectilinear combing machine, as well as a device for implementation of this method.

  The combing cycle of modern rectilinear combers, which are derived from models dating back to the mid-19th century, is well known and can be broken down into two phases, the first of which is called combing of the fiber heads and the second of combing the tails. fiber.

  The combing phase of the fiber heads occurs when the clamp is closed, while the combing phase of the fiber tails occurs at the time of tearing, when the clamp is open.

  The combing phase of the fiber heads is traditionally performed by a segment of needles or teeth arranged on a part of the periphery of a rotary cylinder, commonly called a circular comb, while the combing phase of the fiber tails is carried out by a comb commonly called fixed or straight comb.

  EP-A-1 254 976 also discloses rectilinear combers, in which the combing phase of the fiber heads is, for its part, carried out by the fiber head cleaning device, which comprises a circular comb under shape of a cylinder filled on all its periphery with needles or teeth and whose speed of rotation is continuous.

  Each phase of combing has the consequence of producing the blush, the importance of which is dependent on the sorting base.

  The sorting base is the value of the length of the longest fibers that can be found in the blush and is always less than the value of the spacing between the clamp and the pullers. In this case, when the mechanical spacing of a rectilinear combing machine is set to 34 mm, for example, then we can expect to obtain a sorting base of about 28 mm. This means that fibers longer than 28 mm in the blush should not be found.

  At present, in order to change the sorting base of the rectilinear combers it is necessary to modify the value of the spacing of the machine. The mechanical distance of a straight-edge combing machine is the distance between the end of the lower jaw of the gripper of the fiber nip between the upper tearing cylinder and the pulling sleeve, when the carriage supporting the pulling cylinders is in the extreme position near the clamp. The spacing is expressed in millimeters and the values commonly encountered vary from 25 mm to 40 mm. Thus, for example when the combed materials are short, i.e. they have low average heights, it is preferable to choose a reduced gap value, i.e. reduced sorting, so as not to create too much blush.

  When the materials to be combed are long we can choose, depending on the desired result, either low spacing values, so as not to create too much blush, or high spacings, so as to voluntarily increase the rate of nozzles to remove fibers considered too short and harmful to a good quality of yarn or to increase the average height of the combed fibers. We will also choose, preferably, high spacing values when we try to improve the cleanliness of the combed tape, or when we have to comb very fine fibers such as microfibres, or strong fiber fiber cohesion such as flat synthetic fibers, for example. In addition, high spacing values will be chosen especially when it is sought to achieve high yields by increasing the feed load or the feed value of the combing machine.

  Currently, to increase the sorting base, one is forced to increase the spacing of the rectilinear combers and it is possible, either to move the carriage supporting the tearing cylinders, to move it away from the lower clamp jaw, or move the clamp away from the pullers. These mechanical adjustments must be systematically performed before each launch of a new batch of material, in order to optimize the desired result. They are tedious and time consuming.

  In addition, they require the intervention of a mechanic trimmer. In addition, these settings are to be reproduced on each of the combers who are placed in battery of 4 to 12 machines. These spacing adjustments are costly in terms of labor and delay, which hampers the competitiveness of the user companies.

  In addition, when it is desired to reduce the blurring rate, that is to say when a reduced sorting base is desired, it is systematically forced to choose reduced spacing values, of the order from 28 mm to 30 mm, for example, for fibers called Open Top, which limits the feed load and therefore the production of the combing machine.

  The present invention proposes to overcome these drawbacks and relates to a combing method consisting of adjusting the sorting base at constant spacing of a rectilinear combing machine, as well as a device for implementing this method, allowing a significant reduction of the blush and improved performance of the combing machine.

  For this purpose, the combing method which is the subject of the invention is characterized in that it consists in adjusting the sorting base by making the fiber heads protruding from the open gripper, before the beginning of the combing phase of the heads. , a backward movement so as to reduce the length of the fibers protruding from the clamp when it is closed, while maintaining a good tearing capacity related to a large mechanical gap value.

  According to one characteristic of the invention, the backward movement of the fiber heads is adjustable.

  According to another characteristic of the invention, the backward displacement of the fiber heads is achieved by maintaining said fiber heads by the feed device, before closing the clamp.

  Thus, the rate of nozzles is reduced and the effect obtained is similar to that which one would obtain if one painted this same material with a reduced spacing, but while maintaining a strong capacity of pulling which authorizes larger productions. An identical result, that is to say a reduction of the blush rate for a high gap value, is obtained by performing a supercharging before 360 degrees machine, which is added to the normal feed, followed by a decline in the The invention also relates to a device for the implementation of this method, characterized in that it is in the form of a means for adjusting the sorting base at the same time. constant spacing of a rectilinear combing machine, making a recoil of the feed device, and therefore the fiber heads, before closing the clamp.

  According to one characteristic of the invention, the means for adjusting the constant spacing sorting base is constituted, preferably, by at least one cam cooperating with a roller connected by means of a lever transmission to the grid and comb food, the profile of the cam being such that it achieves the recoil of the grid and the lowered food comb, and therefore the fiber heads, before closing the clamp.

  According to one characteristic of the invention, the means for adjusting the constant gap sorting base consists of several interchangeable cams having the same profile characteristic, but with different amplitudes depending on the desired retraction value.

  Advantageously, the feeding device can be made in the form of a food comb associated with a food grid.

  It is also possible, according to an alternative embodiment of the invention, to provide the feeding device in the form of a caterpillar moving bars equipped with needles or points in the manner of a simple gills.

  According to another alternative embodiment of the invention, the feed device may also be in the form of a cylinder filled with needles or spikes.

  The invention will be better understood, thanks to the following description, which refers to preferred embodiments, given by way of non-limiting examples, and explained with reference to the appended diagrammatic drawings, in which: FIG. a partial view in side elevation and in section of a combing combing combing fiber tails; Figure 2 is a view similar to that of Figure 1 of the combing combing phase of the fiber heads; FIG. 3 is a partial view in side elevation and in section showing the adjustment means of the sorting base according to the invention, and FIGS. 4 to 6 are fragmentary front elevation views of various embodiments of the setting of the sorting base.

  FIG. 1 of the appended drawings shows the rectilinear combing machine according to the invention, in tearing phase, this combing machine comprising a feeding device, a pulling device, a device for cleaning the fiber heads and a cleaning device. tails of fibers.

  FIG. 1 of the appended drawings shows the rectilinear combing machine according to the invention, in tearing phase, this combing machine comprising a feeding device, a pulling device, a device for cleaning the fiber heads and a cleaning device. tails of fibers.

  The feed device is constituted by a food comb 1, which is associated with a food grid 2, by a clamp 3 formed by an upper jaw 4 cooperating with a lower jaw 5 and by a sheet between clamp 6.

  The textile material is moved by the feed device thus formed to be brought into contact with the fiber head cleaning device, which carries out the combing phase of said fiber heads.

  The textile material passes between the food comb 1 and the food grid 2, which are movable in such a way that they can be separated from one another and that they can be moved together, or in the direction of movement of the the textile material, in the opposite direction of the movement of the textile material. In this case, during a machine cycle, the comb 1 deviates from the grid 2, then the comb and the grid recoil together, the comb is then close to the grid and the comb needles cross the textile material. Then, this assembly thus formed advances in bringing with it the textile material, so as to supply a new fiber fringe, the tearing of the previous, and to present the fiber heads 14 to the device of cleaning the fiber heads.

  Then, as shown in Figure 2, the clamp 3 closes and the lower jaw 5, which is articulated to the frame of the machine, is lowered to approach the fiber head cleaning device. The upper jaw 4, which is also articulated to the frame of the machine, is lowered, in order to get closer to the lower jaw 5, until it comes into contact with it to pinch the fibers located between the two jaws 4 and 5 and to retain them, then the upper jaw 4 continues its movement towards the cleaning device of the fiber heads and carries with it the lower jaw 5. This movement of the lower jaw to the circular comb 7 is carried out gradually.

  The combing phase of the fiber heads then begins and is carried out by the fiber head cleaning device, which is constituted by a circular comb 7, which is, for example, in the form of a cylinder packed on its entire periphery. Needles or teeth 8. This cleaning device further comprises a cylindrical brush 9 furnished with bristles, a doffer (not shown) furnished with metal tips and a flapper comb (not shown).

  During their rotation, the needles or the teeth 8 of the circular comb 7 penetrate the fiber heads 14 presented by the clamp 3 and remove the short fibers and impurities (Figure 2). The cylindrical brush 9, whose bristles interpenetrate in the needles or in the teeth 8 of the circular comb 7, rotates faster than said circular comb 7, but in the opposite direction, so as to remove short fibers and impurities transported by the needles or teeth 8 of the circular comb 7 and so as to keep it clean. The doffer (not shown) rotates less rapidly than the cylindrical brush 9 and in the opposite direction of said cylindrical brush 9 and its points are flush with the bristles of the latter and unload said bristles of said cylindrical brush 9 short fibers and impurities carried by the brush.

  The flapper comb (not shown) of the fiber head cleaning device is a blade which is oscillated near the points of the doffer, this blade being responsible for ridding the tips of the doffer of the short fibers and the impurities they carry. . The short fibers and the impurities constitute the blush, which is recovered by gravity and / or by aspiration with a view to its evacuation.

  The textile material is then moved by the feed device to be brought into contact with the pulling device and with the fiber tails cleaning device, these devices carrying out the pulling and cleaning phases of the fiber tails ( figure 1).

  The pulling device is constituted in particular by a carriage (not shown), by a pair of tearing cylinders 10 and 11, and by a pulling sleeve 12. The carriage is animated by an oscillating movement around its articulation low through a lever (not shown) connected to a reciprocating actuator. Thus, the carriage can move between two extreme angular positions separated from each other by a distance commonly called the stroke of the carriage (arrow A). In one of its two extreme positions shown in Figure 1, the combing machine is in tearing phase and the upper end of the carriage is located near the feeder.

  In its upper part, the carriage supports the lower tearing cylinder 10, which is positively rotated according to a so-called pilgrim movement law and which is surmounted by the upper tearing cylinder 11, the pulling sleeve 12 being gripped between the pulling cylinders 10 and 11.

  During the fiber tearing phase (FIG. 1), the upper end of the carriage is located near the feed device and the pulling rolls 10 and 11 associated with the pulling sleeve 12 pinch the ends of the feed heads. fibers 14 presented by the feeding device.

  For this purpose, the clamp 3 is open and the sheet between clamp 6 is advanced in the direction of movement of the fibers, so as to constrain the end of the fiber heads to be between the stripping cylinders 10 and 11. These are rotated to extract the fiber heads 14 from the food comb 1 and the carriage is moved to move away from the clamp 3.

  The combing of the fiber tails using the fiber tails cleaning device will be performed simultaneously with the displacement of said fibers.

  For this purpose, the device for cleaning the fiber tails has a fixed comb 13 secured to an articulated lever. The fixed comb 13 is approached to the fiber heads 14 in such a way that the needles of the fixed comb 13, passing through the material, remove the impurities during the movement of the material by the pulling device. The impurities thus retained are recovered by gravity and / or suction by the circular comb 7 and a pneumatic sensor (not shown).

  The mechanical gap, that is to say the distance separating the end of the lower jaw 5 of the clamp 3 from the fiber nipping line located between the upper tearing cylinder 11 and the tear-off sleeve 12 when the carriage supporting the tearing cylinders 10 and 11 is in extreme position near the clamp 3, is represented by the letter E in Figure 1. The sorting base, that is to say the length of the longest fibers that In this case, when the gauge is set to 34 mm, for example, one can expect to obtain a sorting base of about 28 mm. This means that fibers longer than 28 mm in the blush should not be found.

  In order to change the sorting base of a rectilinear combing machine and obtain an optimum qualitative result, this modification of the spacing sometimes consists in vertically displacing the point of articulation of the carriage supporting the pullers 10 and 11 so that the pinching line of the fibers, located between the lower and upper 10 tearing cylinders 11 is placed in the same plane as that generated by the sheet between clamp 6, which presents the fiber heads tearers. This adjustment of the height of the carriage is no longer to be carried out on combers such as those of EP-A-1 254 976.

  The following adjustment consists in modifying the origin of the amplitude of the oscillation movement of the carriage so as to approach it or to move it away from the clamp 3. To this end, the fixed comb 13 is then moved in order to position it as close to the pullers 10 and 11, in the extreme position of the carriage. In addition, in order to perfect the adjustment of the spacing, it is also necessary to correct the extreme end position of the sheet between clamp 6 with respect to the fixed comb 13 and to make sure that there is no risk of collision. between the different moving parts relative to each other.

  All of these mechanical adjustments of the spacing are to be made generally with each change of batch of material and on each of the combers composing the assortment of combing or repainting.

  According to the combing method according to the present invention, the sorting base is adjusted by making the fiber heads 14 protruding from the clamp 3 open, before the beginning of the combing phase of the heads, a recoil movement so as to reduce the length of the fibers protruding from the clamp 3 when the latter is closed, while maintaining a good tearing capacity linked to a large mechanical gap value E. The backward movement of the fiber heads 14 is advantageously adjustable.

  Preferably, the recoil of the fiber heads 14 is made by the feeder, before closing the clamp 3. Thus, the fiber heads 14 are held between the grid 2 and the food comb 1 when the latter is lowered, before closing the clamp 3.

  The clamp 3 is open between 0 and 90 degrees machine and it closes around 90 degrees machine. The food comb 1 is, moreover, also lowered between 0 and 90 degrees machines. It is before the clamp closes, that is to say before 90 degrees machine and at the earliest after 0 degree machine, when the food comb 1 is lowered and planted between the textile fibers, that is carried out the recoil movement of the grid 2 and the food comb 1, which cause the textile fibers back. This recoil of the fiber heads 14, of a predetermined and adjustable value, has the effect of reducing their length of protrusion of the clamp 3, which reduces the rate of blush, and this is similar to the result that would be obtained in the case of a reduction of the mechanical spacing, but while maintaining a strong pulling capacity, which allows larger productions. Of course, the grid and the food comb will subsequently execute a complementary advance movement, of the same amplitude as the recoil, in order to maintain the same feed length of the textile material, which is expressed in mm / cycle .

  According to an alternative embodiment of the invention, the grid and the food comb of the feeding device can be replaced by a caterpillar moving bars equipped with needles or points in the manner of a simple gills. The feeding device may also be in the form of a cylinder filled with needles or points.

  As shown in FIG. 3 of the appended drawings, the device for carrying out this method is in the form of a means for adjusting the sorting base at constant spacing of a rectilinear combing machine, making a recoil of the device. supply, and thus fiber heads 14, before closing the clamp 3.

  Preferably, this means for adjusting the sorting base consists of at least one cam 15 cooperating with a roller 16 connected by means of a lever transmission 17a, 17b, 17c, 17d ..., to the grid 2 and the food comb 1, the profile of the cam 15 being such that it performs the recoil of the grid 2 and the food comb 1 lowered, and therefore the fiber heads 14, before the closure of the clamp 3.

  According to one characteristic of the invention, it is possible to implement several interchangeable cams 15a, 15b,..., 15g (FIGS. 4 to 6) having the same profile characteristic but with different amplitudes, depending on the value desired recoil.

  According to another characteristic of the invention and as shown in Figures 4 to 6 of the accompanying drawings, when several cams of the same characteristic but of different profiles are provided on the same axis, there is provided a displacement device for the implementation of individual work of each cam. Thus, for example, one can juxtapose five cams 15a, 15b, 15c ..., the first would achieve a decline of 0 mm, the second a decline of 1 mm, the third a decline of 2 mm, the fourth a decline of 3 mm and the fifth a decline of 4 mm.

  The means for adjusting the sorting base of a combing machine is preferably constituted by these cams 15a, 15b, 15c ..., cooperating with a roller 16, which, via a lever transmission 17a, 17b, 17c, 17d ..., performs the retreat of the grid 2 and the food comb 1 lowered before closing the clamp 3.

  The displacement device allowing the individual implementation of each cam can be constituted, according to one embodiment of the invention, in the form of a motorized means for moving the roller 16, constituted by an electric motor 18 which rotates a threaded shaft 19, which linearly displaces a threaded sleeve 20 supporting the roller 16. The threaded sleeve 20 is locked in rotation so that it can move linearly on the threaded shaft 19. Thus, it is possible to position the roller 16 opposite the desired cam 15 as a function of the number of revolutions made by the motor 18, or with the aid of the indications given by a position sensor (not shown). The change of position of the roller 16 with respect to the cams 15a, 15b, 15c ... takes place at a precise angular position of the combing machine, to which all the cams 15a, 15b, 15c ... have, relative to the roller 16, the same amplitude, so that the roller 16 can easily slide from one cam to another. Thus, by driving the motor 18, it becomes possible to move the roller 16, in order to position it in front of the desired cam. The displacement is controlled from the control panel of the combing machine, which makes it possible to display, for example, either the value of the recoil requested in mm or the value of the theoretical spacing required, which is equal to the value of the mechanical gap minus the value of the recoil.

  This displacement device allows the roller 16 to move relative to the cams 15a, 15b, 15c ...

  The roller 16 can be moved manually relative to the cams 15a, 15b, 15c ..., by any conventional means, taking care, of course, to lock the roller on its support shaft.

  It is also possible to make the displacement device in the form of a cam translation means in front of a fixed roller.

  Thus, the operator can, without the assistance of a trimming mechanic, very quickly and ergonomically, change the value of the sorting base by choosing the value of the desired theoretical spacing.

  For example, if we choose, for a set of batches of material A, B, C, to adjust the mechanical distance E of the combing machine to 38 mm, we can, depending on the sorting base that we want obtain, choose a theoretical spacing of 38 minus 4 mm, that is to say 34 mm for the lot of wool A, 38 minus 2 mm, that is to say 36 mm for the batch B, and 38 less than zero, ie 38 mm for batch C. The change in theoretical pitch will be controlled from the control panel of the combing machine. We will start by controlling the stop of the combing machine to a precise angular position, then we will control the movement of the roller, in order to position it in front of the desired cam and, finally, we will be able to restart the combing machine.

  FIG. 5 of the attached drawings shows an alternative embodiment of the invention, in which the device for moving the roller 16 is constituted by an electric motor 18, displacing a fork 21, which makes the roller 16 slide axially on its support shaft , in order to position it in front of the cam 15a, 15b, 15c ... desired, in the manner of a gearbox.

  According to a preferred embodiment of the invention, represented in FIG. 6 of the appended drawings, the device for moving the roller 16 may be constituted by a slider 22, which is mounted with the possibility of linear displacement on at least one guide 23 , in the form of a dovetail or preferably on two parallel guides 23 and 24. This slide 22 is advantageously indexed and held in longitudinal position relative to the guides 23 and 24 via an indexing device.

  Such an indexing device may, for example, be constituted by a ball disposed in a bore and loaded by a compression spring applying said ball against one of the guides 23 or 24, these guides 23 or 24 being provided with impressions intended to cooperate with said ball in blocking position of the displacement of the slide 22 on said guides 23 and 24. Thus, the slide is immobilized on the guides 23 and 24 and holds the roller 16 in position opposite a cam 15a, 15b , ..., 15g.

  The movement of the slider 22 can be effected manually by exerting on the slider a thrust sufficient to overcome the engagement force of the ball of the locking device in the corresponding recess 25 and push it back into its seat against the action of the spring. load, so that the slider can slide on the guides 23 and 24.

  According to one characteristic of the invention, the slider 22 may be connected to at least one actuator 26 for moving the roller 16 in front of the cams 15a to 15g. Advantageously, two actuators 26 and 27 are intended to carry out the movement of the roller 16 in front of the cams 15a to 15g. Preferably, one of the actuators 26 may be an electric jack and the other actuator 27 may be a pneumatic jack. The cam change, in cooperation with the roller 16, is preferably carried out in a precise position of the combing machine in which all the cams 15a to 15g have, relative to the roller 16, the same amplitude.

  The displacement of the slider 22 can be realized, in a manner known per se, by means of a PLC or a microprocessor communicating with a terminal and controlling the actuators 26 and 27.

  Thus, when the roller 16 is, for example, in front of the cam 15b and the operator wishes a displacement in position of the cam 15d, the combing machine is placed in the angular position of cam change and the actuator 27 moves the roller 16 in the initial position in front of the cam 15a and then the actuator 26 moves the slide to the cam 15d, passing successively in front of the cams 15a to 15c. A consecutive displacement, desired by the operator, of the roller 16 in position in front of the cam 15b, will cause a new displacement via the cylinder 27 to the position 15a, then the displacement by means of the electric jack 26 to the position 15b, the ball of the locking device sinking into the required position in the corresponding recess 25, for holding the slide 22 in position.

  Thanks to the invention, it is possible to very simply and very rapidly modify the sorting base, that is to say the value of the theoretical spacing of a rectilinear combing machine, without having to modify the setting of the mechanical spacing of the combing machine. Within an adjustment range, it is no longer necessary to modify the height of the carriage, the origin of the amplitude of the carriage, the depth of the fixed comb or the sheet between clamp.

  The invention also makes it possible to reduce the blusher rate for a given mechanical gap, or to increase the feed load, that is to say the production of the machine, while having the same blusher rate. , that is, the same sorting base.

  The production of the combing machine may therefore be greater, which will proportionally reduce the cost of combing, or repainting, and increase the competitiveness of the user enterprises.

  Of course, the invention is not limited to the embodiments described and shown in the accompanying drawings. Modifications are possible, particularly from the point of view of the constitution of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims (18)

-14-CLAIMS   A combing method for a straight-edge combing machine comprising a feeder, a pick-up device, a fiber-head cleaning device (14) and a fiber-string cleaning device, by a clamp (3) formed by an upper jaw (4) cooperating with a lower jaw (5) and by a plate between clamp (6), characterized in that it consists in adjusting the sorting base by making the fiber heads (14) protruding from the clamp (3) open, before the beginning of the combing phase of the heads, a backward movement so as to reduce the length of the fibers protruding from the clamp (3) when it is closed, while maintaining a good ability to pulling linked to a large mechanical gap value (E).   2. Method according to claim 1, characterized in that the backward movement of the fiber heads (14) is effected in an adjustable manner.   3. Method according to any one of claims 1 and 2, characterized in that the recoil movement of the fiber heads (14) is achieved by holding said fiber heads (14) by the feed device, before the Closing the clamp (3).   4. Device for carrying out the method according to any one of claims 1 to 3, characterized in that it is in the form of a means for adjusting the sorting base at constant spacing of a rectilinear combing machine , realizing a retreat of the feeder, and therefore the fiber heads (14), before closing the clamp (3).   5. Device according to claim 4, characterized in that the means for adjusting the sorting base constant separation is constituted by at least one cam (15) cooperating with a roller (16) connected via a transmission lever (17a, 17b, 17c, 17d ...), to the grid (2) and the food comb (1), the profile of the cam (15) being such that it achieves the recoil of the grid ( 2) and the food comb (1) lowered, and therefore fiber heads (14), before closing the clamp (3).   6. Device according to any one of claims 4 and 5, characterized in that the adjusting means of the sorting base at constant spacing is constituted by several interchangeable cams (15a, 15b, ..., 15g) and having the same profile characteristic, but with different amplitudes depending on the desired recoil value.   7. Device according to claim 4, characterized in that the feeding device is in the form of a food comb (1) associated with a food grid (2).   8. Device according to claim 4, characterized in that the feeding device is in the form of a caterpillar moving bars equipped with needles or points in the manner of a simple gills.   9. Device according to claim 4, characterized in that the feeding device is in the form of a cylinder filled with needles or points.   10. Device according to any one of claims 5 and 6, characterized in that, when several cams of the same characteristic but of different profiles are mounted on the same axis, there is provided a displacement device for individual implementation. of each cam.   11. Device according to claim 10, characterized in that the displacement device for the individual implementation of each cam is formed as a motorized means for moving the roller (16), consisting of an electric motor (18). ) which rotates a threaded shaft (19), which linearly displaces a threaded sleeve (20) supporting the roller (16).   12. Device according to claim 10, characterized in that the device for moving the roller (16) is constituted by an electric motor (18), moving a fork (21), which axially slides the roller (16) on its support shaft, in order to position it in front of the desired cam (15a, 15b, 15c ...), in the manner of a gearbox.   13. Device according to claim 10, characterized in that the device for moving the roller (16) is constituted by a slider (22), which is mounted with possibility of linear displacement on at least one guide (23), shaped dovetail or preferably on two parallel guides (23 and 24).   14. Device according to claim 13, characterized in that the slider (22) is indexed and maintained in longitudinal position relative to the guides (23 and 24) via an indexing device.   15. Device according to claim 14, characterized in that the indexing device is constituted by a ball disposed in a - piercing and loaded by a compression spring applying said ball against one of the guides (23 or 24), these guides (23 or 24) being provided with fingerprints intended to cooperate with said ball in blocking position of the displacement of the slide (22) on said guides (23 and 24).   16. Device according to claim 15, characterized in that the slide (22) is connected to at least one actuator (26) for moving the roller (16) in front of the cams (15a to 15g).   17. Apparatus according to claim 15, characterized in that the slide (22) is connected to two actuators (26 and 27) for effecting the displacement of the roller (16) in front of the cams (15a to 15g).   18. Device according to claim 10, characterized in that the displacement device for the individual implementation of each cam is in the form of a cam translation means in front of a fixed roller (16).