EP2083105B1 - Machine for heat treatment of threads equipped with a device for positioning the moving conveyor belt - Google Patents

Abstract

The machine has a pressurized chamber (1) crossed by a conveyor belt (2) and closed at an end by a sealing head mounted on a frame or mobile door (3) connected to the chamber through a tongue. The head has a pair of stacked horizontal rollers (5, 6) which is pressed against opposite sides of the belt. A conveyor belt positioning device (7) is provided to position the belt in the chamber in unwinding manner, from a side on which a sensor is arranged, below or above the belt. A maintaining unit maintains the belt in distance at height with respect to a position control unit (9) of the device.

Description

The present relates to the field of the textile industry, in particular the treatment of yarns by means of heat treatment machines commonly called heat-setting machines, and relates to such a machine comprising a device for positioning the conveyor conveyor belt provided with means for maintaining the latter spaced apart in height relative to the position control means.

The heat treatment machines essentially consist of a pressurized heat treatment chamber for textile threads deposited on a conveyor belt passing through said chamber, which is closed at its two ends by sealing heads, each comprising a frame or mobile door attached to the housing. pressurized vessel, a pair of superposed horizontal rollers which are pressed against opposite faces of the conveyor belt and sealing means to form a seal between the rollers and the frame.

The horizontal rollers are actuated by clamping means allowing at least one of the rollers to move towards the other, in order to clamp them against the conveyor belt. In addition, the sealing heads are mounted, each via its frame or movable door, pivotally relative to a vertical central axis and are connected to the treatment chamber via a bellows extending between the vertical pivot axis and the frame or movable door of said sealing heads.

During operation, the conveyor belt may undergo a drift between the inlet and outlet of the heat treatment machine, drift may cause, in case of exceeding a predetermined limit, a risk of snagging inside of the machine, which can cause at least stops of the machine to remedy the problem, or even damage.

It has been proposed to solve this problem by predicting a positioning of the conveyor belt between the input and output heads via positron detection cells of said strip at the ends of the machine, that is, that is to say near the sealing heads, these detection cells delivering a control signal for modifying the position of the heads by means of actuators acting on the frame or door mobile of the latter to provoke their pivoting. Such pivoting of the sealing heads has the effect of modifying the position of the axis of the sealing rollers, so that the conveyor belt is straightened in the opposite direction of the deflection observed, because of the nipping of the conveyor belt between the horizontal rollers superimposed. Indeed, during the pivoting of the sealing head the conveyor belt is pivotally driven, due to its nip between the longitudinal rollers, along a transverse generatrix, which induces a corresponding rectification thereof, to correct its drift and bring it back to its normal service position.

Generally, the means for detecting and correcting the position of the conveyor belt of such machines are perfectly suitable for ensuring a good positioning of said conveyor belt. However, there is a problem of detection and thus correction of the deflection when the conveyor belt, following aging, is curved. Indeed, the position sensors of the conveyor belt at the entrance and exit of the machine are sensitive to the deformation of the conveyor belt.

Moreover, because of the mounting of the frames or mobile doors of the sealing heads, each on a vertical pivot axis provided at a distance from said frames or movable doors of the sealing heads, it is necessary to take account in advance of the pivoting. of said sealing heads, which is increased by a lever effect due to the distance between the pivot axis and the plane of the superposed horizontal rollers and the distance between the sensors and the heads, resulting in an amplification of the rectification of the the drift found.

In addition, the mounting of the sealing heads in the manner described above induces a significant overhang of the heads and therefore the corresponding stresses on the pivot axis, requiring a corresponding dimensioning of all the elements of the mounting said heads.

By FR-A-2,894,258 (preamble of claim 1) it is also known a positioning device of the conveyor belt for wire heat treatment machines consisting of a pressurized chamber traversed by a conveyor belt and closed at each end by a sealing head mounted on a frame or movable door connected to the pressurized enclosure via a bellows, each sealing head having a pair of superposed horizontal rollers which are pressed against the opposite faces of the conveyor belt. This device comprises a means of positioning and position control means acting on a very short area in the immediate vicinity of each sealing head.

For this purpose, the positioning means consists of a pivot axis of the frame or movable door directly attached to said frame or movable door and to a pivot actuator of the frame or movable door via a linkage connected to the actuator of the screw jack type. The position control means is constituted by a proportional analog position sensor disposed near at least one edge of the conveyor belt, close to the superposed horizontal rollers of the sealing head, this sensor being connected to a calculating means delivering a correction signal to a servo drive controller of the actuator of the positioning means of the frame or movable door. The sensor forming the position control means is an optical sensor, a pneumatic sensor, a Foucauld current sensor or a probe sensor.

The device according to the latter document makes it possible to ensure good control of the drift of a conveyor belt, by a continuous correction, regardless of the running speed of the belt, and therefore a correct positioning of said belt. However, its implementation still requires relatively complex means.

The object of the present invention is to propose a heat treatment machine comprising a device for positioning the conveying conveyor belt according to FR-A-2,894,258 , allowing continuous control and straightening of the drift of said conveyor belt, while limiting the amplitude of the movements of the sealing heads and whose implementation is simpler and therefore less expensive.

For this purpose, the son heat treatment machine, consisting essentially of a pressurized chamber traversed by a conveyor belt and closed at each end by a sealing head mounted on a frame or movable door connected to the chamber pressurized by the intermediate of a bellows, each sealing head having a pair of superposed horizontal rollers which are pressed against the opposite faces of the conveyor belt, and by a device for positioning the conveyor belt running in the pressurized enclosure, comprising a means of positioning and position control means acting on a very short area in the immediate vicinity of each sealing head, said positioning means consisting of a pivot axis of the frame or mobile door directly attached to said frame or movable door and a pivoting actuator of the frame or movable door acting on said frame or movable door via a linkage mounted between the edge of the frame or movable door and said actuator, which is in the form of at least one jack connected directly to the pivoting drive linkage of the frame or movable door, characterized in that the positioning device of the conveyor belt running in the pressurized enclosure is provided, on the side on which the sensor extends, namely below or at the above the conveyor belt, a means for holding the conveyor belt spaced in height relative to the position control means.

• la figure 1 est une vue partielle en plan d'une machine de traitement thermique de fils équipée du dispositif conforme à l'invention ;
• la figure 2 est une vue en élévation latérale du dispositif suivant la figure, et
• la figure 3 est une vue en coupe transversale du tapis transporteur immédiatement après le bâti ou porte mobile, avec mise en oeuvre d'une variante de réalisation de l'invention.

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:

• the figure 1 is a partial plan view of a son heat treatment machine equipped with the device according to the invention;
• the figure 2 is a side elevational view of the device according to the figure, and
• the figure 3 is a cross-sectional view of the conveyor belt immediately after the frame or mobile door, with implementation of an alternative embodiment of the invention.

The figure 1 By way of example, the appended drawings represent a heat treatment machine for wires consisting essentially of a pressurized enclosure 1 traversed by a conveyor belt 2 and closed at each end by a sealing head mounted on a frame or movable door. 3 connected to the pressurized chamber 1 via a bellows 4, each sealing head having a pair of superposed horizontal rollers 5, 6 which are pressed against the opposite faces of the conveyor belt 2. In order to avoid an inadmissible drift of the conveyor belt, this wire heat treatment machine is equipped with a positioning device 7 of this carpet.

The positioning device 7 comprises a positioning means 8 and a position control means 9 acting on a very short area in the immediate vicinity of each sealing head.

This positioning means 8 consists, according to the embodiment according to the figure 1 , in a pivot axis 10 of the frame or movable door 3 secured directly with said frame or movable door 3 and in an actuator 11 for pivoting the frame or movable door 3 via a linkage 12 mounted between the edge of the frame or movable door 3 and said actuator 11, which is in the form of at least one jack connected directly to the linkage 12 for pivoting drive of the frame or movable door 3.

Only one end of a wire heat treatment machine is shown in plan view on the figure 1 , so that only one roll of the pair of rollers 5 and 6 forming the sealing head is visible. Furthermore, it is clear that the not shown end of the son heat treatment machine is symmetrical to that shown in FIG. figure 1 .

According to the invention, the device for positioning the conveyor belt 2 running in the pressurized enclosure 1 is provided, on the side on which the sensor extends, namely below or above the conveyor belt 2, a means for holding the conveyor belt 2 spaced apart in height relative to the position control means 9. Such a device is more particularly adapted to an implementation with sensors according to the present invention, which will be described later.

For this purpose, according to a first embodiment of the invention, the means for holding the conveyor belt 2 in spaced apart position relative to the position control means 9 may be in the form of a transverse support roll 14 extending in close proximity to the sensor forming the position control means 9 and slightly deflecting upwards or downwards, said conveyor belt 2 with respect to the exit or entry of the superposed horizontal rollers 5, 6 constituting each head of the sealing ( figure 2 ).

Such an arrangement of the transverse support roller 14 between the outlet or inlet of the sealing heads and the sensor forming the position control means 9 ensures sufficient tension on the conveyor belt 2, so that a vertical displacement of the edge or edges of the conveyor belt 2 passing above the sensor forming the position control means 9 is kept constantly at the same vertical distance from said sensor 9. It follows that the load of the conveyor belt 2 may not affect the width of this mat 2 by bending, so that its width remains uniform and that the sensor forming the position control means 9 detects only a transverse displacement of the mat 2, so that is ensured a measurement without disturbance by the sensor forming the position control means 9.

According to another embodiment of the invention, it is also possible to provide that the means for holding the conveyor belt 2 at a distance from the height of the position control means 9 is in the form of a pair of rollers of guide (not shown), provided in close proximity to the sensor forming the position control means 9, on each edge of the conveyor belt 2 and now the edge or edges at a constant spacing height of said sensor.

According to another alternative embodiment of the invention, not shown in the accompanying drawings, the means for holding the conveyor belt 2 at a distance from the height of the position control means 9 may also be in the form of a transverse pad of support deflecting said conveyor belt 2 upwards.

According to another characteristic of the invention, the position control means 9, in the form of at least one proportional analog position sensor, is chosen from the group formed by the inductive sensors and the pressure sensors.

Preferably and as shown more particularly in figure 1 In the accompanying drawings, the actuator 11 is in the form of a pair of flexible or diaphragm cylinders 11 'each acting on one side of the free end of the linkage 12 for pivoting the frame or movable door 3. Such flexible or diaphragm cylinders 11 'are extremely reactive and allow controlled displacements of very small amplitude.

Thus, it is possible to perform, with a very short reaction time, perfectly controlled amplitude swiveling of the frame or movable door 3, so that the sealing head formed by the rollers 5 and 6 is pivoted around its pivot axis 10 and induces a displacement of the conveyor belt 2 in the opposite direction of the observed drift.

According to an alternative embodiment of the invention, not shown in the accompanying drawings, the actuator 11 may be in the form of a single-acting jack acting on one side of the free end of the linkage 12 for pivoting the drive. frame or movable door 3 and recalled in position by means of a return spring. In such a case, the cylinder chamber is fed continuously under a variable pressure depending on the desired movement of the linkage. Thus, an increase in pressure will result in moving the linkage against the action of the return spring and a decrease in this pressure will have consequently a displacement in the opposite direction, proportional to this decrease of pressure. Of course, the movement of the linkage, under the action of the pressure exerted on the piston of the cylinder or the pressure exerted in the opposite direction by the spring, can be controlled by an angular position sensor or the like.

According to another embodiment of the invention, not shown in the accompanying drawings, it is also possible to produce the actuator 11 in the form of a double acting jack acting on the free end of the linkage 12 and whose chambers are alternatively fed with pressure. In such an embodiment, it will suffice to feed one or the other chamber of the double-acting cylinder to carry out the movement of the linkage 12 and thus a pivoting of the frame or the mobile door 3 in one direction or in the other. 'other. In such a case, the two opposite chambers of the double-acting cylinder are each connected to the tank with the interposition of a throttling means allowing perfect control of the movement of the piston rod, in particular smoothly.

Finally, it is also possible to realize the actuator 11 in the form of a double jack (not shown), whose body is connected to the free end of the linkage 12 and each piston rod is connected to a fixed support provided on the corresponding side of the frame of the processing machine. In such a case, the pressure chamber of each cylinder is also advantageously connected to the tank via a throttling means.

According to another characteristic of the invention, the position control means 9, in the form of at least one proportional analog position sensor, is an inductive sensor ( figures 1 and 2 ) positioned as close to the frame or movable door 3 above or below the conveyor belt 2, straddling the edge. Thus, any deviation of the carpet from its normal path under the inductive sensor forming the position control means 9 will have the consequence of disturbing or modifying the magnetic field at said sensor 9, so that a variation signal will be emitted corresponding.

According to a characteristic of the invention, the inductive sensor forming the position control means 9 is connected to an analog proportional distributor 13 for controlling the actuator 11. Such a dispenser makes it possible, for example, to feed the two cylinders flexible or diaphragm 11 'each acting on one side of the free end of the linkage 12 for pivoting the frame or mobile door 3 by its outputs 12 'and 12 ".This such a distributor has a very short response time, namely a few milliseconds, and has a very high flow rate, it is able to balance the pressure in the cylinders 11 'and 11 "almost instantly. Of course, such a proportional distributor is also suitable for controlling the other types of cylinders mentioned above.

It is also possible, according to an alternative embodiment of the invention, to have the inductive sensor forming the position control means 9 between the transverse support roller 14 and the superposed horizontal rollers 5, 6 constituting each sealing head.

According to an alternative embodiment of the invention, not shown in the accompanying drawings, the inductive sensor forming the position control means 9 and the actuator 11 may be unique for the entire machine, the drive linkage 12 in pivoting of the frame or movable door 3 connected to the actuator 11 then being connected to the linkage 12 of the frame or movable door 3 opposite, or directly connected to the frame or to the moving door 3 opposite, by means of an inverted control. Such an inverted control may consist, for example, of a rod connected at one end to one side of the frame or movable door 3 at one end of the machine and at its other end to the opposite side of the frame or movable door 3 of the machine. opposite end of the machine.

The figure 3 the accompanying drawings show an alternative embodiment of the invention, wherein the position control means 9 is constituted by pressure sensors 91 cooperating with the bearings of a concave transverse roller 15 for supporting the conveyor belt 2, said sensors pressure 91 actuating the pivot linkage 12 of the frame or movable door 3 via an actuator 11 controlled by an analog proportional distributor 13.

In this embodiment, the elements for pivoting the frame or mobile door 3, as well as the analog proportional distributor 13, are not represented on the figure 3 but may be identical to those shown in figures 1 and 2 . In this latter embodiment, a transverse displacement of the conveyor belt 2 will have the effect of further loading one end of the concave transverse support roller 15, so that the pressure sensor 91 assigned to the corresponding bearing of said roller 15 will detect a pressure greater than that of the sensor 91 assigned to the opposite bearing and the analog proportional distributor will deliver a control signal proportional to the observed pressure difference, so that the sealing head will be rotated by a value corresponding to the necessary rectification of the trajectory of the conveyor belt 2.

The operation of the device according to the present invention, in particular with regard to the straightening of the carpet, is comparable to that described with regard to the device according to the document FR-A-2,894,258 , that is to say to make pivoting of very small amplitude of the frame or movable door 3 and therefore of the sealing head constituted by the rollers 5 and 6, so as to induce a displacement of the conveyor belt 2 in the opposite direction of the observed drift.

Thanks to the invention, it is possible to perfectly control the drift of a conveyor belt, that it is perfectly new and straightened or worn and having deformations such as an arrow or corrugations by a continuous correction of said drift . The invention therefore makes it possible to position perfectly, over a given portion of its length, a conveyor belt 2 of great length, in continuous movement in a plane.

In addition, the use of two sets of position control means 9 and actuator 11 makes it possible, by prior individual adjustment of these sets, to perfectly control the actions performed at the rear and at the front of the machine, or even to obtain a slightly different actuation between the two ends, for example a straightening of the conveyor belt more important at the machine output than at the machine inlet, or vice versa.

In addition, the use of inductive sensors or pressure sensor makes it possible to pre-position the corresponding sealing head with regulation of the position of the conveyor belt 2 from the beginning of operation of the machine.

Finally, by adjusting the pressure in the jack or cylinders forming the actuator 11, the stiffness of the system can be modified, that is to say that the pivoting movements of the frame or movable door 3 can be more or less abrupt .

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 (14)

1. Machine for the thermal treatment of threads, which consists essentially of a pressurised enclosure (1), through which a conveyor belt (2) passes, and which is closed at each end by a sealing head mounted on a mobile frame or holder (3), which is connected to the pressurised enclosure (1) by means of bellows (4), wherein each sealing head comprises a pair of superimposed horizontal rollers (5, 6), which are pressed against opposite faces of the conveyor belt (2), and by means of a device for positioning the conveyor belt (2) during its advance in the pressurised enclosure (1), which comprises a positioning means (8) and a position control means (9), in the form of a position sensor or detection cell for detecting the position of at least one edge of the conveyor belt (2), acting on a very short area in the immediate proximity of each sealing head and detecting a transverse displacement of the belt (2), wherein said positioning means (8) consists of an axle (10) for pivoting the mobile frame or holder (3), which axle is integrally connected directly to said mobile frame or holder (3), and of an actuator (11) that actuates the pivoting of the mobile frame or holder (3), acting on said mobile frame or holder (3) by means of a rod linkage (12), which is mounted between the edge of the mobile frame or holder (3) and said actuator (11), which is in the form of at least one jack that is connected directly to the rod linkage (12) for driving the mobile frame or holder (3) in a pivoting motion, characterised in that the device for positioning the conveyor belt (2) during its advance in the pressurised enclosure (1) is provided, on the side over which the position sensor (9) extends or the cell for detecting the position of at least one edge of the conveyor belt (2), namely below or above the conveyor belt (2), with a means for holding the conveyor belt (2) at a height separated from the said position control means (9).
2. Machine according to claim 1, characterised in that the means for holding the conveyor belt (2) at a height separated from the position control means (9) is in the form of a transverse support roller (14), which extends in the immediate proximity of the sensor forming the position control means (9) and is shifted slightly downwards or upwards, wherein said conveyor belt (2) constitutes each sealing head with respect to the outlet or the inlet of the superimposed horizontal rollers (5, 6).
3. Machine according to claim 1, characterised in that the means for holding the conveyor belt (2) at a height separated from the position control means (9) is in the form of a pair of guide rollers, which are provided in the immediate proximity of the position sensor or cell for detecting the position of at least one edge of the conveyor belt (2) forming the position control means (9), on each edge of the conveyor belt (2), and maintaining the edge(s) at a constant height separated from said position sensor or detection cell.
4. Machine according to claim 1, characterised in that the means for holding the conveyor belt (2) at a height separated from the position control means (9) is in the form of a transverse support pad that shifts said conveyor belt (2) upwards.
5. Machine according to claim 1, characterised in that the position control means (9), in the form of at least one proportional analogue position sensor, is chosen from a group consisting of inductive sensors and pressure sensors.
6. Machine according to claim 1, characterised in that the actuator (11) is in the form of a pair of flexible or membrane jacks (11') each acting on one side of the free end of the rod linkage (12) for driving the mobile frame or holder (3) in a pivoting motion.
7. Machine according to claim 1, characterised in that the actuator (11) is in the form of a single-acting jack acting on a side of the free end of the rod linkage (12) for driving the mobile frame or holder (3) in a pivoting motion and returned to its position by means of a return spring.
8. Machine according to claim 1, characterised in that the actuator (11) is in the form of a dual-acting jack which acts on the free end of the rod linkage (12), with chambers that are supplied alternatively with pressure.
9. Machine according to claim 1, characterised in that the actuator (11) is in the form of a dual-acting jack, the body of which is connected to the free end of the rod linkage (12), and wherein each of its piston rods is connected to a fixed support provided on the corresponding side of the frame of the processing machine.
10. Machine according to any of claims 1 and 5, characterised in that the position control means (9), in the form of at least one proportional analogue position sensor, is an inductive sensor positioned as close as possible to the mobile frame or holder (3) above or below the conveyor belt (2), straddling the edge.
11. Machine according to claim 10, characterised in that the inductive sensor forming the position control means (9) is connected to an analogue proportional distributor (13) for controlling the actuator (11).
12. Machine according to any of claims 2, 10 and 11, characterised in that the inductive sensor forming the position control means (9) is arranged between the transverse support roller (14) and the superimposed horizontal rollers (5, 6) forming each sealing head.
13. Machine according to any of claims 5 to 12, characterised in that the inductive sensor forming the position control means (9) and the actuator (11) are unique for the assembly of the machine, wherein the rod linkage (12) for driving the mobile frame or holder (3) in a pivoting motion, which is connected to the actuator (11), is connected to the rod linkage (12) of the opposite mobile frame or holder (3), or connected directly to the opposite mobile frame or holder (3), by means of a reverse command.
14. Machine according to claim 5, characterised in that the position control means (9) consists of pressure sensors (91) that work in cooperation with the bearings of a concave transverse support roller (15) of the conveyor belt (2), wherein said pressure sensors (91) actuate the rod linkage (12) for pivoting the mobile frame or holder (3) by means of an actuator (11), which is controlled by an analogue proportional distributor (13).

Images