EP0665069B1 - Process and equipment for straightening a thin metal band - Google Patents

Description

The subject of the invention is a method and an installation. leveling under tension of a thin metal strip.

Thin and hard steel sheets such as irons whites used in particular for manufacturing of packaging, are produced by rolling in the form of long, thin metal strips which then are processed, cut and formed according to intended use.

Generally speaking, a thin metal strip should exhibit a number of qualities such as a excellent flatness, drawing ability, condition surface and mechanical properties in accordance with standards corresponding to the desired applications.

To obtain these qualities, the metal strip undergoes a number of treatments and in particular it is subjected to a leveling often carried out by traction-bending and under imposed extension.

Generally, a leveling machine includes one or more two bending units each consisting of a pair of small diameter cylinders placed on either side of the strip and offset in height so as to determine, by their overlapping, a bent path of the strip producing alternate bending on the two cylinders.

The strip is subjected to a traction between two blocks tensioners placed on either side of the machine and each consisting of several rolls nested on which rolls up the tape. The rolls of the two blocks tensioners are rotated at speeds slightly different so the speed of scrolling of the strip in the downstream tensioning block or slightly higher than the frame rate upstream.

This results in a permanent elongation of the strip, the value can be determined by adjusting the difference scrolling speeds between upstream and downstream.

Leveling is carried out by subjecting the strip under tension at least two alternating flexions on small diameter cylinders. We know that during each bending, the stretched outer part of the strip can find in the field of plastic deformations, even if the applied tensile stress is much lower at the elastic limit. We can thus, without submitting the band to undue hardship, determine, between two tensioning blocks, sufficient elongation to exceed the length of the longest fiber so as to level the strip by equalizing the lengths of all its longitudinal fibers.

The permanent extensions obtained for a product given are all the more important as the radii of curvature are low and tensile stresses high, the latter remaining however always below the elastic limit.

We can thus obtain flat strips but these operations induce internal constraints in the thickness of the strip. These balance, but however, lead to a deformation of the profile of the strip, which generally has a camber in the transverse direction, and often also, in the direction longitudinal.

The transverse camber, generally called "tile", can be fairly easily corrected on a so-called device anti-tile, placed downstream of the leveler and comprising a cylinder resting on the strip on the opposite side to that of the last leveler cylinder and associated with two larger diameter rollers.

The defect in longitudinal camber, also called "hanger", can be corrected on a scouring cylinder.

DE-A-2330064, for example, describes a installation of this type comprising a pair of rollers of dressing by alternating flexions, an anti-tile roller and a camber defect correction roller longitudinal. The latter can be replaced in a embodiment, by a multi-roller assembly comprising a row of lower rollers and a row of upper rollers whose orientation can be set to determine tapering overlaps. This document defines the diameters to be given to rollers so that each defect is corrected by a particular device.

However, for very thin and hard tapes, the correction is difficult to perform, especially due to the very high sensitivity of the devices used. Indeed, for very thin bands, the defects are very fleeting and fluctuating for the same machine setting.

However, a residual longitudinal camber can hinder the introduction of the tape into the installations of following treatment and, in addition, may lead to deformations when the strip is cut into strips, according to the dimensions of the products to be manufactured.

It is possible to act manually on the settings of the machine but, the strip moving at very high speed, thus, only detectable faults can be corrected and, necessarily, with a certain delay time. Moreover, when unwinding another reel, it can be necessary to accept all settings.

The subject of the invention is a method making it possible to Correct satisfactorily the defects induced by the leveling, and in particular the longitudinal camber. The process according to the invention gives great flexibility and allows, after having carried out a first choice, to immediately adapt the settings to the properties tape, if necessary, while scrolling.

In general, the invention has essentially for the purpose of obtaining products with camber weak longitudinal, fairly homogeneous, and, in any case, to keep them, when necessary, in the same sense when it is impossible to get a more result satisfactory.

The method according to the invention is characterized in claim 1. The method applies to a installation comprising a traction-flexion leveler comprising at least one bending unit consisting of a pair of cylinders offset in height and a set of multi-roller dressing with two frames, respectively lower and upper, each carrying a row of parallel rollers, longitudinally offset and in height, so as to determine, by nesting the rollers, a wavy path of the strip with bending alternating means for adjusting the nesting of cylinders of each bending unit, adjustment means the interlocking of the dresser assembly rollers and two tensioning blocks respectively placed upstream and downstream of the installation on the strip path for apply a tensile stress to it likely to determine an elongation of the strip whose the value is imposed by adjusting the speed of scrolling in said blocks.

According to the invention, the defects of flatness in the leveler by adjusting the speeds of scrolling and nesting of the leveling crews of so that the elongation imposed for leveling is, practically done right out of the leveler and corrects at least the defects in the multi-roller assembly of longitudinal camber due to passing through the leveler determining gradual overlaps of the rollers between the input and the output of the multi-roller assembly by tilting one row relative to the other, by so as to cause effects of alternate bending gradually decreasing which determine relaxation constraints, numbers and intensities of inflections alternating being determined by setting the nests respectively at the entrance and at the exit of the set multi-rollers to correct the camber defect without significantly increasing the elongation already achieved in the traction-flexion leveler.

Tile correction can be performed at the same time time as the longitudinal camber correction, in the multi-roller assembly, but we can also place a anti-tile device between the leveler and the assembly multi-rollers to at least partially correct the tile before entering the multi-roller assembly.

According to another particularly characteristic advantageous of the invention, the nests are regulated in the flexion units of the leveler taking into account the dimensional and structural characteristics of the strip so as to achieve elongation in the leveler imposed for the flatness correction while maintaining, generally the tensile stress applied to the band below about 60% of the elastic limit of the metal and we adjust the nests, respectively to the input and output of the multi-roller assembly, for correct camber defects by limiting the increase of traction so that the elongation additional realized in the multi-roller assembly does normally not exceed 0.2%.

According to the invention, the nesting of the leveler and the multi-roller assembly are adjusted for each coil and / or determined in permanence during the running of the tape by a automation system taking into account all dimensional, structural and product quality, known cylinder diameters active, the tensions applied to the strip and the interactions between the different organs of the installation.

Particularly advantageously, the system of automation is associated with a mathematical model on which are displayed, before processing a reel, all the characteristics specific to the product to process and specific to the installation, said model mathematics developing the nesting instructions for different organs from programmed equations and taking into account the indications obtained by measurement or by observation of residual flatness and longitudinal and transverse camber during the treatment of a strip of nature and dimensions analogues.

However, in a simplified embodiment, the automation system determines the nesting of different organs from established tables, for each type of product, taking into account the characteristics machine-specific and information obtained previously by measuring or observing faults longitudinal flatness and camber and transverse during the processing of a strip of nature and similar dimensions.

According to another extremely characteristic advantageous, the operator can at any time correct manually each of the settings controlled by the system of automation based on measurements or observations performed on the product during and / or after treatment.

Preferably, manual corrections as well are recorded, classified and possibly optimized in a self-adaptation system which memorizes and, after unlocking by the operator, introduces the necessary modifications into the system automation so that, later, the instructions thus corrected nesting are imposed on different organs during the course of the tape and for the following bands of the same type.

The invention therefore allows, when one has developed the process of planing a strip of characteristics determined, to automatically apply the same process to all bands having the same characteristics and, in particular, from the same origin, defects flatness resulting, among other things, from the whole history of the strip and its production process from steel liquid to its final and repeating form, generally, on bands of the same origin.

Furthermore, after verification by an authority competent, the corrections recorded in the system self-adaptation can be validated and introduced in the mathematical model which is readjusted so that the elaborate instructions correspond to nesting previously corrected.

However, the invention also provides the means get the right settings very quickly even for reels of a product whose characteristics do not not match those of one of the coils already processed. In this case, in fact, one can choose from these one or more types of reference approaching most of the new reel and we display on the automation system, i.e. the parameters corresponding to a very similar type, either interpolated parameters or extrapolated, so as to determine, according to the reference types, voltage setpoints and of nesting of the different organs, for the new coil. We then control the unwinding of the reel and the operator manually corrects the determined instructions by the automation system according to the effects obtained on the tape in progress.

Corrections thus made to the instructions given by the mathematical model are recorded in the self-adjusting system which can be unlocked by the operator, if the corrections made are appropriate, so that the corrected instructions are used to following the unwinding of the reel and for the reels analogues.

After approval and validation by an authority competent, the corrected instructions can be memorized in the mathematical model to constitute a new model usable, thereafter, for all the coils analogues. An installation for implementing the method according to the invention is characterized in claim 13.

The invention will be better understood from the description following of a particular embodiment, given to as an example and shown in the accompanying drawings.

Figure 1 shows schematically, in section longitudinal, the whole of a leveling installation for implementing the method according to the invention.

Figure 2 is a block diagram of the adjustment of the entire installation.

Figure 3 is a block diagram, to scale enlarged, representing the passage of the strip in the multi-roller assembly.

In Figure 1, there is shown in section longitudinal, the whole of a leveling installation of a metal strip 1 which, in the Figure, scrolls from the right to left passing successively through a upstream tensioning unit 2, a leveler 3 comprising, in the example shown, two bending units 31, 32, one anti-tile device 4, a multi-roller dressing set 5 and a downstream tensioning block 2 '.

All these devices are arranged in a frame 10 in cage shape associated with means not shown for maintenance or replacement of the various organs.

The two tensioning blocks 2, 2 ', are made up each, in the usual way, of several rolls fairly large diameter on which the strip 1 is wound to get the pull ups that are needed and that are rotated by a mechanism not shown, of so that the winding speed on the downstream block 2 'is a little higher than that of the upstream block 2, the speed difference can be set to determine the desired lengthening.

The leveler 3 is of the conventional type and, in particular, each flexure unit 30 comprises two crews of leveling 31, 32, placed, respectively, above and in below the strip.

Each leveling crew 31 (32) comprises a cylinder active 33 (33 ') of small diameter which is supported on the side opposite the strip, on support rollers 34 (34 '), the assembly being placed on a frame 35 (35 ′) which can slide vertically with respect to the cage 10 and the vertical position can be adjusted by one or more hydraulic or mechanical actuators 36 (36 ').

Generally, the upper crew 31 can move, under the action of jacks 36, between a high position standby, away from the web, and a low position of work, in contact with the band. Mechanical cylinders screws 36 allow to vary the level of the crew lower 32 to adjust the nesting of the active cylinders 33, 33 '.

The second bending unit 30a can be adjusted from the same way. Furthermore, it is possible, as we have shown in Figure 1, to completely separate from the band active cylinders, which, depending on the case, to use either one bending unit or both.

The anti-tile device 4, which is of a type conventional, includes an active cylinder 41 placed between two rollers 45, 45 'of larger diameter and also resting on a set of support rollers 42 carried by a sliding frame 43 whose position can be adjusted by a jack 44. This makes it possible to adjust the pressure applied to the strip by the anti-tile cylinder 41 which fits between the two rollers 45, 45 '.

Note that the anti-tile device is not always essential and can be deleted within simplest installations. However, it can be preferable to provide on the frame 10 of the installation a location 46 provided for the anti-tile device which, thus, can be added to the machine if necessary. Of even, the anti-tile cylinder 41 can be simply removed from the strip or put into service according to the qualities of sheets.

The multi-roller assembly 5, which is placed downstream of the anti-tile device 4 and before the downstream tensioning block 2 ', includes two sets of rollers, respectively one upper assembly 50 and a lower assembly 50 'arranged respectively on either side of the scroll plane of band 1.

Each set 50 (50 ') is carried by a chassis, respectively upper 6 and lower 6 ', and includes a row of parallel rollers 51 bearing, on the side opposite strip 1, on one or two rows of rollers support 52.

The two rows of rollers 51, 51 'are offset longitudinally and can thus overlap one another by adjusting the relative levels of the frames 6, 6'. so as to define a zigzag path. Generally, the lower row 51 ′ has one more roll than the upper row 51, but this arrangement depends on the circumstances, and in particular on the nature of the strip 1 and the distribution of the stresses.
The chassis 6 carrying the upper assembly 50 is mounted to slide vertically in two windows 61 of the cage 10 can be placed, by means of one or two jacks 62, either in the low working position, or in the waiting position separated from the band.

Similarly, the 6 'chassis of the assembly lower 50 'is mounted on a box-shaped frame 63 which can slide vertically in 61 'windows the cage 10 and whose position can be adjusted by a jack 64 thus allowing vertical movement, parallel to itself, from the bottom row of rollers 51 '.

However, the lower chassis 6 'forms a cradle which rests on two circular tracks 65 provided on the frame 63 and forming a circular raceway centered on a horizontal axis parallel to the axes of the rollers 51 'and placed substantially at the level of the plane tangent to these last.

The cradle 6 'can thus tilt relative to the frame 63 by turning around the axis of the raceway 65 under the action of a screw jack 66 mounted on the frame 55 and supported, by an articulated link system, on a arm 67 secured to the cradle 6 ', the latter being maintained applied to the raceway 65 by a jack 68 fixed on the frame 63 and allowing the play to be made up.

Other tilting systems could obviously be used for this purpose.

The screw jack 66 therefore makes it possible to give the row of lower rollers 51 'inclination adjustable by compared to upper row 51 while the cylinders screws 64, allow to increase or decrease overall the spacing between the two rows of rollers 51, 51 '.

It is thus possible, by acting separately or simultaneously on screw jacks 64 and 66, to adjust the nesting of rollers at the inlet and outlet of the multi-roller assembly 5 for determining a nesting gradually decreasing rollers in the direction of scrolling of the strip, as shown in the Figure 3.

Of course, other equivalent means, for example hydraulic cylinders or other actuators, can be used to change nestings and orientations of the two sets of rollers.

In general, it is possible, by acting to combined way on the adjustment cylinders 64 and 66, of set the centers A1 at the entry and A2 at the exit leveler, to change the intensity and possibly the number of reverse flexions, as shown on the Figure 3.

• sur les vérins 36, 36a, pour le réglage des imbrications P1, P2, respectivement des deux unités de flexion 30, 30a,
• sur le vérin 44 pour le réglage de l'effet T du dispositif anti-tuile 4,
• sur les vérins à vis 64 et 66, pour le réglage des entraxes A1 à l'entrée et A2 à la sortie de l'ensemble multi-rouleaux 5.

To this end, the installation is advantageously associated with an adjustment system 7, shown diagrammatically in FIG. 2, and comprising positioning means 71 to 75 acting respectively:

• on the jacks 36, 36a, for adjusting the overlaps P1, P2, respectively of the two bending units 30, 30a,
• on the jack 44 for adjusting the effect T of the anti-tile device 4,
• on screw jacks 64 and 66, for adjusting the center distances A1 at the inlet and A2 at the outlet of the multi-roller assembly 5.

Each positioning means 71 to 75 includes a regulator receiving, on a first input 71a to 75a, a positioning order provided by an automation system 8 and, on a second input 71b to 75b, a signal supplied by a measuring device M1 to M5 indicating, at each instant the respective positions of the organs correspondents, so that the correction necessary to adapt the effect of the organ considered at the order given, at the same instant, by the system automation 8.

In addition, pairs of pushbuttons B1 to B5, acting in opposite directions, allow the operator intervene, if necessary, on each means of positioning 71 to 75 to bring, in one direction or in the other, a correction to the position of the organ considered ordered by the automation system 8, taking into account information of all kinds which reaches him, by example by observing the cut product.

• de la nature du produit, du code Qualité et du code Défaut,
• de l'épaisseur et de la largeur,
• de la destination.

The automation system 8 develops the position setpoint, at each instant, of each of the positioning means 71 to 75, from a set of tables and / or a mathematical model 80 programmed so as to take into account the different characteristics the installation and the product to be leveled and, in particular:

• the nature of the product, the Quality code and the Fault code,
• thickness and width,
• of the destination.

We can indeed establish, in a known manner, tables and equations that define the actions to exercise on the product by each of the machine's components taking into account the mechanical characteristics of the machine, of the known diameter of the cylinders and rollers, of their number and their nests, as well as constraints applied on the product and interactions between the different organs.

These tables and these equations are programmed in the mathematical model 80 in which the operator can introduce, via an input 80a, all of the parameters (p) specific to the product and, in particular, those which have been indicated above, and by an entry 80b the parameters (m) machine-specific, such as the diameters of the cylinders and rollers of each of the machine's components, which can be continuously measured or verified during stops. These parameters are introduced by the operator, by means of a console 81, at the arrival of a new coil or a series of coils of a certain type.

On another input 80c of the mathematical model 80, is displayed the elongation A which must be imposed on the strip to correct the flatness defect detected upstream of installation, for example by a measuring roller flatness of known type.

This imposed extension is determined in the manner usual taking into account the characteristics of the product and machine and staying in areas of predetermined voltage stresses.

From all these parameters and the equations programmed, the mathematical model 80 develops, on the one hand, an extension instruction and, on the other hand, instructions nesting of the different organs.

The elongation instruction is displayed at input 76a a device 76 for adjusting the drive mechanism 21 of the tensioning blocks 2, 2 ', such a mechanism allowing, in known manner, to maintain between the blocks upstream and downstream the speed difference corresponding to the imposed extension.

However, the elongation setpoint A depends on the diameters of the tension rollers in the upstream blocks 2 and downstream 2 'and can therefore be corrected by a device 83 to take into account the possible wear of these.

The tensions Te and Ts applied to the strip, respectively at the entrance and exit of the installation, are a consequence of the process and do not intervene, normally in the system for determining instructions. However, these tensions must obviously be limited for security reasons and, in any case, must always remain below the elastic limit of the product and, preferably, between 20 and 60%, approximately, of this, the strongest pulls relating to the thinnest and strongest bands Elastic limit.

To this end, the installation is equipped with devices 22, 23, for measuring the voltages respectively Te at the input and Ts at the output, and the measured voltages are displayed at the input 82a of a device 82 of correction of instructions. If exceeded at predetermined values, the automation system can thus react, either by simple alarm or by action direct on all or part of the instructions it develops.

The nesting instructions P1, P2 ... P5 developed by the mathematical model 80 and thus corrected, are displayed, respectively, on the positioning means 71 to 75. As indicated, the mathematical model holds account of the interactions between the different organs for develop the nesting instructions so that the elongation imposed for the flatness correction either practically entirely carried out in the leveler 3 at by means of the two bending units 30, 30a, or one of them only, as the case may be.

However, the tensile-bending effect applied to the product depends on the diameters of the cylinders and rollers and this is why, before being displayed on each of the means 71 to 75, the corresponding setpoint is corrected in a device 84 associated with each means of positioning to correct the setpoint according to actual diameters of cylinders or rollers of the member considered, which can be measured, for example, at each machine shutdown.

In addition, the operator can also, as we have indicated, intervene on the settings of the different organs of the machine using push buttons B1 to B5.

Of course, such corrections cannot be made only by an authorized operator.

Thanks to these provisions, the adjustment system can operate fully automatically, but with possibility of correcting instructions on intervention of operator to adjust nesting.

Indeed, measuring devices M1 to M5 are associated with each organ and each provide a signal representative of the actual position, at the instant considered, cylinders or rollers of the corresponding member. These signals are displayed on input 85a of a self-adaptation system 85 which, on the operator's order, may intervene on the automation system to correct nesting instructions automatically so that these correspond to the positions measured and that the operator corrections are maintained until the end of the reel as well as for the following coils of the same type.

On the other hand, after validation by an authority competent on an 85c input of the self-adaptation system 85, the latter can intervene on the mathematical model 80 to correct certain values contained in the tables and readjust the mathematical model, according to setting values actually used.

Likewise, the elongation actually achieved is measured. and displayed on input 85b of the self-adaptation system who can thus correct, depending on the effects observed, the elongation setpoint previously displayed on the mathematical model 80.

The self-adaptation system 85 is a system classification and management IT that records all settings, classifies the results and allows choose the optimal values for the band being treatment.

However, all these settings are simply kept in reserve in the self-adaptation system, which is locked by a device 87, the installation remaining driven by the mathematical model with possibility manual operator intervention.

The latter, if he judges the corrections judicious, can, from console 81, unlock the system self-adaptation by means of a dialogue link 86 man / machine to introduce into the automation system the corrected instructions which will thus be used for the continuation of the reel and for the reels of the same type.

All the corrections made remain in memory in the self-adaptation system until verified by a competent authority which, by an order 85c, can order the validation of certain corrections and the corresponding registration of the mathematical model 80.

In this way, the mathematical model established from of equations and theoretical considerations can be adapted to the effects measured or observed on the product.

In addition, the self-adaptation system 85 allows, from a mathematical model established for some almost immediately find the right products adjustments for new products or to adapt the system with new, more efficient instructions.

In practice, when a new coil is introduced in the installation, the operator knows a certain number product-specific parameters such as its different mechanical and dimensional characteristics, thickness, width, hardness, composition, etc ... as well as its destination and enter these parameters, using the desk 81, in the mathematical model 80.

The operator can also know the faults of flatness to be corrected, for example if they are usual in a type of product. But he can also measure them using a device placed upstream of the installation. From tables or abacuses, or according to instructions data by a calculation system, the operator determines the elongation to be imposed in the leveler 3 to correct these faults. This elongation is displayed on the input 80c of the mathematical model 80 which, from programmed equations, determines the voltage imposed by the tensioning blocks 2, 2 ', and the theoretical positions of planing equipments 30, 30a, allowing to realize the lengthening imposed for leveling. The model math also calculates the effects of camber transverse and longitudinal theoretically resulting from actions performed for planing and chooses a combination of tension and bending in the leveler to minimize camber. However, residual effects are calculated and corrected in the multi-roller assembly 5 and, optionally, the anti-tile device 4, the nestings of which are determined by the mathematical model taking into account all the interactions between the elements of installation and so that the additional elongation made in the multi-roller assembly does not exceed 0.2%, the tension stress barely increased there.

The leveling result can be verified by tests performed on the tape leaving the installation and possibly cut into strips. Measures of the longitudinal or transverse camber could, possibly be performed while scrolling the band. Finally, the operator can also, by direct observation, observe imperfections and residual tape defects.

He can thus decide to correct some of the nesting instructions developed by the model math and correct some of the calculated nesting, thanks to pushbuttons B1 to B5.

These corrections being made while scrolling the band, the operator preferably acts on the least sensitive actuators which give greater adjustment latitude. In particular, it can vary first of all the nesting A2 at the end of the set multi-rollers to increase or decrease the number and the intensity of degressive flexions and, if necessary, act on the nesting A1 at the entry, this setting being more sensitive.

Thanks to the wide adjustment possibilities given by the multi-roller assembly, this manual action of the operator is essential for removing the longitudinal camber.

However, the operator can also intervene on the levelers 30, 30a, and possibly the anti-tile device 4, using push buttons B1 to B3, so that take into account the interactions between the two parts of the installation and perfect the leveling according to real characteristics and properties of the tape in course of progress.

As indicated, the corrections made are saved and optimized in the self-adaptation system 85.

If the competent authority considers, after verification, that the settings made are valid for all tapes of the type in progress, for example for all strips of the same thickness and classified in a same category, these settings are validated by the command 85c and, after unlocking the self-adaptation system 85, the corrections previously made and judged are introduced into the model memory mathematical so that, subsequently, the instructions corrected be imposed on other bands of the same category.

Likewise, corrections can be made after validation, to the values found in the self-adaptation system 85.

Similarly, if a new coil does not does not correspond to a known type, we can, depending on certain parameters such as its dimensions, the nature of the metal and its hardness, choose, among the known types, one or several types of reference closest to the new coil and display on the mathematical model either the parameters corresponding to a very similar type, namely parameters obtained by intrapolation or extrapolation.

The mathematical model 80 adjusts the tensions and nesting according to the displayed parameters and then controls the unwinding of the reel.

During the process, the operator can determine, by measurement or observation and from experience clean, the corrections that should be made to overlaps determined by the mathematical model. If the result is satisfactory, these corrections are validated by the competent authority and stored in the mathematical model which thus constitutes a new model subsequently applicable to all coils of the same type.

Of course, the invention is not limited to the details of the embodiment which has just been described by way of simple example and which could be subject to variations without departing from the scope of the claims.

In particular, a complete machine has been described but, in some cases, certain organs could be useless.

We have already indicated, for example, that the leveler could have only one leveling crew 30. The second crew can be placed on the machine and simply put out of service when unnecessary. But we can also, for certain types of products, use a single machine single crew.

Likewise, the multi-roller assembly can correct the tile defect and in some cases we could therefore remove the anti-tile device 4.

In this regard, it should be noted that the provisions leveling crews 30, 30a and antitile device 4 with respect to the strip 1, such that they have been shown in Figures 1 and 2, correspond to the most common case, but could possibly be reversed, the antitile cylinder 41 is then finding it above strip 1.

Generally speaking, in fact, the arrangement of different organs as well as the order and number of active rollers of the multi-roller assembly 5 will determined according to the characteristics, in particular thickness and hardness, from product range to treat, normally, in the installation.

In particular, the upper row of rollers 51 usually has one roll less than the row lower 51 ', as shown in Figures 1 and 2, and the first active roller, on which the strip is completely tense, is often the second in the series, but this provision could be modified according to targeted deformations. For example, the two rows could have the same number of rollers, as in the case of Figure 3, or the longest row could be the top row.

Deflector roller 45 located just after the anti-drug can also be interchangeable and / or smaller diameter, and adjustable in height so as to make it more or less active compared to a simple deflector.

It is quite obvious, on the other hand, that the configuration shown can be changed, some deflectors can be removed or, on the contrary, added to other places in the installation.

Furthermore, an installation has been described particularly advanced in which all settings are developed from tables and a model mathematical. In some simple cases, however, could only use tables established for different types of product, from operations previously performed on the same machine for products analogues.

If you have the necessary equipment, you can also complete the installation with a set of 9 means measuring devices downstream of the output tensioner block 2 ' and comprising, for example, a device 91 for measuring residual flatness defects, for example from voltage constraints, a device 92 for measuring tile, for example by laser, and a device 93 for measuring of the defect in longitudinal camber or "arch", the measurements performed being displayed on the auto-adaptation system 85 which determines correction instructions possible. For example, the flatness measurement performed in 91 can determine a correction on the elongation imposed. Detection of tile or camber faults longitudinal can lead to a correction of nesting, in priority over nesting A2 downstream of the multi-roller assembly 5 and, if necessary, on the nesting A1 at the entrance or on the nesting of the anti-tile device 4 when used.

The belt tension can also be measured at the outside of the installation by blood pressure monitors 94, 95, placed respectively upstream of the input tensioning block 2 and downstream of the output block 2 '. From these measurements external voltages, the automation system 8 can modify the elongation instructions if the coefficients tensor block multipliers become too important. Actions on exterior pull-ups can also be considered in the system, depending production contingencies and capacity regulation of parameters outside the installation. A possible measurement of the intermediate voltage, by example in 96, upstream of the multi-roller assembly 5, can optionally be used to correct nesting of the leveling crews 30, 30a.

The reference signs, inserted after the characteristics techniques mentioned in the claims have for the sole purpose of facilitating the understanding of these and do not limit its scope.

Claims (15)

1. Process for straightening a thin metal strip (1) in an installation comprising a traction-bending straightener (3) including at least one bending unit (30) with two straightening sets (31, 32) offset in height and a multi-roller levelling assembly (5) comprising two chassis, respectively upper (6) and lower (6') each supporting a row of parallel-axis rollers (51, 51') offset longitudinally and in height so as to determine, by imbrication of the rollers, an undulating path of the strip with alternate bending, means for adjusting the imbrication of the straightening sets (31, 32), means for applying a tensile stress on the strip (1) and means for adjusting the imbrication of the rollers (51, 51') of the levelling assembly (5), by tilting one row (51') in relation to the other (51), so as to determine, between the input and output of the multi-roller assembly (5), diminishing imbrications of rollers producing gradually decreasing alternate bending effects capable of correcting at least the longitudinal camber defect due to the passage through the traction-bending straightener (3).
   wherein the tensile stress is applied by two tension blocks (2, 2') placed respectively upstream of the traction-bending straightener (3) and downstream of the multi-roller levelling assembly (5), and maintaining, between said upstream (2) and downstream (2') tension blocks, a difference in travel speed corresponding to an elongation imposed on the strip for flatness correction, and wherein the travel speeds in the two tension blocks (2, 2'), the imbrication of the straightening units (31, 32) of the straightener (3) and the diminishing imbrications of the rollers (51, 51') of the levelling assembly (5) are set by an automatic control system (8) associated with a mathematical model (80) taking into account the main dimensional, structural and qualitative characteristics of the product (1), the known diameters of the active cylinders, the tensions applied on the strip to obtain the imposed elongation and the interactions between the different components of the installation, so that Said imposed elongation is practically completed when the traction-bending straightener (3) comes out and the longitudinal camber defect is corrected in the multi-roller assembly (5) without a substantial increase in the elongation already completed in the traction-bending straightener (3).
2. The straightening process of Claim 1 wherein cross bow correction can be performed at the same time as longitudinal camber correction in the multi-roller assembly (5).
3. The straightening process of Claim 1 wherein cross bow correction is performed; at least partially, in an anti-cross bow device (4) placed between the straightener (3) and the multi-roller assembly (5) to correct the cross bow at least partially before input to the multi-roller assembly (5).
4. The straightening process of any of Claims 1, 2 or 3 wherein the center-to-center distances of the straightening sets (31, 32) are adjusted according to the dimensional and structural characteristics of the strip (1) so as to produce in the straightener (3) the elongation imposed for the flatness correction while maintaining the tensile stress applied to the strip approximately 60% below the metal's tensile strength.
5. The straightening process of Claim 4 wherein the imbrications are adjusted respectively at the input and output of the multi-roller assembly (5) to correct the camber defects while limiting the increase in traction so that the additional elongation obtained in the multi-roller assembly (5) does not exceed 0.2%.
6. The straightening process of Claim 1 wherein the automatic control system (8) is associated with tables and with a mathematical model (80) on which are entered, prior to the processing of a coil, all the characteristics specific to the product (1) to be processed and specific to the installation, said mathematical model (80) generating the imbrication set values for the different devices from programmed equations and taking into account indications obtained by measuring or observing the residual flatness and longitudinal and transversal camber faults during the processing of a strip of similar nature and dimensions.
7. The straightening process of Claim 1 wherein the automatic control system (8) determines the imbrications of the different devices from tables established, for each type of product, taking into account the characteristics specific to the machine and indications obtained previously by measuring and observing the residual flatness and longitudinal and transversal camber defects during the processing of a strip of similar nature and dimensions.
8. The straightening process of any of the preceding claims wherein the operator can at any time manually correct each of the adjustments controlled by the automatic control system (8) according to measurements or observations made on the product (1) during and/or after processing.
9. The straightening process of Claim 8 wherein the manual corrections thus made are recorded, classified and optimized in a self-adapting system (85) which stores them in memory and, after unlocking by the operator, introduces the necessary modifications into the automatic control system (8) so that, subsequently, the imbrication set values thus corrected are imposed on the different devices during the unwinding of the strip and for the following strips of the same type when the same conditions re-occur.
10. The straightening process of Claim 9 wherein, after checking by a competent authority, at least some of the corrections recorded in the self-adapting system (85) can be validated and introduced into the mathematical model (80) which is readjusted so that the generated set values correspond to the previously corrected imbrications.
11. The straightening process of either of Claims 9 or 10 wherein, to process a coil whose characteristics do not correspond to those of one of the coils already processed, one or more reference types corresponding as nearly as possible to the new coil are chosen, and on the automatic control system are entered either the parameters corresponding to the type closest to it, or interpolated or extrapolated parameters so as to determine, according to the type or types of reference, the tension and imbrication set values of the different devices for the new coil, the unwinding of the coil then being activated and the operator then manually correcting the set values determined by the automatic control system (8) according to the effects obtained on the strip during unwinding, the corrections thus made being recorded, on the operator's order, in the self-adapting system (85) so as to correct the set values generated for the rest of the unwinding of the coil and for similar coils.
12. The straightening process of Claim 11 wherein at least some of the corrections made manually are validated by a competent authority and introduced into the mathematical model to reset it and to form a new model adapted to all similar coils.
13. Installation for the implementation of the process of any of the preceding claims, including a traction-bending straightener (3) comprising at least one bending unit (30) with two straightening sets (31, 32) offset in height, means (36') for adjusting the imbrication of the straightening sets (31, 32), a multi-roller levelling assembly (5) comprising two rows of rollers (51, 51') offset longitudinally and in height so as to determine, by imbrication of the rollers, an undulating path of strip with alternate bends and means for adjusting the imbrication and relative levels of the two rows of rollers (51, 51'), at least one (51') of said rows of rollers being supported by a cradle (6') mounted to swing around a horizontal axis parallel to the axes of the rollers and associated with means (63, 64, 66) for vertically displacing and tilting the cradle (6') to adjust the imbrication of the rollers of the two rows (51, 51'), by modifying the center-to-center distances, respectively A1 at the input and A2 at the output of the multi-roller assembly (5) so as to determine, in the direction of travel, diminishing imbrications of the rollers producing gradually decreasing alternate bending effects and means for applying a tensile stress to the strip (1),
    wherein the means for applying the tensile stress consist of two tension blocks (2, 2') placed respectively upstream of the traction-bending straightener (3) and downstream of the multi-roller assembly (5) and associated with means (21) for adjusting the travel speed of said tension blocks (2, 2') allowing the determination of an elongation imposed on the strip (1) for flatness correction, and wherein the installation includes positioning means (71 to 75) associated respectively with means (36') for adjusting the imbrication of the straightening sets (31, 32) and with the means (63, 64, 66) for adjusting the imbrications of the multi-roller assembly (5) and an automatic system (8) for controlling said positioning means (71 to 75), comprising a mathematical model (80) on which can be set, by means of a console (81), the parameters specific, respectively, to the machine and to the product to be processed and capable of generating imbrication set values, respectively for the straightening sets (31, 32) and the multi-roller levelling assembly (5) and wherein said positioning means (71 to 75) each constitute a regulation means receiving, on a first input (71a to 75a), a positioning order generated by the mathematical model (80) and, on a second input (71b to 75b), a signal measuring the real position of the corresponding device, said positioning adjustment means (71 to 75) controlling respectively the corresponding imbrication adjustment means (36', 63, 64, 66) to adapt the measured position to the corresponding imbrication set value.
14. The straightening installation of Claim 13 wherein the means (21) for adjusting the travel speed of the tension blocks (2, 2') are associated with an adjustment device (76) which determines the difference in speed between said tension blocks corresponding to an elongation set value generated by the mathematical model (80), said set value being capable of being corrected according to the known diameter of the rollers of the tension blocks (2, 2').
15. The straightening installation of either of Claims 13 or 14 comprising means (B1 to B5) for manually adjusting the imbrications of the different devices (30, 4, 5) and a self-adapting system (85) capable of classifying and storing in memory the manually performed corrections, said self-adapting system (85) being connected to the mathematical model (80) by a link equipped with a locking system (87) whose unlocking can be activated by a man-machine link (86) in order to introduce and, after possible validation, store in the mathematical model (80) the corrections corresponding to a type of product and optimized by the self-adapting system (85).

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