EP3403737A2 - Straightening machine and method for operating the same - Google Patents

Abstract

The present invention relates to a straightening machine for straightening a metal strip or flat metal parts, comprising a number of upper straightening rolls 15 which are mounted in a top roll mill 12 by means of a respective first and second bearing point 24, 25 and a number of lower straightening rolls 16 , which are mounted by means of a respective first and a second bearing point 24, 25 in a lower roller frame 14.

The upper and lower straightening rollers 15, 16 are arranged so that they form a straightening gap 17 between an inlet 6 and an outlet 7 of the straightening machine 1 in order to act from above and below on the metal band or metal part 10 to be straightened and this through the straightening machine 1 are to lead. Furthermore, the straightening rollers are provided with clutch elements 5 arranged on an end face for coupling drive shafts of a drive device 2, 3, 4 and can be removed from the respective roller frame 12, 14. At least a portion of the straightening rollers 15, 16 is provided at both end faces with coupling elements 5 in order to turn the straightening rollers 15, 16 within their roller mill 12, 14 can.

Description

The present invention relates to a straightening machine for straightening a metal strip or flat metal parts according to the preamble of claim 1 and to a method for operating such a straightening machine according to the preamble of claim 12.

Such a leveler comprises a number of upper straightening rollers mounted in an upper roller mill and a number of lower straightening rollers mounted in a lower roller mill. The upper and lower straightening rollers are arranged so that they form a straightening gap between an inlet and an outlet of the straightening machine to act from above and below on the metal strip or metal part to be straightened and thereby guide the metal strip or metal part through the straightening machine. On one end, the straightening rollers are provided with coupling elements for coupling drive shafts, usually propeller shafts of a drive device. Finally, the leveling rolls can be removed from the respective roll mill, so that they can be replaced after reaching a wear limit.

Straightening machines of the present type are used to eliminate stresses and bumps in metal bands or metal parts. The upper and lower straightening rollers are offset from each other along the straightening gap such that the material to be straightened is guided in a kind of serpentine line through the straightening gap and in this case is alternately bent upwards and downwards on the straightening rollers. The bending takes place in such a way that the material is bent beyond its yield point, at least at the first straightening rolls, so that unwanted bends and stresses in the material are eliminated as completely as possible. Usually, the material is heavily plasticized on the first straightening roll of the leveler. At each further straightening roll becomes The material is bent a little less, and on the last straightening roller, the material is no longer plasticized, ie only elastically deformed.

In the metalworking industry metal straps are often used, which are supplied as so-called coils and processed from there to production. By winding the strip material into coils, but also by any previous thermal treatments and the like, arise unevenness and tension in the strip material, which are unfavorable for further processing. Therefore, metal strips are usually passed after their unwinding from the coil through the aiming gap of a straightening machine of the present type, they leave flat and stress-free.

However, this is not the only application, because even flat metal parts that are to be freed of unwanted bends and stresses are usually addressed in a straightening machine of the present type in order to process them. In particular, in such Teilerichtmaschinen arise by the present invention great advantages.

A straightening machine of the type mentioned is for example from the EP-A-2 712 687 known. This known straightening machine is also particularly suitable for straightening flat metal parts and deals with the problem that the straightening gap of the straightening machine widens during a straightening operation, when the connection between the upper and the lower roll mill is taken over by stud bolts. According to this prior art it is proposed to provide the studs with adjusting devices for varying their effective length so that changes in the effective length of the studs during operation, usually elongations under load, can be compensated for in real time.

Other straightening machines of the present type are for example from the EP-A-2 002 907 , which deals in particular with a gear arrangement for the leveler, and from the EP-A-1 491 270 known.

The leveling rolls of a straightening machine of the present type usually have on a front side a coupling element for coupling drive shafts of the drive device. This is usually designed as a coupling pin with external profile. On the opposite end face of the straightening rollers is a bearing pin for a thrust bearing in the respective roll mill. To remove the straightening roller from the roller mill, the propeller shaft is pulled off the straightening roller on the drive side, the associated bearing point is released and the straightening roller is pulled out of the opposite bearing point.

The leveling rolls of a straightening machine of the present type are exposed to high forces and are therefore subject to a more or less rapid wear. When the straightening rollers have reached a degree of wear that causes visible defects on the surface of the metal straps or metal parts to be straightened, the straightening rollers must be replaced. Due to the necessary high stability, strength and dimensional accuracy of the straightening rollers replacement of straightening rollers is correspondingly costly.

The present invention is therefore an object of the invention to provide a straightening machine of the type mentioned above and a method for operating this straightening machine, with or with which the life of the straightening rollers, especially when the straightening machine is also used for straightening flat metal parts increases can be.

This object is achieved by a leveler with the features of claim 1 and by a method having the features of claim 12. Preferred embodiments of the straightening machine according to the invention can be found in claims 2 to 11; advantageous developments of the method according to the invention are set forth in claims 13 to 15.

According to the invention, it has been recognized that straightening rolls of straightening machines which are used for straightening flat metal parts wear particularly quickly on that side of the straightening machine which lies opposite the drive device. This is related to having a person who the straightening machine operated and the metal parts to be straightened in the inlet of the straightening machine by usually puts them on a arranged before the inlet roller conveyor or other conveyor, this is on the side of the straightening machine, which is opposite to the drive device. Naturally thereby the metal parts to be straightened are, if they are narrower than the width of the inlet, usually not centered but reach the straightening gap in the vicinity of the operator, ie on the side of the leveler facing away from the drive device. As a result, the straightening rollers on the operating side of the leveler wear faster than on the drive side.

According to the invention, it has further been recognized that with such asymmetric loading of straightening rolls and the concomitant substantially unilateral wear thereof, the service life of straightening rolls can be greatly increased simply by turning the straightening rolls within the straightening machine, i. After a number of straightening operations taken from the respective roll mill, turned and used with reversed end faces back into the roll mill.

To make this possible, the invention proposes that the straightening rollers, which are to be turned, not only - as in the prior art - are provided on one end side with coupling elements, but have coupling elements on both end faces.

The coupling elements can, as is customary in the prior art, be configured as a drive journal with a profiled cross-section for axial torque transmission by means of an attachable drive shaft or propeller shaft; Alternatively, it can be provided to design the coupling elements as drive sleeves with profiled cross-section, can be inserted into the correspondingly profiled pin of drive shafts. Both alternatives have in common that the coupling and uncoupling of the thus formed straightening rollers can be done by the drive shafts of a drive device by means of an axial movement.

The inventive reversible design of straightening rolls a much improved life of the straightening rollers can be achieved, the improvement is the greater, the more often metal parts are directed, the off-center, usually shifted to the operator side of the straightening machine, enter the straightening gap. Because by turning the straightening rollers at regular intervals, the areas of the straightening roller which are more heavily loaded and thus wear more quickly are exchanged for the less stressed and thus less worn areas of the straightening roller. Ideally, this results in a substantially uniform stress on the straightening rollers.

In order to increase the service life of the reversible straightening rollers further, it is preferred in the context of the present invention, when the leveling rolls are not only rotated and used with reversed end faces back in the roll mill, but also the order of straightening rolls is reversely reversed along the directional gap. Because it has been recognized that the straightening rollers are stressed during the straightening process the more and accordingly wear the more, the closer they are arranged at the inlet of the straightening machine. If the order of straightening rollers between the inlet and the outlet of the straightening machine regularly exchanged, in turn results in the effect that more strained straightening rollers are replaced by less straightened straightening rollers, so that as a result all straightening rollers are loaded substantially uniformly and wear evenly.

As is known from the prior art, it is also preferred in a straightening machine according to the invention, if each straightening roller are assigned at its side facing away from the bite gap at least two support roller pairs, which support the straightening rollers against deflection during the straightening process.

Naturally, this results in the contact areas between the support rollers and the straightening roller an increased load on the straightening roller, which leads to increased wear, especially at the front edges of the support rollers. It is therefore preferred in the context of the present invention, the support roller pairs for each to arrange a straightening roller such that they are not symmetrically positioned with respect to a center of an imaginary line between the two bearings of the straightening roller. As a result, after the straightening roller has turned, the contact regions between the support rollers and the straightening roller are located at a different point of the straightening roller, so that premature wear in these contact regions and in particular in the region of the frontal edges of the support rollers is avoided. This also further increases the service life of the straightening rollers.

In order to optimally adapt the cycle for the inventive turning of straightening rolls to the individual load of the straightening machine and its leveling rolls, it is preferred in the context of the inventive method, the forces acting in a straightening process between the upper and lower roll mill, and their temporal Track history and sum up. This can be purely quantitative, in that whenever the amount of force that wants to remove the upper roll mill from the lower roll mill is above a certain threshold and at the same time the time interval in which the force is above the threshold exceeds a predetermined minimum duration, a counter is activated, which stands for a completed straightening cycle. Of course, it is also possible to qualitatively detect the forces and / or their time course and to calculate by appropriate integration a load that has acted on the straightening machine during the detected straightening process. This load is accordingly a measure of the load and thus indirectly the expected wear by the corresponding straightening cycle, and it is given a smaller value if, for example, the time interval of the force action is shorter than in a straightening process with a longer time interval, for example because metal parts of different lengths have otherwise the same dimensions and consist of the same material, or it receives a higher value according to a detected asymmetry of the forces.

Preferably, in addition, individual values of forces are measured, which in the straightening machine between the two roll mills at different Locations act simultaneously within the straightening machine, ie, the asymmetrical distribution of forces - where such exists - is preferably detected. Again, this can be done purely quantitatively by counting when thresholds for a corresponding asymmetry of forces and for a time interval in which this asymmetry is above the thresholds are exceeded. However, a better approximation to the actual wear-related processes will be achieved if a possible asymmetrical distribution of the forces and their time course is qualitatively recorded and, if necessary, summed up.

From the quantitatively and / or qualitatively detected forces acting in a straightening process between the upper and the lower roller mill, from their time course and optionally their asymmetrical distribution, an expected value for wear of the straightening rollers is determined according to the invention, and after reaching a predetermined expectation Threshold the straightening rollers are removed from the respective roll mill, turned and used with reversed end faces and possibly also with reversed order along the straightening gap back into the roll mill. Here, a balance between the desired, uniform as possible wear of the straightening rollers and the frequency of the turning process, which is associated with a machine downtime, must be found.

In order to be able to operate the straightening machine according to the invention with the method described above, preferably sensors are provided for detecting forces which act during the straightening process between the upper and the lower roll mill. This detection of forces can in turn be quantitative and / or qualitative. Preferably, in this case, the sensors are distributed in the straightening machine, in addition to detecting the forces acting during the straightening process between the upper and the lower roller mill forces to detect an asymmetric distribution of the same quantitatively and / or qualitatively.

In straightening machines, which, as is known, have studs for connecting the upper and lower roll mills, their elongation during the straightening process is compensated by changing its effective length, the studs are usually provided with sensors, in particular displacement sensors, which detect an elongation of the respective studs. In the context of the present invention, it is therefore advantageous if the sensors for detecting the forces acting between the roll mills and, if appropriate, their asymmetrical distribution are just those sensors which detect a lengthening of the respective studs and are designed, for example, as displacement sensors.

Preferably, the sensors of the straightening machine according to the invention, which detect quantitatively and / or qualitatively the forces acting during the straightening process between the upper and the lower roll mill, their temporal course and / or their asymmetrical distribution, are associated with a load spectrum store. This is used for storing detected forces and / or for storing and totaling from the detected forces quantitatively or qualitatively determined straightening cycles.

Alternatively or additionally, the load collective memory may be designed such that it stores the forces detected during a straightening process and their time course, and - insofar recorded - their asymmetrical distribution and / or calculated from each of a load and, where appropriate, their asymmetric distribution and the calculated value as Load cycle stores. These load cycles are a measure of the wear-inducing loading of the straightening rolls, optionally including an asymmetrical distribution weighted into the load cycles, so that summing up the load cycles that can occur in the load spectrum store allows estimation of the wear generated by the load.

There are several levels of accuracy; a mere counting of loads above a load threshold, which leads to a certain number of straightening cycles, which are summed up in the load collective memory already allows a rough estimate of the straightening caused by the straightening of the straightening rolls, while a qualitative detection of the burden by a qualitative detection and Evaluation of spatially resolved acting Forces and their time course for the calculation of load cycles, which are summed up in the load collective memory, the actual conditions when the wear of the straightening rolls accurately maps.

In any case, it is preferred if the straightening machine according to the invention is provided with a wear calculator designed such that it calculates a wear value from the straightening cycles or load cycles accumulated in the load spectrum storage and outputs a signal for turning the straightening rolls when a predetermined wear threshold is reached , Alternatively, in order to be closer to the actual conditions, the wear calculator can be designed such that it calculates the expected forces for the straightening rollers on the basis of the forces recorded by the sensors in the load collective memory and their time course and, if detected calculated and outputs a signal when reaching a predetermined expectation threshold. The intermediate step of summing the straightening cycles or the load cycles can be omitted in the latter case.

Figur 1

eine schematische Draufsicht auf eine Richtmaschine der vorliegenden Art von oben;

Figur 2

eine schematische Frontansicht einer erfindungsgemäß ausgestalteten Richtmaschine

Figur 3

Detailansichten der Stirnseiten einer Richtwalze nach dem Stand der Technik;

Figur 4

eine Lagerstelle einer Richtwalze nach dem Stand der Technik;

Figur 5

eine Lagerstelle einer Richtwalze in einer erfindungsgemäß ausgestalteten Richtmaschine;

Figur 6

eine schematische Darstellung von Richtwalzen mit zugehörigen Stützrollen.

An exemplary embodiment of a straightening machine configured according to the invention is described and explained in more detail below with reference to the drawings. Show it:

FIG. 1

a schematic plan view of a straightening machine of the present type from above;

FIG. 2

a schematic front view of an inventively designed straightening machine

FIG. 3

Detailed views of the front sides of a straightening roller according to the prior art;

FIG. 4

a bearing of a straightening roller according to the prior art;

FIG. 5

a bearing point of a straightening roll in a straightening machine designed according to the invention;

FIG. 6

a schematic representation of straightening rollers with associated support rollers.

In FIG. 1 is a plan view of a straightening machine of the present type shown. The actual straightening machine 1, in which the (not visible here) straightening rollers are mounted, is provided on a drive side shown here right with a drive device consisting of a drive motor 2 and a gear block 3 and a number of propeller shafts 4, the individual transmission connections connect with coupling elements 5 of the straightening rollers.

An inlet 6 and an outlet 7 of the straightening machine are provided with an inlet roller conveyor 8 and an outlet roller conveyor 9 to give flat metal parts 10 in the inlet 6 and to remove directed from the outlet 7.

From the actual straightening machine 1, only a frame 11 and an upper roller mill 12 and adjusting devices 13 for (not visible here) stud bolts can be seen. The representation in FIG. 1 illuminates the problem with parting machines that caused the findings of the invention and ultimately led to the present invention:
In the FIG. 1 indicated operator has the task to give the metal part to be straightened 10 in the inlet 6 and remove after straightening from the outlet 7 again. For this purpose, she puts the metal part 10, as in FIG. 1 shown, of course, so on the inlet roller conveyor 8, that it is close to the operating side, ie the in FIG. 1 Left side of the leveler 1 comes to rest. When the straightening machine 1, as in the present example, has a wide inlet 6, there are quite often metal parts 10 in operation whose width does not correspond to the width of the inlet 6. These will then, as in FIG. 1 shown, off-center, moved to the operating side, on the inlet roller conveyor 8th hung up. Accordingly, the straightening rollers of the straightening machine 1 are strained during straightening of the metal part 10 only in the areas oriented towards the operating side, while the straightening in the FIG. 1 On the right side of the drive side oriented areas of straightening rollers remain completely unloaded from this straightening process.

FIG. 2 shows a schematic side view of the leveler 1 from FIG. 1 , seen from the operating side. In frame 11, an upper roll mill 12 and a lower roll mill 14 are mounted, wherein the two roll chairs 12, 14 are connected to each other with four studs 20.

In the upper roll mill 12, in the present case, nine upper straightening rolls 15 are mounted, while ten lower straightening rolls 16 are mounted in the lower roll mill 14 in the present case. The upper and lower straightening rollers 15, 16 are each arranged in series one behind the other in such a way that they form a straightening gap 17 between the row of upper straightening rollers 15 and the row of lower straightening rollers 16 extending from the inlet 6 to the outlet 7 by the straightening machine 1 extends. Now, if a metal part is placed in the inlet 6, it is transported in the straightening gap 17 between the upper straightening rollers 15 and the lower straightening rollers 16 through the straightening machine 1 and this alternately about the upper and lower straightening rollers 15, 16 in a serpentine up and down bent. For this purpose, the straightening rollers 15, 16 are arranged offset at the aiming gap 17.

The stud bolts 20, which connect the lower roller mill 14 with the upper roller mill 12, are firmly anchored in the lower roller mill by means of anchors 18, while they are adjustably mounted on the upper roller mill 12. The adjusting devices 13 are in FIG. 1 to recognize; On the one hand, they are fixedly connected to the upper roller frame 12 and, on the other hand, support an abutment for the stud bolts 20. The height of the abutment relative to the upper roller mill can be changed by means of the adjustment devices 13, so that an elongation of the stud bolts 20 during a straightening process in which the Guide gap 17 is widened by a metal part, by moving the anvil can be compensated upward by the bearing of the stud bolts 20 on the upper bearing block 12 in a similar manner "lengthened" is. In this respect, the adjusting device 13 does not change the actual length of the studs 20, but only their effective length, which is proportional to the aiming gap 17, and can keep the aiming gap 17 so constant.

When passing through a metal part 10 through the straightening gap 17, the force flow of the opposing forces from the upper roll mill 12 passes over the stud bolts 20 in the lower roller mill 14. The studs 20 are elongated, the elongation is the more pronounced, the less costly the studs 20 are formed , Due to the elongation of the studs 20, the aiming gap 17 expands, which is compensated by the adjusting device 13.

In order to perform such compensation in real time and to keep the aiming gap 17 constant, 20 sensors 19 are mounted on all four studs, which are designed in the present case as displacement sensors. Due to the values for an elongation of the studs 20 reported by the sensors 19 to a machine control, the adjusting device 13 can correspondingly increase the height of the counter-bearing of the stud bolts 20 on the upper roller mill 12 so that the effective length of the stud bolts 20 does not change despite an elongation thereof and thus the straightening gap 17 remains constant, ie does not expand. This embodiment of a leveler is in itself from the EP-A-2 712 687 known.

According to the invention, the sensors 19, which are present anyway as displacement sensors for the adjusting device 13, can also be used to detect the forces acting on a straightening operation between the upper roller mill 12 and the lower roller mill 14, namely spatially resolved at all four corners Roller mills 12, 14, namely on each stud bolt 20th

Thus, on the basis of the values supplied by the sensors 19, it is possible to deduce forces which prevail in the aiming gap 17, as well as their temporal course the time interval in which they act - and, if necessary, also an asymmetric distribution of forces.

Depending on the desired accuracy, the wear of the leveling rolls 15, 16 can be deduced from the values supplied by the sensors 19 in various variants.

For example, completed straightening cycles can be counted, wherein a straightening cycle is counted when a certain force in the straightening gap 17, or in the present example, a certain way of the sensors 19 for the elongation of the studs 20 is exceeded for the duration of a certain time interval. Or, a number of asymmetrical alignment cycles are counted, which are accordingly defined by detecting a certain asymmetry of sensor values above a certain threshold and over a given time interval.

If the accumulated number of straightening cycles and / or the accumulated number of asymmetrical straightening cycles is so large that a predetermined threshold value is reached, a signal is output at the control of the straightening machine 1, indicating that the straightening rollers 15, 16 turned and / or in their order along the directional gap 17 to be reversed in order to achieve a uniform wear of all straightening rollers 15, 16.

However, it can also be concluded from the position and time-resolved measured values for the forces acting in the aiming gap on a degree of asymmetrical wear of the leveling rolls 15, 16 and this extent as a trigger for a signal for turning and / or exchange of straightening rolls 15, 16 used become.

In order to turn the straightening rollers 15, 16, these are inventively provided on both end faces with coupling elements 5. Based FIG. 3 , which shows the two end faces of a straightening roller 15 according to the prior art, this is illustrated: According to the prior art, the straightening roller 15 only on one of its end faces via a coupling element 5, which is presently designed as a drive pin with profiled cross section for axial torque transmission. At the other end, the straightening roller 15 according to the prior art, a bearing pin 21.

As FIG. 4 shows the straightening roller 15 is mounted according to the prior art by means of this journal 21 in the associated roller mill 12 in a conventional thrust bearing 22.

In order to enable the inventive reversibility of the straightening rollers 15, 16, they are provided on both ends with coupling elements 5, which makes a modification of the storage of the straightening rollers 15, 16 in their roll mills 12, 14 necessary, as in FIG. 5 is shown. The thrust bearing 22, which is arranged in the prior art on an outer side of the roller mill 12, had, as in FIG. 5 represented, be relocated to the inside of the roll mill 12 and 14 respectively.

FIG. 6 Finally, in a schematic representation of a series of lower straightening rollers 16 and two pairs of associated support rollers 23a and 23b. By means of the support rollers 23a, 23b, the straightening rollers 16 are supported against the directional pressure in the roller mill 14, so that on the one hand does not remove the entire directing pressure on the first bearings 24 and the second bearings 24 and on the other hand, a deflection of the straightening rollers 16 is avoided.

According to a preferred embodiment of the present invention, in this embodiment, the support roller pairs 23a, 23b with respect to a center of an imaginary line connecting the two bearings 24, 25 of the straightening rollers 16, not symmetrically positioned, but each one piece moved to the left. By turning the straightening rollers 16, therefore, the track of the support roller pairs 23a, 23b is then in a different region of the straightening rollers 16 and is slightly offset, so that here also a homogenization of the wear generated by the contact between the support rollers 23 and the straightening rollers 16 he follows.

In the present embodiment, therefore, a known from the prior art leveling machine 1 is used and inventively modified in that the straightening rollers 16, 17 are provided at both end faces with coupling elements 5. The already existing sensors 19 can then be used for carrying out the method according to the invention. In the simplest case, this is done so that is detected by different strains of the four studs 20, which are reported by the sensors 19, that a metal part 10 was off-centered in the inlet 6 of the leveler 1, so that the straightening rollers 15, 16 asymmetrically be charged. These straightening cycles, which are identified as asymmetrical, are summed up in a load spectrum memory. Once the sum reaches a predetermined threshold, the straightening rollers 15, 16 are turned or issued a signal that should cause such a turn.

However, since the sensors 19 are capable of delivering values spatially and temporally resolved proportional to the forces prevailing in the aiming gap 17, these values can also be used to calculate more accurate load values for the loading of the straightening rollers 15, 16 associated with wear and possibly with them Asymmetries weighted and summarized as load cycles are stored and summed up. From the load values, or optionally from the load cycle totals, a wear value can be calculated and upon reaching a predetermined wear threshold, a signal for turning and / or interchanging the straightening rollers 15, 16 are output.

Claims (15)

Straightening machine for straightening a metal strip or flat metal parts (10),
with a number of upper straightening rollers (15) mounted in an upper roller mill (12) and a number of lower straightening rollers (16) mounted in a lower roller mill (14),
wherein the upper and lower straightening rollers (15, 16) are arranged so that between an inlet (6) and an outlet (7) of the straightening machine (1) form a straightening gap (17) to from above and from below to directing metal strapping or metal part (10) and passing it through the straightening machine (1),
the straightening rollers (15, 16) being provided with coupling elements (5) arranged on an end face for coupling drive shafts of a drive device (2, 3 4),
and wherein the leveling rolls 815, 16) can be removed from the respective roll mill (12, 14),
characterized,
in that at least some of the straightening rollers (15, 16) are provided with coupling elements (5) on both end faces. Straightening machine according to claim 1, wherein the coupling elements (5) of the leveling rolls (15, 16) are designed as drive pins or drive sleeves with profiled cross section for axial torque transmission. Straightening machine according to one of claims 1 or 2, wherein each straightening roller (15, 16) on its side facing away from the straightening gap (17) side at least two support roller pairs (23) are associated with respect to a center of an imaginary line, the first bearing point (24). and a second bearing (25) of the straightening roller (15, 16) connects, are not positioned symmetrically. Straightening machine according to at least one of claims 1 to 3, wherein sensors (19) are provided for detecting forces acting in the straightening process between the upper and the lower roll mill (12, 14). Straightening machine according to claim 4, wherein the sensors (19) are distributed in the straightening machine (1) in order, in addition to detecting the forces acting in the straightening process between the upper and lower roll mill (12, 14), to also detect an asymmetrical distribution thereof. Straightening machine according to one of claims 4 or 5, wherein the upper and the lower roll mill (12, 14) via a number of studs (20) are interconnected, and wherein at least a part of the studs (20 with sensors (19) is provided which detect an elongation of the respective stud bolts (20). Straightening machine according to claim 6, wherein the sensors (19) are designed as displacement sensors. Straightening machine according to at least one of claims 4 to 7, wherein the sensors (19) is associated with a load collective memory for storing detected forces and / or for storing and totaling determined from the detected forces straightening cycles. Straightening machine according to at least one of claims 4 to 8, wherein the load collective memory is designed so that it stores the forces detected during a straightening process and their time course and, if detected, their asymmetric distribution and / or from the forces detected during a straightening process and off the time course of each of which a load and, if detected, an asymmetrical distribution of the load is calculated, these stored as a duty cycle and summed up the load cycles. Straightening machine according to one of claims 8 or 9, wherein the straightening machine (1) is provided with a wear calculator designed in such a way is that it calculates a wear value from the straightening cycles or load cycles summed up in the load collective memory and outputs a signal when a predefined wear threshold value is reached. Straightening machine according to one of claims 8 or 9, wherein the straightening machine (1) is provided with a wear calculator, which is designed such that it based on the stored in the load collective memory, the sensors (19) detected forces and their time course and when detected whose spatial distribution calculates an expected value for wear of the straightening rollers (15, 16) and outputs a signal when a predefined expected threshold value is reached. Method for operating a straightening machine (1) according to at least one of claims 1 to 11,
wherein the straightening rollers (15, 16) after a number of straightening operations taken from the respective roll mill (12, 14), turned and used with reversed end faces again in the roll mill (12, 14). A method according to claim 12, wherein forces acting in a straightening operation between the upper and lower roll mills (12, 14) and / or their asymmetry are detected and the straightening operations performed are counted as straightening cycles, and after reaching a predetermined straightening cycle threshold value for the number of straightening operations the straightening rollers (15, 16) taken from the respective roll mill (12, 14), turned and used with reversed end faces again in the roll mill (12, 14). The method of claim 12, wherein based on a detection and summation of forces acting in a straightening process between the upper and the lower roller mill (12, 14), and their time course and, if detected, their asymmetric distribution an expectation of wear of Straightening rollers (15, 16) determined and after reaching a predetermined expectation threshold, the straightening rollers (15, 16) from the respective roll mill (12, 14) removed, turned and used with reversed end faces again in the roll mill (12, 14). Method according to one of claims 13 or 14, wherein the straightening rollers (15, 16) are not only turned and used with reversed end faces back in the roll mill (12, 14), but also the order of straightening rolls (15, 16) along the straightening gap (17) is reversed.

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