Tension and guidance device, and method of rolling strip material

Abstract

A rolling system, particularly a cold-rolling system for cold-rolling a metal strip (2): having at least one cold-rolling stand (1) an unwinding device (3) upstream of the cold-rolling stand (1), a unit (10) connected between the unwinding device (3) and the cold-rolling stand (1), including at least three rolls (6, 7, 8) each rotationally driven about a rotational axis (6A, 7A, 8A). Each roll (6, 7, 8) can be adjusted individually or together in the direction of the respective rotational axis (6A, 7A, 8A) and in a direction transverse to the rotational axis (6A, 7A, 8A) by a driving and adjusting device (11).

Claims

1. A cold-rolling mill for cold-rolling of a metal strip, the mill comprising: at least one cold-rolling stand, a decoiler positioned upstream of the cold-rolling stand, and a unit in-line between the decoiler and the cold-rolling stand, the unit is comprised of at least three rollers, each of said at least three rollers of said unit is rotationally driven about a respective axis of rotation; and a drive and positioning facility that controls the driven rotation and the spatial positioning of said at least three rollers of said unit and the decoiler, said drive and positioning facility configured for repositioning, during cold rolling of the metal strip, each of said at least three rollers of said unit in the direction along each of said respective axis of rotation of each of said at least three rollers of said unit and in a direction transverse to said each respective axis of rotation, wherein each of said at least three rollers of said unit is configured to be repositioned with the drive and positioning facility in the direction along said each respective axis of rotation and in the direction transverse to said each respective axis of rotation.

2. The rolling mill as claimed in claim 1, wherein the axis of rotation of a first one of the rollers which is located closer to the decoiler and the axis of rotation of a third one of the rollers which is located closer to the cold-rolling stand lie in a first plane and a second one of the rollers is a central roller arranged between the first and third rollers, wherein the central roller is repositionable to be spatially positioned relative to the first plane, and the central roller is so positioned by the drive and positioning facility.

3. The rolling mill as claimed in claim 2, wherein the central roller is repositionable between an out-of-line position, in which the central roller is not engaged with the rolling strip, and an in-line position, in which a circumferential surface of the central roller is partially wrapped around by the rolling strip.

4. The rolling mill as claimed in claim 3, wherein in the in-line position of the central roller, a wrap-around of the strip on the central roller is arranged beneath the first plane, and a wrap-around of the strip on the first and third rollers is arranged above the first plane.

5. The rolling mill as claimed in claim 4, wherein in the in-line position of the central roller, the wrap-around of the strip on the central roller is greater than 180°.

6. The rolling mill as claimed in claim 5, wherein a distance between the respective axes of rotation of the first and third rollers in the first plane can be adjusted, and the drive and positioning facility is configured and operable for adjusting the distance between the axes of the first and third rollers.

7. The rolling mill as claimed in claims 1, wherein when the central roller is being repositioned, the direction of movement of the central roller is at an angle to a first plane.

8. The rolling mill as claimed in claim 1, wherein the drive and positioning facility is operable to reposition the decoiler, together with or separately from the rollers, in the direction of the axes of rotation of the rollers.

9. The rolling mill as claimed in claim 1, further comprising a measurement device configured for detecting the position of the strip and arranged between the unit and the cold-rolling stand; and the measurement device has a signaling link with the drive and positioning facility.

10. A method of cold-rolling of a metal strip with a rolling mill, the mill comprising at least one cold-rolling stand through which the metal strip is advanced, a decoiler positioned upstream of the cold-rolling stand, a unit configured for influencing the path of the cold-rolled strip is located in-line between the decoiler and the cold-rolling stand, and is comprised of three rollers each driven about a respective axis of rotation, and a drive and positioning facility that controls the driven rotation and the spatial positioning of said three rollers of said unit and the decoiler, the method comprising: selectively repositioning each of said three rollers of said unit during the cold-rolling operation, by means of said drive and positioning facility, both in a direction along each said respective axis of rotation of each of said three rollers of said unit and in a direction transverse to each said respective axis of rotation of each of said three rollers of said unit.

11. The method as claimed in claim 10, further comprising selectively repositioning the axis of rotation of a first one of the rollers located closest to the decoiler and the axis of rotation of a third one of the rollers located closest to the cold-rolling stand to lie in a plane and selectively repositioning the central roller that is between the first and the third rollers in the direction of advance of the strip path to be positioned relative to the plane.

12. The method as claimed in claim 10, further comprising repositioning the central roller between an out-of-line position, in which the central roller is not engaged with the rolling strip, and an in-line position, in which the rolling strip is partially wrapped around a circumferential surface of the central roller.

13. The method as claimed in claim 12, wherein by repositioning the central roller in the in-line position thereof, a wrap-around of the strip on the central roller is arranged beneath the plane, and wrap-around of the strip on the first and third rollers lies above the plane.

14. The method as claimed in claim 13, wherein in the in-line position of the central roller the rolling strip wraps around the central roller over an angle greater than 180°.

15. The method as claimed in claim 14, further comprising adjusting the distance between the axes of rotation of the first and third rollers in the plane is by means of a drive and positioning facility.

16. The method as claimed in claim 15, further comprising adjusting a direction of movement of the central roller when the central roller is being engaged is effected at an angle to the plane.

17. The method as claimed in claim 16, further comprising: adjusting the decoiler together with or separately from the rollers, in the direction of the axes of rotation of the rollers by means of a drive and positioning facility.

18. The method as claimed in claim 17, further comprising detecting a position of the strip between the unit and the cold-rolling stand, and submitting a measurement signal for the position of the strip to be transmitted over a signaling link to a drive and positioning facility for the decoiler and the rollers.

19. The method as claimed in claim 10, further comprising initially feeding the metal strip using a two-part transfer table for the strip, by arranging a first part of the table which is upstream from the rollers to be located beside the decoiler and by arranging a second part of the table between a first one of the rollers and a third one of the rollers in a direction of advancing of the strip.

20. The method as claimed in claim 19 further comprising positioning the transfer table in-line; and during an initial feeding-in of the strip, moving a pinch roller towards the transfer table which has been positioned in-line.

21. The method as claimed in claim 10, wherein the rollers and the decoiler are positioned by means of a drive and positioning facility.

22. A cold-rolling mill for cold-rolling of a metal strip, the mill comprising: at least one cold-rolling stand, a decoiler positioned upstream of the cold-rolling stand, and a unit positioned in-line between the decoiler and the cold-rolling stand, the unit is comprised of at least three rollers, each of said at least three rollers of said unit is rotationally driven about a respective axis of rotation, wherein each of said at least three rollers of said unit is configured to be repositioned individually in a direction transverse to said each respective axis of rotation of said at least three rollers of said unit; and a drive and positioning facility that controls the driven rotation and the spatial positioning of said three rollers of said unit and the decoiler, said drive and positioning facility configured for repositioning, during cold rolling, said each of at least three rollers of said unit in the direction transverse to said each respective axes of rotation of said at least three rollers of said unit.

23. A cold-rolling mill for cold-rolling of a metal strip, the mill comprising: at least one cold-rolling stand, a decoiler positioned upstream of the cold-rolling stand, and a unit positioned in-line between the decoiler and the at least one cold-rolling stand, the unit comprising at least three rollers, each roller of said at least three rollers of said unit is rotationally driven about a respective axis of rotation, wherein each of said at least three rollers of said unit is configured to be repositioned in a direction along each of said respective axis of rotation of said at least three rollers of said unit; and a drive and positioning facility that controls the driven rotation and spatial positioning of said three rollers of said unit and the decoiler, said drive and positioning facility configured for repositioning, during cold rolling, said at least three rollers of said unit in the direction along each of said respective axes of rotation of said at least three rollers of said unit.

24. A method of cold-rolling of a metal strip with a rolling mill, the mill comprising at least one cold-rolling stand through which the metal strip is advanced, a decoiler positioned upstream of the cold-rolling stand, a unit configured for influencing a strip path located in-line between the decoiler and the cold-rolling stand, the unit comprising one or more rollers, each of said one or more rollers of said unit being driven about a respective axis of rotation, and a drive and positioning facility that provides the drive and relative positioning of said one or more rollers of said unit, the method comprising: selectively repositioning each roller of said one or more rollers of the unit during the rolling operation, by means of a drive and positioning facility, in a direction along the respective axis of rotation of each roller of the one or more rollers of said unit to influence the strip path in a cold-rolling operation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) For the purpose of explaining the invention further, the following part of the description refers to the drawings, from which are to be inferred, by reference to an exemplary embodiment which is not to be taken as restrictive, further advantageous embodiments, details and developments of the invention.

(2) In the drawings:

(3) FIG. 1 shows a schematic side view of the inventive rolling mill in an initial feeding-in state, in which the central roller is disengaged;

(4) FIG. 2 shows the cold-rolling mill shown in FIG. 1, in the rolling state, in which the central roller is engaged with the metal strip;

(5) FIG. 3 shows the cold-rolling mill shown in FIG. 1, where the central roller is moved down below the direct passage line, and fluctuations in tension are regulated out by a positioning movement, in the direction of the path of the strip, of the roller on the input side and/or on the output side;

(6) FIG. 4 shows a detailed view of the 3-roller system.

EMBODIMENT OF THE INVENTION

(7) FIG. 1 shows a schematic side view of the inventive rolling mill in a position in which the start of the strip is fed into the roll stand 1. A steel strip 2 which is rolled up into a coil is unwound in a clockwise direction by a decoiler 3 and passes from left to right towards the unit 10. This unit 10 comprises three rollers 6, 7, 8, of which the central roller 7 is pivoted away from the path of the strip and is not engaged with the metal strip 2 (feed-in setting). The metal strip 2 is initially transported on a part of a transfer table 13 and is thereafter supported by the roller 6, by a second part of the transfer table 13 and the roller 8. In the case of very stiff metal strips, this process of feeding-in may, if necessary, also be assisted by a pinch roller 19. The transfer table 13 can be pivoted into and out of the path of the strip by drives, not shown in the drawing.

(8) As indicated in FIG. 1 by the arrows 12, the spatial position of the rollers 6, 7, 8, and if necessary also the decoiler 3, can be changed by means of a drive and positioning facility 11. In other words, each of the rollers 6, 7, 8 can not only be driven rotationally about its associated axis of rotation and positioned in the axial direction (together with each other or separately) 6A, 7A, 8A by the drive and positioning facility 11, but it is also possible to adjust the location of any of the rollers 6, 7, 8 in a direction transverse to its axis of rotation 6A, 7A, 8A by means of the drive and positioning facility 11.

(9) Particularly in the case when the rolling strip has a wedge-shaped cross section it is expedient if the decoiler 3 is positioned in the direction of its axis of rotation 3A at the same time as the 3-roller system is axially positioned. By this means, the metal strip 2 can be guided into the center of the cold-rolling stand 1.

(10) It should be noted at this point that drive and positioning facilities 11, with which it is possible to prescribe or adjust a rotational movement and at the same time also the spatial position of a roller (or if necessary also a decoiler) for a rolling mill, can be actuated hydraulically or electro-mechanically.

(11) In what follows, such facilities are assumed to be familiar, and thus do not need to be explained in more detail here.

(12) FIG. 2 shows the state during cold rolling. After the rolling strip 2 has been initially fed into the gap between the working rollers of the rolling mill 1, and has been gripped by it, a forward tension is exerted on the metal strip 2. As already described in the introduction, it should be possible to prescribe the forward tension and the path of the strip at the region of the infeed to the roll as far as possible independently of the forward tension in the region of the decoiler 3. Fluctuations in the forward tension during decoiling of the coil should as far as possible not reach the region of the infeed to the roll stand 1. As shown in FIG. 2, the unit 10 is provided for this tension decoupling. In this illustration, the central roller 7 of the unit 10 is pivoted to be in-line. The metal strip 2 wraps around part of the area of the outer surface of each of the three rollers 6, 7, 8. As already stated, each roller 6, 7, 8 is driven rotationally by a drive which is not shown in more detail. The drive torque for the rollers 6, 7, 8 is then prescribed by the drive and positioning facility 11 such that, on the one hand, a braking effect is exerted on the metal strip 2. This braking effect enables a desired minimum magnitude of tension to be correctly maintained at the infeed to the cold-rolling stand 1. This back tension is largely independent of and unaffected by fluctuations in the tension which can arise when a loosely wound coil is unwound. Further, the drive and positioning facility 11 also influences the spatial position of the axes of rotation of the rollers 6, 7, 8 (if necessary also that of the decoiler 3 in the direction of its axis of rotation 3A). By a displacement in the axial direction of the rollers, it is possible to exercise an influence over not only the forward tension but also over the path of the strip. This exercise of influence (on both the rotational movement and also on the axial positions of the axes of rotation) is indicated symbolically in FIG. 2 by dashed lines (operating and signaling link 4) and by the arrows 12. For the sake of clarity, the drives and actuators for these positioning operations are not shown in more detail in the drawings.

(13) For the purpose of detecting the position of the strip, a strip position detector 9 is used, this being arranged between the unit 10 and the cold-rolling stand 1. Monitoring of the strip path can be effected, for example, by detecting metrologically the edge(s) of the metal strip. This strip position detector 9 is linked by a signaling link to the drive and positioning facility 11. Using the measurement signal which is fed to it, a conventional regulator is well able to counteract any errors in the path of the metal strip 2. This is particularly advantageous in cases where the metal strip has a cross sectional profile which is wedge-shaped.

(14) FIG. 3 also shows the state during the rolling operation. A difference from the illustration in FIG. 2 is that the central roller 7 has been moved down far below the two rollers 6, 8. As a result, the wrap-around on roller 7 extends over a large angle, with a comparatively larger wrap-around angle also on the rollers 6, 8. This angle of wrap-around can be adjusted by prescribing the position of roller 6 or the position of roller 8, as applicable, as shown in each case by the arrow 14. In doing so, the axis of rotation of one of the rollers 6, 8 can be moved, or even both of them. If the distance 18 between the axes of rotation 6A, 8A is changed in this way, then the wrap-around will also change.

(15) As illustrated in the diagram in FIG. 4, of a detail of the 3-roller system, the central roller 7 can be positioned, for example by a hydraulic actuator which is not shown in more detail, between an out-of-line position 16 and an in-line position 17. This positioning movement 21 can be effected perpendicularly to or at an angle 20 with respect to the plane 15. A change in the angle 20 of the engagement movement 21 influences the wrap-around on the rollers 6, 7, 8.

(16) The axes of rotation 6A, 7A, 8A of the rollers 6, 7, 8 are parallel relative to each other and to the plane 15. With the roller 7 in the position shown in FIG. 4, its wrap-around region is beneath the plane 15 which extends through the axes of rotation 6A, 8A of the rollers 6, 8. The axes of rotation 6A and 8A of the outer rollers 6 and 8 can be moved in the plane 15 (roughly in the direction of the strip path 5) in the direction of the double-ended arrow 14. If the downwards movement of the roller 7 is sufficiently large, the distance 18 between the two rollers 6, 8 can be chosen to be very small, so that the 3-roller system permits the establishment of a high tension to be realized. This is of advantage, in particular, in the cold-rolling of thin and hard metal strips. By prescribing the angle 20 of the engagement movement relative to the plane 15, the wrap-around can be arranged to be different on the rollers 6, 7, 8.

(17) In principle it is also possible that, in the case of a tightly wound coil, the engageable central roller 7 remains positioned aside even during the rolling.

(18) With the 3-roller system illustrated above, it is possible in a simple way to achieve tensional decoupling at the same time as establishing a desired tension in the infeed region and good strip guidance for metal strips. Using the downwards movement of the central roller 7 in conjunction with the ability to effect horizontal positioning of the two outer rollers 6, 8 of the 3-roller system, it is advantageously possible to adjust the tension produced, and hence to ensure a high back tension in the roll stand 1 which follows. In conjunction with the transfer table 13 illustrated above, and if necessary with the assistance of a pinch roller 19, the initial feeding-in operation is comparatively simple, even for stiff metal strips 2.

(19) The possibility of a simultaneous axial positioning of the decoiler 3 and of the 3-roller unit, which may be rigidly coupled to it or may be separately movable, permits very good regulation of the strip path. The advantage of effective strip path regulation comes to the fore particularly in the case of metal strips which have an uneven cross-sectional profile.

(20) Although the invention has been illustrated and described in detail above by reference to a preferred form of embodiment of a cold-rolling mill, the invention is not restricted by this disclosed example. The invention can equally well be used with other rolling mills, e.g. with hot rolling. Over and above this, the person skilled in the art can derive other variations therefrom, without departing from the scope of protection for the invention.

LIST OF REFERENCE CHARACTERS USED

(21) 1 Roll stand, cold-rolling stand 2 Strip 3 Decoiler 4 Link (operating and signaling link) 5 Direction of strip path 6 Roller 7 Roller 8 Roller 9 Strip position detector 10 Unit, 3-roller system 11 Drive and positioning facility 12 Arrow (direction of positioning of rollers 6, 7, 8, vertical) 13 Transfer table 14 Arrow (direction of positioning of rollers 6, 8, horizontal) 15 Plane 16 Out-of-line position of roller 7 17 In-line position of roller 7 18 Distance 19 Pinch roller 20 Angle 21 Arrow, direction of engagement movement for roller 7 3A Axis of rotation of the decoiler 3 6A Axis of rotation of the roller 6 7A Axis of rotation of the roller 7 8A Axis of rotation of the roller 8