Improved grinding of driving rollers

Abstract

A metal strip (1) fed to the drive unit (6) in a horizontal transport direction (x) is guided or deflected obliquely downwards by means of an upper and a lower drive roller (7, 8) of a drive unit (6). A grinding device (13, 14) is associated with the upper and / or the lower drive roller (7, 8). The respective grinding device (13, 14) has a holding arm (15) at the end of which a guide device (19) is arranged in which a frame (20) is movable in a direction parallel to the width direction of the drive rollers (7, 8) between a retracted and an extended position. The frame (20) has a receptacle (21) into which a cassette (22) is inserted as a unit. In the extended position, the frame (20) is arranged laterally next to the drive unit (6).In this state, the cassette (22) can be removed as a unit from the receptacle (21), and then another cassette (26) can be inserted as a unit into the receptacle (21). A number of grinding stones (23) are arranged in the cassette (22) such that the grinding stones (23) extend over a total width (b2) that is at least 80% of the ball length (b1) of the corresponding drive roller (7, 8). The end of the retaining arm (15) is positioned against or away from the corresponding drive roller (7, 8) in the retracted position. In the engaged position, the grinding stones (23) are pressed against the corresponding drive roller (7, 8) over their entire width (b2) and grind the corresponding drive roller (7, 8).

Description

field of technology

[0001] The present invention relates to a driver device, wherein the drive device comprises a drive unit with an upper drive roller and a lower drive roller, by means of which a metal strip supplied to the drive unit in a horizontal transport direction can be guided horizontally or deflected obliquely downwards, wherein the drive device comprises a grinding unit (12) associated with the drive unit (6), which has a grinding device associated with the upper or the lower drive roller.

[0002] The present invention further assumes an operating method for a driver device, wherein in a driving operation of the driving device a metal strip fed to a driving unit of the driving device in a horizontal transport direction is conveyed horizontally or deflected obliquely downwards by means of a lower and an upper drive roller of the drive unit, wherein in a grinding operation of the driving device the associated drive roller is ground by means of a grinding device assigned to the upper or the lower drive roller. State of the art

[0003] A driver device of the type mentioned above and the associated operating procedure are generally known. Summary of the invention

[0004] Driving units are often located at the exit end of rolling mills. They are capable of guiding the metal strip horizontally without changing direction or, by deflecting the strip diagonally downwards, feeding it to a coiling unit, which then coils the strip into a coil. During normal operation of the driving unit, particles, especially scale, can accumulate on the drive rollers. This leads to so-called build-up, which negatively affects the quality of the coiled metal strip. This problem is particularly pronounced with soft steels, which are becoming increasingly important.

[0005] To solve this problem, it is known in the art to use grinding devices with which the drive rollers are ground and cleaned in the process. This involves grinding off the build-up. However, space is particularly limited at the lower drive roller. For example, on the infeed side of the drive unit, there is a so-called transition table with rollers (so-called stator rollers, also known as 'breast rollers'). On the outfeed side, there is a tapered guide element, often referred to as a 'strip switch'. The limited space makes installing the corresponding grinding device difficult. Furthermore, the grinding devices also require regular maintenance. In particular, worn grinding stones must be replaced. Accessibility is therefore also of great importance.

[0006] In some state-of-the-art solutions, it is possible to grind each drive roll simultaneously across its entire width using a grinding device. With such solutions, it is generally necessary to shut down the drive device, and consequently the entire system to which it is integrated, during these maintenance intervals. The resulting downtime reduces the system's productivity. For example, a rolling mill upstream of the drive device cannot roll metal strip during this time, and a reeling unit downstream of the drive device cannot reel the metal strip. Furthermore, the work is cumbersome. In the case of a grinding device assigned to the lower drive roll, it is often necessary to remove at least one of the drive rolls to replace the grinding stones of such a device.In some cases, both drive rollers even have to be removed. Furthermore, space is often very limited. In addition, there are safety risks, so that, for example, fall protection is required when working on the grinding mechanism.

[0007] In another solution, the grinding device is designed such that a single grinding stone is mounted in a holder. Viewed in the width direction of the drive rollers, the single grinding stone extends only over a small portion of the associated drive roller. The holder, along with the grinding stone, is moved back and forth along the drive roller while the grinding stone is pressed against the roller. Over time, this grinds the drive roller across its entire width. At a certain point, however, the drive roller is ground only across a small portion of its width. The holder can be folded away from the drive roller and, in this position, extended laterally. With this solution as well, maintenance of the grinding device requires a shutdown of the drive unit and thus of the entire system.

[0008] The object of the present invention is to provide a means by which simple and efficient grinding of drive rollers is possible. In particular, the grinding stones should be able to be changed even during the operation of the drive unit and thus also during the operation of the system.

[0009] The problem is solved by a driver device having the features of claim 1. Advantageous embodiments of the driver device are the subject of dependent claims 2 to 8.

[0010] According to the invention, a driver device of the type mentioned above is designed by: that the grinding device has a holding arm, that a guide device is arranged at the end of the holding arm in which a frame is movable in a direction parallel to the width direction of the drive rollers between a retracted and an extended position, that the frame has a receptacle into which a cassette is inserted as a unit, that the frame is arranged laterally next to the drive unit in the extended position and in this state the cassette can be removed as a unit from the receptacle of the frame, orAfter removing the cassette, another cassette can be inserted as a unit into the frame's receptacle; the cassette contains a number of grinding stones such that the grinding stones, in their entirety, extend over a width at least 80% of the ball length of the associated drive roller; the end of the retaining arm, in its retracted position, can be positioned against and removed from the associated drive roller; and, in the engaged position of the retaining arm, the grinding stones arranged in the cassette are pressed against the associated drive roller across their entire width and grind the associated drive roller.

[0011] The ability to position the end of the holding arm against the associated drive roller in the retracted position allows for grinding of the associated drive roller in this retracted position. Because the grinding wheels extend over a sufficient width, the associated drive roller can be ground simultaneously across its entire relevant width – possibly with the exception of small gaps between adjacent grinding wheels. Therefore, if any point along the width of the corresponding drive roller is selected at any given time, every relevant point of the lower drive roller will be ground at that moment – ​​possibly with the exception of the small gaps between the grinding wheels.

[0012] The ability to extend the frame laterally provides access to the frame and thus also to the cassette. The movement from the retracted to the extended position and vice versa is possible without removing the drive rollers. This allows for cassette changes during continuous operation of the rolling mill, particularly in continuous operation. Due to the arrangement of the grinding stones within the cassette, the entire cassette can be removed quickly and easily as a single unit, and the replacement cassette can be inserted just as quickly and easily. This reduces the time required to change the grinding stones.

[0013] Typically, the holding arm for positioning and disengaging is associated with an positioning device controlled by a control unit. Preferably, the end of the holding arm is positioned and force-limited, or force-controlled, against the associated drive roller by means of the control unit, and positioned and disengaged from the associated drive roller. This ensures, on the one hand, that the grinding stones are pressed against the associated drive roller with a defined contact force, and on the other hand, that the grinding wheels are moved to a defined position before the frame extends laterally.

[0014] Preferably, an evaluation unit is associated with the grinding device. When the end of the holding arm is in the engaged position, the unit receives information about the position of the end of the holding arm. Based on this position—and, if necessary, in conjunction with the position of the associated drive roller—the wear condition of the grinding stones in the cassette is determined. This makes it easy to determine the wear condition of the grinding stones in the cassette during operation.

[0015] As far as considering the position of the associated drive roller is concerned, this is generally only necessary for the lower drive roller. This is because the lower drive roller is often movable between a forward and a rear working position. These two working positions are offset from each other when viewed in the horizontal transport direction of the metal strip. In the forward working position, the metal strip is deflected diagonally downwards; in the rear working position, it is deflected straight ahead, i.e., still in the transport direction. In some cases, a grinding device associated with the lower drive roller moves together with the lower drive roller. In this case, the position of the lower drive roller is not relevant for determining the wear condition, as the position relative to the lower drive roller is what matters for determining the wear condition.In other cases, a grinding device associated with the lower drive roller is not moved together with the lower drive roller. In this case, the position of the lower drive roller is relevant for determining the wear condition.

[0016] Preferably, the grinding stones in the cassette are arranged such that they completely cover the associated drive roller across their entire width. For example, a single grinding stone with a sufficiently large width can be used, or the grinding stones in the cassette can be arranged in two rows, with the rows spaced apart from each other. Alternatively or additionally, an oscillation device can be assigned to the support arm, by means of which the frame is oscillated in the lateral direction of the drive rollers when the support arm is in the angled position. In this case, the amplitude of the oscillation in the lateral direction of the drive rollers is, on the one hand, greater than half the gap between adjacent grinding stones, but on the other hand, less than the extent of the grinding stones, and in any case less than 10% or at most 15% of the ball length of the associated drive roller.Therefore, only an oscillation with a relatively small amplitude occurs. Depending on requirements, only the frame, only the end of the support arm that holds the frame, or the entire support arm can be oscillated.

[0017] In a particularly preferred embodiment, the driver assembly includes a magazine arranged laterally next to the driver unit. The magazine itself has multiple receptacles, each for a cassette. In this case, the driver assembly also includes a changer mechanism associated with the magazine. Using the changer mechanism, the cassette inserted into the frame receptacle can be removed as a unit from the frame receptacle and placed into a receptacle in the magazine. Furthermore, using the changer mechanism, a cassette arranged in a receptacle in the magazine can be removed from the magazine and inserted as another cassette into the frame receptacle. This allows for the exchange of cassettes. Preferably, the removal of the cassette from the frame and its placement in a receptacle in the magazine are performed by means of a simple changer mechanism.Conversely, removing the next cassette from a magazine slot and inserting it into the frame slot is automatic. In this case, active operator interaction is only required, if at all, when changing the magazine, loading the magazine with additional cassettes, or removing cassettes.

[0018] To position the end of the retaining frame against the associated drive roller and to detach it from the associated drive roller, the end of the retaining frame is preferably pivotable about a pivot axis running parallel to the width direction of the drive rollers. This design is particularly simple and effective.

[0019] Preferably, the retaining arm has a holding device by means of which the cassette inserted into the frame's receptacle is held securely in the retracted position, such that it can only be pulled out of the retaining arm together with the frame in the lateral direction of the drive rollers. This prevents the cassette from falling out of the frame's receptacle and the retaining arm.

[0020] Preferably, the holding arm has a locking device by means of which the frame can be fixed in the holding arm in the lateral direction of the drive rollers, so that the frame cannot be pulled out of the holding arm in the lateral direction of the drive rollers when the locking device is actuated. This allows the frame to be fixed to the holding arm.

[0021] The inventive design of the drive unit is particularly advantageous when the lower drive roller is ground using the grinding device. However, it is equally possible if – alternatively or additionally to the lower drive roller – the upper drive roller is ground. If both drive rollers are ground, an identical design is possible for both grinding devices. Such an identical design is usually implemented. This applies both to the basic principle of the present invention and to the advantageous embodiments. However, space is not as critical for the upper drive roller as for the lower drive roller. Therefore, a different solution can be used for the upper drive roller if necessary.

[0022] The problem is further solved by an operating method with the features of claim 9. Advantageous embodiments of the operating method are the subject of dependent claims 10 to 18.

[0023] According to the invention, an operating method of the type mentioned above is designed by: that in grinding operation of the drive unit, one end of a holding arm is positioned against the drive roller assigned to the grinding unit, so that a number of grinding stones, which in their entirety extend over at least 80% of the ball length of the assigned drive roller, are pressed against the assigned drive roller; that in alternating operation of the drive unit, the following steps are carried out in the sequence specified below: -- the end of the holding arm is released from the assigned drive roller, so that the grinding stones are spaced away from the assigned drive roller; -- a frame arranged at the end of the holding arm is moved in a guide device of the holding arm from a retracted position, in which the frame is located at the level of the assigned drive roller when viewed in the lateral direction of the drive rollers, to an extended position in the lateral direction of the drive rollers.in which the frame is arranged laterally next to the drive unit, so that a cassette inserted into a receptacle of the frame, in which the grinding stones are arranged, can be changed, or the grinding stones arranged in the cassette can be changed without changing the cassette; -- the frame is moved from the extended position to the retracted position, and -- the end of the holding arm is positioned against the associated drive roller, so that the grinding stones arranged in the cassette are pressed against the associated drive roller again.

[0024] The advantages achieved in this way correspond to those of the driver unit. Grinding operation and alternating operation are mutually exclusive due to the characteristics of their respective operating modes. However, grinding operation and alternating operation can be performed as needed, either during or outside of driver operation.

[0025] Preferably, the end of the holding arm is positioned against the associated drive roller during grinding operation by means of an adjusting device controlled by a control unit, with either force limitation or force control, and is positioned away from the associated drive roller during alternating operation. This ensures that the grinding stones are pressed against the associated drive roller with a defined contact force and that the arm moves to a defined position before the frame is extended laterally.

[0026] Preferably, during grinding operation, the position of the end of the holding arm is supplied to an evaluation unit, and the evaluation unit determines the wear condition of the grinding stones in the cassette based on the position of the end of the holding arm – if necessary in conjunction with the position of the associated drive roller. This makes it possible to easily determine the wear condition of the grinding stones in the cassette during operation.

[0027] As far as the consideration of the position of the associated drive roller is concerned, reference is made to the explanations relating to the corresponding device claim.

[0028] Preferably, during grinding, the frame of the holding arm is oscillated parallel to the width direction of the drive rollers by means of an oscillation device with an amplitude such that, viewed in the width direction of the drive rollers, the amplitude is greater than half the gap between adjacent grinding wheels and less than the width of the grinding wheels, but in any case less than 15% of the ball length of the associated drive roller. This allows the associated drive roller to be ground simultaneously across its entire relevant width – optionally with the exception of small gaps between adjacent grinding wheels viewed in the width direction.

[0029] Preferably, in alternating operation, a cassette inserted into the frame's receptacle is removed by means of an exchange device and inserted into a receptacle of a magazine arranged next to the driver unit, which has multiple receptacles for one cassette each, and a cassette is removed from a receptacle of the magazine and inserted as a further cassette into the frame's receptacle. This enables easy cassette exchange. The operation of the exchange device is preferably automated.

[0030] Preferably, the end of the holding arm is pivoted about a pivot axis running parallel to the lateral direction of the drive rollers for positioning and detachment from the associated drive roller. This operating method is particularly simple and effective.

[0031] Preferably, the cassette inserted into the frame's receptacle is held securely in place by a retaining device on the support arm, such that in the retracted position it can only be pulled out of the support arm together with the frame in the lateral direction of the drive rollers. This prevents the cassette from falling out of the frame's receptacle.

[0032] Preferably, the frame is fixed in the support arm in the lateral direction of the drive rollers by means of a locking device when this device is actuated. This allows the frame to be fixed to the support arm.

[0033] During drive operation, the drive rollers rotate at a normal speed. This speed is based on the condition that the winding of the metal strip in the downstream winding unit has already been completed. If grinding occurs during drive operation, this speed must be maintained. However, this speed is suboptimal for grinding. If grinding takes place during a period when the drive unit is not in drive operation, this speed can be selected as optimal for grinding. Therefore, in this case, the drive rollers rotate at a lower speed than normal during grinding. This reduces wear on the grinding wheels and increases the service life of the cassette.

[0034] Preferably, the cassette changeover is performed during the driver operation. Particularly in continuous rolling mill operation, this allows cassette changes to be performed even while a preceding rolling mill is running. This ensures that the productivity of the plant to which the driver unit is integrated is not affected by the cassette changeover.

[0035] Just as with the drive unit itself, the operating procedure of the drive unit with regard to the grinding process can also be implemented exclusively for the upper drive roller, exclusively for the lower drive roller, or for both drive rollers. This applies to both the basic principle and the specific implementations of the operating procedure. Brief description of the drawings

[0036] The properties, features, and advantages of this invention described above, as well as the manner in which they are achieved, will become clearer and more readily understandable in connection with the following description of an exemplary embodiment, which is explained in more detail in conjunction with the drawings. These drawings show: FIG 1 a rolling mill and equipment downstream of the rolling mill, FIG 2 a drive unit, FIG 3 an end of a holding arm and part of a drive roller, FIG 4 a top view of a drive roller and a grinding unit, FIG 5 a drive roller and grinding stones, FIG 6 a flow chart, FIG 7 a cassette change, FIG 8 a grinding operation simultaneously with a drive operation of the drive unit, FIG 9 the grinding operation independent of the drive operation of the drive unit, FIG 10 a block diagram, FIG 11 a flow chart, FIG 12 a flow chart, FIG 13 a top view of a cassette, FIG 14 a top view of a cassette, FIG 15 a top view of a cassette, FIG 16 a top view of an end of a holding arm, FIG 17 a top view of a drive unit and a magazine, FIG 18 a side view of a drive unit and a magazine, FIG 19 drive rollers and frames parked off the drive rollers, and FIG 20 drive rollers and frames attached to the drive rollers. Description of the embodiments

[0037] According to FIG 1 A metal strip 1 is rolled in a rolling mill 2. The rolling mill 2 has a number of rolling stands 3, for example, three, four, five, six, or seven rolling stands 3. A cooling section 4 is often located downstream of the rolling stands 3. The rolling mill 2 can be configured as a conventional rolling mill (HSM = hot strip mill) or as part of a hot strip mill, in which an endless strip is produced as the metal strip 1 (ESP plant, ESP = endless strip production). The metal strip 1 passes through the rolling mill 2 in a horizontal transport direction x. The rolling mill 2 itself is usually a finishing mill.

[0038] A driving device 5 is located downstream of the rolling mill 2. The driving device 5 has a driving unit 6 with an upper drive roller 7 and a lower drive roller 8. By means of the drive rollers 7 and 8 of the driving unit 6, the metal strip 1 can be deflected obliquely downwards from the horizontal transport direction x. This feeds the metal strip 1 to a coiling device 9, which is itself located downstream of the driving device 5. By means of the coiling device 9, the metal strip 1 is coiled into a coil.

[0039] Alternatively, the metal strip 1 can be guided horizontally by the drive unit 6 without changing direction. If the metal strip 1 is guided horizontally by the drive unit 5, it can, for example, be fed to another drive unit 10. The other drive unit 10 can be constructed and function analogously to the drive unit 5. For example, it can also deflect the metal strip 1 diagonally downwards and thereby feed it to another reel unit 11, or guide it horizontally without changing direction. Only the drive unit 5 is discussed below. Analogous designs can apply to the other drive unit 10.

[0040] Both when the metal strip 1 is deflected and when it is guided horizontally by the driver unit 6, the driver unit 5 is in driver mode. Driver mode is not exclusive. It is therefore possible that the driver unit 5 is also in another operating mode. This will become clear in the following explanations.

[0041] According to FIG 2 The driver unit 5 has a grinding unit 12. The grinding unit 12 is assigned to the driver unit 6. The grinding unit 12 has an upper grinding device 13 and / or a lower grinding device 14. The two grinding devices 13, 14 are assigned to the respective drive rollers 7, 8. The upper drive roller 7 can be ground by means of the upper grinding device 13. Similarly, the lower drive roller 8 can be ground by means of the lower grinding device 14. When the two grinding devices 13, 14 are grinding the respective drive rollers 7, 8, the driver unit 5 is in grinding mode. The grinding mode can be performed during or independently of the driver operation. Only the lower grinding device 14 is discussed in detail below. However, analogous descriptions can always apply to the upper grinding device 13.This applies both when both the upper and lower grinding devices 13, 14 are present, and when the upper grinding device 13 is present as an alternative to the lower grinding device 14.

[0042] According to FIG 2 The lower grinding device 14 has a retaining arm 15. The end of the retaining arm 15 can be, as shown in FIG 2 as indicated by arrow 16, it can be positioned against the lower drive roller 8. Likewise, the end of the retaining arm 15 can be positioned as shown in FIG 2 As indicated by arrow 17, the lower drive roller 8 is disengaged. The engagement of the end of the holding arm 15 occurs at the beginning of the grinding operation of the drive unit 5. In this case, the engagement and disengagement of the end of the holding arm 15 is achieved by pivoting the end of the holding arm 15 about a pivot axis 18. The pivot axis 18 runs parallel to the lateral direction of the drive rollers 7, 8. Alternatively, another type of movement is also possible.

[0043] At the end of the retaining arm 15, according to FIG 3 A guide device 19 is arranged. The guide device 19 can, for example, form an elongated U-shaped channel extending parallel to a lateral direction of the drive rollers 7, 8. A frame 20 is arranged in the guide device 19. The frame 20 can be configured according to FIG 4 in a direction parallel to the width direction of the drive rollers 7, 8 between a retracted and an extended position. FIG 3 The frame 20 is shown in the retracted position, in FIG 4 in the extended position. Dashed line indicates in FIG 4 The frame 20 is also indicated in the retracted position. In the retracted position, the frame 20 is located at the level of the lower drive roller 8 when viewed in the lateral direction of the drive rollers 7, 8. In the extended position, however, the frame 20 is located laterally next to the drive unit 6 and thus, in particular, next to the lower drive roller 8 when viewed in the lateral direction of the drive rollers 7, 8.

[0044] Frame 20 shows, according to the FIG 3 und 4 It in turn has a receptacle 21. A cassette 22 is inserted into the receptacle 21 as a unit. A number of grinding stones 23 are arranged in the cassette 22. Often, several grinding stones 23 are arranged side by side in the width direction of the drive rollers 7, 8. In this case, a single grinding stone 23 extends only over a relatively small width. The width of a single grinding stone 23 can be, for example, approximately 20 cm or approximately 30 cm. This width is determined according to the FIG 4 and 5 significantly smaller than the width b1 of the lower drive roller 8. Regardless of their number, the grinding stones 23 together extend over a width b2. The width b2 is according to FIG 5 at least as large as 80% of the ball length of the lower drive roller 8. During grinding operation of the drive unit 5, the grinding stones 23 arranged in the cassette 22 are thus pressed against the lower drive roller 8 over their entire width b2. In this state, the grinding stones 23 grind the lower drive roller 8.

[0045] The engagement of the end of the retaining arm 15 with the lower drive roller 8 and the disengagement of the end of the retaining arm 15 from the lower drive roller 8 take place in the retracted position of the frame 20. During this movement—that is, during the entire movement between the engaged position, in which the grinding stones 23 grind the lower drive roller 8, and the disengaged position, in which the frame 20 can be moved from the retracted to the extended position—the retaining arm 15 and the end of the retaining arm 15, including the guide device 19 and the components therein, preferably remain below the guide line on which the metal strip 1 moves at all times. The guide line is in FIG 2 The transition between the retracted and extended positions of the frame 20 occurs when the end of the retaining arm 15 is disengaged from the lower drive roller 8. If (alternatively or additionally) a similar mechanism is implemented for the upper drive roller 7, the retaining arm 15 and its end, including the guide 19 and the components of the grinding device 13 associated with the upper drive roller 7, preferably remain above the pass line at all times.

[0046] The grinding stones 23 wear down. They must therefore be replaced from time to time. The grinding stones 23 are replaced by alternating operation of the drive unit 5. This alternating operation can only be performed as an alternative to the grinding operation. However, it can be performed as needed during the drive operation or independently of the drive operation. The alternating operation is described below in conjunction with FIG 6 explained in more detail.

[0047] According to FIG 6 In step S1, the end of the retaining arm 20 is first disengaged from the lower drive roller 8. The end of the retaining arm 15 is thus moved in the direction of arrow 17 (see FIG 2 ) moved. In the switched-off state, the grinding stones 23 are spaced apart from the lower drive roller 8. Then (see also FIG 4 ) in step S2 the frame 20 in the guide device 19 is moved from the retracted position to the extended position. In this state, in step S3 (see also in FIG 7 the arrow 24) the cassette 22, which is inserted into the receptacle 21, is removed as a unit from the receptacle 21.

[0048] Now, in one step, S4 (see also in FIG 7 (arrow 25) another cassette 26 is inserted as a unit into the receptacle 21. The additional cassette 26 performs the same function as the previous cassette 22. Thus, in the additional cassette 26, a number of further grinding stones 27 are arranged in the width direction of the drive rollers 7, 8. Often, several additional grinding stones 27 are arranged side by side. The additional grinding stones 27 also extend over a width that is at least as large as 80% of the ball length of the lower drive roller 8. Next, in step S5, the frame 20 (including the additional cassette 26) is moved from the extended position to the retracted position.

[0049] The alternating operation is now complete. The grinding operation can therefore be resumed. In particular, in step S6, the end of the holding arm 15 can be repositioned against the lower drive roller 8. This presses the additional grinding stones 27, arranged in the further cassette 26, against the lower drive roller 8 across their entire width b2. The further cassette 26 and the additional grinding stones 27 thus take over the function previously performed by the cassette 22 and the grinding stones 23.

[0050] Strictly speaking, steps S3 and S4, in which cassette 22 is replaced by cassette 26, are not strictly necessary. Instead of replacing cassette 22, the grinding wheels 23 located in cassette 22 could also be replaced. In this case, the same cassette 22 is used as before, but with new grinding wheels 23. It may even be possible to inspect only cassette 22 and the grinding wheels 23. If the grinding wheels 23 are not yet worn, they do not even need to be replaced.

[0051] The grinding operation and the alternating operation of the drive unit are mutually exclusive. In grinding operation, the end of the holding arm 15 is in the engaged position, while in alternating operation, the end of the holding arm 15 must be in the disengaged position. The driving operation, however, can be independent of this. Provided that it can be ensured that the holding arm 15 and its end, including associated components, remain below the pass line throughout the entire movement between the engaged position, in which the grinding stones 23 grind the lower drive roller 8, and the disengaged position, in which the frame 20 can be moved from the retracted to the extended position, alternating operation, driving operation, and the movement of the holding arm 15 from the engaged to the disengaged position and vice versa are all possible.Even though this cannot be guaranteed, alternating operation is still possible during drive operation, as is grinding operation. Only for transitioning from the off position to the engaged position of the end of the holding arm 15, or vice versa, must a period be selected during which the drive unit 6 does not drive a metal strip. Analogous provisions apply to the upper grinding device 13. In this case, the various components may need to be located above the pass line.

[0052] As already mentioned, the grinding operation can be carried out during the driver operation. During the driver operation, the drive rollers 7, 8 typically rotate at a normal speed. The normal speed corresponds to the illustration in FIG 8 with a corresponding peripheral speed vU of the drive rollers 7, 8. An exception, during which the drive rollers 7, 8 rotate at a lower speed, usually only occurs during the initial winding (i.e., during the winding of the first turns of the coil) and possibly at the end of the winding process. If the grinding operation is carried out simultaneously with the drive operation, the peripheral speed vU is determined by the transport speed of the metal strip 1. It can no longer be freely selected. In particular, the peripheral speed vU must match the transport speed of the metal strip 1. The grinding of the drive rollers 7, 8 must be carried out at the peripheral speed vU or the corresponding normal rotational speed.

[0053] According to the representation in FIG 9 However, the grinding operation can also take place during a period of time when the driver device 5 is not in driver operation.

[0054] This is in FIG 9 This is indicated by the fact that the metal strip 1 itself is not shown, but only the associated guide line and the direction of the feed to the reeling device 9 are indicated by dashed lines. In this case, the rotational speeds of the drive rollers 7, 8 can be freely selected. For example, they can be selected such that the drive rollers 7, 8 rotate only at a reduced peripheral speed vU', which is less than the peripheral speed vU. Theoretically, however, the drive rollers 7, 8 could also rotate at a peripheral speed vU' above the normal peripheral speed vU or even in reverse.

[0055] The positioning and positioning of the end of the holding arm 15 is carried out according to FIG 10 by means of a suitable adjusting device 28, for example a hydraulic cylinder unit. A control device 29 is assigned to the holding arm 15 by means of which the adjusting device 28 is controlled. The associated operating mode is described below in conjunction with FIG 11 explained.

[0056] According to FIG 11 In step S11, the control unit 29 checks whether the grinding operation should be implemented. If so, in step S12, the control unit 29 detects a force F with which the end of the holding arm 15 (and consequently the grinding stones 23) is pressed against the lower drive roller 8. In step S13, the control unit 29 determines a control signal C for the actuator 28. The determination in step S13 is carried out such that the force F is approximated to a target force F*. Thus, if the force F is less than the target force F*, the end of the holding arm 15 is moved closer to the lower drive roller 8. If the force F is greater than the target force F*, the end of the holding arm 15 is moved away from the lower drive roller 8. As a result, the end of the holding arm 15 is pressed against the lower drive roller 8 in a force-controlled manner. In step S14, the control unit 29 controls the actuator 28 accordingly.

[0057] As an alternative to force-controlled positioning, it is also possible to position the end of the holding arm 15 against the lower drive roller 8. In this case, however, the positioning force is limited to a suitable value, for example, the target force F*. In this case, the positioning is position-controlled but force-limited.

[0058] If the grinding operation is not to be implemented, the control unit 29 checks in step S15 whether the alternating operation is to be implemented (more precisely: whether the holding arm 15 is to be moved into the parked position). If this is the case, the control unit 29 detects a position p, which corresponds to the end of the holding arm 15, in step S16. In step S17, the control unit 29 determines the control signal C for the actuator 28. The determination in step S17 is carried out such that the position p is approximated to a target position p*. Thus, if the position p is smaller than the target position p*, the control signal C is determined such that the position p is increased. If, on the other hand, the position p is larger than the target position p*, the control signal C is determined such that the position p is decreased. As a result, the end of the holding arm 15 is thus position-controlled and parked by the lower drive roller 8.transferred to the switched-off position. Then the control device 29 proceeds to step S14.

[0059] Even if alternating operation is not to be implemented, the control unit 29 proceeds to step S18. In step S18, other measures are taken.

[0060] Often, according to the representation in FIG 10 In addition to the control unit 29, an evaluation unit 30 is also present. The evaluation unit 30 can be integrated into the control unit 29. If present, the evaluation unit 30 performs a monitoring procedure during grinding operation, which is described below in conjunction with FIG 12 will be explained in more detail.

[0061] In step S21, the evaluation unit 30 checks whether the grinding operation should be implemented. If so, in step S22, the evaluation unit 30 receives the position p. In step S23, the evaluation unit 30 determines the wear condition V of the grinding stones 23 of the cassette 22 based on the position p of the end of the holding arm 15. If necessary, the evaluation unit 30 can also take the position of the lower drive roller 8 into account in step S23.

[0062] Based on the wear condition V determined in step S23, the evaluation unit 30 takes further measures in step S24. For example, the evaluation unit 30 can issue a corresponding message to an operator (not shown) or control the control unit 29 so that it switches from grinding operation and force control or force-limited position control to alternating operation and position control. The evaluation unit 30 can also initiate a transition from grinding operation to alternating operation in another way.

[0063] Preferably, the grinding stones 23 of the cassette 22 are arranged such that they completely cover the lower drive roller 8 across their entire width. One way to achieve this is to use a single grinding stone 23 that is sufficiently wide. If several grinding stones 23 are used, the grinding stones 23 can be arranged, for example, as shown in FIG 13 be arranged in (at least) two rows. In this case, the grinding stones 23 can be offset from row to row so that the gaps of one row are covered by the grinding stones 23 of (at least) one other row. Alternatively or additionally, it is as shown in FIG 14 It is possible to arrange the grinding stones 23 at an angle, so that the spaces between the grinding stones 23 are also at an angle. Alternatively or additionally, it is possible, as shown in the illustration in FIG 15 It is possible that the holding arm 15 is associated with an oscillation device 31, by means of which the frame 20 is oscillated in the lateral direction of the drive rollers 7, 8 when the holding arm 15 is in the engaged position. The oscillation takes place during the grinding operation.

[0064] In FIG 15 Only the oscillation device 31, the holding arm 15, and the grinding stones 23 are shown. The other elements 19, 20, 21, and 22 are present, but not shown. FIG 15 For the sake of clarity, it is not shown. FIG 15 shows the grinding stones 23 in the position in which they are in FIG 15 are deflected furthest to the left. Additionally, in FIG 15 The position of the item in is also shown with a dashed line. FIG 15 The leftmost grinding stone 23 assumes this position when it is deflected furthest to the right. It is evident that the amplitude A of the oscillation is, on the one hand, greater than half of the space b3 between adjacent grinding stones 22. On the other hand, the amplitude A is less than the extent b4 of the grinding stones 22. In any case, the amplitude A is less than 10% or at most 15% of the ball length of the lower drive roller 8.

[0065] The cassette 22, when inserted into the receptacle 21 of the frame 20 and the frame 20 in the retracted position, is preferably held captive. In this context, "captive held" means that the cassette 22 can only be pulled out of the retaining arm 15 together with the frame 20 in the lateral direction of the drive rollers 7, 8. Thus, there is only a single, linear degree of freedom. To hold the cassette 22 captive, the retaining arm 15 – see FIG. 3 – has a retaining device 32. The retaining device 32 can, for example, be designed as shown in FIG. FIG 3 The outriggers include a section which extends over the cassette 22 in the retracted position of the frame 20 on the side where the grinding stones 23 grind the lower drive roller 8 during grinding operation.

[0066] Furthermore, the frame 20 is preferably lockable in the retracted position so that it cannot move in the lateral direction of the drive rollers 7, 8. For this purpose, the retaining arm 15 can, for example, be positioned as shown in the illustration. FIG 16 The frame 20 has a locking device 33. When the locking device 33 is actuated, the frame 20 can no longer be pulled out of the retaining arm 15 (more precisely: out of the guide device 19) in the lateral direction of the drive rollers 7, 8. The locking device 33 can, for example, be designed and function similarly to the device for locking mounting blocks for rollers of a rolling mill stand 3.

[0067] To change cassettes 22, 26, the driver unit 5 indicates, as shown in the illustration in the FIG 17 und 18 preferably a magazine 34, which is arranged laterally next to the driver unit 6. The magazine 34 in turn has several receptacles 35, each for a cassette 22, 26. Finally, the driver unit 5 has a changer 36, which is associated with the magazine 34. If the frame 20 is positioned according to the illustration in the FIG 17 und 18 When the frame 20 is in the extended position, the cassette 22 inserted into the receptacle 21 of the frame 20 can be removed as a unit from the receptacle 21 of the frame 20 using the changing device 36. This cassette 22 can then be placed into an (empty) receptacle 35 of the magazine 34 using the changing device 36. Subsequently, a cassette can be removed from a receptacle 35 of the magazine 34 using the changing device 36 and inserted as a further cassette 26 into the receptacle 21 of the frame 20. The changing device 26 preferably operates automatically. It performs its actions when the frame 20 is in the extended position and, consequently, the drive unit 5 is in changeover mode.

[0068] The FIG 19 and 20 The figures show essential elements of the present invention in perspective. FIG 19 and 20Only the drive rollers 7, 8 and the grinding devices 13, 14 are shown. The holding arm 15, the pivot axis 18, the guide device 19, and the grinding stones 23 are also visible.

[0069] The present invention offers many advantages. In particular, the cassette can be changed without having to remove the drive rollers 7, 8. Often, it is even possible to perform the cassette change while the drive unit 5 is running. This is advantageous even in a "normal" hot strip mill, but especially in an ESP system. Furthermore, completely analogous designs can be implemented for the upper grinding unit 13 associated with the upper drive roller 7.

[0070] Although the invention has been further illustrated and described in detail by the preferred embodiments, the invention is not limited by the disclosed examples and other variations can be derived from them by the person skilled in the art without leaving the scope of protection of the invention. Reference symbol list

[0071] 1 Metal strip 2 Rolling mill 3 Rolling stands 4 Cooling section 5, 10 Driver devices 6 Driver unit 7, 8 Drive rollers 9, 11 Reel devices 12 Grinding unit 13, 14 Grinding devices 15 Holding arm 16, 17, 24, 25 Arrows 18 Swivel axis 19 Guide device 20 Frame 21, 35 Mounts 22, 26 Cassettes 23, 27 Grinding stones 28 Adjustment device 29 Control device 30 Evaluation device 31 Oscillation device 32 Holding device 33 Locking device 34 Magazine 36 Change device AAmplitude b1 to b4 Widths CControl signal F, F*Forces p, p*Positions S1 to S24Steps VWear condition vU, vU'Circular speeds xTransport direction

Claims

1. Driving device, - wherein the driving device comprises a driving unit (6) with an upper drive roller (7) and a lower drive roller (8), by means of which a metal strip (1) fed to the driving unit (6) in a horizontal transport direction (x) can be guided horizontally or deflected obliquely downwards, - wherein the driving device comprises a grinding unit (12) associated with the driving unit (6), which comprises a grinding device (13, 14) associated with the upper or the lower drive roller (7, 8), - wherein the grinding device (13, 14) comprises a retaining arm (15), - wherein a guide device (19) is arranged at the end of the retaining arm (15), in which a frame (20) is movable in a direction parallel to the width direction of the drive rollers (7, 8) between a retracted and an extended position, - wherein the frame (20) comprises a receptacle (21) into which a cassette (22) is inserted as a unit,- wherein the frame (20) is arranged laterally next to the drive unit (6) in the extended position and in this state the cassette (22) can be removed as a unit from the receptacle (21) of the frame (20) or, after removal of the cassette (22), another cassette (26) can be inserted as a unit into the receptacle (21) of the frame (20), - wherein a number of grinding stones (23) are arranged in the cassette (22) such that the grinding stones (23) extend as a whole over a width (b2) that is at least as large as 80% of the bale length (b1) of the associated drive roller (7, 8), - wherein the end of the retaining arm (15) can be positioned against and removed from the associated drive roller (7, 8) in the retracted position, and - wherein, in the positioned state of the retaining arm (15), the grinding stones (23) arranged in the cassette (22) extend over the entire Width (b2) of the grinding stones (23) to the associated drive roller (7,8) are pressed down and grind the associated drive roller (7, 8).

2. Driver device according to claim 1, characterized by that The holding arm (15) is assigned an adjusting device (28) controlled by a control device (29), by means of which the end of the holding arm (15) can be adjusted to the assigned drive roller (7, 8) in a position-controlled and force-limited or force-controlled manner and can be stopped from the assigned drive roller (7, 8) in a position-controlled manner.

3. Driver device according to claim 2, characterized by that The grinding device (13, 14) is assigned an evaluation device (30) to which, in the engaged state of the end of the holding arm (15), the position (p) of the end of the holding arm (15) is supplied and from which, based on the position (p) of the end of the holding arm (15) - if necessary in conjunction with a position of the assigned drive roller (7, 8) - a wear condition (V) of the grinding stones (23) of the cassette (22) is determined.

4. Driver device according to claim 1, 2 or 3, characterized by that the grinding stones (23) of the cassette (22) are arranged such that they completely cover the associated drive roller (7, 8) over the entire width (b2) of the grinding stones (23) and / or an oscillation device (31) is assigned to the holding arm (15) by means of which the frame (20) is oscillated in the width direction of the drive rollers (7, 8) when the holding arm (15) is in the angled position, wherein an amplitude (A) of the oscillation seen in the width direction of the drive rollers (7, 8) is greater than half of a space (b3) between adjacent grinding stones and less than an extent (b4) of the grinding stones, but in any case less than 15% of the ball length (b1) of the associated drive roller (7, 8).

5. Driver device according to one of the above claims, characterized by thatThe driver device has a magazine (34) arranged laterally next to the driver unit (6), which has a plurality of receptacles (35) for each cassette (22, 26), and the driver device has an exchange device (36) associated with the magazine (34), by means of which the cassette (22) inserted into the receptacle (21) of the frame (20) can be removed as a unit from the receptacle (21) of the frame (20) and placed into a receptacle (35) of the magazine (34), and a cassette (26) arranged in a receptacle (35) of the magazine (34) can be removed from the magazine (34) and inserted as a further cassette (26) into the receptacle (21) of the frame (20).

6. Driver device according to one of the above claims, characterized by thatthe end of the retaining arm (15) is pivotable about a pivot axis (18) running parallel to the width direction of the drive rollers (7, 8) for positioning the end of the retaining arm (15) against the associated drive roller (7, 8) and for positioning it away from the associated drive roller (7, 8).

7. Driver device according to one of the above claims, characterized by that the retaining arm (15) has a retaining device (32) by means of which the cassette (22) inserted into the receptacle (21) of the frame (20) is held in the retracted position in such a way that it can only be pulled out of the retaining arm (15) together with the frame (20) in the width direction of the drive rollers (7, 8).

8. Driver device according to claim 7, characterized by thatthe retaining arm (15) has a locking device (33) by means of which the frame (20) can be fixed in the retaining arm (15) in the lateral direction of the drive rollers (7, 8), so that the frame (20) cannot be pulled out of the retaining arm (15) in the lateral direction of the drive rollers (7, 8) when the locking device (33) is actuated.

9. Operating method for a drive device (5), - wherein in a drive operation of the drive device (5) a metal strip (1) fed to a drive unit (6) of the drive device (5) in a horizontal transport direction (x) is guided horizontally or deflected obliquely downwards by means of a lower and an upper drive roller (7, 8) of the drive unit (6), - wherein in a grinding operation of the drive device (5) the associated drive roller (7, 8) is ground by means of a grinding device (13, 14) assigned to the upper or the lower drive roller (7, 8), - wherein in the grinding operation of the drive device (5) an end of a holding arm (15) is positioned against the drive roller (7, 8) assigned to the grinding device (13, 14), so that a number of grinding stones (23), which in their entirety extend over at least 80% of the ball length of the associated drive roller (7, 8), are pressed against the associated drive roller (8),- wherein in alternating operation of the drive unit (5) the following steps are carried out in the sequence specified below: -- the end of the holding arm (15) is set off from the associated drive roller (7, 8) so that the grinding stones (23) are spaced apart from the associated drive roller (7, 8), -- a frame (20) arranged at the end of the holding arm (15) is moved in a guide device (19) of the holding arm (15) from a retracted position, in which the frame (20) is located at the level of the associated drive roller (7, 8) when viewed in the width direction of the drive rollers (7, 8), in the width direction of the drive rollers (7, 8) to an extended position, in which the frame (20) is arranged laterally next to the drive unit (6), so that a cassette (22) inserted into a receptacle (21) of the frame (20), in which the grinding stones (23) are arranged,The grinding stones (23) arranged in the cassette (22) can be changed, or without changing the cassette (22), -- the frame (20) is moved from the extended position to the retracted position and -- the end of the holding arm (15) is positioned against the associated drive roller (7, 8), so that the grinding stones (27) arranged in the cassette (26) are pressed against the associated drive roller (7, 8) again.

10. Operating method according to claim 9, characterized by that the end of the holding arm (15) is positioned and force-limited or force-controlled against the associated drive roller (7, 8) by means of an adjusting device (28) controlled by a control device (29) during grinding operation and is positioned and force-controlled away from the associated drive roller (7, 8) during alternating operation.

11. Operating method according to claim 10, characterized by thatduring the grinding operation of an evaluation device (30) the position (p) of the end of the holding arm (15) is supplied and that the evaluation device (30) determines a wear condition (V) of the grinding stones (23) of the cassette (22) on the basis of the position (p) of the end of the holding arm (15) - if necessary in conjunction with a position of the associated drive roller (7, 8).

12. Operating method according to claim 9, 10 or 11, characterized by thatThe frame (20) of the holding arm (15) is oscillated during the grinding operation by means of an oscillation device (31) parallel to the width direction of the drive rollers (7, 8) with an amplitude (A), wherein the amplitude (A) seen in the width direction of the drive rollers (7, 8) is greater than half of a space (b3) between adjacent grinding stones (23) and less than an extent (b4) of the grinding stones (23), but in any case is less than 15% of the ball length of the associated drive roller (7, 8).

13. Operating method according to one of claims 9 to 12, characterized by thatIn alternating operation, by means of a changing device (36), the cassette (22) inserted into the receptacle (21) of the frame (20) is removed from the receptacle (21) and inserted into a receptacle (35) of a magazine (34) arranged next to the driver unit (6), which has a plurality of receptacles (35) for each cassette (22, 26), and a cassette (26) is removed from a receptacle (35) of the magazine (34) and inserted as a further cassette (26) into the receptacle (21) of the frame (20).

14. Operating method according to one of claims 9 to 13, characterized by that the end of the holding arm (15) is pivoted about a pivot axis (18) running parallel to the width direction of the drive rollers (7, 8) for positioning against the associated drive roller (7, 8) and for positioning away from the associated drive roller (7, 8).

15. Operating method according to one of claims 9 to 14, characterized by thatthe cassette (22) inserted into the receptacle (21) of the frame (20) is held in a captive manner by means of a holding device (32) of the retaining arm (15) insofar as it can be pulled out of the retaining arm (15) in the retracted position only together with the frame (20) in the width direction of the drive rollers (7, 8).

16. Operating method according to claim 15, characterized by that the frame (20) is fixed in the retaining arm (15) in the width direction of the drive rollers (7, 8) by means of a locking device (33), provided that this is actuated.

17. Operating method according to one of claims 9 to 16, characterized by, - that the drive rollers (7, 8) rotate at a normal speed during the driver operation, - that the grinding operation takes place during a period in which the driver device (5) is not in driver operation, and - that the drive rollers (7, 8) rotate at a speed that is less than the normal speed during the grinding operation.

18. Operating method according to any one of claims 9 to 17, characterized by that The alternating operation is performed during driver operation.

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