Method and device for providing inserts for support and/or work rolls of a roll stand

A method relates to providing shims for backup and/or work rolls of a rolling mill stand. The shims are required when changing over rolls. The method comprises the steps of: a) assembling at least one shim, preferably at least two or three shims, into an shim pack at a first location remote from the rolling mill stand; b) transferring the shim pack into a carrier element at the first location; c) transporting the carrier element together with the shim pack from the first location to the location near the rolling mill stand; d) removing the shim pack from the carrier element at the location near the rolling mill stand; e) using the shims when changing over rolls.

TECHNICAL FIELD

The disclosure relates to a method for providing shims for backup and/or work rolls of a rolling mill stand, which shims are required when changing over rolls. The disclosure also relates to a device for this purpose.

BACKGROUND

In particular when changing over the backup rolls of a rolling mill stand, shims are required, which are placed in a so-called changeover carriage. The shims are used to compensate for roll wear on the lower rolls, such that the level of the upper edge of the lower work rolls is subject to as little fluctuation as possible. The shims are replaced in the changeover carriage. It is usual that the respective shims are transported individually from a preparation workshop to the backup roll changeover pit by means of an overhead crane. Each individual shim is inserted and centered separately in the backup roll changeover carriage. When removing, the corresponding steps are carried out in reverse order.

In U.S. Pat. No. 3,782,161 A the generic method that is used when changing over rolls of a rolling mill stand is described. A number of plates are provided there, which are arranged independently of one another and are used for the individual parts to be changed.

Therefore, the disadvantage of this is that the changeover of backup rolls takes a correspondingly long time: It is necessary to remove the individual shim plates and install the new shim plates, which requires corresponding crane movements; only then can the insertion of new backup rolls be effected.

Up to 30 crane movements may be necessary in order to transport the individual shims to the roll changeover pit (including empty runs of the crane). Each shim is driven and fastened individually. Furthermore, each shim must be centered in the changeover carriage. During assembly/disassembly, the fastening of each shim is effected by means of two eyebolts.

Another problem is that the individual shim plates adhere strongly to one another, since oil between the plates causes high adhesion forces and makes it difficult to disassemble the individual plates. There is a risk of accidents to the extent that plates hanging from the crane and sticking together can come loose during transport and fall down.

SUMMARY

The disclosure is based on the object of simplifying the logistics upon changing over the rolls of a rolling mill stand, in particular the backup rolls, and reducing the changeover times. As a result, the efficiency of the rolling process is to be improved. Thus, the changeover times for shims are to be significantly reduced, which will also lead to a corresponding reduction in changeover times for backup rolls. Ultimately, the aim is to improve employee safety.

The solution to this object provides a method for the provision of shims for backup and/or work rolls of a rolling mill stand, which are required when changing over rolls. The method comprises the steps of:

The above-mentioned step d) can comprise the following step: Intermediately storing the shim pack in an intermediate storage element.

Prior to step e) above, the shim pack can be placed in a roll changeover carriage.

The specified first location is, in particular, a preparation workshop (located some distance from the rolling mill stand whose rolls are to be changed).

The location near the rolling mill stand is preferably a roll changeover pit or a location directly adjacent to it.

The method is used in particular for changing over the backup rolls of the rolling mill stand.

A device for providing and/or transporting shims for backup and/or work rolls of a rolling mill stand, which are required when changing over rolls, comprises a carrier frame, which has means for coupling to a crane, and connecting means for positively connecting shims combined to form a shim pack to the carrier frame.

The connecting means are designed in particular as screws/comprise screws. Particularly preferably, two screws are arranged on the carrier frame, in particular diagonally.

Furthermore, centering means can be arranged on the carrier frame, which centering means are designed for centering the shim pack relative to the carrier frame.

For optimum securing of the individual shims, they can have recesses, preferably two recesses each, which correspond to the position of the screws. With the screws being screwed in, the individual shims are secured in this way.

The device further preferably comprises a base plate, which is formed with threaded holes for engagement of the screws, wherein the base plate is designed to carry the shim pack.

As explained above, another problem is that the shim pack adheres to the base on which it rests due to adhesion (as a result of an oil film). In order to be able to solve this problem, a further development provides that the length of the thread of the screws is greater than the length of the threaded hole in the base plate, preferably greater by 1 mm to 5 mm. Then, by tightening the screws, it can be achieved that the shim pack is pressed away from the substrate, thereby overcoming adhesion.

As explained, the proposed method/the described device is used in particular for changing over the shim packs in the backup roll changeover carriage of rolling systems.

The method/device allows the changeover times of the shims in the (backup roll) changeover carriage to be shortened, thus generally reducing the changeover times of the (backup) rolls.

The shims are combined into shim packs of at least one, preferably at least two or three, and in particular a maximum of five shims. The packet is then transported as one part (by overhead crane). As a result, the need for crane trips is significantly eliminated; the “delivery time” of the shims (to the changeover carriage/changeover pit) is considerably reduced. The specified centering means are provided for the precise centering of the shim pack. A reliable and secure connection between the carrier element and the shim pack can be achieved with just two screws, which offers corresponding advantages in terms of handling.

The shim packs are prepared in the preparation workshop in particular.

The intermediate storage element (a “dummy carriage”, so to speak) is loaded with the required shim packs. The intermediate storage element preferably has a plurality of regions, namely those for used shim packs in each case for the drive and operating side and those for newly adjusted shim packs, also in each case for the drive and operating side. The receptacles in the intermediate storage element are designed in such a way that the shim packs are held there and that the lifting tool (carrier element lifted by the overhead crane) can remove them from there. The intermediate storage element can be transported to the roll changeover pit by crane or by means of other transport equipment.

The intermediate storage element can also be transported with the newly adjusted shim packs, as close as possible to the changeover region (i.e. to the (backup) roll changeover pit), by means of a lifting tool to the rolling system.

The (backup) roll is then moved out of the rolling mill stand and removed from the roll changeover pit.

The intermediate storage element, including the prepared shim packs, is received by means of a lifting tool (crane) and moved to one side (operating side) of the (backup) roll changeover carriage.

The shim packs are preferably fixed manually using the two specified screws. However, the fixing of the shim pack to the carrier element can also be carried out by means of other conventional fixing elements (e.g., by means of an automatic locking mechanism or by means of a lever).

The (old) shim packs are then lifted from the roll changeover carriage with the carrier element and deposited on the intermediate storage element. The fixing element is released.

Now, the carrier element is moved over the new (delivered) shim packs of the respective side (drive or operating side), the shim packs are fixed as described above and are now positioned in the changeover pit in the now empty position and released from the carrier element by loosening the screws.

This operation is then repeated for the site that has not yet been processed.

Fixing/releasing in the carrier element and also fixing in the roll changeover carriage can also be carried out automatically. For this purpose, corresponding devices can be provided on the carrier element.

A gap (approximately 1 to 5 mm) can be created between the shim packs and their support surface (cover of the load cell) by tightening the screws, which makes it easier to release the shim packs (by overcoming adhesion).

This results in an easy installation of the shim packs and a significant time savings compared to the previously known procedure. At the same time, the safety of the method is also ensured.

DETAILED DESCRIPTION

FIG. 1 shows four shims 1 that have been combined to form a shim pack 2. The shims 1 are required for changing over the backup rolls of a rolling mill stand. For this purpose, the shims 1 are prepared in a preparation workshop (which is located at some distance from the rolling mill stand and is not shown in the figures) and then transported (by overhead crane) to the rolling mill stand, where they are needed for the roll changeover. The shim pack 2 rests on a base plate 12, which is (so to speak, temporarily) part of a carrier element 3, which is provided for transporting the shims 1. On the other hand, the entire pack consisting of the shims 1 and the base plate 12 is mounted in the rolling mill stand, such that the base plate 12 then remains part of the pack 2.

FIG. 1a shows that the base plate 12 has a recess in its lower region, into which a shim part is placed, which is fitted with a threaded hole 13. Screws 8, 9 are screwed into the threaded hole 13, which screws secure the shim pack 2 to the carrier element 3. In order to achieve this reliably, the individual shims 1 have recesses 11, in which the shafts of the screws 8, 9 come to rest if they are screwed into the base plate 12. The two recesses 11 per shim 1 are provided diagonally, as shown in FIG. 1.

FIG. 2 shows how the carrier element 3 grasps a shim pack 2, in order to receive and transport it. The carrier element 3 consists of a carrier frame 7, which can be coupled to an overhead crane (not shown in the figures).

A plurality of centering means 10 (six in the exemplary embodiment) are fastened to the carrier frame 7, which are designed as rods extending in a vertical direction, which have an insertion slope 14 in the lower end region, as can be seen in FIG. 2a.

FIG. 3 shows how the carrier element 3 has grasped a shim pack 2 and the latter is firmly (positively) connected to the carrier element. For this purpose, the two screws 8 and 9 are guided through corresponding through-holes in the upper region of the carrier frame 7. The screws 8, 9 are screwed into the base plate 12 and into the threaded holes 13 provided there (see FIG. 1a). The shim pack 2 is secured relative to the carrier element 3 by the recesses 11 (see FIG. 1).

Problems occasionally arise because the underside of the shim pack 2 and in particular the base plate 12 is held to the substrate by adhesion. In order to avoid this, the length of the thread LG of the screws 8, 9 is designed to be longer than the length of the threaded hole LB, as shown in FIG. 3a. This makes it possible to press the underside of the base plate 12 away from the substrate by screwing in the screws 8, 9 accordingly, thus eliminating adhesion effects.

FIG. 4 shows once again how the carrier element 3 has grasped a shim pack 2 located beneath it. It is then transported (by overhead crane) to an intermediate storage element 4, which is shown in FIG. 5. In the exemplary embodiment, the intermediate storage element 4 has four receptacles 15 for the respective shim packets 2. FIG. 5 shows how two of the receptacles 15 (namely the two middle receptacles) are in each case loaded with a new shim pack 2′, wherein the carrier element 3, which has just moved a shim pack 2′ into the receptacle 15 of the intermediate storage element 4, is shown here again.

FIGS. 6 to 9 show various stages that illustrate the sequence of providing new shim packs 2′ for the roll changeover of a backup roll of a rolling mill stand, wherein the new shim packs 2′ replace the old shim packs 2″. The old shim packs 2″ are transported away from the rolling mill stand/the roll changeover carriage.

FIG. 6 initially shows the intermediate storage element 4 with the loading of two new shim packs 2′ (as shown in FIG. 5). The intermediate storage element 4 is located directly adjacent to a roll changeover pit 6, on which a roll changeover carriage 5 is arranged. In FIG. 6, the roll changeover carriage 5 is still fitted with two used shim packs 2″, which have been removed from the rolling mill stand. The gripping of a shim pack 2, either from the intermediate storage element 4 or from the roll changeover carriage 5, is illustrated once again in FIG. 6a.

FIG. 7 shows how a new shim pack 2′ is transported from the intermediate storage element 4 to the roll changeover carriage 5. The intermediate storage element 4 is still loaded with a new shim pack 2′ and already loaded with a used shim pack 2″.

FIG. 8 shows how the new shim pack 2′ was moved into the roll changeover carriage 5. At this stage, the exchange of the old shim packs 2″ for new shim packs 2′ has taken place for half of one side of the rolling mill stand (the drive side or the operating side).

Finally, FIG. 9 shows how the two old shim packs 2″ were moved into the intermediate storage element 4, while the two new shim packs 2′ are placed in the roll changeover carriage 5.

Depending on requirements, the intermediate storage element 4 can be positioned either to the side or behind the roll changeover pit 6 by overhead crane.

Through the described arrangement and procedure, the logistics for supplying the rolling mill stand/the roll changeover carriage with new shim packs can be simplified, consequently significantly reducing the number and duration of crane trips.

LIST OF REFERENCE SIGNS