METHOD FOR REPLACING WORK ROLL(S) IN A ROLLING MILL AND GRASPING TOOL SUITABLE FOR THE IMPLEMENTATION OF THE METHOD

Abstract

A tool intended to be handled by a handling system, the grasping tool including: a support frame forming at least one pair of compartments for the storage of two work rolls, independent gripping systems including a first gripping system configured to secure one end of a work roll in a first compartment and a second gripping system configured to secure one end of a work roll in a second compartment, a push/pull system including one or more actuating cylinder(s) configured to extract or insert the worn/new rolls from/into the compartment by a selective movement of each of the gripping systems associated with the compartments, by causing a movement of the work roll according to an axis of the roll.

Description

FIELD

The invention relates to a method for replacing a work roll of a rolling mill, in particular in the presence of a metal strip rolled between the two work rolls, including an upper work roll and a lower work roll, the method being suitable for the extraction of at least one work roll from the roll stand of a rolling mill, in particular the extraction of at least one worn work roll, and the insertion of at least one work roll, in particular a new one, as a replacement.

The present disclosure also relates to a grasping tool suitable for the implementation of the method, the grasping tool being suitable for the extraction of at least one worn work roll and for the insertion and the set-up into the roll stand of the rolling mill of at least one lower and/or upper new work roll.

The present disclosure also relates to an assembly comprising a handling system, such as a carriage system or a robotic system and a grasping tool, handled by the handling system, typically in the three directions of space, and possibly according to one or more degree(s) of rotation.

Thus, the present invention finds an advantageous application for multi-roll rolling mills for the implementation of maintenance operations, such rolling mills typically consisting of “Sendzimir” 20-high rolling mills.

BACKGROUND

Cold rolling allows obtaining the final thickness of a metal strip through successive passes of this strip between rolls in the presence of high forces simultaneously compressive and tensile.

A “Sendzimir”-type rolling mill includes a plurality of rolls, or barrels, which are arranged with respect to one another so as to enable a change in the mechanical characteristics of a metal strip and obtaining a strip thickness that could typically be smaller than 3 millimetres.

More particularly, a “Sendzimir” rolling mill is known which may include twenty rolls; and embodiment of such a 20-high rolling mill is illustrated in the documents U.S. Pat. Nos. 5,193,377 and 5,471,859.

FIG. 1 represents a schematic view of a cross-section of a 20-high rolling mill. In this figure, the rolls are distributed into a lower group GI and an upper group Gs; more specifically, these groups GI and Gs have a symmetrical structure and each includes ten rolls including: one work roll 12, two first intermediate rolls 13, three seconds intermediate rolls 14 and 15, and four backup rolls, or backup rollers, which are outside the arrangement and which are denoted A, B, C and D for the upper group GS and E, F, G, H for the lower group GI.

This nomenclature for the different constituent rolls of a 20-high rolling mill is common in the rolling mill field, and is well known to a person skilled in the art.

By convention, in the present disclosure, and as represented in FIG. 1, an orthogonal reference frame XYZ is selected wherein:

• • the longitudinal direction X, is oriented according to the running direction of the strip between the two work rolls of the rolling mill,
  • the transverse direction Y, corresponds to the widthwise direction of the strip, which extends from a first edge of the strip up to a second strip edge of the strip,
  • the direction Z, is perpendicular to the direction X and to the direction Y and is typically the vertical direction.

It is well-known in the rolling mill field that this roll arrangement illustrated in FIG. 1 allows working a metal strip BM efficiently to obtain the desired strip thickness.

Because of the stresses exerted on the work rolls 12 during working of a metal strip BM, these parts 12 require a very regular maintenance because of wearing thereof: it is therefore desirable to be able to extract and replace the work rolls 12, in a safe manner for the operators, and while minimising the time during which the rolling operations should be stopped.

PRIOR ART

Thus, the state of the art includes handling systems, typically with carriages, and possibly robotic systems for example as disclosed by WO2022/223927A1 of the present Applicant, or else JPS634312 which allow implementing an extraction of the worn rolls, and then replacement thereof with new work rolls.

According to the observations of the Inventors, the handling system of the prior art such as the robotic systems according to WO2022/223927A1 or JPS634312 comprise a grasping tool which is configured to be moved by the handling system typically according to at least three directions of space, and possibly also according to one or more degree(s) of rotation.

The roll replacement operations require stopping the rolling operations, including stopping running of the metal strip, and proceeding with opening of the roll stand of the rolling mill by relieving the two work rolls, and possibly when the roll stand includes two portions, respectively lower and upper ones, movable relative to one another, by spacing apart the two portions in order to facilitate access to the work rolls.

The grasping tool is then configured to grasp a work roll in order to proceed with removal thereof, then with deposition thereof typically on a rack, at a distance from the roll stand of the rolling mill disclosed by WO2022/223927A1 or JPS634312.

Typically, it is proceeded with the removal of the upper work roll. To this end, the handling system positions the grasping tool in line with a maintenance hatch of the roll stand of the rolling mill and proceeds with centring of the tool according to the transverse direction and/or according to the vertical direction, in order to align an axis of the grasping tool with the roll to be grasped. After grasping the work roll, the robotic system proceeds with the removal of the roll, by a movement of the roll according to an axis parallel to the transverse direction Y. Afterwards, the handling system moves the work roll away from the hatch, then deposits the lower work roll on an empty compartment on the rack by moving the grasping tool by the handling system.

The handling system moves the grasping tool again, from the rack until alignment with the maintenance hatch of the roll stand to repeat these operations for removal of the lower work roll, then deposition of the lower work roll, on a second empty compartment of the rack.

The handling system returns again up to the rack to proceed with grasping of a first new work roll on the rack, then moves it up to the maintenance hatch to proceed with the insertion thereof into the roll stand of the rolling mill, for example as a lower work roll, after centring with a lower room in the roll stand of the rolling mill. The handling system returns again up to the rack to proceed with grasping of a second new work roll on the rack, then moves it up to the maintenance hatch to proceed with the insertion thereof into the roll stand of the rolling mill, for example as an upper work roll, after centring with an upper room in the roll stand of the rolling mill.

Once the replacement operations are completed, the work rolls can be tightened on the strip, which is set again in motion, to restart the rolling operations.

According to the observations of the Applicant, such a work roll replacement solution imposes stopping the rolling operations throughout the entire duration of the back-and-forth cycles from the rolling mill to the racks which reduces the yield of the rolling plant.

A second state of the art is known which is described as a prior art in WO2022/223927A1 and illustrated in the first two figures of this prior document.

According to this robotic prior art, the robotic system comprises a robot comprising:—a carriage comprising a first frame provided with wheels cooperating with rails disposed on the ground, extending according to the direction Y, in line with the access trap of the roll stand of the rolling mill, said first frame being configured to move according to the transverse direction Y along the rails, under the action of first motor means driving the wheels,

• • a second frame and a first slide system linking the second frame and the first frame configured to move the second frame relative to the first frame according to the longitudinal direction X, under the action of second motor means,
  • a third frame and a second slide system linking the third frame and the second frame, configured to move the third frame relative to the second frame according to the vertical direction Z, under the action of third motor means.

A grasping tool is secured to the third frame and such a robotic system according to the prior art is configured to ensure the extraction of one or two roll(s), by holding one single roll at once, by the implementation of the following steps:

• • aligning the grasping tool with the axis of the roll to be grasped by moving the tool oriented according to the direction X by the action of the second motor means and according to the direction Z by the action of the third motor means,
  • grasping the roll by the grasping tool by advancing the carriage along the rails,
  • extracting the roll out of the roll stand of the rolling mill by moving the carriage backwards along the rails according to the direction Y, under the action of the first motor means.

Upon completion of extraction of the roll operated by the backward movement of the robot along the rails, the extracted roll is completely outside the roll stand of the rolling mill, oriented axially parallel to the transverse direction Y. The roll is then in an intermediate position where the work roll is located between, on the one hand, the access hatch of the roll stand of the rolling mill, left open by the door system and, on the other hand, the carriage of the robot.

In such a state of the art, the deposition of the roll requires a motor-driven additional piece of equipment illustrated as a prior art in the document WO2022/223927A1, including a motor-driven system of deposition racks, at least horizontally according to the direction X so as to position it between the rolling mill and the robot. This rack system may also be movable in a motor-driven manner according to the horizontal direction Y.

Thus, the rack system itself may comprise a carriage with a first frame configured to move along rails disposed parallel to the rail of the robot, laterally to the robot, according to the transverse direction Y by a first motor, and a second frame carrying the rack for loading/unloading the rolls, configured to be moved, relative to the first frame, according to the direction X thanks to a slide system between the second frame and the first frame, and second motors.

Thus, the rack is moved by the first frame along the rails, according to the direction Y, then by a movement of the second frame according to the direction X, cantilevered with respect to the first frame, to ensure the deposition of the roll by the robot on the rack which is done, by the action of the third motor means, while the roll is still oriented according to the direction Y, in a position where the movable rack is positioned midway between the rolling mill and the robot.

According to the observations of the Inventor, the movable rack system is a piece of equipment that is brought close to the robotic system and the roll stand of the rolling mill during the operations of replacing rolls, which allows reducing the movements of the grasping tool necessary for the replacement of the work rolls, in comparison with the aforementioned prior art. Nonetheless, and as discussed in the introduction of the document WO2022/223927A1, this solution clutters up the maintenance aisle, which extends, according to the direction X, along the access openings of the different rolling mills.

According to the observations of the Applicant, there is since a very long time a need for a method for replacing the work rolls of a rolling mill, as well as a grasping tool suitable for the implementation of such a method which considerably reduce the time during which the rolling operations should be stopped, advantageously without cluttering up the maintenance aisle, unlike the aforementioned prior art.

SUMMARY

The present invention aims to improve the situation.

According to a first aspect, and in particular according to a first possibility, a method is provided for replacing the work rolls of a rolling mill, in the presence of a metal strip rolled between the two work rolls, the rolling mill having a roll stand receiving at least one upper work roll and one lower work roll, each of said work rolls has a generatrix of contact with the metal strip, said contact generatrices and the axes of the work rolls lie in a plane substantially perpendicular to a running direction of the metal strip, roller members such as first intermediate rolls, being in contact according to two contact generatrices with each of the work rolls, the roller members ensuring the transmission of a rolling force to the lower and upper work rolls in contact with the metal strip during the rolling operations, in which method the replacement of a work roll of the roll stand of a rolling mill is ensured characterised by:

• • /A/ providing a handling system, such as a robotic system, and providing a grasping tool handled by the handling system, at least by a movement according to a longitudinal direction oriented according to a longitudinal running direction X of the strip between the two work rolls and/or according to a vertical direction Z and/or according to a rotation about the axis of the direction Y, and possibly with a movement according to a transverse direction Y said grasping tool comprising at least one pair of compartments for work rolls, the compartments extending longitudinally, parallel to one another, said at least one pair of compartments comprising a first compartment for a worn work roll provided with a first gripping system and a second compartment for a new work roll provided with a second gripping system, said at least one pair configured for simultaneously holding the worn work roll and the new work roll in parallel
  • and wherein it is proceeded with the replacement of at least one upper or lower worn work roll,
  • /B/ pre-loading the second compartment with a new work roll, the first compartment for a worn roll being left free, pre-loading being carried out during the operations of rolling the metal strip between the upper work roll and the lower work lower,
  • /C/ stopping the rolling operations and opening by spacing apart the upper work roll and the lower work roll,
  • /D/ centring the first compartment, free of the grasping tool by a movement caused by the handling system according to the longitudinal direction X and/or according to the vertical direction Z and/or according to a rotation about the axis Y, in order to align the first compartment with the worn work roll in the roll stand of the rolling mill, consisting of the upper work roll or the lower work roll,
  • /E/ grasping the worn work roll by the first gripping system of the grasping tool, and extracting the worn work roll according to an axis of the work roll, parallel to the transverse direction Y until obtaining loading of the worn work roll in the first compartment, the removed worn work roll leaving an empty clearance in the roll stand of the rolling mill,
  • /H/ centring the second compartment of the grasping tool pre-loaded with the new work roll, by moving the grasping tool by the handling system according to the longitudinal direction X and/or according to the vertical direction Z and/or according to a rotation about the axis Y, in order to align the new work roll with the empty clearance of the roll stand of the rolling mill, and while the first compartment is loaded with the removed worn work roll.
  • /I/ inserting the new work roll contained in the second compartment in the free clearance of the roll stand of the rolling mill by pushing the second gripping system.

According to an advantageous embodiment, and in particular according to a second possibility, the grasping tool comprises said first compartment for a first worn work roll provided with the first gripping system and said second compartment for a second new work roll provided with a second gripping system, the first and second compartments forming a first pair of compartments, but also a third compartment for a second worn work roll provided with a third gripping system and a fourth compartment for a second new work roll provided with a fourth gripping system, the third compartment and the fourth compartment forming a second pair of compartments,

• • and wherein it is proceeded with the replacement of the upper worn work roll and the lower worn roll in the roll stand of the rolling mill through the following steps
  • said step /A/ of providing a handling system, such as a robotic system, and a grasping tool handled by the handling system, at least according to a longitudinal direction oriented according to a longitudinal running direction X of the strip between the two work rolls and/or at least according to a vertical direction Z, and/or at least a rotation according to the axis Y, and possibly a movement according to a transverse direction Y,
  • said step /B/ of pre-loading the second compartment with a first new work roll, and also pre-loading the fourth compartment for a second new work roll, the first compartment for a first worn roll and the third compartment for a second worn roll being left free, pre-loading being carried out during the operations of rolling the strip between the upper work roll and the lower work roll,
  • said step /C/ of stopping the rolling operations and opening by spacing apart the upper work roll and the work roll,
  • said step /D/ of centring the free first compartment, by a movement of the grasping tool caused by the handling system according to the longitudinal direction X and/or according to the vertical direction Y, in order to align the first compartment with a first worn work roll in the roll stand of the rolling mill, which is the upper work roll or the lower work roll,
  • said step /E/ of grasping the first worn work roll by the first gripping system of the grasping tool, and extracting the worn work roll according to an axis of the work roll, parallel to the transverse direction Y until obtaining loading of the worn work roll in the first compartment, the worn work roll leaving a first empty clearance in the roll stand,
  • /F/ centring the third compartment, free of the grasping tool by a movement of the grasping tool caused by the handling system according to the longitudinal direction X and/or according to the vertical direction Z and/or rotation according to the axis Y, in order to align the third compartment with a second worn work roll, a lower work roll or an upper work roll in the roll stand of the rolling mill,
  • /G/ grasping the second worn roll by said third gripping system of the grasping tool, and extracting the worn work roll according to an axis of the work roll, parallel to the transverse direction Y until obtaining loading of the second worn work roll in the third compartment, the worn work roll leaving a second empty clearance in the roll stand,
  • the step /H/ of centring the second compartment of the grasping tool pre-loaded with the first new work roll by a movement of the grasping tool by the handling system 1 according to the longitudinal direction X and/or according to the vertical direction Z, and/or rotation according to the transverse direction Y, in order to align the first work roll with the empty clearance of the roll stand of the grasping tool, the first empty clearance or the second empty clearance, and while the first compartment and the third compartment are loaded with the first worn work roll and the second worn work roll,
  • the step /I/ of inserting the first new work roll contained in the second compartment into the empty clearance, by pushing the second gripping system,
  • /J/ centring the fourth compartment pre-loaded with the second new roll by a movement of the grasping tool by the handling system 1 according to the longitudinal direction X and/or according to the vertical direction Z, and/or rotation according to the transverse direction Y, in order to align the second new roll with the other free clearance by a movement of the grasping tool caused by the handling system, and while the first compartment and the third compartment are loaded with the first worn work roll, and the second worn work roll,
  • /K/ inserting the second new work roll contained in the fourth compartment into the other empty clearance by pushing the fourth gripping system.

According to one embodiment, the different compartments are provided with independent gripping systems, configured to secure one end of a work roll, each gripping system configured to ensure a push during an insertion of a work roll or configured to ensure a pull during an extraction of a roll, by moving the gripping system along the compartment.

According to one embodiment, the gripping systems consist of mechanised clamps or magnetic chucks or pneumatic chucks

• • and wherein the mechanised clamps or the magnetic chucks or the pneumatic chucks are configured to grasp one end of a work roll. According to one embodiment, the grasping tool comprises a push/pull system comprising one or more actuating cylinder(s) configured to extract or insert the worn/new rolls from/into the compartments by selective movement of each of the gripping systems associated with the compartments, by causing a movement of the work roll according to a longitudinal axis of the work roll, and in particular a pull of the worn roll in the first compartment when the method is according to the first possibility, and possibly pulls of the worn rolls in the first compartment and the third compartment when the method is according to the second possibility, and to insert into the roll stand of the rolling mill the new roll contained in the second compartment when the method is according to the first possibility, or to insert into the roll stand of the rolling mill the first new roll contained in the second compartment and the second new roll contained in the fourth compartment when the method is according to the second possibility. According to one embodiment, the push/pull system comprises:
  • a unique actuating cylinder to proceed with the selective movement of the gripping systems of the different compartments, and in particular with the selective movement of the first gripping system and of the second gripping system of said at least one pair of compartments consisting of the first compartment and the second compartment when the method is according to the first possibility or with the selective movement of the first gripping system, of the second gripping system, of the third gripping system, of the fourth gripping system of said first compartment, second compartment, third compartment and fourth compartment when the method is according to the second possibility
  • a mechanism for ensuring coupling of a movable drive portion of the actuating cylinder selectively with the gripping systems of the different compartments, and in particular selectively with the first gripping system or the second gripping system when the method is according to the first possibility, or selectively with the first gripping system, the second gripping system, the third gripping system or the fourth gripping system when the method is according to the second possibility.

According to one embodiment, the compartments comprise said gripping systems configured to insert or extract the work rolls, by moving the work rolls according to the axis of the work roll throughout open distal ends of the longitudinal compartments, the compartments respectively have according to the length of the compartments, lateral load/unload openings, coupled to load/unload systems associated with the compartments, said load systems, independent, configured to load said compartments during the pre-loading step /B/, each load/unload system configured to ensure loading/or unloading of one of the compartments throughout the lateral openings.

According to one embodiment, said compartments for the worn roll(s) and the new roll(s) are arranged in parallel around a central axis of the grasping tool, said grasping tool comprising a drum forming a support frame including longitudinal cradles, angularly distributed around the central axis configured to receive the worn and new rolls, defining said compartments respectively.

According to one embodiment, said handling system comprises motor-driven means to ensure pivoting of the drum about the central axis and wherein the independent load/unload systems comprise for each compartment, a pair of gripping arms comprising a first arm and a second arm hinged respectively on two longitudinal edges of the cradle, configured to switch from a closure position for which the two arms hold a work roll in the cradle, and up to an opening position for which the two arms are spaced apart by a distance larger than a diameter of the work roll enabling loading/or unloading of the cradle throughout the lateral opening. Preferably, loading and/or unloading of one of the cradles is performed by rotation of the drum until positioning the cradle to be loaded/unloaded by orienting the lateral opening downwards, and by switching the pair of gripping arms from the opening position up to the closure position during loading, and by switching the pair of gripping arms from the closure position up to the closure position during unloading, enabling unloading by gravity throughout the lateral opening.

According to one embodiment, said unique actuating cylinder is arranged within a tubular room of the drum centred on the central axis and wherein said drum is configured to pivot about the actuating cylinder, mounted so as not to pivot relative to the handling system, the movable drive portion, projecting radially, said mechanism for ensuring coupling of the movable drive portion of the actuating cylinder selectively with the gripping systems, comprising the drum pivotally mounted about the actuating cylinder under the action of motor-driven means so that coupling is obtained by pivoting of the drum so as to set the movable drive portion of the actuating cylinder in correspondence selectively with the first gripping system, the second gripping system when the method is according to the first possibility or selectively with the first gripping system, the second gripping system, the third gripping system, or the fourth gripping system when the method is according to the second possibility.

According to one embodiment, the method is implemented in a rolling plant comprising the rolling mill comprising said roll stand and said set of rolls, internal to the roll stand, including the two work rolls, the backup rolls or the backup rollers, and possibly the intermediate rolls in particular first intermediate rolls and second intermediate rolls, the roll stand of a rolling mill having said access hatch, possibly closed by the door system, the metal strip extending longitudinally according to the horizontal direction X, and transversely according to the horizontal direction Y, parallel to the axes of the rolls of the rolling mill and

• • wherein said plant comprises a load/unload rack, removably positioned on a support frame anchored to the ground in an anchor position at a distance from the rolling mill according to the transverse direction Y so as to clear a maintenance aisle according to the longitudinal direction X, and wherein the pre-loading in /B/ is implemented at a distance from an access hatch of the roll stand by loading the grasping tool with one or more new roll(s) arranged on the load/unload rack.

According to a second aspect, the present disclosure is a grasping tool suitable for the implementation of the method according to the present disclosure, intended to be handled by a handling system, the grasping tool comprising:

• • a support frame comprising at least one pair of two cradles forming at least one pair of compartments for the storage of two work rolls forming at least one first compartment intended for a new work roll and a second compartment intended for a worn work roll, said two work rolls extending longitudinally, in parallel in said at least two cradles,
  • independent gripping systems including a first gripping system configured to secure one end of a work roll in the first compartment and a second gripping system configured to secure one end of a work roll in the second compartment,
  • a push/pull system comprising one or more actuating cylinder(s) configured to extract or insert the worn/new rolls from/into the compartments by selective movement of each of the gripping systems associated with the compartments, by causing a movement of the work roll according to an axis of the roll and wherein said grasping tool is configured to enable a replacement of a worn work roll with a new work roll by
  • removal of a worn work roll off the roll stand of a rolling mill by grasping the first gripping system and pulling the roll by actuation of the actuating cylinder until obtaining loading of the worn work roll in the first compartment, then
  • insertion of a new work roll into the roll stand of a rolling mill contained in the second compartment by pushing the second gripping system and while the first compartment contains the worn work roll.

According to one embodiment, the support frame comprises two pairs of cradles forming two pairs of compartments for the storage of two work rolls comprising besides the first compartment intended for a first worn work roll and the second compartment, intended for a first new work roll, a third compartment intended for a second worn work roll, and a fourth compartment intended for a second new work roll, said gripping systems, further comprising the first gripping system and the second gripping system, a third gripping system configured to secure one end of a work roll in the third compartment and a fourth gripping system configured to secure one end of a work roll in the fourth compartment,

• • and wherein said grasping tool is configured to enable a replacement of a first worn work roll with a first new work roll and a replacement of a second worn work roll with a second new work roll by:
    • removal of the first worn work roll off the roll stand of a rolling mill by grasping the first gripping system and pulling the work roll by actuation of the actuating cylinder until obtaining loading of the worn work roll in the first compartment,
    • removal of the second worn work roll off the roll stand of a rolling mill by grasping the third gripping system and pulling the roll by actuation of the actuating cylinder until obtaining loading of the worn work roll in the third compartment,
    • insertion of the first new work roll into the roll stand of a rolling mill contained in the second compartment by pushing the second gripping system and insertion of the second new work roll contained in the fourth compartment, and while the first compartment contains the first worn work roll and the third compartment contains the 25 second worn work roll.

According to one embodiment, said push/pull system comprises:

• • a unique actuating cylinder, to proceed with the selective movement of the gripping systems of the different compartments, and in particular with the selective movement of the first gripping system and of the second gripping system of said at least one pair of compartments consisting of the first compartment and the second compartment in particular when the tool comprises one pair of compartments, or with the selective movement of the first gripping system, of the second gripping system, of the third gripping system, of the fourth gripping system of said first compartment, second compartment, third compartment and fourth compartment when the tool comprises two pairs of compartments,
  • a mechanism for ensuring coupling of a movable drive portion of the actuating cylinder selectively with the gripping systems of the different compartments, and in particular selectively with the first gripping system or the second gripping system when the grasping tool comprises one pair of compartments, or selectively with the first gripping system, the second gripping system, the third gripping system or the fourth gripping system when the grasping tool comprises two pairs of compartments.

According to one embodiment, the compartments comprise said gripping systems configured to insert or extract the work rolls, by moving the work rolls according to the axis of the work roll throughout open distal ends of the longitudinal compartments, the compartments respectively having according to the length of the compartments, lateral load/unload openings, coupled to load/unload systems associated with the compartments, said load systems, independent, each load/unload system configured to ensure loading/or unloading of one of the compartments throughout the lateral openings.

According to one embodiment, said compartments for the worn roll(s) and the new roll(s) are arranged in parallel around a central axis of the grasping tool, said grasping tool comprising a drum forming a support frame including longitudinal cradles, angularly distributed around the central axis configured to receive the worn and new rolls, respectively defining said compartments and wherein the drum is configured to pivot about the central axis.

According to one embodiment, the independent load/unload systems comprise for each compartment, a pair of gripping arms comprising a first arm and a second arm, configured to switch from a closure position for which the two arms hold a work roll in the cradle, and up to an opening position for which the two arms are spaced apart by a distance larger than a diameter of the work roll enabling loading/or unloading of the cradle throughout the lateral opening.

According to one embodiment, said unique actuating cylinder is arranged within a tubular room of the drum centred on the central axis and wherein said drum is configured to pivot about the actuating cylinder, mounted so as not to pivot relative to the handling system the movable drive portion, projecting radially in a fixed angular position, said mechanism for ensuring coupling of the movable drive portion of the actuating cylinder selectively with the gripping systems, comprising the drum pivotally mounted about the actuating cylinder under the action of motor-driven means of the handling system so that coupling is obtained by pivoting of the drum so as to set the movable drive portion of the actuating cylinder in correspondence selectively with the first gripping system, the second gripping system when the grasping tool comprises one pair of compartments or selectively with the first gripping system, the second gripping system, the third gripping system, or the fourth gripping system when the grasping tool comprises two pairs of compartments.

According to a third aspect, the present disclosure also relates to an assembly comprising a handling system for a plant for rolling a metal strip, and a grasping tool according to the present disclosure, handled by the handling system, suited to ensure the operations of replacing work rolls of the rolling mill, to ensure an extraction of a worn work roll and an insertion of a new work roll in the roll stand of the rolling mill.

According to one embodiment, the handling system comprises a robot comprising:

• • a carriage comprising a first frame provided with wheels cooperating with rails disposed on the ground, extending according to a direction Y, in line with the access trap of the roll stand of the rolling mill, said first frame being configured to move according to the direction Y along the rails, under the action of first motor means driving in particular the wheels,
  • a second frame and a first slide system linking the second frame and the first frame configured to move the second frame relative to the first frame according to a direction X, under the action of second motor means,
  • a third frame and a second slide system linking the third frame and the second frame, configured to move the third frame relative to the second frame according to a vertical direction Z, under the action of third motor means,
  • a grasping system movable with the third frame comprising an actuator configured to control locking and unlocking of grasping of a proximal end of the grasping tool.

BRIEF DESCRIPTION OF DRAWINGS

Other features, details and advantages will appear upon reading the detailed description hereinafter, and analysing the appended drawings, wherein:

FIG. 1 is a schematic configuration of a 20-high rolling mill.

FIG. 2a

FIG. 2a is a view, according to the transverse direction Y, of the grasping tool with respect to the roll stand of the rolling mill (the metal strip being hidden), the grasping tool including a drum which can be handled in rotation about a central axis, including four cradles angularly distributed around the central axis, the four cradles respectively forming a first compartment for a first worn work roll, a second compartment for a first new work roll, a third compartment for a second worn work roll, and a four compartment for a second new work roll, said first compartment, second compartment, third compartment and four compartment being respectively provided with independent roll gripping systems, comprising a first gripping system associated with the first compartment, a second gripping system associated with the second compartment, a third gripping system associated with the third compartment and a fourth gripping system associated with the four compartment, the different gripping systems being able to be actuated independently of each other to enable the extraction or the insertion of a work roll, by moving the work roll according to the longitudinal axis of the roll, FIG. 2a illustrating the grasping tool in a centred position for which the first room, directed upwards, is aligned with the position of the lower work roll in the roll stand of the rolling mill, enabling the extraction of a lower worn work roll, bearing on the first two intermediate rolls, in particular contained between the lower first two intermediate rolls and the strip, in the roll stand, until loading thereof in the cradle forming the first compartment.

FIG. 2b is a perspective view of FIG. 2a.

FIG. 2c is a sectional view of FIG. 2a, according to a sectional plane passing through the central axis of the drum.

FIG. 3a is a view of the grasping tool according to FIG. 2a, after pivoting of the drum about the central axis in order to orient the third compartment upwards, and vertical movement of the grasping tool up to a position for which the third compartment is aligned with the position of the upper work roll in the roll stand of the rolling mill enabling the extraction of an upper worn work roll, in particular bearing on the ends of two spray rails in the roll stand, between the two upper first intermediate rolls and the strip, up into the cradle forming the third compartment.

FIG. 3b is a perspective view of the grasping tool in the position of FIG. 3a.

FIG. 4 is a detail view of the grasping tool, illustrating:

the third compartment and the third gripping system including a two-jaw clamp, as well as a (third) load/unload system enabling loading of a lateral roll, through a lateral opening of the cradle, and

the fourth compartment and the fourth gripping system, as well as a (fourth) load/unload system,

and wherein each gripping system including one said two-jaw clamp configured to grasp one end of a work roll, in particular by fitting into a peripheral groove of the roll,

and wherein the load/unload systems are independent, each including two arms consisting of a first arm and a second arm, hinged according to two parallel axes of rotation, arranged on either side of the cradle, according to the length of the cradle, the first arm and the second arm configured to switch from a closure position, illustrated in FIG. 4 for which the two arms hold a work roll in the cradle, and up to an opening position for which the two arms are spaced apart by a distance larger than a diameter of the work roll enabling loading/or unloading of the cradle throughout the lateral opening of the cradle.

FIG. 5 is a detail view of FIG. 4, illustrating the gripping systems of the grasping tool ensuring securing of one end of a roll, the two jaws simultaneously engaged with the peripheral groove, each gripping system configured so as to be movable according to the lengthwise direction of the cradle in order to push the roll according to the longitudinal direction of the cradle during the insertion of a roll into the roll stand of a rolling mill, or on the contrary to pull it from a position in the roll stand of the rolling mill up into a cradle of the drum.

FIG. 6 shows a view of a unique actuating cylinder arranged on a central support, crossing a tubular room of the drum, the actuating cylinder including a movable drive portion, projecting upwards, which is configured to be coupled selectively with the different gripping systems associated with the compartments, including coupling of the movable drive portion with:

a first gripping system associated with the first compartment in a first relative position of the drum with respect to the actuating cylinder,

a second gripping system associated with the second compartment in a second relative coupling position of the drum with respect to the actuating cylinder,

a third gripping system associated with the third compartment in a third relative coupling position of the drum with respect to the actuating cylinder,

a fourth gripping system associated with the fourth compartment in a fourth relative coupling position of the drum with respect to the actuating cylinder, and wherein the selective coupling is achieved by rotation of the drum about the central axis to switch from a relative coupling position to another, amongst the first, second, third and fourth relative coupling position.

FIG. 7 is a view of a rolling plant including a rolling mill and a set comprising a handling system (in particular robotic) for a plant for rolling a metal strip, and a grasping tool according to the present disclosure, handled by the handling system, suited to ensure the operations of replacing work rolls of the rolling mill, to ensure an extraction of a worn work roll and an insertion of a new work roll into the roll stand of the rolling mill, the operations of pre-loading or unloading the grasping tool carried out at a distance from the roll stand of the rolling mill, on a rack, while leaving a maintenance aisle between an access hatch of the roll stand of the rolling mill and the rack.

FIG. 8 is a view of a possible embodiment of the handling system which may be robotic.

DETAILED DESCRIPTION

The present disclosure relates to a method for replacing work rolls 12 of a rolling mill 10, in particular in the presence of a metal strip BM intended to be rolled between the two work rolls 12, including an upper work roll 12 and a lower work roll 12.

The present invention finds a particular application for a 20-high rolling mill, and as illustrated in FIG. 1. It may consist of a rolling mill wherein the roll stand of the rolling mill is made into two portions, comprising a lower roll stand portion, transmitting a clamping force to the lower rolls, including the lower work roll 12; and possibly to said sets of lower rollers, and an upper roll stand portion, movable vertically relative to the lower roll stand portion transmitting a clamping force to the upper rolls, including the upper work roll 12, and possibly to said sets of upper rollers.

Thus, the roll stand 2 can receive:

• • in the upper portion, within the upper roll stand portion, the upper work roll 12, as well as first two upper intermediate rolls 13, second three upper intermediate rolls 14, 15, and four sets of upper backup rollers A, B, C, D,
  • in the lower portion, within the lower roll stand portion of the rolling mill, the lower work roll 12, as well as first two lower intermediate rolls 13, second three lower intermediate rolls 14, 15, and four sets of lower backup rollers H, G, F, E.

For such a two-portion roll stand, the at least partial opening of the roll stand is obtained by spacing apart the upper roll stand portion relative to the lower roll stand portion.

Nonetheless, the present disclosure still finds a particular application for which the roll stand is made in one-piece.

The roll stand also typically receives:

• • a pair of spray rails, below the metal strip to be rolled, the two rails disposed on either side of a rolling plane passing through the axes of the work rolls and/or
  • a pair of spray rails, above the metal strip to be rolled, the two rails disposed on either side of a rolling plane passing through the axes of the work rolls.

During the operations of replacing a roll of the rolling mill, the two upper spray rails may be typically oriented so as to form a support cradle for the upper work roll 12, and so as to leave a clearance below the strip to extract/insert the lower work roll. On the contrary, when it is necessary to extract/insert the upper work roll, the upper rails can be moved downwards so as to press the metal strip downwards and so as to leave a clearance above the strip to extract/insert the upper work roll.

During the rolling operations, each of the work rolls 12 has a generatrix of contact with the metal strip, said contact generatrices and the axes of the work rolls lying substantially in a plane substantially perpendicular to a running direction of the metal strip, roller members in particular first intermediate rolls 13 being in contact according to two contact generatrices with each of the work rolls 12, the roller members ensuring the transmission of a rolling force to the lower and upper work rolls 12 in contact with the metal strip BM.

According to the replacement method according to the present disclosure, at least according to a first possibility, it is proceeded with the replacement of at least one upper or lower worn work roll 12u by:

• • /A/ providing a handling system 1, such as a robotic system, and providing a grasping tool OT handled by the handling system, at least by a movement according to a longitudinal direction oriented according to a longitudinal running direction X of the strip between the two work rolls and/or according to a vertical direction Z, and/or according to a rotation about the axis of the direction Y, and possibly according to a transverse direction Y, said grasping tool comprising at least one pair of compartments E1, E2; E3, E4 for work rolls, the compartments E1, E2; E3, E4 extending longitudinally, parallel to one another, said at least one pair of compartments comprising a first compartment E1 for a worn work roll 12u provided with a first gripping system SP1 and a second compartment E2 for a new work roll 12n provided with a second gripping system SP2, said at least one pair configured for simultaneously holding the worn work roll 12u and the new work roll 12n in parallel
  • /B/ pre-loading the second compartment E2 with a new work roll 12n, the first compartment E1 for a worn roll being left free, pre-loading being carried out during the operations of rolling the metal strip between the upper work roll and the lower work lower,
  • /C/ stopping the rolling operations and opening by spacing apart the upper work roll 12 and the lower work roll 12,
  • /D/ centring the first compartment E1, free of the grasping tool by a movement caused by the handling system 1 according to the longitudinal direction X and/or according to the vertical direction Z, and/or by a rotation about a transverse direction Y, in order to align the first compartment E1 with a worn work roll 12u in the roll stand of the rolling mill, consisting of the upper work roll or the lower work roll,
  • /E/ grasping the worn work roll 12u by the first gripping system SP1 of the grasping tool, and extracting the worn work roll 12u according to an axis of the work roll, parallel to the transverse direction Y until obtaining loading of the worn work roll 12u in the first compartment E1, the removed worn work roll leaving an empty clearance in the roll stand of the rolling mill,
  • /H/ centring the second compartment E2 of the grasping tool pre-loaded with the new work roll 12n, by moving the grasping tool by the handling system 1 according to the longitudinal direction X and/or according to the vertical direction Z, and/or a rotation according to the transverse direction Y, in order to align the new work roll with the empty clearance of the roll stand of the rolling mill, and while the first compartment E1 is loaded with the removed worn work roll,
  • /I/ inserting the new work roll 12 contained in the second compartment E2 in the free clearance of the roll stand of the rolling mill 10 by pushing the second gripping system SP2.

The present disclosure also relates to a grasping tool in particular suitable for the implementation of such a method for replacing work rolls.

Such a grasping tool OT is configured to be handled by a handling system, comprising:

• • a support frame comprising at least one pair of cradles forming at least one pair of compartments E1, E2; E3, E4 for the storage of two work rolls forming at least one first compartment E1 intended for a new work roll and a second compartment E2 intended for a worn work roll, said two work rolls extending longitudinally, in parallel in said at least two cradles,
  • gripping systems SP1, SP2; SP1, SP2 including at least a first gripping system SP1 configured to secure one end of a work roll in the first compartment E1 and a second gripping system SP2 configured to secure one end of a work roll in the second compartment E1,
  • a push/pull system comprising one or more actuating cylinder(s) VR configured to extract or insert the worn/new rolls from/into the compartment E1, E2, E3, E4 by a selective movement of each of the gripping systems SP associated with the compartments E1, E2, E3, E4, by causing a movement of the work roll according to an axis of the roll.

Advantageously, such a grasping tool is configured to enable a replacement of a worn work roll with a new work roll by:

• • removal of a worn work roll off the roll stand of a rolling mill by grasping the first gripping system SP1 and pulling the roll by actuation of the actuating cylinder until obtaining loading of the worn work roll in the first compartment E1, then
  • insertion of a new work roll into the roll stand of a rolling mill contained in the second compartment by pushing the second gripping system and while the first compartment contains the worn work roll.

Thus, the tool according to the present disclosure allows removing at least one worn work roll off the rolling mill and proceeding with the replacement thereof with at least one new roll, advantageously without requiring the deposition of said at least one worn roll, during the insertion operations.

Thus, such a grasping tool and the implemented method are also advantageous in that step /B/ of pre-loading the second compartment E2 with a new work roll is preferably performed:

• • in masked time during the rolling operations, and/or
  • at a distance from the access hatch of the roll stand of the rolling mill, for example from a rack Ra, supporting new rolls, removably set over a support structure CHa anchored to the ground and in particular as illustrated according to an indicative example in FIG. 7.

The method and the grasping tool according to the present disclosure are advantageous in that they allow replacing at least one work roll, while reducing the time during which the rolling operations should be stopped. Another advantage of this solution is that it consists of a technical solution allowing leaving the maintenance aisle extending in front of the roll stand and the access hatch of the roll stand of the rolling mill clear.

According to a second possibility, said grasping tool OT may be configured to replace the two lower and upper work rolls 12 of the rolling mill by enabling the insertion of two new work rolls into the rolling mill, advantageously without requiring the deposition of the two worn work rolls.

To this end, the support frame of the grasping tool OT then comprises two pairs of cradles forming two pairs of compartments E1, E2, E3, E4 for the storage of two work rolls comprising:

• • the first compartment E1 intended for a first worn work roll and,
  • the second compartment E2, intended for a first new work roll; but also
  • a third compartment E3 intended for a second worn work roll, and
  • a fourth compartment E4 intended for a second new work roll.

The gripping systems SP1, SP2, SP3, SP4 then further comprise the first gripping system SP1 and the second gripping system SP2, a third gripping system SP3 configured to secure one end of a work roll in the third compartment E3 and a fourth gripping system SP4 configured to secure one end of a work roll in the fourth compartment E4.

Said grasping tool comprising the four compartments E1, E2, E3, E4 is configured to enable a replacement of a first worn work roll with a first new work roll and a replacement of a second worn work roll with a second new work roll by:

• • removal of the first worn work roll off the roll stand of a rolling mill by grasping the first gripping system SP1 and pulling the roll by actuation of the actuating cylinder until obtaining loading of the worn work roll in the first compartment E1,
  • removal of the second worn work roll off the roll stand of a rolling mill by grasping the third gripping system SP3 and pulling the roll by actuation of the actuating cylinder until obtaining loading of the worn work roll in the third compartment E3,
  • insertion of the first new work roll into the roll stand of a rolling mill contained in the second compartment E2 by pushing the second gripping system SP2 and insertion of the second new work roll contained in the fourth compartment E4, and while the first compartment E1 contains the first worn work roll and the third compartment E3 contains the second worn work roll.

Thus, the grasping tool according to the present disclosure allows removing the two lower and upper worn work rolls off the rolling mill, and proceeding with replacement thereof with two new rolls, advantageously without requiring the deposition of either one of the worn rolls, during the extraction and insertion operations.

Whether for the grasping tool according to the first possibility, or for the grasping tool according to the second possibility, the grasping tool according to the present disclosure advantageously limits the movements necessary for the tool during the replacement operations to remove and insert the work roll(s), and in comparison with the prior art, as set out in the introduction, thereby leading to a substantial reduction of the duration during which the rolling operations should be stopped, since the grasping tool is moved in particular according to the direction X, and the direction Z, to proceed with the different centring operations (step /D/ and /H/ in particular) during the successive extraction and insertion operations, without requiring the deposition of the worn work roll. Hence, the movements necessary to the different centring, grasping and extraction and insertion operations, operated successively when the rolling operations are stopped have limited amplitudes, as the handling system always remains in line with the access hatch of the roll stand and typically according to an amplitude of the movement of the grasping tool limited in the height direction (according to the direction Z). Once the last new work roll is inserted, the rolling operations can be resumed, advantageously without waiting for the unload of the worn roll(s) recovered in the grasping tool OT, as the operations of unloading the grasping tool can be operated in masked time with the rolling operations.

Such a grasping tool and the implemented method are also advantageous in that step /B/ of pre-loading the second compartment E2 and the fourth compartment E4 with two new work rolls is preferably performed:

• • in masked time during the rolling operations, and/or
  • at a distance from the access hatch of the roll stand of the rolling mill, for example from a rack Ra, supporting new rolls, removably set over a support structure CHa anchored to the ground.

Thus, according to the second possibility, it is advantageously possible to proceed with the replacement of the upper worn work roll and of the lower worn work roll in the roll stand of the rolling mill 10 through the following steps:

• • said step /A/ of providing a handling system 1, such as a robotic system, and a grasping tool OT handled by the handling system, at least according to a longitudinal direction oriented according to a longitudinal running direction X of the strip between the two work rolls and/or according to a vertical direction Z, and/or a rotation according to the axis Y, and possibly according to a transverse direction Y,
  • said step /B/ of pre-loading the second compartment E2 with a first new work roll, and also pre-loading the fourth compartment E4 for a second new work roll, the first compartment E1 for a first worn roll and the third compartment E3 for a second worn roll being left free, pre-loading being carried out during the operations of rolling the metal strip between the upper work roll and the lower work roll,
  • said step /C/ of stopping the rolling operations and opening by spacing apart the upper work roll and the work roll,
  • said step /D/ of centring the free first compartment E1, by a movement of the grasping tool caused by the handling system according to the longitudinal direction X and/or according to the vertical direction Z, and/or a rotation according to the transverse direction Y, in order to align the first compartment E1 with a first worn work roll in the roll stand of the rolling mill, which is the upper work roll or the lower work roll,
  • said step /E/ of grasping the first worn work roll by the first gripping system SP1 of the grasping tool, and extracting the worn work roll according to an axis of the work roll, parallel to the transverse direction Y until obtaining loading of the worn work roll in the first compartment E1, the worn work roll leaving a first empty clearance in the roll stand,
  • /F/ centring the third compartment E3, free of the grasping tool by a movement of the grasping tool caused by the handling system according to the longitudinal direction X and/or according to the vertical direction Z and/or rotation according to the transverse direction Y, in order to align the third compartment E3 with a second worn work roll, a lower work roll or an upper work roll in the roll stand of the rolling mill,
  • /G/ grasping the second worn roll by said third gripping system SP3 of the grasping tool, and extracting the worn work roll according to an axis of the work roll, parallel to the transverse direction Y until obtaining loading of the second worn work roll in the third compartment E3, the worn work roll leaving a second empty clearance in the roll stand,
  • the step /H/ of centring the second compartment E2 of the grasping tool pre-loaded with the first new work roll by a movement of the grasping tool by the handling system 1 according to the longitudinal direction X and/or according to the vertical direction Z, and/or rotation according to the transverse direction Y, in order to align the first work roll with the empty clearance of the roll stand of the grasping tool, the first empty clearance or the second empty clearance, and while the first compartment and the third compartment are loaded with the first worn work roll and the second worn work roll,
  • the step /I/ of inserting the first new work roll contained in the second compartment into the empty clearance, by pushing the second gripping system SP2,
  • /J/ centring the fourth compartment E4 pre-loaded with the second new roll by a movement of the grasping tool by the handling system 1 according to the longitudinal direction X and/or according to the vertical direction Z, and/or rotation according to the transverse direction Y, in order to align the second new roll with the other free clearance by a movement of the grasping tool caused by the handling system, and while the first compartment E1 and the third compartment E4 are loaded with the removed first worn work roll, and the second worn work roll,
  • /K/ inserting the second new work roll contained in the fourth compartment E4 into the other empty clearance by pushing the fourth gripping system.

In general:

• • the rolling operations can advantageously be resumed, after insertion of the last work roll of the roll stand of the rolling mill, and without having to wait for the worn roll(s) recovered in the first compartment E1, and possibly the third compartment E3, to be unloaded.
  • the operations of unloading the compartments (first compartment E1 and third compartment E3) may be operated at a distance from the access hatch of the roll stand of the rolling mill, for example from a rack Ra, supporting new rolls, removably set over a support structure CHa anchored to the ground, in particular as illustrated according to an indicative example in FIG. 7.

According to the method according to the present disclosure (according to the first possibility or according to the second possibility), the different compartments E1, E2, E3, E4, in particular the first compartment E1, the second compartment E2, and possibly the third compartment E3 and the fourth compartment E4 are provided with the independent gripping systems SP1, SP2, SP3, SP4, configured to secure one end of a work roll, each gripping system SP1; SP2, SP3, SP3 configured to ensure a pull by a movement of the gripping system along the compartment E1; E2; E3; E4 during an extraction and a push during an insertion of a roll.

In particular, the first pair of compartments is provided with:

• • the first roll gripping system SP1 arranged in the first compartment E1 which ensures extraction in /E/ by pulling until obtaining loading of the worn work roll 12u in the first compartment E1 and,
  • the second roll gripping system SP2 arranged in the second compartment E2 which ensures insertion in /I/ by pushing the new work roll 12n from the second compartment up into the roll stand of the rolling mill.

The second pair of compartments is provided with:

• • the third roll gripping system SP3 arranged in the third compartment E3 which allows ensuring the extraction in /G/ by pulling until obtaining loading of the worn work roll 12u in the third compartment E3,
  • the fourth gripping system SP4 arranged in the fourth compartment E4 which ensures the insertion in /K/ by pushing the new work roll 12n from the fourth compartment up into the roll stand of the rolling mill.

In general, each gripping system SP, (in particular the first, second, third or fourth gripping system SP1 to SP4) is configured to switch from a state of grasping one end of a work roll 12, so as to enable a push of the work roll according to an axis of the roll in a first direction safely, but also a pull of the work roll, in an opposite second direction, up to a release state enabling the release of the roll.

Once the (new) work roll is inserted into the roll stand of the rolling mill 10 by pushing the gripping system, the latter is configured to switch from the grasping state up to the release state in order to enable the return of the gripping system, without pulling the inserted work roll.

In general, the gripping systems SP may consist of mechanised clamps, or magnetic chucks or pneumatic chucks. The mechanised clamps, the magnetic or pneumatic chucks are configured to grasp one end of a work roll in the grasping state and to allow releasing the work roll in the release state.

According to one embodiment (not illustrated), the clamps may consist of magnetic chucks, configured to secure the end of a roll by magnetic attraction of the chuck. The switch from the grasping state up to the release state is ensured by activation or deactivation of the magnetic attraction field of the magnetic chuck: it may in particular consist of an electromagnetic chuck, or with a permanent magnet whose movement is controlled by an actuator to switch from activation to deactivation of grasping of the end of the work roll.

According to one embodiment (not illustrated), the clamps may consist of pneumatic chucks, configured to secure the end of a roll by depression of the chuck. The switch from the grasping state up to the release state is ensured by an activation or a deactivation of the depression of the pneumatic chuck.

According to one embodiment (illustrated), the clamps may be mechanised. Each mechanised clamp may comprise two jaws consisting of a first jaw MR1 and a second jaw MR2 configured to switch from an opening position for which the clamp releases the work roll (release state) up to a closure position for which the two jaws is closed against the end of the work roll thereby ensuring grasping. In order to improve grasping, one should notice that the two jaws, the first jaw MR1 and the second jaw MR2 may be configured to engage with a relief at the end of the roll, and in particular fit into a circular groove G, visible according to the illustrated example. The switch from the opening position into the closure position is controlled by an actuator, typically electrical or pneumatic.

According to an advantageous embodiment, said push/pull system may advantageously comprise:

• • a unique actuating cylinder to proceed with the selective movement of the gripping systems SP of the different compartments E1, E2, E3, E4, namely with the pushing or pulling movement, and in particular with the selective movement of the first gripping system SP1 and of the second gripping system SP2 of said at least one pair of compartments consisting of the first compartment E1 and the second compartment E2 when the method is according with the first possibility or with the selective movement of the first gripping system SP1, of the second gripping system SP2, of the third gripping system SP3, of the fourth gripping system of said first compartment E1, second compartment E2, third compartment E3 and fourth compartment E4 when the method is according to the second possibility,
  • a mechanism for ensuring coupling of a movable drive portion PE of the actuating cylinder VR selectively with the gripping systems SP1, SP2, SP3, SP4 of the different compartments E1, E2, E3, E4, and in particular selectively with the first gripping system SP1 or the second gripping system SP2 when the method is according to the first possibility, or selectively with the first gripping system SP1, the second gripping system SP2, the third gripping system SP3 or the fourth gripping system SP4 when the method is according to the second possibility.

Such an embodiment is advantageous in that a unique actuator (the unique actuating cylinder VR) can operate the different gripping systems, one after another, to push or on the contrary pull each of the work rolls into/from the different compartments E1 to E4, and in particular in order to insert or extract a work roll.

According to a possible configuration (not illustrated), the compartments may be arranged, parallel to one another, one after another, in a straight line. According to another possible configuration (illustrated), said compartments E1, E2, E3, E4 for the worn roll(s) and the new roll(s) are arranged in parallel around a central axis Ac of the grasped tool OT.

Said grasping tool then comprising a drum TB forming a support frame including longitudinal cradles. The cradles are angularly distributed around the central axis configured to receive the worn and new rolls, respectively defining said compartments E1, E2, E3, E4. The cradles may respectively have lateral openings OL lengthwise, enabling loading or unloading, according to directions radial to the drum.

The drum TB is configured to pivot about the central axis AC. To this end, said handling system 1 may comprise motor-driven means M6 to ensure pivoting of the drum TB about the central axis AC.

According to an embodiment illustrated in particular in the figures, said unique actuating cylinder VR may be arranged within a tubular room of the drum TB centred on the central axis AC and said drum TB is configured to pivot about the actuating cylinder VR, mounted so as not to pivot relative to the handling system 1.

The mechanism for ensuring coupling of the movable drive portion PE of the actuating cylinder VR selectively with the gripping systems SP, then comprises the drum TB pivotally mounted about the actuating cylinder under the action of motor-driven means M6 so that coupling is obtained by pivoting the drum TB so as to set the movable drive portion PE of the actuating cylinder VR in correspondence selectively with the first gripping system SP1, the second gripping system SP2, in particular when the method is according to the first possibility, or selectively with the first gripping system SP1, the second gripping system SP2, the third gripping system SP3, and the fourth gripping system SP4 when the method is according to the second possibility.

Thus, in general, the unique actuating cylinder VR is arranged on a central support, crossing a tubular room of the drum, the actuating cylinder including the movable drive portion PE which is configured to be coupled selectively with the different gripping systems associated with the compartments E1, E2, E3, E4, including coupling of the movable drive portion with:

• • the first gripping system SP1 associated with the first compartment E1 in a first relative position of the drum TB with respect to the actuating cylinder VR,
  • the second gripping system SP2 associated with the second compartment E2 in a second relative coupling position of the drum E2 with respect to the actuating cylinder VR,
  • the third gripping system SP3 associated with the third compartment E3 in a third relative coupling position of the drum TB with respect to the actuating cylinder VR,
  • the fourth gripping system SP4 associated with the fourth compartment E4 in a fourth relative coupling position of the drum with respect to the actuating cylinder VR.

The selective coupling is obtained by rotation of the drum TB about the central axis to switch from a relative coupling position to another, amongst the first, second, third and fourth relative coupling position, typically by the action of the motor means M6 of the handling system.

The movable drive portion PE projects radially at a fixed angular position around the central axis AC, and in particular projects upwards, typically according to the direction Z, and as illustrated for indicative purposes in FIG. 6. One should notice that a nosing piece NZ, secured to a distal portion of the central support of the actuating cylinder VR, the nosing piece NZ is positioned at the fixed angular position, configured to extend the cradle of the compartment whose gripping system is selectively coupled to the movable drive portion PE.

This nosing piece NZ is configured to ensure an additional guidance and support, between the roll stand of the rolling mill, and the cradle aligned with the nosing piece when the gripping system coupled to the actuating cylinder moves the work roll by pushing or pulling it. This nosing piece may have a V-like section, and be provided typically with roller members OR.

Also, the compartments E1, E2, E3, E4 comprise said gripping systems SP1, SP2, SP3, SP4 configured to insert or extract the work rolls, by moving the work rolls 12 according to the axis of the work roll throughout open distal ends Ed of the longitudinal compartments E1, E2, E3, E4. The work rolls are pushed or extracted throughout these openings at the distal ends Ed of the compartments, during a roll insertion or extraction.

According to one embodiment, the compartments E1, E2, E3, E4 also have respectively according to the length of the compartments, the load/unload lateral openings OL, coupled to load/unload systems SCH associated with the compartments E1, E2, E3, E4. These lateral openings OL extend lengthwise according to the lengths of the compartments E1, E2, E3, E4.

The load systems SCG are independent, each load/unload system configured to ensure loading/or unloading of one of the compartments throughout the lateral openings OL.

Thus, said independent load systems SCG can be configured to load said compartments E1, E2, E3, E4 during the pre-loading step /B/ in particular with said new work roll according to the method according to the first possibility, or with the two new work rolls, each load/unload system configured to ensure loading/or unloading of one of the compartments throughout the lateral openings.

Thus, said independent load systems SCG can be configured to load said compartments E1, E2, E3, E4 during unloading of the worn work roll received in the first compartment E1, according to the first possibility or of the worn work rolls received respectively in the first compartment E1 and the third compartment according to the second possibility.

According to one embodiment, the independent load/unload systems SCH may comprise for each compartment, a pair of gripping arms comprising a first arm B1 and a second arm B2, configured to switch from a closure position for which the two arms B1, B2 hold a work roll in the cradle, and up to an opening position for which the two arms are spaced apart by a distance larger than a diameter of the work roll in order to enable loading of the cradle throughout the lateral opening OL. On the contrary, the reverse movements of the arms B1, B2, namely from the opening position up to the closure position can allow loading a work roll in the cradle. In particular, the two arms, the first arm B1 and the second arm B2, can be provided pivotable about two hinge axes AB1, AB2, on both sides of the cradle, parallel to a longitudinal direction of the cradle.

In the closure position of the two arms B1, B2, each work roll 12 is held, according to any direction perpendicular to the longitudinal direction of the compartment E1, E2, E3, E4, the work roll blocked between the cradle formed by the support frame, and the two arms brought close to one another. In this closure position, the gripping system can always push or on the contrary pull the work roll received in the compartment, according to the longitudinal direction of the compartment.

In order to limit frictions between the cylindrical wall of the work roll and the support frame or the arms during the insertion or extraction operations, roller members OR, such as castors may be provided over at least one wall of the cradle and/or over the arms. The work roll pushed or pulled by the gripping system, throughout the movement, is configured to roll over the roller members OR of the arms and/or of the cradle, and therefore without any risk of scratching of the face of the work roll.

When said handling system 1 comprises the motor-driven means M6 to ensure pivoting of the drum TB about the central axis AC, loading and/or unloading of one of the cradles is performed by rotation of the drum TB until positioning the cradle to be loaded/unloaded by orienting its lateral opening OL downwards, and by switching the pair of gripping arms from the opening position up into the closure position during loading, and by switching the pair of gripping arms from the closure position up into the closure position during unloading, thereby enabling unloading by gravity throughout the lateral opening OL.

The method according to the present disclosure and the grasping tool according to the present disclosure find application in a rolling plant comprising the rolling mill comprising said roll stand and said set of rolls, internal to the roll stand, including the two work rolls 12, the backup rolls or the backup rollers A, B, C, D, E, F, G, H, and possibly the intermediate rolls in particular first intermediate rolls 13 and second intermediate rolls 14, 15, the roll stand of the rolling mill having said access hatch, possibly closed by the door system as illustrated as example in FIG. 7. The metal strip Bm extends longitudinally according to the horizontal direction X, and transversely according to the horizontal direction Y, parallel to the axes of the rolls of the rolling mill.

Said plant may comprise a load/unload rack R, removably positioned on a support frame Cha anchored to the ground in an anchor position at a distance from the rolling mill according to the transverse direction Y so as to clear a maintenance aisle according to the longitudinal direction X. According to the present disclosure, the pre-loading in /B/ is implemented at a distance from the access hatch of the roll stand by loading the tool with one or more new roll(s) arranged on the load/unload rack. After replacement of the work rolls of the roll stand of the rolling mill, the worn work roll(s) can be unloaded on such a rack, supported by the support frame.

The present disclosure also relates to an assembly comprising a handling system 1 for a plant for rolling a metal strip, and a grasping tool OT according to the present disclosure, handled by the handling system, suited to ensure the operations of replacing work rolls of the rolling mill, to ensure an extraction of a worn work roll and an insertion of a new work roll in the roll stand of the rolling mill.

According to an embodiment of said assembly, said handling system may comprise a robot Ro comprising:

• • a carriage comprising a first frame 2 provided with wheels 20 cooperating with rails Ra1 disposed on the ground, extending according to a direction Y, in line with the access trap of the roll stand of the rolling mill, said first frame 2 being configured to move according to the direction Y along the rails Ra1, under the action of first motor means M1 driving in particular the wheels 20,
  • a second frame 3 and a first slide system G linking the second frame 3 and the first frame 2 configured to move the second frame 3 relative to the first frame 2 according to a direction X, under the action of second motor means M2,
  • a third frame 4 and a second slide system G2 linking the third frame 4 and the second frame 3, configured to move the third frame 4 relative to the second frame 3 according to a vertical direction Z, under the action of third motor means M3,
  • a grasping system 6 movable with the third frame 4 comprising an actuator configured to control locking and unlocking of grasping of a proximal end of the grasping tool OT.

The operations of centring by movement the grasping tool OT according to the direction X may be operated by a movement of the third frame 3 relative to the second frame 2, under the action of the second motor means M2 and the operations of centring the grasping tool OT according to the direction Z by a movement of the fourth frame 4 relative to the third frame 3 under the action of the third motor means M3.

In particular, it may consist of a robotic system according to WO2022/223927A1 which includes a fourth frame 5, and rotational guide means linking the fourth frame and the third frame about a vertical axis of rotation, configured to drive the rotation of the fourth frame 5 relative to the third frame 4, under the action of fourth motor means M4. Such a robotic system 1 is configured to ensure the extraction of a roll by grasping the roll by the grasping tool OT locked by the grasping system, with the deposition of the roll, laterally to the rails in particular on the rack Ra, after pivoting of the grasping tool OT by rotation of the fourth frame 5 relative to the third frame 4 about the vertical axis of rotation, typically by 90° and as schematised in FIG. 7.

the grasping system 6 may be hinged to the fourth frame according to a second horizontal hinge axis perpendicular to the vertical axis of rotation between the fourth frame 5 and the third frame 4, called first axis of rotation, and perpendicular to the axis of the grasping tool OT, the robotic system including motor means M5, in particular fifth motor means, configured to set the inclination of the grasping system 6, and thus the inclination of the grasping tool OT about said second axis of rotation.

The grasping system 6 may also be set in rotation about the axis of rotation, coaxial with the central axis AC of the grasping tool OT oriented substantially according to the transverse direction L, using motor means M6, in particular sixth motor means and in particular in order to ensure rotation of the drum TB about its central axis AC. List of the reference signs.

LIST OF THE REFERENCES

Rolling Mill:

• • 10: Rolling mill
  • Gi, Gs. Respectively upper group and lower group,
  • 12. Work rolls,
  • 12 u. Worn work rolls,
  • 12 n. New work rolls,
  • 13. First intermediate rolls,
  • 14,15. Second intermediate rolls,
  • A, B, C, D. respectively the four backup rolls or sets of backup rollers of the upper group,
  • E, F, G, H. respectively the four backup rolls or sets of backup rollers of the lower group,

Handling System:

• • 1. Handling system in particular robotic,
  • Ro. Robot,
  • Ra1. Rail according to the direction Y,
  • 2. First frame,
  • 20. Wheels,
  • M1. First motor means (movement of the carriage according to the direction Y),
  • 3. Second frame,
  • G1. First slide system according to the direction X (between the second and first frames),
  • M2. Second motor means (movement of the carriage according to the direction X),
  • 4. Third frame,
  • G2. Second slide system according to the direction Z,
  • M3. Third motor means (movement of the third frame along the second slide system according to the direction Z),
  • 5. Fourth frame,
  • Av. Vertical axis of rotation (between the fifth and fourth frames), called first axis of rotation,
  • M4. Fourth motor means (pivoting of the fourth frame relative to the third frame about the vertical axis of rotation),
  • Ah. Horizontal axis of rotation between the grasping system and the fourth frame,
  • M5. Fifth motor means (pivoting of the grasping system about the horizontal axis of rotation enabling setting of the inclination of the grasped roll by the grasping system,
  • 6. Grasping system,
  • 60. Tubular frame,
  • 7. Locking/unlocking device,
  • M6. Sixth motor means (pivoting of the grasped roll by the grasping system about its axis, or a parallel axis.

Grasping Tool

• • OT. Grasping tool,
  • TB. Drum,
  • VR. Actuating cylinder,
  • PE. Movable drive portion,
  • E1, E2, E3, E4. First compartment, second compartment, third compartment and fourth compartment,
  • SP. Gripping systems,
  • SP1, SP2, SP3, SP. First, second, third and fourth gripping system,
  • MR1, MR2. First jaw and second jaw (clamp),
  • Distal end (compartment),
  • OL. Lateral openings (compartment),
  • SCH. Load/unload system,
  • B1, B2. First arm and second arm (Pair of arms of the load/unload system),
  • PE. Movable drive portion (Actuating cylinder),
  • NZ. Nosing piece,
  • OR. Roller member,
  • Ed Distal ends (compartments),
  • Ep. Proximal end (grasping tool).

Claims

1. A method for replacing the work rolls of a rolling mill, in the presence of a metal strip rolled between the two work rolls, the rolling mill having a roll stand receiving at least one upper work roll and one lower work roll, each of said work rolls has a generatrix of contact with the metal strip, said contact generatrices and the axes of the work rolls lie in a plane substantially perpendicular to a running direction of the metal strip, roller members such as first intermediate rolls, being in contact according to two contact generatrices with each of the work rolls, the roller members ensuring the transmission of a rolling force to the lower and upper work rolls in contact with the metal strip during the rolling operations, in which method the replacement of a work roll of the roll stand of a rolling mill is ensured characterised by:/A/ providing a handling system, such as a robotic system, and providing a grasping tool handled by the handling system, at least by a movement according to a longitudinal direction oriented according to a longitudinal running direction X of the strip between the two work rolls and/or according to a vertical direction Z and/or according to a rotation about the axis of the direction Y, and possibly with a movement according to a transverse direction Y said grasping tool comprising at least one pair of compartments for work rolls, the compartments extending longitudinally, parallel to one another, said at least one pair of compartments comprising a first compartment for a worn work roll provided with a first gripping system and a second compartment for a new work roll provided with a second gripping system, said at least one pair configured for simultaneously holding the worn work roll and the new work roll in parallel,

2. The method according to claim 1, wherein the grasping tool comprising said first compartment for a first worn work roll provided with the first gripping system and said second compartment for a second new work roll provided with a second gripping system, the first and second compartments forming a first pair of compartments, but also a third compartment for a second worn work roll provided with a third gripping system and a fourth compartment for a second new work roll provided with a fourth gripping system, the third compartment and the fourth compartment forming a second pair of compartments, and wherein it is proceeded with the replacement of the upper worn work roll and the lower worn roll in the roll stand of the rolling mill through the following steps: said step /A/ of providing a handling system, such as a robotic system, and a grasping tool handled by the handling system, at least according to a longitudinal direction oriented according to a longitudinal running direction X of the strip between the two work rolls and/or at least according to a vertical direction Z, and/or at least a rotation according to the axis Y, and possibly a movement according to a transverse direction Y,said step /B/ of pre-loading the second compartment with a first new work roll, and also pre-loading the fourth compartment for a second new work roll, the first compartment for a first worn roll and the third compartment for a second worn roll being left free, pre-loading being carried out during the operations of rolling the strip between the upper work roll and the lower work roll,said step /C/ of stopping the rolling operations and opening by spacing apart the upper work roll and the work roll,said step /D/ of centering the free first compartment, by a movement of the grasping tool caused by the handling system according to the longitudinal direction X and/or according to the vertical direction Y, in order to align the first compartment with a first worn work roll in the roll stand of the rolling mill, which is the upper work roll or the lower work roll,said step /E/ of grasping the first worn work roll by the first gripping system of the grasping tool, and extracting the worn work roll according to an axis of the work roll, parallel to the transverse direction Y until obtaining loading of the worn work roll in the first compartment, the worn work roll leaving a first empty clearance in the roll stand,/F/ centering the third compartment, free of the grasping tool by a movement of the grasping tool caused by the handling system according to the longitudinal direction X and/or according to the vertical direction Z and/or rotation according to the axis Y, in order to align the third compartment with a second worn work roll, a lower work roll or an upper work roll in the roll stand of the rolling mill,/G/ grasping the second worn roll by said third gripping system of the grasping tool, and extracting the worn work roll according to an axis of the work roll, parallel to the transverse direction Y until obtaining loading of the second worn work roll in the third compartment, the worn work roll leaving a second empty clearance in the roll stand,the step /H/ of centering the second compartment of the grasping tool pre-loaded with the first new work roll by a movement of the grasping tool by the handling system 1 according to the longitudinal direction X and/or according to the vertical direction Z, and/or rotation according to the transverse direction Y, in order to align the first work roll with the empty clearance of the roll stand of the grasping tool, the first empty clearance or the second empty clearance, and while the first compartment and the third compartment are loaded with the first worn work roll and the second worn work roll,the step /I/ of inserting the first new work roll contained in the second compartment into the empty clearance, by pushing the second gripping system,/J/ centering the fourth compartment pre-loaded with the second new roll by a movement of the grasping tool by the handling system 1 according to the longitudinal direction X and/or according to the vertical direction Z, and/or rotation according to the transverse direction Y, in order to align the second new roll with the other free clearance by a movement of the grasping tool caused by the handling system, and while the first compartment and the third compartment are loaded with the removed first worn work roll, and the second worn work roll, and/K/ inserting the second new work roll contained in the fourth compartment into the other empty clearance by pushing the fourth gripping system.

3. The method according to claim 1, wherein the different compartments are provided with independent gripping systems configured to secure one end of a work roll, each gripping system configured to ensure a push during an insertion of a work roll or configured to ensure a pull during an extraction of a roll, by moving the gripping system along the compartment.

4. The method according to claim 3, wherein the gripping systems consist of mechanised clamps or magnetic chucks or pneumatic chucks and wherein the mechanised clamps or the magnetic chucks or the pneumatic chucks are configured to grasp one end of a work roll.

5. The method according to claim 3, wherein the grasping tool comprises a push/pull system comprising one or more actuating cylinder(s) configured to extract or insert the worn/new rolls from/into the compartments by selective movement of each of the gripping systems associated with the compartments, by causing a movement of the work roll according to a longitudinal axis of the work roll, and in particular a pull of the worn roll in the first compartment and possibly pulls of the worn rolls in the first compartment and the third compartment and to insert into the roll stand of the rolling mill the new roll contained in the second compartment.

6. The method according to claim 5, wherein the push/pull system comprises: a unique actuating cylinder to proceed with the selective movement of the gripping systems of the different compartments and in particular with the selective movement of the first gripping system and of the second gripping system of said at least one pair of compartments consisting of the first compartment and the second compartment,a mechanism for ensuring coupling of a movable drive portion of the actuating cylinder selectively with the gripping systems of the different compartments, and in particular selectively with the first gripping system or the second gripping system.

7. The method according to claim 1, wherein the compartments comprise said gripping systems configured to insert or extract the work rolls, by moving the work rolls according to the axis of the work roll throughout open distal ends of the longitudinal compartments, the compartments respectively have according to the length of the compartments, lateral load/unload openings, coupled to load/unload systems associated with the compartments, said load systems, independent, configured to load said compartments during the pre-loading step /B/, each load/unload system configured to ensure loading/or unloading of one of the compartments throughout the lateral openings.

8. The method according to claim 7, wherein said compartments for the worn roll(s) and the new roll(s) are arranged in parallel around a central axis of the grasping tool, said grasping tool comprising a drum forming a support frame including longitudinal cradles, angularly distributed around the central axis configured to receive the worn and new rolls, defining said compartments respectively.

9. The method according to claim 8, wherein said handling system comprises motor-driven means to ensure pivoting of the drum about the central axis and wherein the independent load/unload systems comprise for each compartment, a pair of gripping arms comprising a first arm and a second arm hinged respectively on two longitudinal edges of the cradle, configured to switch from a closure position for which the two arms hold a work roll in the cradle, and up to an opening position for which the two arms are spaced apart by a distance larger than a diameter of the work roll enabling loading/or unloading of the cradle throughout the lateral opening and wherein loading and/or unloading of one of the cradles is performed by rotation of the drum until positioning the cradle to be loaded/unloaded by orienting the lateral opening downwards, and by switching the pair of gripping arms from the opening position up to the closure position during loading, and by switching the pair of gripping arms from the closure position up to the closure position during unloading, enabling unloading by gravity throughout the lateral opening.

10. The method according to claim 8, wherein: the push/pull system comprises: a unique actuating cylinder to proceed with the selective movement of the gripping systems of the different compartments and in particular with the selective movement of the first gripping system and of the second gripping system of said at least one pair of compartments consisting of the first compartment and the second compartment,a mechanism for ensuring coupling of a movable drive portion of the actuating cylinder selectively with the gripping systems of the different compartments, and in particular selectively with the first gripping system or the second gripping system, andsaid unique actuating cylinder is arranged within a tubular room of the drum centered on the central axis and wherein said drum is configured to pivot about the actuating cylinder, mounted so as not to pivot relative to the handling system the movable drive portion, projecting radially, said mechanism for ensuring coupling of the movable drive portion of the actuating cylinder selectively with the gripping systems, comprising the drum pivotally mounted about the actuating cylinder under the action of motor-driven means so that coupling is obtained by pivoting of the drum (so as to set the movable drive portion of the actuating cylinder in correspondence selectively with the first gripping system, the second gripping system.

11. The method according to claim 1, implemented in a rolling plant comprising the rolling mill comprising said roll stand and said set of rolls, internal to the roll stand, including the two work rolls, the backup rolls or the backup rollers, and possibly the intermediate rolls in particular first intermediate rolls and second intermediate rolls, the roll stand of a rolling mill having said access hatch, possibly closed by the door system, the metal strip Bm extending longitudinally according to the horizontal direction X, and transversely according to the horizontal direction Y, parallel to the axes of the rolls of the rolling mill and wherein said plant comprises a load/unload rack, removably positioned on a support frame anchored to the ground in an anchor position at a distance from the rolling mill according to the transverse direction Y so as to clear a maintenance aisle according to the longitudinal direction X, and wherein the pre-loading in /B/ is implemented at a distance from an access hatch of the roll stand by loading the grasping tool with one or more new roll(s) arranged on the load/unload rack.

12. A grasping tool suitable for the implementation of the method according to claim 1, intended to be handled by a handling system, the grasping tool comprising: a support frame comprising at least one pair of two cradles forming at least one pair of compartments for the storage of two work rolls forming at least one first compartment intended for a new work roll and a second compartment intended for a worn work roll, said two work rolls extending longitudinally, in parallel in said at least two cradles,independent gripping systems including a first gripping system configured to secure one end of a work roll in the first compartment and a second gripping system configured to secure one end of a work roll in the second compartment, a push/pull system comprising one or more actuating cylinder(s) configured to extract or insert the worn/new rolls from/into the compartments by selective movement of each of the gripping systems associated with the compartments, by causing a movement of the work roll according to an axis of the roll, andwherein said grasping tool is configured to enable a replacement of a worn work roll with a new work roll by:removal of a worn work roll off the roll stand of a rolling mill by grasping the first gripping system and pulling the roll by actuation of the actuating cylinder until obtaining loading of the worn work roll in the first compartment, theninsertion of a new work roll into the roll stand of a rolling mill contained in the second compartment by pushing the second gripping system and while the first compartment contains the worn work roll.

13. The grasping tool according to claim 12, wherein the support frame comprises two pairs of cradles forming two pairs of compartments for the storage of two work rolls comprising besides the first compartment intended for a first worn work roll and the second compartment, intended for a first new work roll, a third compartment intended for a second worn work roll, and a fourth compartment intended for a second new work roll, said gripping systems, further comprising the first gripping system and the second gripping system, a third gripping system configured to secure one end of a work roll in the third compartment and a fourth gripping system configured to secure one end of a work roll in the fourth compartment, and wherein said grasping tool is configured to enable a replacement of a first worn work roll with a first new work roll and a replacement of a second worn work roll with a second new work roll by: removal of the first worn work roll off the roll stand of a rolling mill by grasping the first gripping system and pulling the work roll by actuation of the actuating cylinder until obtaining loading of the worn work roll in the first compartment,removal of the second worn work roll off the roll stand of a rolling mill by grasping the third gripping system and pulling the work roll by actuation of the actuating cylinder until obtaining loading of the worn work roll in the third compartment,insertion of the first new work roll into the roll stand of a rolling mill contained in the second compartment by pushing the second gripping system and insertion of the second new work roll contained in the fourth compartment, and while the first compartment contains the first worn work roll and the third compartment contains the second worn work roll.

14. The grasping tool according to claim 12, wherein said push/pull system comprises: a unique actuating cylinder, to proceed with the selective movement of the gripping systems of the different compartments, and in particular with the selective movement of the first gripping system and of the second gripping system of said at least one pair of compartments consisting of the first compartment and the second compartment,a mechanism for ensuring coupling of a movable drive portion of the actuating cylinder selectively with the gripping systems of the different compartments, and in particular selectively with the first gripping system or the second gripping system.

15. The grasping tool according to claim 12, wherein the compartments comprise said gripping systems configured to insert or extract the work rolls, by moving the work rolls according to the axis of the work roll throughout open distal ends of the longitudinal compartments, the compartments respectively having according to the length of the compartments, lateral load/unload openings, coupled to load/unload systems associated with the compartments, said load systems, independent, each load/unload system configured to ensure loading/or unloading of one of the compartments throughout the lateral openings.

16. The grasping tool according to claim 12, wherein said compartments for the worn roll(s) and the new roll(s) are arranged in parallel around a central axis of the grasping tool, said grasping tool comprising a drum forming a support frame including longitudinal cradles, angularly distributed around the central axis configured to receive the worn and new rolls, respectively defining said compartments (and wherein the drum is configured to pivot about the central axis.

17. The grasping tool according to claim 15, wherein the independent load/unload systems comprise for each compartment, a pair of gripping arms comprising a first arm and a second arm, configured to switch from a closure position for which the two arms hold a work roll in the cradle, and up to an opening position for which the two arms are spaced apart by a distance larger than a diameter of the work roll enabling loading/or unloading of the cradle throughout the lateral opening.

18. The grasping tool according to claim 16, wherein: said push/pull system comprises: a unique actuating cylinder, to proceed with the selective movement of the gripping systems of the different compartments, and in particular with the selective movement of the first gripping system and of the second gripping system of said at least one pair of compartments consisting of the first compartment and the second compartment,a mechanism for ensuring coupling of a movable drive portion of the actuating cylinder selectively with the gripping systems of the different compartments, and in particular selectively with the first gripping system or the second gripping system,said unique actuating cylinder is arranged within a tubular room of the drum centered on the central axis and wherein said drum is configured to pivot about the actuating cylinder, mounted so as not to pivot relative to the handling system the movable drive portion, projecting radially in a fixed angular position, said mechanism for ensuring coupling of the movable drive portion of the actuating cylinder selectively with the gripping systems, comprising the drum pivotally mounted about the actuating cylinder under the action of motor-driven means of the handling system, so that coupling is obtained by pivoting of the drum so as to set the movable drive portion of the actuating cylinder in correspondence selectively with the first gripping system, the second gripping system.

19. An assembly comprising a handling system for a plant for rolling a metal strip, and a grasping tool according to claim 12, handled by the handling system, suited to ensure the operations of replacing work rolls of the rolling mill, to ensure an extraction of a worn work roll and an insertion of a new work roll in the roll stand of the rolling mill.

20. The assembly according to claim 19, wherein said handling system comprises a robot comprising: a carriage comprising a first frame provided with wheels cooperating with rails disposed on the ground, extending according to a direction Y, in line with the access trap of the roll stand of the rolling mill, said first frame being configured to move according to the direction Y along the rails, under the action of first motor means driving in particular the wheels,a second frame and a first slide system linking the second frame and the first frame configured to move the second frame relative to the first frame according to a direction X, under the action of second motor means,a third frame and a second slide system linking the third frame and the second frame, configured to move the third frame relative to the second frame according to a vertical direction Z, under the action of third motor means,