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.

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,   
       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/ centering 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/ centering 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, and 
 /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. 
 
     
     
         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, and 
   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, 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, 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.   
     
     
         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,   
       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.