Tool and method for changing a work roll in a rolling mill

Abstract

A grasping tool including a support shaft, as well as a first finger and a second finger, secured to the support shaft, movable relative to one another from a first spacing position between the first finger and the second finger, larger than the length between the distance between a first sidewall and a second sidewall of a work roll, and up to a second position for which the first finger and the second finger are brought close to one another until penetrating respectively a first centering cavity of the first sidewall and a second centering cavity of the second sidewall to ensure grasping of the work roll.

1 . A method for changing the two work rolls of a rolling mill, in particular in the presence of a metal strip intended to be rolled between the two work rolls, including an upper work roll and a lower work roll, each of said work rolls has a cylindrical surface and sidewalls, including a first sidewall and a second sidewall having, at the two longitudinal ends of the work roll, respectively centering cavities centered on an axis of the work roll, including a first centering cavity on the first sidewall and a second centering cavity on the second sidewall and wherein in a closure position of a stand of the rolling mill configured for rolling the metal strip, each of said work rolls has a contact generatrix with the metal strip, said contact generatrixes and the axes of the work rolls lie in a plane substantially perpendicular to a running direction of the metal strip, rolling members such as first intermediate rolls, being in contact along two contact generatrixes with each of the work rolls, the rolling members ensuring transmission of a rolling load to the lower and upper work rolls in contact with the metal strip, in which method the extraction of a work roll from the rolling mill stand is ensured after opening, at least partially, the stand of the rolling mill wherein the work rolls are brought away from one another with respect to the positions of the work rolls in the closure position of the stand of the rolling mill, thereby clearing a room, by implementation of the following steps:
 /a1/ providing a grasping tool comprising a support shaft as well as a first finger and a second finger, secured to the support shaft, the first finger arranged at a distal end of the support shaft, the second finger at a grasping proximal end of the support shaft, the first finger and/or the second finger being movable between a first spacing position between the first finger and the second finger wherein the spacing is larger than the distance between the first sidewall and the second sidewall of the work roll, and up to a second position wherein the first finger and the second finger are brought close to one another in order to grasp the work roll,   /b1/ inserting the grasping tool, preferably in a robotic manner, into the room, parallel to the axis of the work roll to be grasped, the first finger and the second finger being in a first spacing position between the first finger and the second finger wherein the spacing is larger than the distance between the first sidewall and the second sidewall of the work roll until positioning the first finger and the second finger, along the direction of the work roll, on either side of the work roll, at least the shifted first finger of the work roll along a radial direction of the work roll,   /c1/ centering the grasping tool until positioning the first finger and the second finger, coaxial with the axis of the work roll,   /d1/grasping the work roll by the first sidewall and the second sidewall, by bringing the first finger and the second finger close to one another up to the second spacing position of the fingers, with fitting of the first finger in the first centering cavity and fitting of the second finger in the second centering cavity,   /e1/ extracting the work roll grasped by removal of the grasping axially, along the direction of the work roll, in particular outside the room and the stand of the rolling mill, and possibly   /f1/ depositing the work roll outside the stand of the rolling mill by moving the first finger and the second finger from the second position up to the first position.   
     
     
         2 . A method for changing the two work rolls of a rolling mill in the presence of a metal strip intended to be rolled between the two work rolls, including an upper work roll and a lower work roll, each having a cylindrical surface and sidewalls, including a first sidewall and a second sidewall respectively having, at both longitudinal ends of the roll, centering cavities centered on an axis of the work roll, including a first centering cavity on the first sidewall and a second centering cavity on the second sidewall, and wherein in a closure position of the rolling mill configured for rolling the metal strip, each of said work rolls has a contact generatrix with the metal strip, and wherein said contact generatrixes and the axes of the work rolls lie in a plane substantially perpendicular to a running direction of the metal strip, rolling members such as first intermediate rolls, being in contact along two contact generatrixes with each of the work rolls, the rolling members ensuring the transmission of a rolling force to the lower and upper work rolls in contact with the metal strip, in which method the insertion of the new or ground work rolls into the rolling mill stand in the presence of the metal strip and the rolling members is ensured after opening at least partially the stand of the rolling mill thereby clearing a room, by implementation of the following steps, for said upper and/or lower work roll:
 /a2/ providing a grasping tool comprising a support shaft, as well as a first finger and a second finger, secured to the support shaft, the first finger arranged at a distal end of the support shaft, the second finger at a grasping proximal end of the shaft, the second finger and/or the first finger being movable between a first spacing position between the first finger and the second finger, larger than the distance between the first sidewall and the second sidewall of the work roll, and up to a second position wherein the first finger and the second finger are brought close to one another in order to grasp the work roll,   /b2/ grasping a work roll out of the stand in the second position wherein the first finger and the second finger respectively fit with the first centering cavity and the second centering cavity of the work roll,   /c2/ inserting the work roll grasped by moving the grasping tool in the room,   /d2/ depositing the work roll in the stand of the rolling mill by moving the fingers from the second spacing position up to the first position,   /e2/ shifting the first finger until it is shifted from the work roll along a radial direction of the work roll, and   /f2/ removing the grasping tool out of the stand.   
     
     
         3 . The method according to  claim 1 , wherein the centering step /c1/ is obtained by joint rotation of the support and of the first finger and of the second finger secured to the support shaft, in particular according to a pivot axis coaxial with the support shaft. 
     
     
         4 . The method according to  claim 1 , wherein the second finger, at the proximal end of the support shaft, possibly movable axially relative to the support shaft, is secured to the support shaft, at a fixed angular position on the support shaft and wherein the first finger is movable relative to the support shaft between a stowed position for which the first finger and the second finger are offset, up to a centering position for which the first finger and the second finger are aligned, and
 wherein the centering step /c1/ is completed by moving the first finger from the stowed position up to the centering position, without pivoting the support shaft.   
     
     
         5 . The method according to  claim 4 , wherein the grasping tool comprises the first finger and the second finger forming a first pair of fingers, ensuring grasping according to step /d1/ of the work roll in the rolling mill stand and extraction according to step /e1/, and wherein the grasping tool comprises a second pair of fingers comprising a third finger and a fourth finger, the third finger and the fourth finger being movable between a third spacing position between the third finger and the fourth finger, larger than the distance between the first sidewall and the second sidewall of the work roll, and up to a fourth position for which the third finger and the fourth finger are brought close to one another, the fourth finger, arranged at the proximal end of the support shaft, possibly movable axially to the support shaft is secured to the support shaft, at a fixed angular position on the support shaft and wherein the third finger is movable relative to the support shaft between a stowed position for which the third finger and the fourth finger are offset, up to a centering position for which the third finger and the fourth finger are aligned configured to penetrate the centering cavities of a new work roll and hold a new work roll, and
 wherein the first pair of fingers and the second pair of fingers are arranged on the support shaft, configured so that the first pair of fingers ensures grasping according to step /d1/ of the work roll and extraction according to step /e1/ of the work roll that is a worn work roll, and while the second pair of fingers holds a new work roll, parallel to the worn roll held by the first pair of fingers.   
     
     
         6 . The method according to  claim 5 , wherein the worn work roll, held between the first finger and the second finger, is extracted by moving the grasping tool along the direction of the work roll according to step /e1/ up to a position outside the stand, at least partially, enabling a pivoting of the grasping about its axis,
 and wherein the grasping tool is pivoted, together with the worn work roll, held by the first pair of fingers, and the new work roll, held by the second pair of fingers, up to an angular position enabling the insertion of the new work roll,   and wherein the insertion of the new work roll into the rolling mill stand is ensured, without having deposited the extracted worn roll, held by the first pair of fingers, through the following steps:   inserting the new work roll, held by the second pair of fingers, by moving the grasping tool into the room of the stand,   depositing the new work roll in the stand of the rolling mill by moving the fingers from the fourth position up to the first third,   shifting the third fingers by moving the third finger relative to the support shaft from the centering position up to the stowed position, and   pulling the grasping tool out of the stand.   
     
     
         7 . The method according to  claim 1 , wherein the method is configured for the extraction of the work roll from the stand of the rolling mill, or the method according to  claim 2  configured for the insertion of the work roll in the stand of the rolling mill, wherein steps /a1/ to /e1/ are implemented without any contact between the grasping tool and the cylindrical surface of the work roll intended to be in contact with the strip to be rolled. 
     
     
         8 . The method according  claim 1 , wherein the stand of the rolling mill comprises a lower stand portion, transmitting a clamping force to the lower rolls, including to the lower work roll; and possibly to said sets of lower rollers, and an upper stand portion, movable vertically relative to the lower stand portion transmitting a clamping force to the upper rolls, including to the lower work roll, and possibly to said sets of upper roller, and wherein the stand receives:
 at the upper portion, within the upper stand portion, the upper work roll, as well as two upper first intermediate rolls, three upper second intermediate rolls, and four upper sets of backup rollers,   at the lower portion, within the lower stand portion of the rolling mill, the lower work roll, as well as two lower first intermediate rolls, three lower second intermediate rolls, and four lower sets of backup rollers,   and wherein the at least partial opening of the stand is completed by bringing the upper stand portion away from the lower stand portion.   
     
     
         9 . A grasping tool suited in particular for the implementation of the method according to  claim 1 , comprising: a support shaft, as well as a first finger and a second finger, secured to the support shaft, movable relative to one another from a first spacing position between the first finger and the second finger, larger than the distance between a first sidewall and a second sidewall of a work roll, and up to a second position for which the first finger and the second finger are brought close to one another until penetrating respectively a first centering cavity of the first sidewall and a second centering cavity of the second sidewall to ensure grasping of the work roll and wherein said support shaft is provided with an endpiece configured for gripping the grasping tool. 
     
     
         10 . The grasping tool according to  claim 9 , wherein the support shaft is extended by the endpiece at a proximal end of the support shaft, the first finger arranged at the distal end of the shaft, secured to the distal end by a bracket, the second finger being arranged, along the direction of the support shaft between the first finger and the endpiece, and wherein the first finger is fixed with respect to the support shaft, the second finger being movable under the action of an actuator, to switch from the first spacing position into the second spacing position between the first finger and the second finger. 
     
     
         11 . The grasping tool according to  claim 9 , wherein the support shaft is extended by the endpiece at a proximal end of the support shaft, the first finger arranged at the distal end of the shaft, secured to the distal end of the support shaft by a pivoting arm on the support shaft, the second finger being arranged, along the direction of the support shaft between the first finger and the endpiece, the second finger arranged at the proximal end of the support shaft, possibly movable axially to the support shaft, the second finger being secured to the support shaft, at a fixed angular position on the support shaft and wherein the first finger is movable relative to the support shaft by rotation of the pivoting arm between a stowed position for which the first finger and the second finger are offset, and while the first finger and the second finger are in the first position. 
     
     
         12 . The grasping tool according to  claim 11 , the grasping tool comprises the first finger and the second finger forming a first pair of fingers, suited to ensure the extraction of a first work roll and wherein the grasping tool comprises a second pair of fingers comprising a third finger and a fourth finger, the third finger and/or the fourth finger being movable between a third spacing position between the third finger and the fourth finger, larger than the distance between the first sidewall and the second sidewall of the work roll, and up to a fourth position wherein the third finger and the third finger are brought close to one another to grasp a work roll, the fourth finger, arranged at the proximal end of the support shaft, possibly movable axially to the support shaft, is secured to the support shaft, at a fixed angular position on the support shaft and wherein the third finger is movable relative to the support shaft between a stowed position wherein the third finger and the fourth finger are offset, up to a centering position wherein the third finger and the fourth finger are aligned, configured to penetrate the centering cavities of a new work roll and hold a new work roll after having brought the third finger and the fourth finger close to one another in the third position, and
 wherein the first pair of fingers and the second pair of fingers are arranged on the support shaft, configured so that the first pair of fingers ensures grasping of a first work roll which is a worn work roll, and then the second pair of fingers holds a second work roll, which is typically a new roll, parallel to the first work roll held by the first pair of fingers.   
     
     
         13 . A set comprising a robotic system for a plant for rolling a metal strip, and a grasping tool according to  claim 9 , handled by the robotic system, suited to ensure the operations of changing work rolls of the rolling mill, by extraction of the worn work rolls from the stand of the rolling mill. 
     
     
         14 . The set according to  claim 13 , wherein said robotic system comprising a robot comprising:
 a carriage comprising a first frame provided with wheels cooperating with rails arranged on the ground, extending along the Y direction, opposite an access opening of the stand of the rolling mill, said first frame being configured to move along the Y direction along the rails, under the action of first motor means driving in particular the wheels,   a second frame and a first slide system connecting the second frame and the first frame configured to move the second frame relative to the first frame along an X direction, under the action of second motor means,   a third frame and a second slide system connecting the third frame and the second frame, configured to move the third frame relative to the second frame along 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 the endpiece of the grasping tool.   
     
     
         15 . The set according to  claim 14 , wherein the grasping system comprises a tubular frame inside which a locking/unlocking device is provided, pivotably mounted via rolling bearings, about an axis of rotation, intended to be parallel, and possibly coincident with the axis of the support shaft of the grasping tool, via motor means, in particular six motor means, and wherein the locking/unlocking device comprises the actuator, including motor means configured to switch the locking device from a locking state of the endpiece into an unlocking state of the endpiece.