Tool and method for changing the working roll in a rolling mill

A method for changing work roll in a rolling mill which limits the risk of scratching the work roll, or even the risk of scratching the metal strip, upon extracting or inserting the work roll, by virtue of a mechanical separation element, in particular of the branches of a fork system, inserted by a robotic element.

FIELD

The invention is related to a method for changing work rolls of a rolling mill in the presence of a metal strip to be rolled between both work rolls, including an upper work roll and a lower work roll suitable for extracting the work rolls from the roll stand.

The invention further relates to a method for changing the work rolls of a rolling mill in the presence of a metal strip to be rolled between both work rolls, including an upper work roll and a lower work roll, suitable for inserting and placing the lower or upper, in particular new or ground, work rolls.

The present disclosure further relates to a work roll changing tool configured for carrying out the method suitable for extracting work rolls and/or for inserting and placing upper and/or lower, in particular new or ground, work rolls into the roll stand.

BACKGROUND

The present invention thus finds advantageous application for multi-roll mills, such mills typically being “Sendzimir” mills.

Cold rolling makes it possible to obtain the final thickness of a metal strip by successive passages of this strip between rolls in the presence of high forces simultaneously in pressure and pulling.

A “Sendzimir” type rolling mill includes a plurality of rolls, or rollers, which are arranged in relation to each other to allow change of the mechanical characteristics of a metal strip and to obtain a strip thickness which may be less than3millimetres.

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

FIG.12represents a schematic view of a transverse cross-section of a twenty-roll mill. In this figure, the rolls are divided into a lower group LG and an upper group UG; more precisely, these groups LG and UG have a symmetrical structure and each include ten rolls, of which: a work roll12, two first intermediate rolls13, three second intermediate rolls14and15, and four back-up rolls, or back-up rollers, which are outside the arrangement and which are noted A, B, C and D for the upper group UG and E, F, G, H for the lower group LG.

This nomenclature for the various rolls making up a twenty roll mill is customary in the field of rolling mills, and is well known to the person skilled in the art.

It is recognised in the field of rolling mills that this arrangement of rolls illustrated inFIG.12allows for efficient work of a metal strip MS to obtain the desired strip thickness.

Due to the stresses exerted on the work rolls12and upon working a metal strip MS, these parts12require very regular maintenance: it is therefore desirable to be able to remove and replace the work rolls12quickly, and safely for the operators.

In a 20-roll (“20 Hi”) rolling mill, it is still noticed that the opening of the stand is small, in particular when the roll stand is a single piece, because obtained in this case only by the backup rollers eccentrically outwardly pivoting (A, B, C, D for the upper group UG and E, F, G, H for the lower group LG). According to the inventor's findings, there is a significant risk of collisions and friction between the work roll, during its extraction (or insertion) and the components of the surrounding rolling mill such as the first two intermediate rolls13, or even the metal strip MS present in the stand.

There is a need to be able to change work rolls, without marking the metal strip, without worsening the surface condition of the work roll, or even the first intermediate rolls, either during the removal step, or upon placing a new or ground work roll in the roll stand.

The present disclosure thus finds particular application for changing the work rolls of a cold rolling mill, typically used to perform bright annealing. In such a mill, the work rolls have a so-called mirror polish surface condition at a very low roughness.

PRIOR ART

Based on the knowledge of the applicant, from prior art, robotic systems are known, such as a multi-axis arm equipped with a gripper configured to ensure removal of the rolls from a rolling mill. These robotic systems allow for the removal of rolls from the rolling mill with minimal risk of injury to operators, and in comparison with hoist changeover methods, which require the physical presence of an operator in the proximity of the work roll being handled, to conduct extraction of the roll and its replacement with a new or ground roll.

However, and based on the inventor's findings, none of the known robotic systems can guarantee safe extraction (or insertion) of the work rolls, in a 20 Hi rolling mill, avoiding the risks of marking between the work roll, on the one hand, and the metal strip, or even the first intermediate rolls, on the other hand.

SUMMARY

The present disclosure improves the situation.

According to a first aspect, there is provided a method for changing work rolls of a rolling mill in the presence of a metal strip to be rolled between both work rolls, including an upper work roll and a lower work roll, and wherein in a closing position of the roll stand configured to roll the metal strip, said work rolls each have a contact generatrix with the metal strip, the contact generatrices and the axes of the work rolls lying 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 generatrices between each of the work rolls and the rolling members, the rolling members ensuring transmission of a rolling force to the lower and upper work rolls in contact with the metal strip, method in which extraction of the work rolls from the roll stand is ensured after at least partially opening the roll stand for which the work rolls are spaced apart from each other with respect to the positions of the work rolls in the closing position of the roll stand by carrying out the following steps, for said upper and/or lower work roll:an insertion step a) comprising:robotically inserting mechanical separation means between said work roll and the metal strip to a separation position in which the metal strip and said work roll are physically separated along the length of the work roll, and until ensuring suppression of the contact between the work roll and the metal strip and/orrobotically inserting mechanical separation means between the work roll and the rolling members to a separation position in which said work roll and the rolling members are physically separated along the length of the work roll, until ensuring removal of the contact between the work roll and the rolling members,a removal step b) comprising:robotically extracting said work roll, by gripping one end of said work roll and moving said work roll along its axis with respect to the metal strip and the rolling members present in the roll stand, wherein said mechanical separation means are:in said separation position in which the work roll and the metal strip are physically separated so as to avoid any friction between the work roll and the metal strip upon moving, or/andin said separation position in which the work roll and the rolling members are physically separated and so as to avoid any friction between the work roll and the rolling members upon moving.

According to a second aspect, there is provided a method for changing the work rolls of a rolling mill in the presence of a metal strip to be rolled between both work rolls, including an upper work roll and a lower work roll, and wherein in a closing position of the roll stand configured to roll the metal strip, said work rolls each have a contact generatrix with the metal strip, the contact generatrices and the axes of the work rolls lying 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 generatrices between each of the work rolls and the rolling members, the rolling members ensuring transmission of a rolling force to the lower and upper work rolls in contact with the metal strip (MS), method in which insertion of the new or ground work rolls into the roll stand is ensured in the presence of the metal strip and the rolling members after at least partially opening the roll stand by carrying out the following steps, for said upper work roll and/or the lower work rollan insertion step c) comprising:robotically inserting mechanical separation means between the metal strip and the work roll to be inserted ensuring suppression of the contact between the work roll and the metal strip and/orrobotically inserting mechanical separation means between the rolling members and said work roll to be inserted ensuring suppression of the contact between the work roll and the rolling membersan insertion step d), concurrent or subsequent to the insertion step c) comprising inserting said work roll robotically, by pushing one end of said work roll and moving said work roll along its axis with respect to the metal strip and the rolling members present in the roll stand, wherein said mechanical separation means are:in a separation position in which the work roll and the metal strip are physically separated so as to avoid any friction between the work roll and the metal strip upon moving, or/andin a separation position in which the work roll and the rolling members are physically separated so as to avoid any friction between the work roll and the rolling members upon moving.

According to a third aspect, the present disclosure relates to a tool suitable for changing work rolls of a rolling mill configured to be handled by motor means comprising:a fork system comprising two branches configured to be inserted into the stand of a rolling mill in a position of the branches spaced apart on either side of an upper work roll of the rolling mill, said branches being movable relative to a fork support, said branches being configured to move from their spaced apart position to a close position in which the branches ensure lifting of the upper work roll guaranteeing physical separation between the work roll and the metal strip upon extracting a work roll, and/or the fork system comprising both branches configured to be inserted in the stand of a rolling mill in their close position, said branches being movable with respect to a fork support, configured to move from their close position to their spaced apart position to cause the upper, work roll to be deposited onto the metal stripa gripping device, comprising a gripper connected by an actuator to the fork support, configured to grip one end of the work roll and to pull the work roll along the branches of the fork system, in particular upon extracting the work roll, or even configured to push the work roll along the branches of the fork system upon inserting a new or ground work roll.

According to one embodiment, a movable backup element connected by a second actuator to the fork support is configured to ensure locking of the end of the work roll gripped and pulled by the gripping device, clamped between the movable backup element and a counter-backup element in the vicinity of the fork support, when the branches are in a close position.

According to one embodiment, the tool may comprise two wings, with an insert function, respectively integral with both branches of the fork system and ensuring:when both branches are moved closer to each other, and concurrently to the insert wings, from their spaced apart position to their close position, the mechanical separation between the work roll and the rolling members, in which said work roll and the rolling members are physically separated along the length of the work roll, by said insert wings guaranteeing suppression of the contact between the work roll and the rolling members, in particular suppression of both contact generatrices of the lower work roll with the rolling members, and/orreleasing the lower work roll on the insert wings between the work roll and the rolling members, in the close position of the branches in the roll stand, and then depositing the lower work roll onto the rolling members when the branches and the insert wings have moved from their close position to their spaced apart position.

DESCRIPTION

The following drawings and description contain, for the most part, elements of certainty. Therefore, they may serve not only to further the understanding of the present disclosure, but also to help define it, if necessary.

Thus, the present disclosure first relates to a method for changing the work rolls12of a rolling mill referenced10, in the presence of a metal strip MS to be rolled between both work rolls12, including an upper work roll, and a lower work roll.

In a closing position of the roll stand configured to roll the metal strip MS, the work rolls12each have a contact generatrix with the metal strip, the contact generatrices and the axes of the work rolls12lying in a plane substantially perpendicular to a running direction of the metal strip.

In the closing position of the stand, rolling members such as first intermediate rolls13are in contact along two contact generatrices between each of the work rolls12and the rolling members, the rolling members ensuring transmission of a rolling force to the lower and upper work rolls12in contact with the metal strip MS.

According to the method of the present disclosure, extraction of the work rolls12from the roll stand is ensured after at least partially (or even totally) opening the roll stand in which the work rolls12are spaced apart from each other, and with respect to the positions of the work rolls12, in the closing position of the roll stand, by carrying out the following steps for said upper and/or lower work rollan insertion step a) comprising:robotically inserting mechanical separation means1between said work roll12and the metal strip MS to a separation position SP1in which the metal strip MS and said work roll12are physically separated along the length of the work roll, and up to guarantee suppression of the contact between the work roll12and the metal strip MS and/orrobotically inserting mechanical separation means1between the work roll12and the rolling members to a separation position SP2in which said work roll12and the rolling members are physically separated along the length of the work roll, up to guarantee suppression of the contact between the work roll12and the rolling members,a removal step b) comprising:robotically extracting said work roll12, by gripping one end of said work roll12and moving said work roll12along its axis with respect to the metal strip MS and the rolling members present in the roll stand, wherein said mechanical separation means are:in said separation position SP1in which the work roll12and the metal strip MS are physically separated so as to avoid any friction between the work roll and the metal strip upon moving, or/andin said separation position SP2in which the work roll12and the rolling members are physically separated and so as to avoid any friction between the work roll and the rolling members upon moving.

Thus and notably, the method comprises an insertion step a), prior to the removal step b), with robotic insertion of mechanical separation means guaranteeing suppression of the contact between the work roll12and the metal strip MS, in the separation position SP1, and alternatively or preferably additionally, with robotic insertion of mechanical separation means guaranteeing suppression of the contact between the work roll12and the rolling members, in the separation position SP2.

The removal step b) is then implemented while said mechanical separation means are in said separation position SP1in which the work roll12and the metal strip MS are physically separated or/and preferably in said separation position SP2in which the work roll12and the backup members are physically separated from each other.

The method according to the present disclosure advantageously makes it possible, during the removal step b), to avoid any friction between the work roll, on the one hand, and the metal strip and/or the rolling members, upon moving the work roll for removing it from the roll stand.

It becomes possible to extract the lower or upper work roll without marking the work roll, or without marking neither the metal strip nor the rolling elements upon removing the work roll by moving along its axis.

The method according to the present disclosure finds particular application in a 20Hi rolling mill as represented schematically inFIG.12.

The method according to the present disclosure can advantageously be implemented by a roll changing tool8, comprising a fork system, with two branches20,21. When the branches20,21are inserted between the metal strip MS and the work roll12to be extracted, parallel to the axis of the work roll, said branches, advantageously interposed between the metal strip MS and the work roll12, make it possible to guarantee suppression of the contact between the metal strip and the work roll.

Thus, the insertion step a) and the extraction step b) can be carried out for the upper work roll12, and as visible inFIGS.5to9, the separation means1between said upper work roll12and the metal strip MS comprising said fork system2with its two branches20,21, parallel to each other, held to a same fork support22.

Both branches20,21of the fork system are movable with respect to said fork support, to assume, on the one hand, a spaced apart position SAP, visible inFIG.6, configured to ensure insertion of both branches20,21of the fork system, on either side of the upper work roll, without friction with said upper work roll12, currently is still in contact with the metal strip via the contact generatrix, and on the other hand a close position CP, visible inFIG.7, in which both branches of the fork system are moved closer to each other.

In the close position CP, both branches are advantageously configured so as to come into contact respectively with two generatrices of the upper work roll12in order to space apart the upper work roll from the metal strip MS by lifting it, thus suppressing contact between the upper work roll and the metal strip, and as visible inFIG.7.

To this end, and according to one embodiment, both branches20,21of the fork system2can advantageously have a cross-section, along a plane perpendicular to the direction of the branches20,21, comprising two slopes25,26, belonging to both branches20,21facing each other respectively, tilted with respect to the plane of the metal strip MS along the running direction of the metal strip. Both slopes25,26are configured to come into contact with two generatrices of the upper work roll12to ensure lifting of the upper work roll, by forming a cradle for holding the upper work roll12, in the close position CP of the branches20,21of the fork system2.

Notably, the branches20,21of the fork system may have a metal body machined to form the slopes25,26. A protective coating, for example of plastic or Teflon, may cover the metal body at least at the slopes25,26intended to come into contact with the work roll12. Such a coating makes it possible to protect the surface condition of the work roll when the latter is made to roll or slide on the slopes25,26of the branches, and thus to avoid marking/scratching the work roll.

According to one advantageous embodiment:the separation means between said work roll12and the metal strip MS comprise said fork system2, including both branches20,21, movable with respect to each other from their spaced apart position SAP to the close position CP in which both branches20,21of the fork system are interposed between said upper or lower work roll12and the metal strip MS guaranteeing suppression of the contact between the work roll12and the metal strip MS, and additionallythe mechanical separation means between said work roll12and the rolling members, especially the first intermediate rolls13, comprise two wings3,4, with an insert function, respectively hingedly integral with said two branches20,21of the fork system and concurrently ensuring, when both branches20,21move close to each other from their spaced apart position SAP to their close position CP the mechanical separation between the work roll12and the rolling members, wherein said work roll12and the rolling members are physically separated along the length of the work roll by said wings3,4as an insert guaranteeing suppression of the contact between the work roll12and the rolling members.

Thus, and inFIG.3, it is noticed that both branches20and21of the fork system are provided with a first wing3, and a second wing4respectively. The first wing3extends longitudinally to the branch20, and is hinged along a pivot axis30to said branch20and the second wing4extends longitudinally to the branch21, and is hinged along a pivot axis40to the other branch21.

It is noticed that both wings3and4extend, along a cross-section perpendicular to the direction of the branches of the fork system, from their pivot axis30or40, toward each other, each being tilted with respect to the plane passing through the axes of both branches, by an angle allowing introduction of a free edge31, or41, of each of the wings3or4between the work roll and the corresponding rolling members, namely both of the first intermediate rolls in the case of a 20Hi rolling mill.

Thus, and according to one embodiment of the method:the separation means between said work roll and the metal strip comprise said fork system2, including both branches20,21, movable with respect to each other from their spaced apart position SAP to the close position CP in which both branches20,21of the fork system are interposed between said upper or lower work roll12and the metal strip MS guaranteeing suppression of the contact between the work roll12and the metal strip MS andthe mechanical separation means between said work roll12and the rolling members comprise both wings3,4, with an insert function, respectively hingedly integral with said two branches20,21of the fork system and concurrently ensuring, when both branches20,21move closer to each other from their spaced apart position SAP to their close position CP, mechanical separation between the work roll and the rolling members, wherein said work roll12and the rolling members are physically separated along the length of the work roll, by said wings3,4as an insert, guaranteeing suppression of the contact between the work roll12and the rolling members.

Thus, and inFIG.6, upon extracting the upper work roll12, it is noticed that the branches20,21of the fork system moving closer to each other not only allows the branches20,21to lift the upper work roll12by spacing it apart from the metal strip MS, but moreover allows insertion of the wing referenced3between the work roll12and one of the first two intermediate (left) rolls13, but also the insertion of the wing marked4, between the work roll12and the other (right) of the first two intermediate rolls.

It is then possible to extract the upper work roll, without any risk of friction with the metal strip MS, by virtue of the branches20,21interposed between the work roll12and the metal strip, but also without any risk of friction between the work roll12and the first two intermediate rolls, by virtue of the wings3,4interposed between the work roll and the first two intermediate rolls13respectively.

According to one embodiment of the present disclosure, the insertion step a) and the extraction step b) are carried out for the lower work roll, and wherein said separation means between said work roll and the metal strip comprise the fork system2comprising both branches20,21parallel to each other, held to a same fork support22and wherein both branches of said fork system have free ends23, advantageously provided with slopes24.

These slopes24are particularly visible inFIGS.3and4and are tilted with respect to the plane of the metal strip MS, along the direction perpendicular to the running direction of the metal strip, when both branches20,21of the fork system have axes contained in a plane parallel to the plane of the metal strip MS.

As illustrated inFIGS.13and14, these slopes24are advantageously configured to cooperate with the edge of the metal strip MS to lift the metal strip upon insertion of the branches20,21in a movement parallel to the direction of the lower work roll, causing the metal strip MS to be spaced apart from the lower work roll12, and thus suppressing contact between the lower work roll12and the metal strip MS.

Both branches can be directly inserted in their close position CP when the work roll changing tool is free of the wings3,4with insert function. Alternatively, and when both branches20,21are provided with said wings3and4, said branches20,21are inserted during the insertion step a), in their spaced apart position SAP between the metal strip MS, and the lower work roll12, and as visible inFIG.10.

Advantageously, the movement from the spaced apart position SAP of both branches20,21as shown inFIG.10, to the close position CP, not only makes it possible to interpose both branches20,21of the fork system between the lower work roll12and the metal strip, guaranteeing not only suppression of any contact between the metal strip MS and the lower work roll12, but also to interpose concurrently the wings3and4, between the lower work roll and the rolling members, in particular the first two intermediate rolls. It is noticed indeed that the branches20,21moving closer to each other causes the wings3,4to do the same, until a position of the wing referenced3inserting between the lower work roll12and the left-hand one of the first intermediate rolls, the wing referenced4inserting between the lower work roll12and the first, right-hand, intermediate roll13.

It is thereby possible to extract the lower work roll12, without any risk of friction with the metal strip MS, by virtue of the branches20,21interposed between the work roll12, especially the upper or lower one, and the metal strip MS, but also without any risk of friction between the work roll12, especially the lower or upper one, and the first two intermediate rolls, by virtue of the wings3,4interposed between the work roll and the first two intermediate rolls13respectively.

The wings3,4with an insert function may be made of a plastic material, or the like, at least at its surfaces to come into contact with the work roll and the rolling members, in particular the first intermediate rolls.

According to one embodiment of the present disclosure, gripping the end of the work roll during the removal step b) is implemented by a gripping device5configured to grip the end of the work roll comprising a gripper50with an electromagnetic suction cup, or a pneumatic suction cup cooperating with a base of the roll, or having a clamp whose jaws engage the cylindrical periphery of the end of the roll.

According to one embodiment, the removal step b) is implemented by moving the gripper50of the gripping device5along the direction of the work roll so as to ensure that the work roll12is pulled.

According to one embodiment of the present disclosure, the gripping device5comprises said gripper50, but also an actuator51connecting the fork support22to the gripper50, configured to move the gripper50relative to the fork support22, along a direction parallel to the branches of the fork system. For example inFIG.8, the gripping device comprises a gripper50, especially an electromagnetic suction cup, and the actuator comprises a rack52. This rack52supports the gripper50at one end thereof. A motor unit,53integral with the fork support22, comprises a pinion (not visible because it is internal) which meshes with teeth of the rack. The motor drive of the pinion in one direction of rotation allows the gripper50to be pulled in the direction of the branches20,21of the fork system2. The motor drive of the pinion in the opposite direction allows the work roll to be pushed into the roll stand upon inserting a new or ground work roll.

According to one embodiment of the present disclosure, a movable backup element6connected by a second actuator60to the fork support22is configured to ensure locking of the end of the work roll gripped and pulled by the gripping device5, the roll being locked, clamped between the movable backup element6and a counter-backup element7in the vicinity of the fork support, when the branches are in the close position CP.

Thus, when the gripper50is at the end of its retraction stroke, as visible inFIG.8, it is noticed that the end of the work roll gripped is positioned on the counter-backup element7, which extends from the branches20,21of the fork system currently in the close position CP. The second actuator60is then configured to ensure that the movable backup element6is moved closer to the counter-backup element7, until locking of the work roll on the fork system, clamped between both backup elements6and7is achieved.

Such a locking makes it possible to proceed with the complete removal of the work roll12by moving the whole of fork system and of the work roll locked between the movable backup element6and the counter-backup element7, in particular when the work roll is the upper work roll which is then held by gravity against the branches20,21upon removing, or when the work roll is a lower work roll currently positioned under the branches20,21of the fork system.

In the case of removal of the upper work roll, this still allows deposition of the upper work roll, by turning the whole of the fork system/work roll locked between the backup elements6,7. The work roll12is then positioned by a robotic means on a removal support. The movable backup element6is spaced apart from the counter-backup element7, then the gripper is deactivated, in order to ensure deposition of the work roll.

Thus, the removal step b) may comprise:a first removal sub-step in which the gripper50grips the end of said work roll12and proceeds to partially remove the work roll12with respect to the fork system whose branches12are in the close position CP, immobile in the roll stand10, by moving the work roll12along the branches20,21of the fork system,a second removal sub-step in which a backup element6, movable along a direction perpendicular to the direction of the branches, connected to said support by a second actuator60, engages with the periphery of the work roll, in the proximity of the end gripped in order to ensure locking of the work roll, clamped between the motor-driven backup element6, on the one hand, and a counter-backup element7in the vicinity of the fork support12,a third removal sub-step in which the work roll locked between the backup element6and the counter-backup element7is removed entirely from the roll stand by moving the whole of the fork system and work roll locked.

According to one embodiment illustrated in the figures, the fork system2, the gripping device5comprising in addition to said gripper50, the actuator51connecting the support of the fork system to the gripper and the backup element6connected to the support by said second actuator60is a self-supporting assembly forming a same work roll change tool8, handled by a robotic means Ro.

InFIG.1, the robotic means Ro handling the work roll change tool8is represented in the work zone in front of the maintenance access of the roll stand.

An orthonormal reference frame (x,y,z) defines three directions in space, with:the x-direction, namely the horizontal direction perpendicular to the running direction of the metal strip,the y-direction, namely the horizontal direction parallel to the running direction of the metal stripthe z-direction, namely the vertical direction.

The robotic means Ro includes a motor carriage, movable along rails Rai oriented along the x-direction.

In the insertion step a) (or the removal step), the changing tool8is oriented in the axis of the work roll12to be gripped, with the parallel branches20,21, substantially contained in a plane parallel to the plane of the metal strip MS, oriented parallel to the axis of the work roll to be gripped.

For gripping the upper work roll12, the gripping device is positioned above the branches20,21, whereas for gripping the lower work roll, both branches are above the gripping device5.

The work roll changing tool8is mounted to a support S movably mounted through a motor unit along a column C carried by the carriage of the robotic means. By vertically moving the support S up (or down) along the column C, the height of the tool can be adjusted.

The tilt of the longitudinal axis of the changing tool parallel to the axis of the branches can be adjusted by a pivot P between the tool8and the support S via a motor unit. A further degree of freedom in pivoting allows the changing tool8to be pivoted about its longitudinal axis, and to allow the changing tool to be turned through 180°.

It is understood that the robotic means can take many other forms such as, for example, a six-axis robotic arm handling the work roll changing tool8.

Thus, and according to one exemplary embodiment, the upper work roll and the lower work roll can advantageously be successively removed by said same work roll change tool8, handled by the robotic means Ro, said robotic means comprising means for moving the self-supporting assembly:along an x-direction parallel to the axis of the work roll12to be gripped, during the insertion step or the removal step, for example by moving the carriage along the rails Rai,in height along a direction z, to move from a position allowing extraction of the upper work roll to a position allowing extraction of the lower roll, especially by motor movement of the support S along the column C,by pivoting along an axis of rotation parallel to the direction of the branches of the fork system in order to move from a configuration of the self-supporting assembly allowing extraction of the upper work roll to a configuration in which the self-supporting assembly is pivoted through 180° allowing extraction of the lower work roll.

The method according to the present disclosure finds particular application in a 20Hi rolling mill as represented schematically inFIG.12.

The present disclosure further relates to such a tool8suitable for changing work rolls configured to be handled by motor means Ro. This tool8comprises the fork system2comprising two branches20,21configured to be inserted into the stand of a rolling mill in a spaced apart position SAP of the branches, on either side of an upper work roll12of the rolling mill, said branches20,21being movable relative to a fork support22, said branches20,21being configured to move from their spaced apart position SAP to a close position CP in which the branches20,21ensure lifting of the upper work roll12by guaranteeing the physical separation between the work roll12and the metal strip MS upon extracting a work roll.

The tool further comprises the gripping device5comprising the gripper50connected by an actuator51to the fork support, configured to grip an end of the work roll12and pull the work roll12along the branches20,21of the fork system.

The work roll changing tool8may further comprise the movable backup element6connected by a second actuator60to the fork support22configured to ensure locking of the end of the work roll gripped and pulled by the gripping device5, clamped between the movable backup element6and a counter-backup element7in the vicinity of the fork support, when the branches20,21are in the close position CP.

It should be noted that this work roll change tool is suitable not only for extracting the work roll, but also for gripping and inserting a new, or ground, work roll into the rolling mill to replace the upper work roll.

Thus, the replacement of the work roll removed from the roll stand in the presence of the metal strip and the rolling elements, in particular the first intermediate rolls, can be carried out by reversing the steps of the method ensuring extraction of the work roll.

For the replacement of the upper roll, the new or ground work roll is inserted, locked along both branches20,21of the fork system, currently in the close position CP, thus allowing insertion of the new or ground work roll12without any risk of marking with the metal strip MS, or even without any risk of marking with the rolling members, in particular both first intermediate rolls13when the tool further comprises the wings3and4with insert function. Said branches20,21are movable with respect to a fork support22, configured to move from their close position CP to their spaced apart position SAP to cause the upper work roll12to be deposited onto the metal strip MS. In this way, the upper work roll12is deposited in a controlled manner, without falling, especially by virtue of the slopes25,26of the branches, which ensure a smooth descent of the work roll when the branches20,21are spaced apart from each other.

Prior to this deposition by spacing apart the branches20,21of the fork system, and when the tool comprises the movable backup element6and the counter-backup element7, it is understood that the movable backup element6is spaced apart from the counter-backup element7, so as to release the work roll; then the gripper50is pushed by the actuator51in order to completely push the work roll into the roll stand in the desired position, along the axial direction of the roll.

The tool may also comprise both wings3,4, with an insert function, respectively hingedly integral with both branches20,21of the fork system and ensuring:when both branches20,21, and concurrently the insert wings3,4, move closer, from their spaced apart position SAP to their close position CP, mechanical separation between the work roll12and the rolling members, in which said work roll and the rolling members are physically separated along the length of the work roll, by said insert wings3,4guaranteeing suppression of the contact between the work roll and the rolling members, in particular suppression of both contact generatrices of the lower work roll with the rolling members, and/orreleasing the lower work roll12onto the wings3,4as an insert between the work roll12and the rolling members, in the close position CP of the branches in the roll stand, and then the deposition of the lower work roll onto the rolling members when the branches20,21and the wings3,4as an insert have moved from their close position CP to their spaced apart position SAP.

The wings3and4with insert function are thus of interest upon extracting the work roll; both wings are inserted between the lower or upper work roll12and the rolling members, in particular the first two intermediate rolls13, advantageously avoiding any marking of the work roll and the first two intermediate rolls upon moving the work roll, either by the gripping device, or by the movement caused by the robotic means when the work roll is completely extracted from the roll stand.

These wings3and4are also of considerable interest for ensuring replacement of the work roll removed from the roll stand, in the presence of the metal strip, and of the rolling elements, in particular of the first intermediate rolls, by suppressing the risk of marking between the new (or ground) roll and the first two intermediate rolls.

In particular and with regard to the insertion of the new or ground lower work roll, and when the unlocking of the movable backup element and the deactivation of the gripper may cause a (very slight) fall; this fall is advantageously triggered in the close position CP of the branches20and21and therefore of the wings so that the release of the lower, new or ground work roll takes place on the wings3,4, thus avoiding the risk of marking between the work roll12and the first intermediate rolls during this release. The work roll is then partially inserted into the roll stand, and before the gripper completely pushes the work roll into the roll stand.

Secondly, the new or ground roll is deposited onto the rolling elements, especially the first intermediate rolls, by moving the arms from their close position, visible inFIG.11, to their spaced apart position, which results in the removal of the wings3,4, respectively between the work roll and both first intermediate rolls, as visible inFIG.10.

Such a tool thus advantageously makes it possible not only to extract the work rolls without risk of marking the work roll, but also to insert a new or ground work roll, especially a mirror-finish one, and advantageously without risk of marking the new or ground work roll, which is a great advantage.

Thus, in general, the present disclosure still relates to a method for changing the work roll suitable for inserting a work roll into the roll stand in the presence of the metal strip and the rolling elements. This method is particularly advantageous in that it suppresses or greatly reduces the risk of friction of the new or ground work roll and thus of scratching the work roll.

Thus, the present disclosure also relates to a method for changing the work rolls12of a rolling mill10in the presence of a metal strip MS to be rolled between both work rolls12, including an upper work roll and a lower work roll, and wherein in a closing position of the roll stand configured to roll the metal strip MS, said work rolls12each have a contact generatrix with the metal strip, the contact generatrices and the axes of the work rolls lying in a plane substantially perpendicular to a running direction of the metal strip, rolling members, such as first intermediate rolls13, being in contact along two contact generatrices between each of the work rolls12and the rolling members, the rolling members ensuring transmission of a rolling force to the lower and upper work rolls12in contact with the metal strip MS, method in which the insertion of the work rolls12, in particular new or ground work rolls, into the roll stand in the presence of the metal strip and the rolling members is ensured after at least partially opening the roll stand by carrying out the following steps, for said upper and/or lower work rollan insertion step c) comprising:robotically inserting mechanical separation means1between the metal strip MS and the work roll to be inserted ensuring removal of the contact between the work roll12and the metal strip MS and/ora robotic insertion of mechanical separation means1between the rolling members and said work roll12to be inserted guaranteeing suppression of the contact between the work roll12and the rolling membersan insertion step d), concurrent or subsequent to the insertion step c) comprising robotically inserting said work roll12, by pushing an end of said work roll12and moving said work roll along its axis with respect to the metal strip MS and the rolling members present in the roll stand, wherein said mechanical separation means are:in a separation position SP1in which the work roll12and the metal strip MS are physically separated so as to avoid any friction between the work roll and the metal strip upon moving, or/andin a separation position SP2in which the work roll12and the rolling members are physically separated and so as to avoid any friction between the work roll and the rolling members upon moving.

Thus and notably, the method comprises an insertion step c), prior to or together with the insertion step d), with robotically inserting mechanical separation means guaranteeing suppression of the contact between the work roll12and the metal strip MS, in the separation position SP1, and alternatively or preferably additionally, with robotically inserting mechanical separation means guaranteeing suppression of the contact between the work roll12and the rolling members, in the separation position SP2.

The step of inserting d) the work roll is then carried out while said mechanical separation means are in said separation position SP1in which the work roll12and the metal strip MS are physically separated or/and preferably in said separation position SP2in which the work roll12and the backup members are physically separated.

The method according to the present disclosure advantageously makes it possible, during the insertion step d), to avoid any friction between the new, or ground work roll, to be inserted, on the one hand, and the metal strip and/or the rolling members, on the other hand, upon moving the work roll for inserting it into the roll stand.

It becomes possible to insert the lower or upper work roll without marking the work roll, or without marking neither the metal strip nor the rolling elements upon removing the work roll by moving along its axis.

Thus, the method can have the insertion step c) comprising robotically inserting the mechanical separation means between said upper or lower work roll12to be inserted and the metal strip MS to the separation position SP1in which the metal strip MS and said upper or lower work roll12are physically separated along the length of the work roll, guaranteeing suppression of the contact between the work roll and the metal strip, and inserting in which said work roll insertion is robotically performed, by moving said work roll12along its axis with respect to the metal strip and the rolling members, in said separation position SP1in which the upper or lower work roll12and the metal strip MS are physically separated so as to avoid any friction between the work roll and the metal strip upon moving.

The method according to the present disclosure can be advantageously implemented by a roll changing tool8especially as previously described for extraction, comprising a fork system, with two branches20,21. When the branches20,21are inserted between the metal strip MS and the work roll12to be inserted, parallel to the axis of the work roll, said branches20,21are advantageously interposed between the metal strip MS and the work roll12enable suppression of the contact between the metal strip and the work roll to be guaranteed.

Thus, the insertion step c) and the insertion step d) can be implemented for the upper work roll12, and by inverting the steps described for the extraction and as visible fromFIGS.5to9, the separation means1between said upper work roll12and the metal strip MS comprising said fork system2with its two branches20,21, parallel to each other, held to a same fork support22.

Thus, the insertion step c) and the insertion step d) can be implemented for the upper work roll12. Said separation means1between said upper work roll12, and the metal strip MS may comprise a fork system2comprising two branches20,21, parallel to each other, held to a same fork support22. Both branches of the fork system are movable with respect to said fork support, to assume, on the one hand, during the insertion step c) and the insertion step d) a close position CP in which both branches of the fork system are moved closer to each other, configured so as to come into contact respectively with two generatrices of the upper work roll12to move the upper work roll apart from the metal strip MS, then, on the other hand, a spaced apart position SAP, configured to ensure deposition of the upper work roll12onto the metal strip with the presence of a contact generatrix between the upper work roll and the metal strip, both branches then being arranged on either side of the upper work roll.

Thus and according to this embodiment, it is possible to insert the upper work roll12during the insertion step d), between the metal strip MS and the rolling members, without any risk of friction between the work roll and the metal strip MS by virtue of the branches20,21of the fork system, interposed between the work roll and the metal strip, in their close position CP and as illustrated inFIG.7. Once the work roll12is inserted in position in the roll stand, the deposition is achieved by spacing apart the branches20,21to their spaced apart position SAP, which causes the descent of the work roll until it comes into contact with the metal strip MS, by gravity, and as illustrated inFIG.6.

According to one embodiment, both branches20,21of the fork system2may have the section, along a plane perpendicular to the direction of the branches20,21, comprising two slopes25,26, belonging respectively to both branches20,21facing each other, tilted with respect to the plane of the metal strip MS along the running direction of the metal strip, both slopes25,26being configured to come into contact with two generatrices of the upper work roll12to ensure holding of the upper work, forming cradle for holding the upper work roll12, in the close position CP of the branches20,21of the fork system2, and then a controlled deposition of the upper work roll onto the metal strip, by virtue of the slopes25,26when both branches are moved to their spaced apart position SAP.

With respect to the lower work roll12, the insertion step c) and the insertion step d) can be implemented for the lower work roll, and wherein said mechanical separation means between said work roll and the metal strip comprise a fork system2comprising two branches20,21, parallel to each other, held to a same fork support22and wherein both branches of said fork system have free ends23, provided with slopes24, which when both branches20,21of the fork system have axes contained in a plane parallel to the plane of the metal strip MS, are tilted with respect to the plane of the metal strip MS, along the direction perpendicular to the running direction of the metal strip.

The slopes24at the ends of the branches21are configured to cooperate with the edge of the metal strip MS to lift the metal strip upon inserting the branches20,21in a movement parallel to the direction of the lower work roll, with the metal strip MS being spaced apart from the lower work roll12.

Thus, and as understandable fromFIG.11, the insertion of the branches of the fork system, with the slopes24at the ends of the branches20,21allows the metal strip MS to be lifted, and both branches20,21to be provided as a mechanical separation preventing any friction between the lower work roll and the metal strip upon inserting it.

The lifting of the metal strip, by working the slopes24, can be carried out in the close position CP of the branches20,21of the fork system, or even in conjunction with the insertion of the lower work roll, currently positioned just below the branches20,21of the fork system during the insertion step d), and much as the example of the working of the slopes upon extracting the work roll (FIGS.13and14).

According to one advantageous embodiment, the method allows not only to avoid friction between the (upper or lower) work roll12to be inserted and the metal strip MS, but also to avoid friction between said (lower or upper) work roll and the rolling members, in particular between the upper work roll12and the upper first intermediate rolls13, or between the lower work roll12and the lower first intermediate rolls13.

To this end, said insertion step c) comprises:said robotically inserting the mechanical separation means1between the metal strip MS and the work roll to be inserted guaranteeing suppression of the contact between the work roll12and the metal strip MS, andsaid robotically inserting mechanical separation means1between the rolling members and said work roll12to be inserted guaranteeing suppression of the contact between the work roll12and the rolling members,

and wherein said insertion step d) comprises robotically inserting said work roll, by pushing an end of said work roll and moving said work roll along its axis with respect to the metal strip MS and the rolling members, and wherein said mechanical separation means1are:in said separation position SP1in which the work roll12and the metal strip2are physically separated so as to avoid any friction between the work roll and the metal strip upon moving, and simultaneouslyin said separation position SP2in which the work roll (12) and the rolling members are physically separated and so as to avoid any friction between the work roll and the rolling members upon moving.

To this end, and according to one embodiment, the separation means between said work roll and the metal strip may comprise said fork system2, including both branches20,21, movable with respect to each other to move from a close position CP in which both branches20,21of the fork system are interposed between said upper or lower work roll12and the metal strip MS ensuring suppression of the contact between the work roll12and the metal strip MS during the insertion step c) and the insertion step d) and wherein the mechanical separation means between said work roll12and the rolling members comprise additionally, two wings3,4, with an insert function, respectively integral with said two branches20,21of the fork system and concurrently ensuring, in a close CP position, mechanical separation between the work roll and the rolling members wherein said work roll12and the rolling members are physically separated along the length of the work roll, by said wings3,4as an insert, ensuring suppression of the contact between the work roll12and the rolling members during the insertion step c) and the insertion step d)

For example the insertion step c) and the insertion step d) are implemented for the upper work roll12, and wherein said separation means1between said upper work roll12and the metal strip MS comprise the fork system2comprising two branches20,21, parallel to each other, held to a same fork support22.

Both branches of the fork system are movable with respect to said fork support, in order to assume, on the one hand, during the insertion step c) and the insertion step d), a close position CP in which both branches20,21of the fork system are moved closer to each other, configured so as to come into contact respectively with two generatrices of the upper work roll12in order to space apart the upper work roll from the metal strip MS, both wings3,4concurrently ensuring mechanical separation between the work roll12and the rolling members, and then, on the other hand, a spaced apart position SAP, configured to ensure deposition of the upper work roll12onto the metal strip MS with a contact generatrix between the upper work roll12and the metal strip. In their spaced apart position SAP, both branches are then arranged on either side of the upper work roll, which concurrently causes the wings3,4to retract into a spaced apart position where the latter release interspaces between the work roll and the rolling members.

According to one embodiment, pushing the end of the work roll12in the insertion step d) is implemented by a gripper5comprising a gripper50configured to push the end of the work roll and wherein the insertion step d) is implemented by moving the gripper50along the direction of the work roll providing pushing of the work roll12.

According to one embodiment, the gripper5further comprises an actuator51connecting the fork support22to the gripper50, configured to move the gripper50relative to the fork support22, along a direction parallel to the branches of the fork system, the insertion step d) comprising:a first, insertion, sub-step in which the work roll12, locked between a backup element6and a counter-backup element7on board the fork support is partially inserted into the roll stand between the metal strip MS and the upper or lower work roll12the branches20,21of the fork system, or even the wings3,4in their close position CP, guaranteeing suppression of the contact between the metal strip MS and the work roll12, possibly guaranteeing suppression of the contact between the work roll and the rolling members by the wings3,4as an insert,a second, unlocking, sub-step in which said movable backup element6, connected to said support by a second actuator60along a direction perpendicular to the direction of the branches is spaced apart from the counter-backup element to release (unlock) the work roll,a third, insertion, sub-step in which the partially inserted work roll is pushed by the actuator51to its final axial position in the roll stand, by sliding the upper work roll onto the branches20,21of the system, the fork currently in the close position CP, or even sliding the lower roll onto the insert wings3,4.

Depositing the upper work roll12is ensured by spacing apart the branches20,21from their close position CP to their spaced apart position SAP, which also causes the wings3,4to retract, with releasing the interspace between the work roll and the rolling members, especially the first two upper intermediate rolls13.

Depositing the lower work roll12is ensured by spacing apart the branches20,21, and thus concurrently spacing apart the wings3,4as an insert until their spaced apart position SAP in which the lower work roll12comes into contact with the rolling members, in particular with both first lower intermediate rolls13, and along both contact generatrices between the work roll and respectively both first lower intermediate rolls13.

The work roll change tool8, handled by a robotic means Ro, as previously described may be suitable for implementing the insertion step a) and the removal step b) for extracting the work rolls.

The work roll changing tool8, handled by a robotic means Ro, as previously described may be further suitable, for implementing the insertion steps c) and the insertion step d) for inserting the new or ground work rolls.

The present disclosure makes it possible to avoid damage to the metal strip, to the rolling members such as the first intermediate rolls, but also to the work roll, not only upon extracting the work roll from the roll stand, but also advantageously upon inserting a new or ground work roll.