Rolling mill including a hump cage

Abstract

This disclosure relates to a four-roll or six-roll rolling mill (1) comprising a rolling mill stand having a first pair of uprights (M1, M2) and a second pair of uprights (M3, M4), a lateral offset adjustment system configured for implementing a lateral offset, viewed along the rolling direction, between, on the one hand, an axis of the lower working roll (or respectively of the upper working roll), and on the other hand, an axis of a roll bearing on the working roll such as a lower (or respectively upper) bearing roll. The uprights of the first pair of uprights and the second pair of uprights have prominent bosses (B2; B4), directed in pairs towards each other. Abstract figure: Figure 1

Description

Title of the invention: Rolling mill comprising a boss stand

[0001] The present disclosure relates to a four-roller, or six-roller, rolling mill comprising a rolling stand having a first pair of uprights and a second pair of uprights, a lateral offset adjustment system configured for implementing a lateral offset, viewed along the rolling direction, between on the one hand, an axis of the lower working roll (or respectively of the upper working roll), and on the other hand, an axis of a roll bearing on the working roll such that a lower (or respectively upper) support roll, the uprights of the first pair of uprights and the second pair of uprights having prominent bosses, directed two by two towards each other.

[0002] In the context of this disclosure, the upper working cylinder and the lower working cylinder each have guide ends which are mounted in sockets; the guide ends mounted to rotate relative to the sockets via bearings typically of the bearings.

[0003] The bosses of the uprights have internal flanks configured to serve as a support by the lateral offset system which is configured to come to rest laterally with the grips of the working cylinders, on either side of the working axis.

[0004] These bosses on the cage advantageously allow, compared to a cage design with straight uprights (without bosses), bringing the two supports closer together at the two ends of the working cylinder, and thus reducing the slenderness, namely the spacing between the guide bearings (i.e. the bearings) which corresponds to the unguided part of the cylinder, which is likely to generate a deflection of the working cylinder during rolling operations. technical field

[0005] The present disclosure relates to the field of cold rolling, and more particularly to six-roll (6-High) or four-roll (4-High) rolling mills with motorized working rolls, and more particularly to such reversible rolling mills, namely configured to roll the strip by alternating the direction of the strip's movement through the rolling mill. Previous technique

[0006] A four-roll rolling mill comprises, as illustrated in diagram (a) of [Fig. 10]: - two working cylinders, distributed respectively below and above the metal strip, the upper working cylinder bearing along a line of contact upper cylinder with the belt following a widthwise direction of the belt, and lower cylinder supported along a lower contact line with the belt, following the widthwise direction of the belt, - two support cylinders, including an upper support cylinder bearing against the upper working cylinder, on the side opposite the band by a line of contact, and a lower support cylinder bearing against the lower working cylinder on the side opposite the band by a line of contact.

[0007] A six-roll rolling mill comprises, as illustrated in diagram (b) of [Fig. 10]: - two working cylinders, distributed below and above the metal strip, the upper cylinder supported along a superior contact line with the strip, following a direction in the width of the strip, and the lower cylinder supported along a inferior contact line with the strip, following the width of the strip, - two support cylinders, including an upper support cylinder and a lower support cylinder; - two intermediate cylinders, including an upper intermediate cylinder, in contact by a first line of contact with the upper support cylinder, and in contact by a second line of contact with the upper working cylinder, and a lower intermediate cylinder, in contact by a first line of contact with the lower support cylinder, and in contact by a second line of contact with the lower working cylinder.

[0008] In both cases, whether it is a 4-roller or a 6-roller rolling mill, hydraulic clamping pots exert a clamping force between the upper support cylinder and the lower support cylinder, tending to bring the axes of rotation of the two support cylinders closer together in order to transmit a clamping force to the working cylinders, directly between each support cylinder and each working cylinder, in the case of a four-roller rolling mill, or via the intermediate cylinders in the case of a 6-roller rolling mill.

[0009] A rolling mill with six rolls, also known as a laterally supported rolling mill, is also known, as illustrated in diagram (c). This rolling mill comprises two support rolls, two intermediate rolls, and two work rolls, but also, for each work roll, two lateral support rolls, one to the right and one to the left of each work roll, bearing against it via contact lines on both sides of the roll. In such a laterally supported six-roll rolling mill, the work rolls are typically floating and not directly driven; the drive unit directly drives the intermediate rolls.

[0010] A rolling mill with 20 rolls, comprising, on either side of the strip, an upper group and a lower group, is also known, as illustrated in diagram (d) of [Fig.10].

[0011] Each of the groups, upper and lower, comprises: - a working cylinder, in contact with the strip, to be rolled, - two first intermediate cylinders, in contact by two support lines with the working cylinder, - three second intermediate cylinders, in contact by four support lines with the first two intermediate cylinders, - four sets of support rollers, in contact along six support lines with the second intermediate cylinders.

[0012] In such a 20-roll rolling mill, the working rolls are not driven in rotation directly, but only via the intermediate second rolls.

[0013] This disclosure relates exclusively to the rolling mill, with 4 rolls according to the diagram (a), or to the rolling mill with 6 rolls according to the diagrams (b), namely whose working rolls are not supported laterally.

[0014] In such a 4-roll or 6-roll rolling mill, each of the two work rolls is pivotally mounted at its guide ends in bearings, each work roll being a machined metal body comprising a rolling surface, typically cylindrical, but also two extending guide ends of smaller diameters than the rolling surface. The guide ends comprise a first guide end configured to pivotally mount in the first bearing, typically via bearings such as roller bearings, and a second guide end configured to pivotally mount in the second bearing, typically via bearings such as roller bearings.

[0015] Such a rolling mill includes a cage which includes an entrance window, delimited between two front uprights of the cage, and on the opposite side of the cage, two rear uprights of the cage.

[0016] During maintenance operations, such as changing cylinders, the cylinders, including the working cylinders, can be extracted axially through the inlet window. The drive mechanism for the working cylinders is operated from the other side, namely from the side of the two rear uprights of the cage.

[0017] In such a rolling mill: - the first swaging tool, at one end of the working cylinder (lower or upper), can be guided vertically between the two front uprights of the cage, but the position of the swaging tool along the direction of the band is blocked by supports on the two front uprights, - the second grip at the other end of the working cylinder (lower or upper) can be guided vertically between the two rear uprights of the cage, but the position of the grip along the direction of the band is blocked by supports on the two rear uprights.

[0018] In such a rolling mill, with 4 or 6 rolls, the work rolls are driven, preferably directly, to transmit counter-rotating torques to the two lower and upper work rolls, respectively, in order to assist the rolling action. Direct drive of the work rolls is preferred to drive of the intermediate rolls for a six-roll mill.

[0019] Indirect motorization can cause slippage between cylinders leading to degradation of the surface condition of the cylinder table, and this makes it possible to avoid direct motorization of the working cylinders.

[0020] In such a rolling mill, with 4 or 6 rolls, vertical forces are applied to the work roll during rolling to ensure the reduction of the strip thickness by the work roll still being subjected to the action of horizontal forces.

[0021] As illustrated in [Fig.9], there are four main horizontal forces applied to the working cylinder: - the horizontal component of the clamping force, - the difference in band tension, - the rolling force due to the transmission of torque to the working cylinder, which only needs to be taken into account when the working cylinders are driven directly by the motor, - the horizontal component of the forces exerted by the handles on the guide ends of the working cylinder.

[0022] Vertical and horizontal forces unbalance the working cylinder, causing it to camber. Under the effect of the vertical component of the forces on each working cylinder, the working cylinder cambers along a vertical component, and under the effect of the horizontal component of the forces, the working cylinder cambers along a horizontal component.

[0023] The rolling mill can typically include an opening and closing mechanism comprising, at the front and rear of the stand, a left-hand cylinder system interposed between one of the front (or respectively rear) uprights and the two handles of the lower and upper working cylinders, on this left side, comprising a right-hand cylinder system interposed between the other right-hand upright and the two handles on the right side.

[0024] Each cylinder system (right or left) can be removably coupled to the two ends of the lower and upper cylinders. Generally, extending the cylinders vertically separates the ends of the upper and lower cylinders, thus opening the rolling mill. These cylinders can also be used to vertically constrain the guide ends of the work rolls to vertically balance the work rolls and thereby reduce the vertical component of camber.

[0025] For a four-roller or six-roller rolling mill, without lateral support, the driving torque caused by the direct drive of the work roll, while the ends of the work roll are blocked by the clamps, typically induces a camber in the work roll, in a horizontal plane, with a deflection that is maximum between the two ends of the work roll. The deflection is oriented in the opposite direction to the direction of travel of the strip, namely that the horizontal component of the camber extends upstream of the strip in the direction of travel.

[0026] In a four-roll or six-roll rolling mill, it is known to balance the horizontal components acting on the work roll, and thus reduce the horizontal component of camber, by offsetting the axis of the work roll along the direction of the strip's travel, hereinafter referred to as the rolling direction. As illustrated in [Fig. 9], the axis of the work roll is offset relative to the roll bearing on the work roll in the same direction as the strip's travel.

[0027] For a reversible rolling mill, it is also known to reverse the change in direction of the offset, in case of reversal of the direction of the strip during rolling.

[0028] A first type of lateral offset system for the working cylinders' bearing surfaces is known from the prior art. This system comprises horizontal hydraulic cylinders that apply the bearing surfaces against a reference surface, where the offset generated by the actuation of the cylinders is typically on / off. Such a prior art system is described, for example, in document JP2790741 or WO2323 / 073998. This type of offset system allows for proper balancing of the working cylinders when the cylinders are not too small to avoid excessive horizontal deflection.

[0029] A second offsetting system based on the use of straight, angled wedges is also known from the prior art, including first angled wedges inserted to the left of the crossbar and the left upright, and second angled wedges inserted to the right of the crossbar and the right upright, on both sides of the cage.

[0030] Each wedge extends lengthwise, parallel to the longitudinal axis of the working cylinder, and is configured to slide on a wear plate of the upright along a first surface, and along supporting spacers which are supported, on the one hand, on a second inclined surface of the wedge, and on the other hand on a vertical guide plate, intended for the vertical guidance of the vertical cylinder system for opening the cage.

[0031] Such an adjustment system makes it possible to adjust the lateral offset of the shims, by synchronizing the movements of the first shims and the second shims, namely that when the first shims are moved longitudinally in a direction tending to move the shim away from the left upright, the second shim is moved longitudinally in the opposite direction to allow the shim to move closer to the right upright.

[0032] Such a prior art, for example taught by US patent 4,736,609, has the advantage of offering a wide range of adjustment. When the ratio of the working cylinder diameter to the band width becomes small, typically less than 0.23, the inclined wedge adjustment system is sufficiently precise to correctly balance the forces acting on the working cylinders, and to avoid excessive horizontal deflection, which is generally not possible with prior art based on horizontal cylinders.

[0033] According to the inventors' findings, such a sloping wedge system includes, for each straight wedge, a substantial bulk which extends in length, not only along the length of the sloping wedge, but also in length along the length of an actuating cylinder which extends longitudinally the wedge, cantilevered outwards from the stand, in a direction transverse to the rolling mill, and on both sides of the stand, at the front and at the rear.

[0034] Such a slanted wedge adjustment system substantially increases the bulk of the rolling mill, beyond the limits of the stand, and in particular on the side of the rolling mill access window, penalizing maintenance operations.

[0035] Another defect identified by the inventors of such a sloping wedge system is that its sloping guide surfaces are soiled by rolling impurities, in particular rolling oils and rolling metal particles, during operations and therefore require periodic maintenance.

[0036] Beyond the defects of lack of progressiveness compared to the prior art according to WO2323 / 073998, or defects relating to the bulk along the transverse direction and / or defects relating to the sensitivity to soiling according to US 4,736,609, the inventors note that the aforementioned rolling mills according to the prior art only aim to offer solutions by generating a lateral offset aimed solely at compensating for the deflection of the working cylinder, and not in itself at reducing the sensitivity of the cylinder to bend under the rolling forces.

[0037] The present disclosure improves this situation in whole or in part by proposing a rolling mill with a lateral offset adjustment system configured for the implementation of a lateral offset, in order to compensate for the deflection of the cylinders, but also a rolling mill stand having specific bosses configured to cooperate with the adjustment system, to allow a rapprochement of the work rolls' handles, and thus a reduction in the slenderness in order to decrease the sensitivity of the work rolls to deflection, and by comparison to a rolling mill stand according to the prior art, devoid of the bosses. Summary

[0038] This disclosure improves the situation.

[0039] A four-roller or six-roller cold rolling mill is proposed, configured for rolling a metal strip, - a rolling mill stand comprising, on the front side, a first pair of uprights, and on the rear side, a second pair of uprights, - an upper working cylinder comprising a rolling table configured to come into contact with the upper surface of the metal strip and two guide ends, - a lower working cylinder comprising a rolling table configured to come into contact with the lower surface of the metal strip and two guide ends, - an upper support cylinder, configured to transmit a clamping force to the upper working cylinder, either directly along a line of contact between the upper working cylinder and the upper support cylinder, or indirectly via an upper intermediate cylinder by means of a first line of support between the upper support cylinder and the upper intermediate cylinder and a second line of support between the upper intermediate cylinder and the upper working cylinder, - a lower support cylinder, configured to transmit a clamping force to the lower working cylinder, either directly along a line of contact between the lower working cylinder and the lower support cylinder, or indirectly via a lower intermediate cylinder by means of a first line of support between the lower support cylinder and the lower intermediate cylinder and a second line of support between the lower intermediate cylinder and the lower working cylinder; - two upper grips arranged at the two guide ends of the upper working cylinder, including a first upper grip interposed between the two uprights of the first pair of uprights, and a second upper grip interposed between the two uprights of the second pair of uprights.the two guide ends of the upper working cylinder mounted on pivots in the upper supports via bearings such as roller bearings, - two lower supports arranged at the two guide ends of the lower working cylinder, including a first lower support interposed between the two uprights of the first pair of uprights, and a second lower support interposed between the two uprights of the second pair, the two guide ends of the lower working cylinder pivotally mounted in the lower supports via bearings such as roller bearings, - a lateral offset adjustment system configured for implementing a lateral offset, viewed along the rolling direction between, on the one hand, an axis of the lower working roll or respectively of the upper working roll, and on the other hand, an axis of a roll bearing on the working roll consisting of the lower or upper intermediate roll when the rolling mill has six rolls, and consisting of the lower or upper support roll when the rolling mill has four rolls, and in which the adjustment system includes: — a first left-hand thrust mechanism between one of the left uprights of the first pair, on the one hand, and the assembly of the first upper and first lower supports, on the other hand, configured to exert a thrust force on the assembly of the first upper and first lower supports to move said assembly in a first direction along the rolling direction — a first straight thrust mechanism between the other straight uprights of the first pair on the one hand, and the first upper brace and the first lower brace on the other hand, configured to exert a thrust force on the assembly of the first upper brace and the first lower brace to move said assembly in a second direction along the rolling direction, — a second left-hand thrust mechanism between one of the uprights of the second pair, on the one hand, and the assembly of the second upper and second lower grips, on the other hand, configured to exert a thrust force on the assembly of the second upper and second lower grips to move said assembly in the first direction along the rolling direction — a second right-hand thrust mechanism between the other right-hand uprights of the second pair, on the one hand, and the assembly of the second upper and second lower grips, on the other hand, configured to exert a thrust force on the assembly of the second upper and second lower grips to move said assembly in the second direction along the rolling direction.

[0040] According to this disclosure: - the left upright of the first pair and the left upright of the second pair are formed respectively by bodies extending vertically in height, the left upright of the first pair and the left upright of the second pair presenting respectively mutually facing vertical lateral surfaces, as well as a first left boss projecting from the lateral surface of the left upright of the first pair, extending from the upright from a base to a top of the boss, and a second left boss projecting from the lateral surface of the left upright of the second pair, extending from the upright from a base to a top of the boss, the first left boss and the second left boss directed towards each other, following a direction parallel to the axes of the working cylinders, -.the right upright of the first pair and the right upright of the second pair are formed respectively by bodies extending vertically in height, the right upright of the first pair and the right upright of the second pair respectively having mutually facing vertical lateral surfaces, as well as a first right boss projecting from the lateral surface of the right upright of the first pair, extending from the upright from a base to a top of the boss, and a second right boss projecting from the lateral surface of the right upright of the second pair, extending from the upright from a base to a top of the boss, the first right boss and the second right boss directed towards each other, in a direction parallel to the axes of the working cylinders, and in which: - The first left-hand thrust mechanism bears at least partially on an inner flank of the first left-hand boss and is configured to exert a thrust on the first upper and first lower arms, which are located overlapping the first boss in a direction parallel to the axes of the working cylinders and in a vertical direction. - the first right-hand thrust mechanism bears at least partially on an internal flank of the first right-hand boss and is configured to exert a thrust on the first upper and first lower bosses, which are located overlapping the first right-hand boss in a direction parallel to the axes of the working cylinders and in a vertical direction, - The second left thrust mechanism bears at least partially on an inner flank of the second left boss and is configured to exert a thrust on the second upper and second lower arms, which are located overlapping the second left boss in a direction parallel to the axes of the working cylinders and in a vertical direction; - The second right thrust mechanism bears at least partially on an inner flank of the second right boss and is configured to exert a thrust on the second upper and second lower arms, which are located overlapping the second straight boss following a direction parallel to the axes of the working cylinders and in a vertical direction.

[0041] The features described in the following paragraphs may optionally be implemented independently of each other or in combination with each other:

[0042] According to one possible embodiment: — the span of the upper working cylinder forming the unguided portion of the working cylinder, has a distance L along the axis of the working cylinder defined between the bearings at the two guiding ends which is intermediate between, on the one hand, the distance separating a vertex of the first left boss and a vertex of the second left boss and, on the other hand, the distance separating the base of the first left boss and the base of the second left boss, - the span of the upper working cylinder forming the unguided portion of the working cylinder, has a distance along the axis of the working cylinder defined between the bearings at the two guiding ends which is intermediate between, on the one hand, the distance separating a top of the first right boss and a top of the second right boss and, on the other hand, the distance separating the base of the first right boss and the base of the second right boss.

[0043] According to one embodiment, the rolling mill may have six rolls, having the lower intermediate roll and the upper intermediate roll, each comprising a rolling table extended by guide ends of smaller diameter, the guide ends rotatably mounted in upper bearings for the upper intermediate roll via bearings and the guide ends rotatably mounted in lower bearings for the lower intermediate roll, and wherein: - the reach of the upper intermediate cylinder is greater than the reach of the upper working cylinder, - the reach of the lower intermediate cylinder is greater than the reach of the lower working cylinder.

[0044] According to one embodiment: - The first left-hand thrust mechanism comprises a rotating helical thrust device including a first piece bearing on the left upright of the first pair, and at least partially on the inner flank of the first left-hand boss, and a second piece configured to laterally push the first lower and upper supports - the first right-hand thrust mechanism comprises a rotating helical thrust device including a first part bearing on the right-hand upright of the first pair, and at least partially on the flank of the second right-hand boss, and a second piece configured to push laterally the first lower and upper supports - The second left-hand thrust mechanism comprises a rotating helical thrust device including a first piece bearing on the left upright of the second pair, and at least partially on the inner flank of the second left-hand boss, and a second piece configured to laterally push the second lower and upper struts - The second right-hand thrust mechanism comprises a rotating helical thrust device including a first piece bearing on the right-hand upright of the second pair, and at least partially on the side of the second right-hand boss, and a second piece configured to laterally push the second lower and upper supports and in which the first part and the second part of each rotating helical thrust device are configured to pivot relative to each other, around an axis of rotation under the action of an actuator, the first part and the second part of each rotating thrust device comprise helical guide surfaces arranged around said rotation, mutually supporting, configured to cause a separation of the second part relative to the first part along the direction of the axis of rotation, during a relative rotation between the first part (5) and the second part.

[0045] According to one embodiment Helical guide surfaces can be: - cam surfaces of the first piece and the second piece which are a first cam and a second cam, or, - internal and external threads respectively mutually engaging between the first piece (5) and the second piece.

[0046] According to one embodiment, the helical guide surfaces of each rotating helical thrust device are arranged overlapping, along the transverse direction, with the width of one of the uprights on which the rotating helical device is supported at least partially on the inner side of the bosses, the helical guide surfaces of diameter D contained along the transverse direction, along the width of the upright including the boss.

[0047] According to one embodiment, the body of each upright has a reduced width section, typically constant, along the transverse direction of the rolling mill, and a greater width section at the bosses, consisting of: - the first left boss for the left upright of the first pair, - the second left boss for the left upright of the second pair, - the first right boss for the right upright of the first pair, - the second right boss for the right upright of the second pair.

[0048] According to one embodiment, the body of each upright, including the boss, is a single piece of metal.

[0049] According to one embodiment, the bosses consisting of the first left boss, the second left boss, the first right boss, the second right boss are blocks attached and fixed by a fastening means, for example screws, to the lateral surfaces of the bodies of the uprights consisting respectively of the left upright of the first pair, the left upright of the second pair, the right upright of the first pair, and the right upright of the second pair.

[0050] According to one embodiment, the upper and lower working rolls comprise drive shafts coupled to a motor for directly driving the rotating working rolls. However, as an alternative, the upper and lower working rolls are not driven directly, but only by the friction of the rolls bearing against the working roll, such as the intermediate rolls in the case of a 6-roll mill, which can be driven in rotation, or the lower and upper support rolls in the case of a 4-roll mill, which can be driven in rotation.

[0051] According to one embodiment, the reach of the upper working cylinder or the lower working cylinder forming the unguided portion of the working cylinder has a distance L along the axis of the working cylinder and in which the lower working cylinder and the upper working cylinder have a diameter D, and in which the ratio D / L is less than or equal to 23%.

[0052] According to a second aspect, the present disclosure relates to a process for rolling a metal strip implemented by a rolling mill 1 according to the present disclosure comprising: / A / a rolling of the metal strip B as it passes between the two upper and lower working cylinders, which are held under pressure on the strip by a hydraulic clamping action between the two support cylinders WAS, WAI, lower and upper, and by transmission of drive torques to the upper working cylinder WRS and the lower working cylinder WRI, / B / balancing of the upper and lower working cylinders, by - a lateral, upper offset, between the upper working cylinder (WRS) and the axis of the cylinder bearing on the working cylinder, - a lower lateral offset between the axis of the lower WRI working cylinder and the axis of the cylinder bearing on the cylinder. Brief description of the drawings

[0053] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analysis of the accompanying drawings, on which:

[0054] Other features, details and advantages will become apparent from reading the detailed description below, and from analyzing the accompanying drawings, in which: Fig. 1

[0055] [Fig-1] shows a six-roller rolling mill, in perspective view. Fig. 2

[0056] [Fig.2] is a cross-sectional view of the rolling mill of [Fig.1], along a vertical plane passing by the axis of the support cylinders. Fig. 3

[0057] [Fig.3] is a front view of the rolling mill, illustrating the cylinder swages, y including the upper and lower working cylinder supports, as well as a lateral offset adjustment system configured for implementing a lateral offset, viewed along the rolling direction between, on the one hand, an axis of the working cylinder and an axis of a cylinder supported on the working cylinder consisting of the intermediate cylinder and comprising a first mechanism.a left thrust mechanism interposed between the left upright and the first upper and lower supports, and on the other hand, a first right thrust mechanism interposed between the right upright and the first upper and lower supports, the first and second thrust mechanisms comprising a helical thrust device with a play compensation function, the helical thrust devices comprising a first part and a second part articulated in rotation, and actuated relative to the other in rotation by actuators with jacks, the jacks extending along the height of the left and right uprights on the facade. Fig. 4

[0058] [Fig.4] is a rear view of the rolling mill, on the side of the cylinder drive. work, illustrating the lateral offset adjustment system on this side, comprising a second left push mechanism interposed between the left upright and the second upper and lower supports, and on the other hand, a second right push mechanism, interposed between the right upright and the second upper and lower supports, the first and second push mechanisms comprising a helical push device with a backlash compensation function, the push devices comprising a first part and a second part articulated in rotation, by actuators with jacks, the jacks extending along the height of the uprights behind the cage. Fig. 5

[0059] [Fig. 5] is a cross-sectional view, along a vertical plane passing through the axis of rotation, of the right and left helical thrust devices, interposed respectively, between the first upper and lower grips of the working cylinders, and the left and right uprights Fig. 6

[0060] [Fig. 6] is a cross-sectional view, along a horizontal plane passing through the axis of rotation, of the right and left helical thrust devices, interposed respectively, between the first upper and lower grips of the working cylinders, and the left and right uprights Fig. 7A

[0061] [Fig.7A] is a view of a helical thrust device (protective cover not shown), comprising a first part formed by a first cam and a second part formed by a cam, articulated in rotation with respect to each other, cooperating mutually by helical guiding surfaces. Fig. 7B

[0062] [Fig.7B] is a detail view of the second cam which has helical guide surfaces, as well as a radial extension forming a lever arm configured to be connected to an actuator. Fig. 7C

[0063] [Fig.7C] is a detail view of the first cam. Fig. 7D

[0064] [Fig.7D] is a detailed view of internal guiding elements, interposed between the first cam and the second cam. Fig. 7E

[0065] [Fig.7E] is a detailed view of internal guide members, interposed between the first cam and the second cam. Fig. 8

[0066] [Fig.8] is a detail view illustrating the arrangement of the actuator of a helical thrust device, consisting of a substantially vertical cylinder, extending along the upright on which the cams rest, the cylinder articulated by one end on a radial extension of the second cam, and by another end to the upright. Fig. 9

[0067] [Fig.9] illustrates: - the forces involved during rolling and experienced by a work cylinder, when this work cylinder, guided and held at its ends by shims, receives a driving torque, - a lateral offset, viewed along the direction of the tape's travel, between the axis (of rotation) of the working cylinder and the axis (of rotation) of the cylinder bearing on the working cylinder, the offset being in the same direction as the direction of the tape's travel, configured to balance the working cylinder, by limiting the camber of the working cylinder in the horizontal plane. Fig. 10

[0068] [Fig. 10] schematically illustrate different rolling mill configurations, and in particular: - (a) a four-roll rolling mill configuration, including powered work rolls, - (b) a six-roll rolling mill configuration, including powered work rolls, - (c) a six-roll rolling mill configuration, referred to as laterally supported, comprising work rolls held laterally by lateral support rolls, and motorized intermediate rolls, -(d) a 20-roll rolling mill configuration. Fig. 11

[0069] [Fig. 11] is a partial view of the rolling mill according to [Fig.1], showing only the rolling mill stand, the work rolls, and the lateral offset adjustment system, the stand comprising the first pair of uprights and the second pair of uprights which notably have bosses directed, two by two towards each other, at the level of the lower and upper work roll areas, the figure illustrating the first right boss of the right upright of the first pair and the second right boss of the right upright of the second pair. Fig. 12

[0070] [Fig. 12] are three cross-sectional views according to [Fig. 11] along three parallel cutting planes, namely: - (a) a first cross-sectional view passing through the left uprights of the first pair of uprights and the second pair of uprights, the figure illustrating the first left boss of the left upright of the first pair and the second left boss of the left upright of the second pair, - (b) a second cross-sectional view, juxtaposed, passing through: — the first left-hand thrust mechanism between the left upright of the first pair, on the one hand, and the assembly of the first upper and first lower lugs, formed by a rotating thrust device located partially on the first left-hand boss — the second left-hand thrust mechanism between one of the left uprights of the second pair, on the one hand, and the assembly of the second upper and second lower supports, formed by a rotating thrust device located partially on the second left-hand boss, - (c) a third cross-sectional view, juxtaposed, passing through the axes of the working cylinders, illustrating the grips receiving the guide ends which are guided in the grips by means of bearings. Fig. 13

[0071] [Fig. 13] is a view according to [Fig. 11], along a horizontal cutting plane passing through the bosses of the uprights, illustrating the positioning of the various rotating thrust devices, supported on the internal sides, and the respective grips of the lower working cylinder, the figure further illustrating the dimension L of the spacing between the bearings at the two ends of the working cylinder guide, namely the unguided portion of the cylinder's length that is liable to flex during rolling, as well as the relative positions of the grips (and their internal bearings) with respect to the various bosses of the uprights. Description of the implementation methods

[0072] The present disclosure relates to a cold rolling mill 1 configured for rolling a metal strip, and in particular to four rolls as illustrated in diagram (a) of [Fig. 10], or to a six roll, as illustrated in diagram (b) of [Fig. 10].

[0073] This disclosure focuses more specifically on such rolling mills whose work rolls are driven (directly) by a motor. However, it can also be applied to rolling mills whose intermediate rolls are driven or even those whose support rolls are driven by a motor.

[0074] The rolling mill 1 comprises, and in particular as illustrated in Figures 3 and 4: - a rolling mill cage 2 comprising, on a front side, a first pair of uprights M1, M2, and on a rear side, a second pair of uprights M3, M4, - a WRS upper working cylinder comprising a rolling table configured to come into contact with the upper surface of the metal strip and two guide ends, - a lower WRI working cylinder comprising a bearing table configured to come into contact with the lower surface of the metal strip and two guide ends, - a WAS upper support cylinder, configured to transmit a clamping force to the upper working cylinder, directly along a line of contact between the upper working cylinder and the upper support cylinder, in the case where the rolling mill has four rolls, or indirectly via an upper intermediate roll WIS, by a first support line between the upper support roll WAS and the upper intermediate roll WIS and by a second support line between the upper intermediate roll WIS and the upper working roll WRS, when the rolling mill has six rolls, - a lower support cylinder WAI, configured to transmit a clamping force to the lower working cylinder WRI, either directly along a line of contact between the lower working cylinder and the lower support cylinder, or indirectly via a lower intermediate cylinder WII by means of a first line of support between the lower support cylinder WAS and the lower intermediate cylinder WII and a second line of support between the lower intermediate cylinder WII and the lower working cylinder WRI, - two upper supports arranged at the two guide ends of the upper working cylinder WRS, including a first upper support E1S interposed between the two uprights M1, M2 of the first pair of uprights, and a second upper support E2S interposed between the two uprights M3, M4 of the second pair of uprights, - two lower supports arranged at the two guide ends of the lower working cylinder, including a first lower support Eli interposed between the two uprights M1, M2 of the first pair of uprights, and a second lower support E2I interposed between the two uprights of the second pair M3, M4.

[0075] The two guide ends of the lower work roll WRI are pivotally mounted in the lower supports Eli, E2I via bearings such as roller bearings. The intermediate portion of the lower work roll extending between the two bearings (typically roller bearings) extends lengthwise over a distance L, usually referred to as slenderness by those skilled in the art, which is susceptible to flexing under the rolling operations of the metal strip.

[0076] The two guide ends of the upper work roll WRS are pivotally mounted in the upper supports E1S, E2S via bearings such as roller bearings. The intermediate portion of the lower work roll extending between the two bearings (typically roller bearings) extends lengthwise over a distance L, usually referred to as slenderness by those skilled in the art, which is susceptible to flexing under the rolling operations of the metal strip.

[0077] In general: - The upper support roll WAS includes a bearing table, supported by the bearing table of the upper working roll WRS, in the case of a four-roll mill, or supported by the bearing table of the upper intermediate roll WIS, when the mill has six rolls. The bearing table of the The upper support cylinder WAS is extended by guide ends, which are rotationally guided within two upper supports EAS. The two upper supports EAS are received and guided vertically, respectively, between the two uprights M1 and M2 of the first pair of uprights on the front side, and between the two uprights M3 and M4 of the second pair of uprights on the rear side of the stand. The lower support cylinder WAI comprises a bearing table, which rests on the bearing table of the upper working cylinder WRI in the case of a four-roll mill, or on the bearing table of the lower intermediate cylinder WII when the mill has six rolls. The bearing table of the lower support cylinder WAI is extended by guide ends, which are rotationally guided within two lower supports EAI.The two lower EAS supports are received and guided vertically respectively between the two uprights M1, M2 of the first pair of uprights, on the front side, and between the two uprights M3, M4 of the second pair of uprights.

[0078] Generally, and as illustrated in [Fig. 2], the rolling mill includes hydraulic clamping means configured to transmit a rolling force (or clamping force) by bringing the support cylinders together, and in particular hydraulic pots configured to bear against the ends of the support cylinders. The two hydraulic pots PT can be arranged in the upper part of the stand, respectively positioned between the uprights M1, M2 of the first pair and the uprights M3, M4 of the second pair, to bear against the two upper ends EAS of the upper support cylinder WAS, as illustrated in the figures. Alternatively, the hydraulic pots can be arranged in the lower part of the stand to act on the lower ends EAI of the lower support cylinder WAI, according to another embodiment (not illustrated).

[0079] Generally, the 4-roller (or 6-roller) rolling mill may include a pass line adjustment system, configured to adjust the height of the pass line.

[0080] Generally, and with reference to [Fig. 1], and in this disclosure, an X, Y and Z coordinate system is defined with: - the X direction, called longitudinal, oriented along the direction of travel DL of the strip B between the working cylinders, typically horizontal, - the Y direction, also called transverse, is perpendicular and extends along the width of the metal strip. - the Z direction, is the vertical direction of the cage uprights.

[0081] In the case of the present disclosure, the support cylinders, working cylinders and even intermediate cylinders are oriented substantially parallel to the transverse direction Y.

[0082] As illustrated in figures 1 or 2, and according to one embodiment, such a PST pass line adjustment system is arranged in the lower part of the cage, to cooperate with the lower grips EAI of the lower support cylinder WAI, when the hydraulic pots engage with the upper grips EAS of the upper support cylinder WAS.

[0083] The cut line adjustment system comprises one or more straight angled shims configured to actuate the two EAI shims of the lower support cylinder and change the vertical position of the shims when the angled shim is moved by an actuator. In the case where the hydraulic pots are in the lower position, cooperating with the lower shims of the support cylinders, the cut line adjustment system comprising the angled shim is arranged in the upper portion of the cage to cooperate with the upper EAS shims of the upper support cylinder.

[0084] Generally, and in the case of a 6-roll mill, the lower and upper intermediate rolls WII and WIS each comprise a rolling table extended by guide ends of smaller diameter. The guide ends are rotatably mounted in upper brackets EIS for the upper intermediate roll and lower brackets Eli for the lower intermediate roll. Rotational guidance between the guide ends and the brackets EIS or Eli is provided by bearings, typically roller bearings. Figure 2 illustrates the span Pwl of the roll (unguided) between the bearings at a distance L.

[0085] The Eli or EIS clamps of each intermediate cylinder WII or WIS are vertically between the cage uprights to transmit the clamping force.

[0086] The rolling mill can be equipped with a first device for adjusting the axial position of the upper intermediate roll WIS, comprising a first actuator configured to move the upper swages EIS along the axis of the upper intermediate roll WIS, and a second device for adjusting the axial position of the lower intermediate roll, comprising a second actuator configured to move the upper swages EIS along the axis of the lower intermediate roll WII. The first and second actuators can be VRI cylinders, respectively.

[0087] Generally, as illustrated in [Fig.4], the first and second devices are configured to move the two intermediate cylinders axially in opposite directions, in order to allow adjustment of the axial overlap area between the two lower and upper intermediate cylinders, and typically in such a way as to allow adjustment of the overlap area to the width dimension of the band.

[0088] Generally, a system (not shown here) can be configured to move the two working cylinders axially in opposite directions, in order to allow an axial overlap zone adjustment between the two lower and upper working cylinders, and typically in such a way as to allow adjustment of the overlap zone to the width dimension of the band.

[0089] Generally, the rolling mill includes an opening and closing system which may include: - a first opening / closing mechanism 9, left, with a vertical cylinder, comprising an upper part 90 coupled on the left, laterally to the first upper bracket E1S, and a lower part 91 coupled on the left laterally to the first lower bracket Eli, as well as a hydraulic cylinder VR connecting the upper and lower parts 90, 91, the cylinder configured to move the first lower and upper brackets Eli and E1S apart or together, said first opening mechanism interposed between the left upright M1 and the first upper and lower brackets, - a first opening / closing mechanism 10, right, with a vertical cylinder comprising an upper part 100 coupled on the right, laterally to the first upper bracket E1S, and a lower part 101 coupled on the right laterally to the first lower bracket Eli, as well as a hydraulic cylinder connecting the upper and lower parts 100, 101,the jack configured to move the first lower and upper supports apart, or bring them together, said first opening mechanism interposed between the right upright M2 and the first upper and lower supports, - a second opening / closing mechanism, left-hand, with a vertical cylinder comprising an upper part coupled on the left, laterally to the second upper bracket E2S, and a lower part coupled on the left laterally to the second lower bracket E2I, as well as a hydraulic cylinder connecting the upper and lower parts, the cylinder configured to move the first brackets apart or together, said first opening mechanism interposed between the left-hand upright M3 and the second upper and lower brackets, - a second opening / closing mechanism, right-hand, with a vertical cylinder comprising an upper part coupled on the left, laterally to the second upper bracket E2S, and a lower part coupled on the left laterally to the second lower bracket E2I as well as a hydraulic cylinder connecting the upper and lower parts, the cylinder configured to move the first brackets apart or together, said first opening mechanism interposed between the left upright M3 and the second upper and lower brackets.

[0090] When the cage is opened, the vertical cylinders of the first and second mechanisms can be deployed to separate, on the one hand, the first upper and lower supports E1S Eli from each other, and on the other hand, the second upper and lower supports E1S Eli from each other, thus separating the working cylinder upper WRS relative to the lower working cylinder WRI along the vertical direction Z.

[0091] The vertical cylinders can still be stressed during rolling operations, under the pressure of the PT hydraulic pots to balance the upper and lower working cylinders, in particular with regard to vertical forces.

[0092] The upper working roll WRS and the lower working roll WRI typically include ARB drive shafts coupled to a motor for the direct rotation of the lower and upper working rolls in opposite directions. The use of drive shafts coupled to a motor for the direct drive of the working rolls ensures efficient and constant transmission of motor torque. This improves the accuracy and stability of the rolling operation, reducing the risk of slippage and wear.

[0093] During rolling, the working cylinder is subjected to the action of the strip which includes the vertical clamping force FS

[0094] As illustrated in [Fig. 9], three main horizontal forces applied to the rolling table of the working cylinder include: - the horizontal component of the clamping force FC of the cylinder bearing against the working cylinder, - half the voltage difference T between that of the input band Tf and that of the output band Tb (1 / 2T) - the rolling force CirF due to the transmission of motor torque to the work cylinder, when the work cylinders are driven directly by the motor.

[0095] In the case of a rolling mill where the intermediate rolls are driven by a motor or in the case where the support rolls are driven by a motor, the Cirf component is doubled by a force corresponding to the drive force of the motorized roll.

[0096] According to the Applicant's experiments, the horizontal arrow can be approximated by the following formula:

[0097] [Math.l]

[0098] Where: - L is the slenderness of the cylinder, namely the dimension of spacing between the bearings, typically the bearings at the two guiding ends of the working cylinder (lower or upper), - D is the diameter of the working cylinder and K is a variable dependent on other parameters which are independent of the diameter and slenderness of the working cylinder.

[0099] The importance of the L3 / D4 ratio in the value of the horizontal deflection is noted here. The present disclosure focuses primarily on reducing the parameter L, namely the possibility of reducing as much as possible the spacing between the guide bearings of the working cylinder (lower or upper), which advantageously allows for a reduction in deflection, while working with small working cylinder diameters.

[0100] The span PWR of the upper working cylinder WRS or of the lower cylinder WRI) forming the portion of the unguided working cylinder, can thus have a distance L along the axis of the working cylinder and the lower working cylinder and the upper working cylinder can have a diameter D (at the level of the rolling table), the ratio D / L being less than or equal to 23%.

[0101] The working cylinder is still subject to the horizontal component of the FE forces exerted by the handles E1S, Eli, E2S, E2I on the guide ends of the working cylinder.

[0102] When the axes of the cylinders are contained in the same vertical plane, the rolling force due to the transmission of the motor torque on the working cylinder, while the cylinder is held by its guide ends by the grips, cambers the working cylinder by generating a deflection which is of maximum amplitude between the guide ends, directed upstream of the cylinder in the direction of the strip's movement.

[0103] Offsetting the axis of the working cylinder relative to the axis of the cylinder supported on the working cylinder along the direction of the strip, makes it possible to obtain a horizontal component of the rolling clamping force FC in the opposite direction to the horizontal component of the rolling force, thus making it possible to balance the working cylinder, and thus to reduce the horizontal component of the deflection due to the motor torque.

[0104] As illustrated in [Fig.9], it is important to be able to adjust the value of the OFS offset between the axis of the working roll (lower or upper) and the axis of the roll bearing on the working roll (namely the intermediate roll or the support roll) preferably in a progressive manner (and not all or nothing), in particular during rolling operations, and so as to be able to optimally control the horizontal balance of the working roll during rolling operations.

[0105] The present disclosure finds particular application for small diameter work cylinders, typically where the ratio of work cylinder diameter to maximum strip width is less than 0.23 and which are more sensitive to bending than larger diameter cylinders.

[0106] For this purpose, the rolling mill includes an adjustment system 3 for a lateral offset configured to implement a lateral offset OFS, viewed along the rolling direction DL between, on the one hand, an axis Awr of the lower work roll WRI or respectively of the upper working cylinder WRS, and on the other hand, an axis Ap of a cylinder resting on the working cylinder.

[0107] The cylinder in support on the lower or upper working cylinder WRI, WRS consists of the lower intermediate cylinder WII; or upper cylinder WIS when the rolling mill has six cylinders.

[0108] The cylinder in support on the lower or upper working cylinder WRI, WRS consists of the lower or upper support cylinder WAI or WAS when the rolling mill has four cylinders.

[0109] Such a lateral offset adjustment system 3 comprises: - a first left-hand thrust mechanism 31g between one left Ml of the uprights of the first pair and the assembly of the first upper grip E1S and first lower grip Eli, the first left-hand mechanism configured to exert a thrust force on the assembly of the first upper grip E1S and first lower grip Eli to move said assembly in a first direction along the rolling direction DL - a first right-hand thrust mechanism 31d between the other right-hand member M2 of the uprights of the first pair on one side, and the first upper brace E1S and the first lower brace Eli, the first right-hand mechanism configured to exert a thrust force on the assembly of the first upper brace E1S and the first lower brace Eli to move said assembly in a second direction along the rolling direction DL — a second left-hand thrust mechanism 32g between one left-hand M3 of the uprights of the second pair, on the one hand, and the assembly of the second upper grip E2S and second lower grip E2I, the second left-hand mechanism configured to exert a thrust force on the assembly of the second upper grip E2S and second lower grip E2I to move said assembly in the first direction along the rolling direction DL - a second straight push mechanism 32d between the other straight M4 of the uprights of the second pair on the one hand, and the assembly second upper grip E2 and second lower grip E2I, the second straight configured to exert a push force on the assembly second upper grip E2S and second lower grip E2I to move said assembly in the second direction along the rolling direction DL.

[0110] The adjustment system may further include a control and command unit, synchronizing: - the first left-hand push mechanism 31g and the second left-hand push mechanism 32g to simultaneously push the first upper and lower handles, on the one hand, and on the other hand the second upper and lower handles, to move the axes of the lower and upper working cylinders, following the first direction along the rolling direction, - the second right-hand thrust mechanism 31d and the second right-hand thrust mechanism 32d to simultaneously push the first upper and lower presses, on the one hand, and on the other hand, the second upper and lower presses, to move the axes of the lower and upper working cylinders, in the second direction according to the rolling direction,

[0111] Generally, the first and second left thrust mechanisms 31g, 32g and the first and second right thrust mechanisms 31d, 31d being antagonistic, the control unit controls the right mechanisms 31g, 32g and the left mechanisms 31d, 32d in reverse order, namely that: - When the left mechanisms 31g, 32g exert a pushing force on the grips, the right mechanisms 31d, 32d retract so as not to oppose the movement of the grips of the working cylinders in the first direction - when the right mechanisms 31d, 32d exert a pushing force on the levers, the left mechanisms 31g, 32g retract so as not to oppose the movement of the levers in the second direction.

[0112] The control and command unit synchronizes the first and second left push mechanisms 31g, 32g and the first and second right mechanisms 31d, 32d, to ensure play recovery, to the right and left of the upper and lower handles Eli, E1S, E2I, E2S.

[0113] In general: - the first left push mechanism 31g can be interposed between the left upright Ml said first left opening / closing mechanism 9 - the first right-hand push mechanism 31d can be inserted between the right-hand upright M2 and said first right-hand opening / closing mechanism 10, - the second left-hand push mechanism 32g can be inserted between the left-hand upright M3 and said second right-hand opening / closing mechanism, - the second left adjustment mechanism 32d can be inserted between the left upright M4 and said second right opening / closing mechanism.

[0114] The left upright Ml of the first pair and the left upright M3 of the second pair are formed respectively by bodies extending vertically in height, the left upright Ml of the first pair and the left upright M3 of the second pair respectively presenting lateral surfaces, typically vertical, of mutually facing bodies.

[0115] According to this disclosure, the left upright Ml has a first left boss B1 projecting from the lateral surface of the left upright body Ml of the first pair, the first left boss B1 extending from the upright from a base up to a top of the boss, following the transverse direction Y. The [Fig. 13] illustrates the height H1 of the first left boss B1.

[0116] According to this disclosure, the left upright M3 has a second left boss B3 projecting from the lateral surface of the left upright M3 of the second pair, the boss B3 extending from the upright from a base to a boss apex, along the transverse direction Y, and as illustrated in [Fig. 12]. [Fig. 13] illustrates the height H3 of the second left boss B3.

[0117] The first left boss B1 and the second left boss B3 are directed towards each other, in a direction parallel to the axes of the working cylinders, namely in the transverse direction Y.

[0118] The right upright M2 of the first pair and the right upright M4 of the second pair are formed respectively by bodies extending vertically in height, the right upright M2 of the first pair and the right upright M4 of the second pair respectively having lateral surfaces, typically vertical, mutually facing each other.

[0119] According to this disclosure, the right upright B2 has a first right boss B2 projecting from the lateral surface of the right upright of the first pair, the boss B2 extending from the upright from a base to a top of the boss in the transverse direction Y. [Fig. 13] illustrates the height H2 of the first right boss B2.

[0120] According to this disclosure, the right upright M4 has a second right boss B4 projecting from the lateral surface of the right upright M4 of the second pair, extending from the upright from a base to a top of the boss in the transverse direction Y. [Fig. 13] illustrates the height H4 of the second right boss B4.

[0121] The first straight boss B2 and the second straight boss B4 are directed towards each other, in a direction parallel to the axes of the working cylinders, namely in the transverse direction Y, and as illustrated in particular in figures 1 and 11.

[0122] In general, the bosses Bl, B2, B3, B4 may have a trapezoidal, for example isosceles, section when viewed along a vertical plane parallel to the transverse direction, the larger base of the trapezoid forming the base of the boss, the smaller base of the trapezoid forming the smaller base of the boss.

[0123] Notably, and as illustrated by way of example in [Fig. 13]. - the first left thrust mechanism 31g bears at least partially on an internal flank of the first left boss B1 and is configured to exert a thrust on the first upper grip E1S and the first lower grip Eli, which are advantageously located overlapping the next first boss Bl a direction parallel to the axes of the working cylinders, namely along the transverse direction Y and along the vertical direction Z. - the first right-hand thrust mechanism 31d bears at least partially on an internal flank of the first right-hand boss B2 and is configured to exert a thrust on the first upper grip E1S and the first lower grip Eli, which are advantageously located overlapping the first right-hand boss B2 in a direction parallel to the axes of the working cylinders and in a vertical direction; - the second left-hand thrust mechanism 32g bears at least partially on an internal flank of the second left-hand boss B3 and is configured to exert a thrust on the second upper grip E2S and the second lower grip E2I, which are advantageously located overlapping the second left-hand boss B3 in a direction parallel to the axes of the working cylinders, namely in the transverse direction Y and in the vertical direction Z. - the second right thrust mechanism 32d bears at least partially on an internal flank of the second right boss B4 and is configured to exert a thrust on the second upper arm E2S and the second lower arm E2I, which are located overlapping the second right boss B4 in a direction parallel to the axes of the working cylinders and in a vertical direction.

[0124] In general, as illustrated by way of example in [Fig. 13], the supports of the internal sides provided by the bosses Bl, B2, B3, B4 make it possible to bring together the two supports supporting each working cylinder (lower or upper) in the transverse direction, and thus to reduce the distance L separating the guide bearings at the two guide ends, by comparison of cage according to the prior art without the bosses.

[0125] In particular, the span PWR of the upper working cylinder WRS forming the unguided portion of the working cylinder has a distance L along the axis of the working cylinder defined between the bearings at the two guiding ends which is intermediate between, on the one hand, the distance separating a top of the first left boss Bl and a top of the second left boss B3 and, on the other hand, the distance separating the base of the first left boss Bl and the base of the second left boss B3: In other words, the distance L is typically greater than the distance separating the two tops of the bosses Bl and B3, but typically less than the distance separating the two bases of the bosses Bl and B3.

[0126] Furthermore, the PWR bearing surface of the upper working cylinder WRI, forming the unguided portion of the working cylinder, has a distance L along the axis of the working cylinder defined between the bearings at the two guide ends, which is intermediate between, on the one hand, the distance separating a vertex of the first right boss B2 and a The apex of the second right-hand boss B4 and, on the other hand, the distance separating the base of the first right-hand boss B2 and the base of the second right-hand boss B4. In other words, the distance L is typically greater than the distance separating the two apexes of bosses B2 and B4, but typically less than the distance separating the two bases of bosses B2 and B4.

[0127] Generally, the body of each upright has a reduced width section, typically constant, along the transverse direction Y of the rolling mill, and a greater width section at the bosses, consisting of: - the first left boss B1 for the left upright M1 of the first pair, - the second left boss B3 for the left upright M3 of the second pair, - the first right boss B2 for the right upright M2 of the first pair, - the second right boss B4 for the right upright M4 of the second pair.

[0128] Generally, the body of each upright, including the boss, may be a single piece of metal.

[0129] According to another possibility, these bosses Bl, B2, B3, B4 can be added elements (blocks) and fixed by any means of fastening, for example screws, to the lateral surfaces of the upright bodies M1 to M4 respectively. Such a multi-part embodiment can facilitate the manufacture of the uprights with bosses.

[0130] Generally, when the rolling mill has six rolls, having (in addition to the two working rolls and the two support rolls) the lower intermediate roll WII and the upper intermediate roll WIS.

[0131] The lower intermediate cylinder WII and the upper intermediate cylinder WIS each comprise a bearing table, extended by guide ends, of smaller diameter, the guide ends rotatably mounted in upper sockets EIS for the upper intermediate cylinder WIS via bearing and the guide ends rotatably mounted in lower sockets Eli for the lower intermediate cylinder WII.

[0132] According to one possibility: - the PW1 span of the upper intermediate cylinder IS, (namely the spacing between the two spokes at the two guide ends), is greater than the span of the upper working cylinder WRS, - the PW1 span of the lower intermediate cylinder II, (namely the spacing between the two bearings at the two guide ends) is greater than the span of the lower working cylinder WRI.

[0133] According to one embodiment of the present disclosure, and as illustrated in particular in the figures of this application, the first thrust mechanisms 31g, 31d left and right, and the second thrust mechanisms 32g, 32d left and right, comprise in whole or in part, rotating helical thrust devices 4.

[0134] In particular, the adjustment system comprises: - a (first left) rotating helical thrust device for the first left thrust mechanism 31g, - a (first right) rotating helical thrust device for the first right thrust mechanism 31d, - a (second left) rotating helical thrust device for the second left thrust mechanism 32g, - a (second right) rotating helical thrust device for the second right thrust mechanism 32d.

[0135] Each rotating helical thrust device comprises a first part 5 bearing (directly or indirectly) on one of the uprights M1,M2 of the first pair or respectively bearing on one of the uprights M3, M4 of the second pair and a second part 6 configured to laterally push the first lower and upper supports Eli, E1S in the case of the first thrust mechanisms (left or right), or respectively to push respectively the second lower and upper supports E2I, E2S in the case of the second thrust mechanisms (left and right).

[0136] The first part 5 and the second part 6 of each rotating helical thrust device are pivotally articulated with respect to each other, around a rotation axis A4 under the action of an actuator AT, said rotation axis A4 typically oriented along the rolling direction DL (namely along the X direction).

[0137] The first part 5 and the second part 6 comprise helical guide surfaces 7 around said rotation axis A4, mutually supporting, configured to cause a separation of the second part 6 from the first part 5 along the direction of the rotation axis A4, during a relative rotation between the first part 5 and the second part 6.

[0138] The helical guide surfaces 7 can be cam surfaces of the first part 5 and the second part 6 which are respectively a first cam and a second cam, and as illustrated according to the embodiment in the figures.

[0139] According to an embodiment not illustrated, the helical guide surfaces may further be threads, respectively internal and external, mutually engaging between the first part 5 and the second part 6, the first part 5 and the second part 6 cooperating by screwing with each other. The internal and external threads may be simple threads distributed between the first and second parts.

[0140] Helical guide surfaces can still have multiple threads, including several internal threads, engaging simultaneously with several external threads, the internal and external threads arranged respectively between the first piece 5 and the second piece 6.

[0141] Thus, by controlling the angular position of the second part 6 relative to the second part 5, it becomes possible to adjust the gap between the second part 6 and the first part 5, along the direction of the axis of rotation 4 and thus to exert a pushing action by increasing the gap between the two cams 5 and 6, or on the contrary to reduce the gap on the other side of the grips in order to take up the play on the opposite side of the grips undergoing the push.

[0142] According to this disclosure, this is a progressive preference control, namely that the angular position of the second part 6 relative to the first cam can take various intermediate angular positions between: - a first angular position between the second part 6 and the first part 5 corresponding to a minimum gap between the second cam 6 and the first cam 5 - a second angular position between the second part 6 and the first part 5 corresponding to a maximum gap between the second cam 6 and the first cam 5.

[0143] The intermediate positions can thus allow different spacings to be obtained between the two parts 5, 6, with the spacing increasing from the first angular position to the second angular position. In particular, parts 5, 6 can allow continuous adjustment between the two extreme angular positions, between the first and second positions.

[0144] In particular, and as illustrated in the embodiment of the rotating helical thrust device, the helical guide surfaces 7 can extend along one or more helical trajectories around said axis of rotation A4 on the first part 5 and on the second part 6.

[0145] In particular, and according to an embodiment shown in Figures 7A to 7C: - the first part 5 forms a first cam which may include a first helical guide surface 70 extending over a first angular portion 71 of the first cam around said axis of rotation A4 and a second helical guide surface 71 extending over a second angular portion of the first cam, 1 - the second part 6 forms a second cam which includes a third helical guide surface 72 extending over a first angular portion of the second cam and a fourth helical guide surface 73 extending over a second angular portion of the second cam.

[0146] Generally, the first angular portion and the second angular portion (of the first part, in particular the cam, and of the second part, in particular the cam) may have the same angular range less than or equal to 180°

[0147] The first helical guide surface 70 and the second helical guide surface 71 of the first cam are configured to cooperate in guiding simultaneously with the third helical guide surface 72 and the fourth helical guide surface 73 of the second cam.

[0148] The first angular portion and the second angular portion of the first cam are respectively less than or equal to 180°. For example and according to one embodiment, the first helical guide surface 70, with a helical trajectory, extends over an angular portion of 180° around said axis of rotation and the second helical guide surface 71, with a helical trajectory, extends over a second angular portion of 180°.

[0149] The first angular portion and the second angular portion of the second cam 6 are respectively less than or equal to 180°. For example, and according to one embodiment, the third helical guide surface 72 extends over an angular portion of 180° around said axis of rotation and the fourth helical guide surface 73 has a helical trajectory over a second angular portion of 180°.

[0150] A first advantage of rotating helical thrust devices is their small size, and by comparison to the prior art with inclined wedge described in the introduction.

[0151] In particular, the helical guide surfaces 70 of the parts 5, 6 of each rotating helical thrust device 4 can be arranged overlapping, along the transverse direction Y, with the width of one of the uprights M1, M2, M3, M4 on which the rotating helical thrust device 4 is supported; the helical guide surfaces 7 of diameter D of each rotating helical thrust device can advantageously be contained along the transverse direction Y, along the width of the upright (respectively M1, M2, M3 or M4) comprising the boss (respectively B1, B2, B3 or B4).

[0152] Thus, for example, in [Fig. 6], the rotating helical thrust device of the thrust mechanism, left, 31g, has an obstruction of the helical guide surfaces 7, of diameter D, which is contained within the width of the upright M1, left of the first pair including the height H1 of the first left boss BL

[0153] The rotating helical thrust device, of the straight thrust mechanism 31d, has a footprint of the helical guide surfaces 7, of diameter D, which is contained along the width of the upright M2, straight, of the first pair, including the height H2 of the first straight boss B2.

[0154] Similarly, the rotating helical device of the thrust mechanism, left, 32g, has a footprint of the helical guide surfaces 7, of diameter D, which is contained according to the width of the upright M3, left of the second pair including the height H3 of the second left boss B3.

[0155] The rotating helical thrust device, of the straight thrust mechanism 32d, has a footprint of the helical guide surfaces 7, of diameter D, which is contained along the width of the upright M4, straight, of the second pair, including the height H4 of the second straight boss B4.

[0156] In general: - the first left thrust mechanism 31g and the first right thrust mechanism 31d each comprise a single pair first piece 5 and second piece 6 (in particular a single pair first cam and second cam) extending in height, overlapping the height of the assembly first upper foot E1S and first lower foot Eli; in particular and as seen on the left in [Fig.5], the helical guide surfaces 7 of diameter D of the first mechanism (left or right) can extend, overlapping, along the Z direction, of the first upper and lower feet Eli, El S. - the second left thrust mechanism 32g and the second right thrust mechanism 31d each comprise a single pair first piece 5 and second piece 6 ((in particular a single pair first cam and second cam) extending in height, overlapping the height of the assembly second upper foot E2S and second lower foot E2I, in particular the helical guide surfaces 7, of diameter D of the first mechanism (left or right) can extend, overlapping, along the Z direction, of the second upper and lower feet E2I, E2S.

[0157] By using a single pair of parts 5, 6 for each thrust mechanism, the system simplifies the design while ensuring precise adjustment of the lateral offset. This improves adjustment efficiency and reduces mechanical complexity. This configuration allows the entire height of the rollers to be covered, ensuring a uniform distribution of the applied forces. This minimizes stress on the rollers and improves the stability of the work rolls. By reducing the number of components required, the system decreases maintenance needs and the risk of failure, thus contributing to more reliable and durable operation of the rolling mill.

[0158] The adjustment system can therefore comprise only four rotating helical thrust devices 4 for the first thrust mechanisms, left 31g and right 31d, respectively, and the second thrust mechanisms, left 32g and right 32d.

[0159] According to an advantageous embodiment (illustrated in the figures), limiting the footprint of the rolling mill along the transverse direction Y, the AT actuators of the helical thrust devices can be typically hydraulic cylinders or electric, extending longitudinally along the height of the uprights M1, M2, M3, M4. By integrating the jacks along the uprights, the system optimizes space and reduces bulk, facilitating access for maintenance and improving the ergonomics of the installation.

[0160] A first cylinder, left, extending substantially longitudinally along the height of the (first) left upright Ml configured for controlling the angular position of the second part 6 relative to the first part 5 of the first push mechanism, left 31g.

[0161] A second, straight jack extending substantially longitudinally along the height of the (second) upright M2, configured for controlling the angular position of the second part relative to the first part of the first thrust mechanism, straight 31d.

[0162] A third cylinder, left, extending substantially longitudinally along the height of the (third) left upright M3 configured for controlling the angular position of the second part relative to the first part of the second thrust mechanism, left 32g.

[0163] A fourth, straight jack extending substantially longitudinally along the height of the (fourth) upright M4 straight configured for controlling the angular position of the second part relative to the first part of the second thrust mechanism, straight 31d.

[0164] The second part 6 may have an extension 60 or a lever arm extending outwards, radially to said second part 6 around the axis of rotation 4, beyond the diameter D of the helical guide surfaces 7, for example beyond the third and fourth guide surfaces 72,73.

[0165] Said extension 60 or more generally the lever arm protrudes from the upright (in particular first upright M1, second upright M2, third upright M3, or fourth upright), typically outwards from the cage along the transverse direction Y, the cylinder VR (in particular first cylinder, second cylinder, third cylinder or fourth cylinder) being articulated by its first end of the hydraulic cylinder on said extension 60 or more generally on the lever arm.

[0166] All or part of the VR cylinders (namely the first cylinder, the second cylinder, the third cylinder and the fourth cylinder) are articulated to said second part 6 via a first end of the cylinder, and articulated via a second end to one of the uprights M1, M2, M3, M4 by a pivot axis Av, in particular parallel to the axis of rotation 4 of said rotary cam thrust device 4.

[0167] When the cylinder extends or retracts, it causes the second part 6 to rotate relative to the first part 5, while pivoting slightly relative to the upright relative to said pivot axis Av.

[0168] In order to limit the bulk along the transverse direction Y, by bringing the substantially vertical cylinder VR and the upright as close as possible, a notch ECH in depth of the upright can extend at the right of the cylinder coupled to the upright, along the direction Y. When the cylinder is deployed or retracted, this allows the cylinder to pivot around said pivot axis Av, entering the notch ECH, and without interference between the upright.

[0169] According to another embodiment (not illustrated), the rotational movement between the first part 5 and the second part 6 can be obtained by a toothed ring mounted to rotate with the second part (or the first part), coaxial with said axis of rotation, the toothed ring meshing via a drive pinion driven by an electric geared motor constituting the actuator. The geared motor can be regulated during control, in terms of force or position.

[0170] According to an advantageous embodiment, the first part 5 and the second part 6 are preferably encapsulated in a housing 8 protecting the helical guide surfaces 7 from the external environment, in particular the housing comprising a cylindrical wall with an axis coaxial to the axis of rotation A4 of the rotating helical thrust device 4. The encapsulation of the parts (in particular the cams) in a housing protects the helical guide surfaces (in particular the guide surfaces of the cams or the internal and external threads) from external contaminants, such as oils and metal particles. This reduces the need for frequent maintenance and extends the service life of the components.

[0171] This disclosure further relates to a method for rolling a metal strip implemented by a rolling mill 1 according to this disclosure, comprising: / A / rolling the metal strip B as it passes between the two upper and lower work rolls, which are held under pressure on the strip by a hydraulic clamping action between the two support rolls WAS, WAI, lower and upper, and by transmission of drive torques to the upper work roll WRS and the lower work roll WRI, / B / balancing the upper and lower work rolls, by - a lateral, upper offset between the axis of the upper WRS working cylinder and the axis of the cylinder bearing on the upper working cylinder, - a lower lateral offset between the axis of the lower WRI working cylinder and the axis of the cylinder bearing on the lower working cylinder, and in which the upper and lower OFS lateral offsets are obtained in particular by progressive real-time control of the angular position of the first part 5 relative to the second part 6 of each rotating helical device 4 to ensure a lateral thrust of the first lower and upper arms Eli, E1S and of the second lower and upper working cylinders E2I, E2S.

[0172] The rolling process using real-time progressive control of the angular position of the parts 5,6 allows for precise adjustment of the lateral offset during rolling. This ensures optimal balancing of the working rolls, improving the quality of the final product.

[0173] Real-time control allows for rapid adaptation of rolling parameters to changing conditions, thereby optimizing process efficiency and productivity.

[0174] In summary, this disclosure may offer all or some of the following advantages. 1) a rolling mill stand having the first pair of uprights M1, M2 and the second pair of uprights M3, M4, which advantageously have bosses projecting inwards towards the inside of the stand, along the transverse direction Y, the bosses configured to serve respectively as bearing surfaces for the lateral offset adjustment mechanisms 31g, 31d, 32g, 32f advantageously allowing a reduction of the distance L between the guide bearings of each work roll, and in order to decrease the sensitivity to deflection of the small diameter work rolls. 2) The use of rotating helical thrust devices in the lateral offset adjustment system allows for precise and gradual adjustment of the working roll shanks' position. This improves the balancing of horizontal forces and reduces roll camber, which is important for maintaining rolling quality, especially when the working roll diameters are small. 3) The use of rotating helical thrust devices makes it possible to limit the overall size of the rolling mill in the transverse direction Y, and compared to the rolling mill equipped with straight cam thrust devices, as taught by US 4.736.609. 4) The use of rotating helical thrusts allows the guide surfaces to be protected by a hood, preventing these surfaces from being soiled by the oils and metallic particles of rolling contained in the oil. List of reference signs

[0175] - 1: Rolling mill, - 2. Cage, - 3. Lateral offset adjustment system, - 31g, 31d. First mechanisms for adjusting the lateral offset, respectively left and right, - 32g, 32d. Second lateral offset adjustment mechanisms, left and right respectively, - 4. Helical thrust device, - A4. Axis of rotation, - 5, 6, respectively first piece and second piece, - 7. Helical guide surfaces, - 71, 72, 73, 74. First, second, third and fourth helical guiding surfaces - B. (Metallic) band, -M1, M2. Uprights (first pair of uprights of the cage, respectively left and right), - Bl, B2. Respectively, first left boss and first right boss - M3, M4. Uprights (second pair of uprights in the cage, left and right respectively), - B3, B4. Respectively second boss on the left and second boss on the right. - PT: Hydraulic clamping pots, - PST. Pass line adjustment system - WRI. Lower working cylinder, - WRS. Upper working cylinder, - PWr. Reach of the working cylinder (lower or upper) extending between the bearings, - L. Distance - WAI Upper Support Cylinder, - WAS. Lower support cylinder, — PWA. Reach of the support cylinder (lower or upper) extending between the bearings - WII. Lower intermediate cylinder, - WIS. Upper intermediate cylinder, - - PWL Reach of the intermediate cylinder (lower or upper) extending between the bearings - E1S, E2S. First upper grip and second upper grip (for the upper working cylinder WRS), -Eli, E2I. First lower grip and second lower grip (for the lower working cylinder WRI), - Eli, EIS. Lower and upper empoise (for the intermediate cylinder), - EAI, EAS. Lower and upper grips (for the support cylinder), - VRI. Cylinders (axial adjustment device for intermediate cylinders) - 8. Hood, - 9. First opening / closing mechanism, left, - 90, 91. Lower and upper parts respectively, - 10 First opening / closing mechanism, right., - 100, 101. Lower and upper parts respectively

Claims

1. Demands Cold rolling mill (1) with four or six cylinders, configured for rolling a metal strip, - a rolling mill stand (2) comprising, on a front side, a first pair of uprights, and on a rear side, a second pair of uprights, - an upper working cylinder (WRS) comprising a rolling table configured to come into contact with the upper surface of the metal strip and two guide ends, - a lower working cylinder (WRI) comprising a bearing table configured to come into contact with the lower surface of the metal strip and two guide ends, - an upper support cylinder (WAS), configured to transmit a clamping force to the upper working cylinder, either directly along a contact line between the upper working cylinder and the upper support cylinder, or indirectly via an upper intermediate cylinder (WIS) by means of a first contact line between the upper support cylinder and the upper intermediate cylinder and a second contact line between the upper intermediate cylinder and the upper working cylinder, - a lower support cylinder (WAI), configured to transmit a clamping force to the lower working cylinder, directly along a contact line between the lower working cylinder and the lower support cylinder,or indirectly via a lower intermediate cylinder (WII) by means of a first support line between the lower support cylinder and the lower intermediate cylinder and a second support line between the lower intermediate cylinder and the lower working cylinder - two upper supports arranged at the two guide ends of the upper working cylinder (WRS), including a first upper support (ElS) interposed between the two uprights (M1, M2) of the first pair of uprights, and a second upper support (E2S) interposed between the two uprights (M3, M4) of the second pair of uprights, the two guide ends of the upper working cylinder (WRS) pivotally mounted in the upper supports (ElS, E2S) via bearings such as roller bearings, - two lower supports arranged at the two guide ends of the lower working cylinder, including a first lower support (Eli) interposed between the two uprights (M1, M2) of the first pair of uprights, and a second lower support (E2I) interposed between the two uprights of the second pair (M3, M4), the two guide ends of the lower working cylinder (WRI) pivotally mounted in the lower supports (Eli, E2I) via bearings such as roller bearings, - an adjustment system (3) for a lateral offset configured for implementing a lateral offset, viewed along the rolling direction (DL), between, on the one hand, an axis (Awr) of the lower work roll (WRI) or respectively of the upper work roll (WRS), and on the other hand, an axis (Ap) of a roll bearing on the work roll, consisting of the lower or upper intermediate roll (WII; WIS) when the mill has six rolls, and consisting of the lower or upper support roll (WAI, WAS) when the mill has four rolls, and in which the adjustment system comprises: — a first left-hand thrust mechanism (31g) between one left (Ml) of the uprights of the first pair, on the one hand, and the first upper grip (E1S) and first lower grip (Eli) assembly, on the other hand, configured to exert a thrust force on the first upper grip (E1S) and first lower grip (Eli) assembly to move said assembly in a first direction along the rolling direction (DL) — a first straight thrust mechanism (31d) between the other straight (M2) of the uprights of the first pair on the one hand, and the first upper brace (E1S) and the first lower brace (Eli) on the other hand, configured to exert a thrust force on the assembly first upper brace (E1S) and first lower brace (Eli) to move said assembly in a second direction along the rolling direction (DL), — a second left-hand thrust mechanism (32g) between one left (M3) of the uprights of the second pair, on the one hand, and the assembly of the second upper brace (E2S) and second lower brace (E2I), on the other hand, configured to exert a thrust force on the assembly of the second upper brace (E2S) and second lower press (E2I) to move said assembly in the first direction along the rolling direction (DL) — a second straight thrust mechanism (32d) between the other straight (M4) of the uprights of the second pair on the one hand, and the assembly of the second upper strut (E2S) and second lower strut (E2I) on the other hand, configured to exert a thrust force on the assembly of the second upper strut (E2S) and second lower strut (E2I) to move said assembly in the second direction along the rolling direction (DL), characterized in that - the left upright (Ml) of the first pair and the left upright (M3) of the second pair are formed respectively by bodies extending vertically in height, the left upright (Ml) of the first pair and the left upright (M3) of the second pair respectively having mutually facing vertical lateral surfaces, as well as a first left boss (Bl) projecting from the lateral surface of the left upright (Ml) of the first pair, extending from the upright from a base to a top of the boss, and a second left boss (B3) projecting from the lateral surface of the left upright (M3) of the second pair, extending from the upright from a base to a top of the boss, the first left boss (Bl) and the second left boss (B3) directed towards each other, following a direction parallel to the axes of the working cylinders, -.the right upright (M2) of the first pair and the right upright (M4) of the second pair are formed respectively by bodies extending vertically in height, the right upright (M2) of the first pair and the right upright (M4) of the second pair respectively having mutually facing vertical lateral surfaces, as well as a first right boss (B2) projecting from the lateral surface of the right upright of the first pair, extending from the upright from a base to a top of the boss, and a second right boss (B4) projecting from the lateral surface of the right upright (M4) of the second pair, extending from the upright from a base to a top of the boss, the first right boss (B2) and the second right boss (B4) directed towards each other, following a direction parallel to the axes of the working cylinders, and in which: - the first left thrust mechanism (31g) bears at least partially on an internal flank of the first left boss (B1) and is configured to exert a thrust on the first upper grip (E1S) and the first lower grip (Eli) which are located overlapping the first boss (B1) in a direction parallel to the axes of the working cylinders and in a vertical direction - the first right thrust mechanism (31d) bears at least partially on an internal flank of the first right boss (B2) and is configured to exert a thrust on the first upper grip (E1S) and the first lower grip (Eli) which are located overlapping the first right boss (B2) in a direction parallel to the axes of the working cylinders and in a vertical direction,- The second left thrust mechanism (32g) bears at least partially on an inner flank of the second left boss (B3) and is configured to exert a thrust on the second upper grip (E2S) and the second lower grip (E2I), which are located overlapping the second left boss (B3) in a direction parallel to the axes of the working cylinders and in a vertical direction; - The second right thrust mechanism (32d) bears at least partially on an inner flank of the second right boss (B4) and is configured to exert a thrust on the second upper grip (E2S) and the second lower grip (E2I), which are located overlapping the second right boss (B4) in a direction parallel to the axes of the working cylinders and in a vertical direction.

2. Rolling mill (1) according to claim 1, wherein: - the bearing surface (PWR) of the upper work roll (WRS) forming the unguided portion of the work roll has a distance L along the axis of the work roll defined between the bearings at the two guide ends which is intermediate between, on the one hand, the distance separating a crest of the first left boss (B1) and a crest of the second left boss (B3) and, on the other hand, the

3.

4. distance separating the base of the first left boss (Bl) and the base of the second left boss (B3), - the span (PWR) of the upper working cylinder (WRI) forming the portion of the unguided working cylinder, has a distance along the axis of the working cylinder defined between the bearings at the two guiding ends which is intermediate between, on the one hand, the distance separating a top of the first right boss (B2) and a top of the second right boss (B4) and, on the other hand, the distance separating the base of the first right boss (B2) and the base of the second right boss (B4). Rolling mill according to claim 1 or 2 with six rolls, having the lower intermediate roll (WII) and the upper intermediate roll (WIS), each comprising a rolling table, extended by guide ends of smaller diameter, the guide ends rotatably mounted in upper bearings (EIS) for the upper intermediate roll (WIS) via bearings and the guide ends rotatably mounted in lower bearings (Eli) for the lower intermediate roll (WII), and wherein: - the reach (PW1) of the upper intermediate cylinder (IS) is greater than the reach of the upper working cylinder (WRS), - the reach (PW1) of the lower intermediate cylinder (II) is greater than the reach of the lower working cylinder (WRI). Rolling mill according to any one of claims 1 to 3 wherein - the first left-hand thrusting mechanism (31g) comprises a rotating helical thrusting device (4) comprising a first part (5) bearing on the left-hand upright (Ml) of the first pair, and at least partially on the inner flank of the first left-hand boss (Bl), and a second part (6) configured to laterally push the first lower and upper bosses (Eli, EIS) - the first right-hand thrust mechanism (31d) includes a rotating helical thrust device (4) comprising a first piece (5) bearing on the right-hand upright (M2) of the first pair, and at least partially on the side of the second right-hand boss (B2), and a second piece (6) configured to laterally push the first lower and upper supports (Eli, EIS) - the second left-hand thrust mechanism (32g) comprises a rotating helical thrust device (4) including a first part (5) bearing on the left upright (M3) of the second pair, and at least partially on the inner flank of the second left boss (B3), and a second part (6) configured to laterally push the second lower and upper arms (E2I, E2S) o - the second right-hand thrust mechanism (32d) comprises a rotating helical thrust device (4) including a first part (5) bearing on the right upright (M4) of the second pair, and at least partially on the flank of the second right boss (B4), and a second part (6) configured to laterally push the second lower and upper arms (E2I, E2S) and wherein the first part (5) and the second part (6) of each rotating helical thrust device (4) are configured to pivot relative to each other,around an axis of rotation (A4) under the action of an actuator (AT), the first part (5) and the second part (6) of each rotating thrust device comprise helical guide surfaces (7) arranged around said rotation (A4), mutually supporting, configured to cause a separation of the second part (6) with respect to the first part (5) along the direction of the axis of rotation (A4), during a relative rotation between the first part (5) and the second part (6).

5. Rolling mill according to claim 4, wherein the helical guide surfaces (7) are: - cam surfaces of the first piece (5) and of the second piece (6) which are a first cam and a second cam, or, - internal and external threads respectively mutually engaging between the first piece (5) and of the second piece (6).

6. Rolling mill according to claim 4 or 5, wherein the helical guide surfaces (7) of each rotating helical thrust device (4) are arranged overlapping, along the transverse direction (Y), with the width of one of the uprights (M1, M2, M3, M4) on which the rotating helical device is supported at least partially on the inner flank of the bosses (B1, B2, B3, B4), the helical guide surfaces (7) of diameter D contained along the transverse direction (Y), along the width of the upright comprising the boss (B1, B2, B3, B4).

7. Rolling mill according to any one of claims 1 to 6, wherein the body of each upright has a reduced width section, typically constant, along the transverse direction (Y) of the rolling mill, and a greater width section at the level of the bosses, consisting of: - the first left boss (Bl) for the left upright (Ml) of the first pair, - the second left boss (B3) for the left upright (M3) of the second pair, - the first right boss (B2) for the right upright (M2) of the first pair, - the second right boss (B4) for the right upright (M4) of the second pair.

8. Rolling mill according to claim 7 in which the body of each upright, including boss, is a single piece of metal.

9. Rolling mill according to claim 7, wherein the bosses consisting of the first left boss (B1), the second left boss (B3), the first right boss (B2) the second right boss (B4) are blocks attached and fixed by a fastening means, for example screws, to the lateral surfaces of the bodies of the uprights consisting respectively of the left upright (M1) of the first pair, the left upright (M3) of the second pair, the right upright (M2) of the first pair, and the right upright (M4) of the second pair.

10. Rolling mill according to any one of claims 1 to 9, wherein the upper work roll (WRS) and the lower work roll (WRI) comprise drive shafts (ARB) coupled to a motorization for the direct drive of the rotating work rolls.

11. Rolling mill according to any one of claims 1 to 10, wherein the span (PWR) of the upper work roll (WRS) or of the lower work roll (WRI) forming the unguided portion of the work roll, has a distance L along the axis of the work roll and wherein the lower work roll and the upper work roll have a diameter D, and wherein the ratio D / L is less than or equal to 23%.

12. A method for rolling a metal strip implemented by a rolling mill 1 according to any one of claims 1 to 11 comprising: / A / a rolling of the metal strip (B) as it passes between the two upper and lower working cylinders, which are held under pressure on the strip by a hydraulic clamping action between the two support cylinders (WAS, WAI), lower and upper, and by transmission of drive torques to the upper working cylinder (WRS) and the lower working cylinder (WRI), / B / balancing of the upper and lower working cylinders, by - a lateral, upper offset between the axis of the upper working cylinder (WRS) and the axis of the cylinder bearing on the working cylinder, - a lower lateral offset between the axis of the lower working cylinder (WRI) and the axis of the cylinder bearing on the working cylinder.

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