Rolling mill comprising a bossed stand

Abstract

The present disclosure relates to a four-high or six-high rolling mill (1) comprising a roll stand having a first pair of uprights (M1, M2) and a second pair of uprights (M3, M4), a lateral-offset adjustment system configured to implement a lateral offset, seen in the direction of rolling, between, on the one hand, an axis of the lower work roll (or respectively of the upper work roll), and, on the other hand, an axis of a roll pressing against the work roll, such as a lower (or respectively upper) backup roll, the uprights of the first pair of uprights and of the second pair of uprights noticeably having bosses (B2; B4), pointing towards one another in pairs.

Description

Rolling mill including a hump cage

[0001] This disclosure relates to a four-roller or six-roller rolling mill comprising a rolling mill 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 as a lower (or respectively upper) support roll, the uprights of the first pair of uprights and the second pair of uprights having notable bosses, directed two by two towards each other.

[0002] In this disclosure, the upper working cylinder and the lower working cylinder each have guide ends which are mounted in sockets; the guide ends are 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 support by the lateral offset system which is configured to press laterally with the grips of the working cylinders, on either side of the working axis.

[0004] These bosses on the cage, compared to a cage design with straight uprights (without bosses), allow the two supports at the two ends of the working cylinder to be brought closer together, 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.

[0005] This disclosure relates to the field of cold rolling, and more specifically 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 travel through the mill.

[0006] A four-roll rolling mill comprises, as illustrated in diagram (a) of the: - two work rolls, distributed respectively below and above the metal strip, the upper work roll bearing along a superior line of contact with the strip in a direction in the width of the strip, and the lower roll bearing along a inferior line of contact with the strip, in the direction in the width of the strip, - two support rolls, including an upper support roll bearing against the upper work roll, on the side opposite the strip by a line of contact, and a lower support roll bearing against the lower work roll on the side opposite the strip by a line of contact.

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

[0008] In both cases, whether it is a 4-roller or 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] We also know, as illustrated in diagram (c), of a rolling mill called a six-roller, or laterally supported rolling mill, namely a rolling mill that includes two support rolls, two intermediate rolls, two work rolls, and, for each work roll, two lateral support rolls, one to the right and one to the left of each work roll, which are supported by contact lines on both sides of the roll. In such a six-roller rolling mill with lateral support, the work rolls are typically floating, not directly driven; the drive unit directly drives the intermediate rolls.

[0010] We also know, as illustrated in diagram (d) of the, a rolling mill with 20 cylinders, comprising, on either side of the strip, an upper group and a lower group.

[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 diagram (a), or to the rolling mill with 6 rolls according to diagrams (b), namely whose working rolls are not laterally supported.

[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 is a machined metal body comprising a rolling surface, typically cylindrical, and two guide ends extending from the guide, with diameters smaller than the rolling surface. The guide ends comprise a first guide end configured to pivot in the first bearing, typically via bearings such as roller bearings, and a second guide end configured to pivot 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 cylinder replacement, the cylinders, including the working cylinders, can be extracted axially through the entry window. The drive mechanism for the working cylinders is located on the opposite side, namely on the side of the two rear uprights of the cage.

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

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

[0019] Indirect drive can cause slippage between cylinders, leading to degradation of the surface condition of the cylinder table, thus avoiding direct drive 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, while the work roll is still subjected to the action of horizontal forces.

[0021] As illustrated in the figure, 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 motorization, - the horizontal component of the forces exerted by the grips 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 may 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 upper and lower 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 them and thereby reduce the vertical component of camber.

[0025] For a four- or six-roll rolling mill without lateral support, the driving torque generated by the direct drive of the work roll, while the ends of the work roll are held in place by the clamps, typically causes the work roll to camber in a horizontal plane, with a maximum deflection between the two ends of the work roll. This deflection is oriented in the opposite direction to the direction of the strip's travel; that is, 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 Figure 1, 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 still known to reverse the change in direction of the offset, in case of reversal of the direction of the strip during rolling.

[0028] A prior art system for lateral offsetting of the working cylinder heads is known, comprising horizontal hydraulic cylinders that apply them against a reference surface. The offset generated by the actuation of the cylinders is typically an all-or-nothing operation. Such a prior art system is described, for example, in documents JP2790741 and WO2323 / 073998. This type of offset system allows for proper balancing of the working cylinders when the cylinders are not too small, thus preventing excessive horizontal deflection.

[0029] We also know from the state of the art a second offset system based on the use of straight, angled wedges, including the first angled wedges inserted to the left of the stile and the left upright, and the second angled wedges inserted to the right of the stile 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 one side, by a second inclined surface of the wedge, and on the other side by a vertical guide plate, intended for the vertical guidance of the vertical cylinder system for opening the cage.

[0031] Such an adjustment system allows the lateral offset of the shims to be adjusted by synchronizing the movements of the first and 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 as taught in 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 strip width becomes small, typically less than 0.23, the inclined wedge adjustment system is sufficiently precise to properly balance the forces acting on the working cylinders and to prevent 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 along the wedge, cantilevered out of 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 bulkiness 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 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 to implement a lateral offset, in order to compensate for the deflection of the cylinders, but also a rolling mill stand with specific bosses configured to cooperate with the adjustment system, to allow a rapprochement of the work rolls' handles, and thus a reduction in 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 a front side, a first pair of uprights, and on a rear side, a second pair of uprights, - an upper work roll comprising a treadle configured to come into contact with the upper surface of the metal strip and two guide ends, - a lower work roll comprising a treadle configured to come into contact with the lower surface of the metal strip and two guide ends, - an upper support roll, configured to transmit a clamping force to the upper work roll, directly along a line of contact between the upper work roll and the upper support roll.or indirectly via an upper intermediate cylinder by means of a first support line between the upper support cylinder and the upper intermediate cylinder and a second support line 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, directly along a contact line between the lower working cylinder and the lower support cylinder, or indirectly via a lower intermediate cylinder 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 grips arranged at the two guide ends of the upper working cylinder,including a first upper clamp interposed between the two uprights of the first pair of uprights, and a second upper clamp interposed between the two uprights of the second pair of uprights, the two guide ends of the upper work roll pivotally mounted in the upper clamps via bearings such as roller bearings, - two lower clamps arranged at the two guide ends of the lower work roll, including a first lower clamp interposed between the two uprights of the first pair of uprights, and a second lower clamp interposed between the two uprights of the second pair, the two guide ends of the lower work roll pivotally mounted in the lower clamps 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 cylinder or respectively of the upper working cylinder, and on the other hand, an axis of a cylinder bearing on the working cylinder consisting of the lower or upper intermediate cylinder when the rolling mill has six rolls, and consisting of the lower or upper support cylinder when the rolling mill has four rolls, and in which the adjustment system comprises:-- a first left-hand thrust mechanism between one of the left-hand uprights of the first pair, on the one hand, and the assembly of the first upper and first lower uprights, on the other hand, configured to exert a thrust force on the assembly of the first upper and first lower uprights to move said assembly in a first direction along the rolling direction-- a first right-hand thrust mechanism between the other right-hand 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 left uprights of the second pair, on the one hand, and the assembly of the second upper brace and the second lower brace, on the other hand, configured to exert a thrust force on the assembly of the second upper brace and the second lower brace to move said assembly in the first direction along the rolling direction -- a second right-hand thrust mechanism between the other right upright of the second pair, on the one hand, and the assembly of the second upper brace and the second lower brace, on the other hand,configured to exert a pushing force on the assembly of the second upper grip and second lower grip 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 respectively having 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, in 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, following a direction parallel to the axes of the working cylinders,and in which: - the first left thrust mechanism bears at least partially on an internal flank of the first left 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 thrust mechanism bears at least partially on an internal flank of the first right boss and is configured to exert a thrust on the first upper and first lower arms which are located overlapping the first right boss in a direction parallel to the axes of the working cylinders and in a vertical direction.- The second left-hand thrust mechanism bears at least partially on an internal flank of the second left-hand boss and is configured to exert a thrust on the second upper and second lower arms, which are located overlapping the second left-hand boss in a direction parallel to the axes of the working cylinders and in a vertical direction. - The second right-hand thrust mechanism bears at least partially on an internal flank of the second right-hand boss and is configured to exert a thrust on the second upper and second lower arms, which are located overlapping the second right-hand boss in 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 bearing surface 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 top of the first left boss and a top 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 bearing surface 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 mounted rotatably in upper bearings for the upper intermediate roll by means of bearings and the guide ends mounted rotatably in lower bearings for the lower intermediate roll, and in which: - the span of the upper intermediate roll is greater than the span of the upper working roll, - the span of the lower intermediate roll is greater than the span of the lower working roll.

[0044] According to one embodiment: - the first left-hand thrust mechanism comprises a rotating helical thrust device including a first part bearing on the left-hand upright of the first pair, and at least partially on the inner flank of the first left-hand boss, and a second part 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 part configured to laterally push the first lower and upper supports; - the second left-hand thrust mechanism comprises a rotating helical thrust device including a first part bearing on the left-hand upright of the second pair, and at least partially on the inner flank of the second left-hand boss.and a second part configured to laterally push the second lower and upper supports - the second right-hand pushing mechanism comprises a rotating helical pushing device including a first part 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 part configured to laterally push the second lower and upper supports, and wherein the first and second parts of each rotating helical pushing device are configured to pivot relative to each other, around an axis of rotation under the action of an actuator, the first and second parts of each rotating pushing device comprising helical guiding surfaces arranged around said rotation, mutually supporting,configured to cause the second part to move away from 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, the helical guide surfaces can be: - cam surfaces of the first part and the second part which are a first cam and a second cam, or, - internal and external threads respectively mutually engaging between the first part (5) and the second part.

[0046] According to one embodiment, the helical guide surfaces of each rotating helical thrust device are arranged in overlap, 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 level of 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 added and fixed by a means of fixing, for example screws, on 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] In one embodiment, the upper and lower working rolls include drive shafts coupled to a motor for directly driving the rotating working rolls. Alternatively, however, 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 also 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 metal strip rolling process implemented by a rolling mill 1 according to the present disclosure comprising: / A / rolling of the metal strip B in motion between the two upper and lower work rolls 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 driving torques to the upper work roll WRS and the lower work roll WRI, / B / balancing of the upper and lower work rolls, by - a lateral offset, upper, between the axis of the upper work roll WRS and the axis of the roll bearing on the work roll, - a lateral offset, lower, between the axis of the lower work roll WRI and the axis of the roll bearing on the roll.

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

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

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

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

[0057] is a front view of the rolling mill, illustrating the cylinder shanks, including the shanks of the upper working cylinder and the lower working cylinder, as well as a lateral offset adjustment system configured for the implementation of a lateral offset, view along the rolling direction between, on the one hand, an axis of the working cylinder and an axis of a cylinder bearing 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 front. Fig. 4

[0058] is a rear view of the rolling mill, on the side of the drive of the working rolls, 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 cylinders, the cylinders extending along the height of the uprights behind the stand. Fig. 5

[0059] 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] 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] 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] is a detailed view of the second cam which features helical guide surfaces, as well as a radial extension forming a lever arm configured to be connected to an actuator. Fig. 7C

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

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

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

[0066] is a detailed 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 at one end on a radial extension of the second cam, and at the other end to the upright. Fig. 9

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

[0068] 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, known as laterally supported, including work rolls held laterally by lateral support rolls, and powered intermediate rolls,- (d) a 20-roll rolling mill configuration. Fig. 11

[0069] is a partial view of the rolling mill according to the, 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] are three cross-sectional views according to 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 braces, formed by a rotating thrust device located partially on the first left 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 braces, formed by a rotating thrust device located partially on the second left 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] is a view along, 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 spacing between the bearings at the two ends of the working cylinder guide, namely the unguided length portion of the cylinder likely 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.

[0072] This 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 the, or to a six roll mill, as illustrated in diagram (b) of the.

[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 stand 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, - an upper work roll WRS comprising a treadle configured to come into contact with the upper surface of the metal strip and two guide ends, - a lower work roll WRI comprising a treadle configured to come into contact with the lower surface of the metal strip and two guide ends, - an upper support roll WAS, configured to transmit a clamping force to the upper work roll, either directly along a line of contact between the upper work roll and the upper support roll, in the case where the rolling mill has four rolls, or indirectly via an intermediate upper roll WIS,by a first support line between the upper support cylinder WAS and the upper intermediate cylinder WIS and by a second support line between the upper intermediate cylinder WIS and the upper work cylinder WRS, when the rolling mill has six rolls, - a lower support cylinder WAI, configured to transmit a clamping force to the lower work cylinder WRI, either directly along a contact line between the lower work cylinder and the lower support cylinder, or indirectly via a lower intermediate cylinder WII by a first support line between the lower support cylinder WAS and the lower intermediate cylinder WII and by a second support line between the lower intermediate cylinder WII and the lower work cylinder WRI, - two upper supports arranged at the two guide ends of the upper work 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 E1I 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 E1I, E2I via bearings such as roller bearings. The intermediate portion of the lower work roll extending between the two bearings (typically roller bearings) has a length L, usually referred to as slenderness by those skilled in the art, which is susceptible to deflection during 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) has a length L, usually referred to as slenderness by those skilled in the art, which is susceptible to deflection during 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 upper support roll WAS is extended by guide ends, which are guided in rotation 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 roll WAI includes a bearing table, which rests on the bearing table of the upper working roll WRI in the case of a four-roll mill, or on the bearing table of the lower intermediate roll WII when the mill has six rolls. The bearing table of the lower support roll WAI is extended by guide ends, which are guided in rotation within two lower supports EAI. The two lower 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.

[0078] In general, and as illustrated in Figure 1, 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, positioned respectively 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 Figures 2. 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] In general, the 4-roller (or 6-roller) rolling mill may include a cut line adjustment system, configured to adjust the cut line height.

[0080] In general, and with reference to the, and in this disclosure we define a frame X, Y and Z with:- the direction X, called longitudinal oriented along the direction of movement DL of the strip B between the working cylinders, typically horizontal,- the direction Y, called transverse, perpendicular extending along the width direction of the metal strip,- the direction Z, is the vertical direction of the cage uprights.

[0081] In the case of this 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 includes 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. When the hydraulic pots are in the lower position, cooperating with the lower shims of the support cylinders, the cut line adjustment system, including 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, in the case of a 6-roll mill, the lower and upper intermediate rolls WII and WIS each include a roller table extended by smaller-diameter guide ends. The guide ends are rotatably mounted in upper bearings EIS for the upper intermediate roll and in lower bearings EII for the lower intermediate roll. Rotational guidance between the guide ends and the EIS or EII bearings is provided by bearings, typically roller bearings. The span P illustrates this. WI of the cylinder (unguided) between the bearings of distance L.

[0085] The EII 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] In general, as illustrated in, 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] In general, a system (not shown here) can be configured to move the two working cylinders axially in opposite directions to allow axial overlap zone adjustment between the two lower and upper working cylinders, and typically to allow adjustment of the overlap zone to the width dimension of the band.

[0089] In general, 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 frame E1S, and a lower part 91 coupled on the left laterally to the first lower frame E1I, 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 frames E1I and E1S apart or together, said first opening mechanism interposed between the left upright M1 and the first upper and lower frames, - 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 frame E1S, and a lower part 101 coupled on the right laterally to the first lower frame E1I,as well as a hydraulic cylinder connecting the upper and lower parts 100, 101, the cylinder 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 support E2S, and a lower part coupled on the left laterally to the second lower support E2I as well as a hydraulic cylinder connecting the upper and lower parts, the cylinder configured to move the first supports apart or bring them together, said first opening mechanism interposed between the left upright M3 and the second upper and lower supports, - a second opening / closing mechanism, right-hand, with a vertical cylinder comprising an upper part coupled on the left,laterally to the second upper brace E2S, and a lower part coupled laterally to the second lower brace E2I, as well as a hydraulic cylinder connecting the upper and lower parts, the cylinder configured to move the first braces apart or together, said first opening mechanism interposed between the left upright M3 and the second upper and lower braces.

[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 arms E1S E1I from each other, and on the other hand, the second upper and lower arms E1S E1I from each other, thus separating the upper working cylinder WRS from the lower working cylinder WRI along the vertical direction Z.

[0091] The vertical cylinders can still be used during rolling operations, under the pressure of the PT hydraulic pots to balance the upper and lower working cylinders, particularly 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 direct rotation of the upper and lower working rolls in opposite directions. The use of drive shafts coupled to a motor for direct drive of the working rolls ensures efficient and constant transmission of motor torque. This improves rolling accuracy and stability, 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 the figure, 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 on the working cylinder, - half of the tension difference T between that of the infeed strip Tf and that of the outfeed strip Tb (1 / 2T) - the rolling force CirF due to the transmission of the motor torque to the working cylinder, when the working cylinders are driven directly by the motorization.

[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]

[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] Note here the importance, in the value of the horizontal arrow, of the ratio L 3 / D 4 . This disclosure focuses primarily on reducing the L parameter, 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 range P WRof the upper working cylinder WRS or of the lower cylinder WRI) forming the portion of the unguided working cylinder, can thus present 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 bearing 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 E1S, E1I, E2S, E2I supports 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 swages, 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 travel.

[0103] Offsetting the axis of the working cylinder relative to the axis of the cylinder resting on the working cylinder along the direction of the strip allows obtaining a horizontal component of the rolling clamping force FC in the opposite direction to the horizontal component of the rolling force, thus allowing the working cylinder to be balanced, and thus reducing the horizontal component of the deflection due to the motor torque.

[0104] As illustrated in the figure, it is important to be able to adjust the OFS offset value between the axis of the working roll (lower or upper) and the axis of the roll bearing on the working roll (i.e. the intermediate roll or the support roll) preferably progressively (and not all or nothing), particularly during rolling operations, and so as to be able to optimally control the horizontal balance of the working roll during rolling operations.

[0105] This disclosure has 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 susceptible to bending than larger diameter cylinders.

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

[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 supporting 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 push mechanism 31g between one left M1 of the uprights of the first pair and the assembly of the first upper brace E1S and the first lower brace E1I, the first left-hand mechanism configured to exert a push force on the assembly of the first upper brace E1S and the first lower brace E1I to move said assembly in a first direction along the rolling direction DL - a first right-hand push mechanism 31d between the other right M2 of the uprights of the first pair on the one hand, and the first upper brace E1S and the first lower brace E1I,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 E1I 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 the second lower brace E2I, the second left-hand mechanism configured to exert a thrust force on the assembly of the second upper brace E2S and the second lower brace E2I to move said assembly in the first direction along the rolling direction DL- a second right-hand thrust mechanism 32d between the other right M4 of the uprights of the second pair, on the one hand, and the assembly of the second upper brace E2 and the second lower brace E2I,the second right configured to exert a pushing force on the assembly of the 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 also 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 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 first direction according to the rolling direction, - the second right-hand push mechanism 31d and the second right-hand push 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] In general, 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, namely that: - when the left mechanisms 31g, 32g exert a thrust force on the handles, the right mechanisms 31d, 32d retract so as not to oppose the movement of the handles of the working cylinders in the first direction - when the right mechanisms 31d, 32d exert a thrust force on the handles, the left mechanisms 31g, 32g retract so as not to oppose the movement of the handles 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 E1I, E1S, E2I, E2S.

[0113] In general: - the first left push mechanism 31g can be inserted between the left upright M1 and said first left opening / closing mechanism 9 - the first right push mechanism 31d can be inserted between the right upright M2 and said first right opening / closing mechanism 10, - the second left push mechanism 32g can be inserted between the left upright M3 and said second right 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 M1 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 M1 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 M1 has a first left boss B1 projecting from the lateral surface of the left upright body M1 of the first pair, the first left boss B1 extending from the upright from a base to a boss apex, following the transverse direction Y. La 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, following the transverse direction Y, and as illustrated in Figure 1. Figure 1 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, following a direction parallel to the axes of the working cylinders, namely along the transverse direction Y.

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

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

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

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

[0122] In general, bosses B1, B2, B3, B4 may have a trapezoidal cross-section, for example isosceles, 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 Figure 1, 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 E1I, which are advantageously located overlapping the first boss B1 in 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 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 E1I, which are advantageously 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 internal 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 advantageously located overlapping the second left boss B3 in a direction parallel to the axes of the working cylinders, namely along the transverse direction Y and along 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 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.

[0124] In general, as illustrated by way of example, the supports of the internal sides provided by the bosses B1, B2, B3, B4 allow the two supports supporting each working cylinder (lower or upper) to be brought closer together in the transverse direction, and thus reduce the distance L separating the guide bearings at the two guide ends, by comparison of cage according to the state of the art without the bosses.

[0125] In particular, the P range WRof 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 B1 and a top of the second left boss B3 and, on the other hand, the distance separating the base of the first left boss B1 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 bosses B1 and B3, but typically less than the distance separating the two bases of bosses B1 and B3.

[0126] Again, the P range WRThe 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. This distance is intermediate between, on the one hand, the distance separating a crest of the first straight boss B2 and a crest of the second straight boss B4, and, on the other hand, the distance separating the base of the first straight boss B2 and the base of the second straight boss B4. In other words, the distance L is typically greater than the distance separating the two crests of bosses B2 and B4, but typically less than the distance separating the two bases of bosses B2 and B4.

[0127] In general, the body of each upright has a reduced width section, typically constant, following 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 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] Alternatively, these bosses B1, B2, B3, B4 can be added elements (blocks) and fixed by some means of fastening, for example screws, to the lateral surfaces of the upright bodies M1 to M4 respectively. Such a multi-part construction can facilitate the manufacture of the uprights with bosses.

[0130] Generally, when the rolling mill has six rolls, it has (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 lesser 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 EII for the lower intermediate cylinder WII.

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

[0133] According to one embodiment of this 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 includes: - 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 includes 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 arms E1I, E1S in the case of the first thrust mechanisms (left or right), or respectively to push the second lower and upper arms E2I, E2S respectively 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 (i.e. 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 shown, the helical guide surfaces may be internal and external threads, respectively, 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] The helical guide surfaces can still have multiple threads, including several internal threads, engaging simultaneously with several external threads, the internal and external threads respectively arranged between the first part 5 and the second part 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, following 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 different 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 thus allow for different spacings between the two parts 5 and 6, with the spacing increasing from the first angular position to the second angular position. Parts 5 and 6 can, in particular, allow for 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 visible 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, - 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) can 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, compared to the state of the 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, and for example and at the, the rotating helical thrust device of the thrust mechanism, left, 31g, has a footprint of the helical guide surfaces 7, of diameter D, which is contained according to the width of the upright M1, left of the first pair including the height H1 of the first left boss B1.

[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 push mechanism, left, 32g, has a footprint of helical guide surfaces 7, of diameter D, which is contained along 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 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 part 5 and second part 6 (in particular a single pair first cam and second cam) extending vertically, overlapping the height of the assembly first upper foot E1S and first lower foot E1I; in particular and as seen on the left in the figure, the helical guide surfaces 7 of diameter D of the first mechanism (left or right) can extend, overlapping, along the Z direction, the first upper and lower feet E1I, E1S.- 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 or 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 for full coverage of the swages, ensuring even distribution of applied forces. This minimizes stress on the swages 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 sustainable rolling mill operation.

[0158] The adjustment system can therefore only include four rotating helical thrust devices 4 for respectively the first thrust mechanisms, left 31g and right 31d, 31d 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 Y direction, the AT actuators of the helical thrust devices can be typically hydraulic or electric cylinders, extending longitudinally along the height of the uprights M1, M2, M3, M4. By integrating the cylinders along the uprights, the system optimizes space and reduces the footprint, 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 M1 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 M3 upright 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) right M4 upright configured for controlling the angular position of the second part relative to the first part of the second thrust mechanism, right 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] The 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 the 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 VR cylinder and the upright as close as possible, a deep notch ECH in the upright can extend at the right of the cylinder coupled to the upright, along the Y direction. When the cylinder deploys or retracts, 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 the axis of rotation. The toothed ring meshes with a drive pinion driven by an electric geared motor constituting the actuator. The geared motor can be regulated during control, either 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 that protects the helical guide surfaces 7 from the external environment. In particular, the housing comprises a cylindrical wall with an axis coaxial to the axis of rotation A4 of the rotating helical thrust device 4. Encapsulating the parts (especially the cams) in a housing protects the helical guide surfaces (in particular the cam guide surfaces or the internal and external threads) from external contaminants, such as oils and metallic particles. This reduces the need for frequent maintenance and extends the service life of the components.

[0171] This disclosure further relates to a metal strip rolling process implemented by a rolling mill 1 according to this disclosure comprising: / A / rolling of the metal strip B as it passes between the two upper and lower work rolls 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 of the upper and lower work rolls, by - an upper lateral offset between the axis of the upper work roll WRS and the axis of the roll bearing on the upper work roll, - a lower lateral offset between the axis of the lower work roll WRI and the axis of the roll bearing on the lower work roll,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 E1I, E1S and of the second lower and upper arms E2I, E2S of the lower and upper working cylinders.

[0172] The rolling process, which uses 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, thus optimizing process efficiency and productivity.

[0174] In summary, the present 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 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 in the distance L between the guide bearings of each work roll, and in order to decrease the sensitivity to deflection of small-diameter work rolls. 2) The use of rotating helical thrust devices in the lateral offset adjustment system allows for precise and progressive adjustment of the position of the work roll supports.This improves the balancing of horizontal forces and reduces the camber of the cylinders, which is important for maintaining rolling quality, especially when the diameters of the working cylinders are small. 3) The use of rotating helical thrust devices makes it possible to limit the overall footprint of the rolling mill in the transverse Y direction, 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 makes it possible to protect the guide surfaces by a hood, preventing these surfaces from being contaminated by rolling oils and metallic particles contained in the oil.

[0175] - 1: Rolling mill, - 2. Stand, - 3. Lateral offset adjustment system, - 31g, 31d. First lateral offset adjustment mechanisms, left and right respectively, - 32g, 32d. Second lateral offset adjustment mechanisms, left and right respectively, - 4. Helical thrust device, - A4. Rotation axis, - 5, 6, first and second parts respectively, - 7. Helical guide surfaces, - 71, 72, 73, 74. First, second, third, and fourth helical guide surfaces, - B. Strip (metal), - M1, M2. Uprights (first pair of stand uprights, left and right respectively), - B1, B2. First left boss and first right boss respectively, - M3, M4. Uprights (second pair of stand uprights, left and right respectively), - B3, B4. Second boss on the left and second boss on the right respectively.- PT: Hydraulic clamping pots,- PST: Pass line adjustment system- WRI: Lower working cylinder,- WRS.Upper working cylinder,- P. WR. Working cylinder reach (lower or upper) extending between the bearings, - L. Distance - WAI Upper support cylinder, - WAS. Lower support cylinder, - P WA. Support cylinder span (lower or upper) extending between the bearings - WII. Lower intermediate cylinder, - WIS. Upper intermediate cylinder, - PW I.Intermediate cylinder reach (lower or upper) extending between the bearings - E1S, E2S. First upper bearing and second upper bearing (for the upper working cylinder WRS), - E1I, E2I. First lower bearing and second lower bearing (for the lower working cylinder WRI), - EII, EIS. Lower and upper bearing (for the intermediate cylinder), - EAI, EAS. Lower and upper bearing (for the support cylinder), - VRI. Cylinders (axial adjustment device for the intermediate cylinders) - 8. Cover, - 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

A four-roll or six-roll cold rolling mill (1), 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 work roll (WRS) comprising a treadle configured to come into contact with the upper surface of the metal strip and two guide ends, - a lower work roll (WRI) comprising a treadle configured to come into contact with the lower surface of the metal strip and two guide ends, - an upper support roll (WAS), configured to transmit a clamping force to the upper work roll, directly along a line of contact between the upper work roll and the upper support roll,or indirectly via an upper intermediate cylinder (WIS) by means of a first support line between the upper support cylinder and the upper intermediate cylinder and a second support 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 grips arranged at the two guide ends of the upper working cylinder (WRS),including a first upper bracket (E1S) interposed between the two uprights (M1, M2) of the first pair of uprights, and a second upper bracket (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 brackets (E1S, E2S) via bearings such as roller bearings; - two lower brackets arranged at the two guide ends of the lower working cylinder, including a first lower bracket (E1I) interposed between the two uprights (M1, M2) of the first pair of uprights, and a second lower bracket (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 brackets (E1I, E2I) via bearings such as roller bearings 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 working roll (WRI) or respectively of the upper working roll (WRS), and on the other hand, an axis (Ap) of a roll bearing on the working 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 (M1) of the uprights of the first pair, on the one hand, and the assembly of the first upper press (E1S) and first lower press (E1I), on the other hand,configured to exert a thrust force on the assembly of the first upper brace (E1S) and first lower brace (E1I) to move said assembly in a first direction along the rolling direction (DL) -- a first right thrust mechanism (31d) between the other right (M2) of the uprights of the first pair on the one hand, and the first upper brace (E1S) and the first lower brace (E1I), on the other hand, configured to exert a thrust force on the assembly of the first upper brace (E1S) and first lower brace (E1I) to move said assembly in a second direction along the rolling direction (DL), -- a second left thrust mechanism (32g) between the 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 support (E2S) and second lower support (E2I) to move said assembly in the first direction along the rolling direction (DL)-- a second right thrust mechanism (32d) between the other right (M4) of the uprights of the second pair on the one hand, and the assembly of the second upper support (E2S) and second lower support (E2I), on the other hand, configured to exert a thrust force on the assembly of the second upper support (E2S) and second lower support (E2I) to move said assembly in the second direction along the rolling direction (DL), characterized in that- the left upright (M1) 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 (M1) of the first pair and the left upright (M3) of the second pair have mutually facing vertical lateral surfaces, as well as a first left boss (B1) projecting from the lateral surface of the left upright (M1) of the first pair, extending from the upright from a base to a boss apex, 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 boss apex, the first left boss (B1) and the second left boss (B3) directed towards each other, in 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 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, in 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 (E1I) 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 (E1I) 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. Rolling mill (1) according to claim 1, wherein: - the span (P WR) 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 crest of the first left boss (B1) and a crest of the second left boss (B3), and, on the other hand, the distance separating the base of the first left boss (B1) and the base of the second left boss (B3), - the span (P WR ) of the upper working cylinder (WRI) 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 (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 (EII) for the lower intermediate roll (WII), and wherein: - the bearing surface (P WI ) of the upper intermediate cylinder (IS) is greater than the reach of the upper working cylinder (WRS),- the reach (P WI ) 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) including a first part (5) bearing on the left-hand upright (M1) of the first pair, and at least partially on the inner flank of the first left-hand boss (B1), and a second part (6) configured to laterally push the first lower and upper thrusts (E1I, E1S); - the first right-hand thrusting mechanism (31d) comprises a rotating helical thrusting device (4) including a first part (5) bearing on the right-hand upright (M2) of the first pair, and at least partially on the flank of the second right-hand boss (B2), and a second part (6) configured to laterally push the first lower and upper thrusts (E1I,E1S) - the second left 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 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). 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). 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). 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 (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. Rolling mill according to claim 7 in which the body of each upright, including boss, is a single piece of metal. 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. Rolling mill according to any one of claims 1 to 9, wherein the upper working roll (WRS) and the lower working roll (WRI) comprise drive shafts (ARB) coupled to a motor for the direct drive of the rotating working rolls. Rolling mill according to any one of claims 1 to 10, wherein the range (P WR) of the upper working cylinder (WRS) or of the lower working cylinder (WRI) 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%. A method for rolling a metal strip implemented by a rolling mill 1 according to any one of claims 1 to 11 comprising: / A / rolling the metal strip (B) as it passes between the two upper and lower work rolls 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 - an upper lateral offset between the axis of the upper work roll (WRS) and the axis of the roll bearing on the work roll, - a lower lateral offset between the axis of the lower work roll (WRI) and the axis of the roll bearing on the work roll.

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