EP0283342A1 - Rolling mill having axially shifting rolls, and roll profile control method - Google Patents

Abstract

In a rolling mill having axially shifting rolls comprising, inside a support stand 4, at least two work rolls 1, 1' with roll-curvature means 6, the curvature means are rams bearing in the direction of the curvature force on a T-shaped sliding piece 7, comprising a portion forming a foot engaging in a machined part (53) produced in the block (5) containing the curvature rams (6), so as to permit translational guiding in the vertical plane, and provision is made for the chocks (3) of the work rolls bearing on the pieces 7 and thereby receiving the curvature force also to be able to shift over the pieces 7 by sliding when it is desired to axially shift the rolls. …<IMAGE>…

Description

The subject of the invention is a rolling mill with axially displaceable rollers and also covers a method of adjusting the profile and distributing wear of the rolls in such a rolling mill.

In general, a rolling mill comprises, inside a support cage, at least two working rolls resting, in a clamping plane, on at least two support rolls. The cylinders are carried at their two ends by means of bearings, in chocks mounted mobile, parallel to the clamping plane, in windows provided on each upright of the support cage, each chock being provided with two lateral guide faces. sliding along corresponding sliding faces formed on the amount of the cage on either side of the chock.

Usually called "quarto" rolling mills comprising two working rolls, each resting on a support cylinder and so-called "sexto" rolling mills in which intermediate rolls are interposed between the support rolls and the working rolls. In both cases, the axes of the cylinders are placed in the clamping plane, generally vertical, but it is also possible to support each working cylinder on a larger number of intermediate and / or support cylinders placed symmetrically on either side. other of the clamping plane.

To control the thickness of the rolled product and in particular to obtain a thickness equal in the direction transverse to the rolling direction, a bending or bending of the working rolls and possibly of the rolls is carried out. dres intermediaries by means of cambering devices acting on the chocks of the corresponding cylinder. Generally, the bending device consists, for each chock, of two sets of jacks placed symmetrically on either side of the chock. In addition, each support part of the chock rests on two cylinders spaced axially symmetrically on either side of the median plane of the chock bearings so that the bending force is well distributed on the bearings.

The rolling mill stand is symmetrical with respect to a median plane perpendicular to the clamping plane and which corresponds to the median plane of the rolled product. Normally the cylinders are therefore centered on this plane with respect to which the chocks are arranged symmetrically.

However, it may be advantageous to carry out a displacement of certain cylinders parallel to their axis and in the opposite direction or not, in order to satisfy various objectives such as the regularity of the wear of the cylinders or the control of the flatness or of the profile of the rolled product. .

It is understood that the axial displacement of the cylinders presents difficulties when the latter are subjected to a bending force. This is why generally, the two operations are carried out separately, the bending effort being eliminated when an axial movement is carried out.

However, it is advantageous, during rolling, to combine the effects of axial displacement and the camber of the rolls and therefore to be able to effect the axial displacement of the cy lindres while maintaining the camber. In addition, the torque is generally applied to a single pair of cylinders, and the camber of the working cylinders, corresponding by friction. However, it is necessary that all the cylinders remain driven at the same peripheral speed.

Moreover, the bending of the working rolls also ensures a balancing effect between the rolls which it is useful to maintain during the axial adjustment even when the rolling force is eliminated.

The subject of the invention is a device allowing axial displacement of the cylinders without ceasing to exert the bending effort.

To this end, it has already been proposed to associate with each displaceable cylinder and its chocks a frame consisting of two beams mounted to slide axially on the stand of the rolling mill and on which the bending devices which thus move are supported. together with the cylinders, their chocks and the frame. This arrangement however complicates the production of the rolling mill.

The invention relates to a new device making it possible to carry out at the same time the bending and the axial displacement of the working rolls or of the intermediate rolls without appreciably modifying the constitution of the rolling mill. The invention makes it possible in particular to avoid the high friction between guide surfaces liable to disturb the vertical adjustment movements of the chocks.

The invention therefore applies to a rolling mill with axially displaceable rollers comprising, inside a support cage at least two working rolls resting on a clamping plane P1, on at least two support rolls and the ends of which are carried, by means of bearings in chocks slidably mounted in the support cage, at least one of the working cylinders being associated, on the one hand, with means for moving said cylinder along its axis on either side of a position for centering the working cylinders on the median plane P2 of the cage, and on the other hand means for bending said cylinder comprising, for each chock two symmetrical assemblies of at least two cambering cylinders spaced apart from one another in the axial direction, and acting respectively on support parts provided on each side of the chock, said sets of cylinders being placed inside a block of support secured to the cage.

According to the invention, each set of cambering cylinders is supported in the direction of the cambering force on a sliding part mounted to slide vertically between two pairs of guide faces formed in a machining carried out inside the block of support and respectively parallel and perpendicular to the rolling plane P1 and the corresponding support part of the chock rests with the possibility of sliding on a flat and smooth face formed on said sliding part on the side opposite to the camber cylinder.

In this way, the bending effort is exerted by means of fixed jacks bearing on each end, on one side on the support block secured to the cage and on the other on a part on which the chock can slide. during axial displacements, this part being slidably mounted on the support block in the direction of application of the bending force and associated with embedding means making it possible to resist the effects of overturning in the direction of the axial displacement of the cylinders .

In a preferred embodiment, the sliding part comprises support parts in the cambering direction of each cambering cylinder, extending horizontally above each cylinder and at least one part in the form of a guide foot s extending vertically by engaging between two spaced apart sides of the sliding guide of said foot, perpendicular to the rolling plane and formed on two opposite faces of the machining carried out inside the support block 5.

In the most common case where each cambering assembly comprises two jacks spaced from each other and centered in a plane parallel to the rolling plane, the sliding part has the shape of a T having a central internal part forming the guide leg extending vertically between the two cylinders inside the support block and an outer part forming two wings extending horizontally on either side of the guide leg, each above one said jacks.

The guidance thus produced makes it possible to resist the overturning forces resulting from the offset of the support parts of the chock with respect to the sliding part during axial displacements and, taking into account the length of the guide foot, the latter s 'performs with low friction and does not penalize vertical movements.

According to another particularly advantageous characteristic, the sliding part is slidably mounted between two guide faces parallel to the rolling plane and formed in a second machining carried out inside the support block and extending outward the internal machining in which engages the guide foot.

Preferably, these two guide faces parallel to the rolling plane are symmetrically spaced apart on either side of the plane passing through the axes of the cambering cylinders and the support part of the chock is itself centered in the same plane in which thus pass all the forces applied by the bending.

In this way, in the case where each cambering assembly comprises two cylinders spaced from one another, the machining carried out in the support block comprises an enlarged external part passing above the two cambering cylinders in which is guided the external part of the sliding part 7 in the shape of a T on which rests on one side the chock and on the other the camber cylinders and an internal part forming a central well in which the foot of the guide of the sliding part.

In most cases, the embedding effect of the guide foot makes it possible at the same time to carry out the axial displacement and the camber of the working rolls by opposing the moment of overturning which results from the offset of the median plane of the bearing by relation to the plane of symmetry of the two pairs of camber cylinders. However, if this offset becomes too large, it results in friction which can oppose the sliding of the sliding part.

In this case, according to another embodiment of the invention, it is advantageous to apply different pressures on the two jacks of each pair, taking into account the axial offset of the cylinder so as to cancel the sum of the overturning moments exerted on the sliding part and thus reducing to the minimum the guide friction of this part.

For this purpose, the offset of the working cylinder relative to the centering position on the median plane of the product is measured at all times and the individual pressure exerted by each cylinder is permanently adjusted for each chock. offset measured so that, for each sliding part, the moment resulting from the sum of the moments of each cambering cylinder and that of the reaction of the chock is zero.

Advantageously, the two chocks of each displaceable cylinder being each associated with two symmetrical sets of camber cylinders, arranged on either side of the rolling plane, the jacks placed respectively, in each of the assemblies, in the same relative positions. with respect to the median plane of their respective rotation are connected in parallel to the same branch of a common circuit for supplying pressurized fluid comprising as many branches as there are jacks in each assembly, each branch being provided with means for individually adjusting the pressure of the fluid with maintenance of equal flows in all branches.

The means for individually adjusting the pressures in the jacks comprise, on each branch of the supply circuit, a servo-valve controlled by a means of calculating the corrections to be made to the pressures as a function of the offset measured and displayed on the calculation means and respective positions of the cylinders supplied by the branch in question.

According to another particularly advantageous characteristic of the invention, each chock can be associated with positive bending means each comprising at least two jacks. These sets of cylinders are formed in hydraulic blocks placed on either side of the clamping plane, in the windows of the cage; each block consists of a massive support piece comprising a central part machined to receive the T-shaped pieces on which the support ears of the chock rest, these each being provided with a face of continuous sliding parallel to the sliding axis.

• La figure 1 représente schématiquement,en perspective, la disposition d'un laminoir quarto à cylindres déplaçables .
• La figure 2 est une vue partielle de dessus-­d'un cylindre de travail et de ses moyens de dé­placement.
• La figure 3 est une vue partielle de la cage du laminoir montrant les deux cylindres de travail et les dispositifs de cambrage, en coupe par un plan parallèle au plan de laminage et passant par les axes d'un jeu de vérins de cambrage dans une réalisation utilisant des poutres continues tra­versant la cage et ayant des extrémités en forme de T.
• La figure 4 est une vue partielle des dispo­sitifs de cambrage, en coupe par un plan parallè­le au plan de laminage et passant par les axes d'un jeu de vérins de cambrage dans la réalisa­tion utilisant des pièces intermédiaires séparées en forme de T.
• La figure 5 montre la section particulière de ces pièces en coupe par un plan transversal,les empoises étant écartées l'une de l'autre.
• La figure 6 est une vue des empoises des deux cylindres de travail et des dispositifs de cam­brage en coupe par un plan perpendiculaire au plan de laminage et passant par les axes des vé­rins de cambrage.
• La figure 7 donne un schéma hydraulique du dispositif d'équilibrage dans un mode de réali­sation plus perfectionné.

Other features and other advantages of the invention will appear in the following description of a particular embodiment, given by way of example and shown in the accompanying drawings.

• Figure 1 shows schematically, in perspective, the arrangement of a quarto rolling mill with movable cylinders.
• Figure 2 is a partial top view of a working cylinder and its displacement means.
• Figure 3 is a partial view of the rolling mill cage showing the two working rolls and the bending devices, in section through a plane parallel to the rolling plane and passing through the axes of a set of bending cylinders in one embodiment using continuous beams crossing the cage and having T-shaped ends
• Figure 4 is a partial view of the bending devices, in section through a plane parallel to the rolling plane and passing through the axes of a set of bending cylinders in the embodiment using separate intermediate parts in the shape of a T.
• Figure 5 shows the particular section of these parts in section through a transverse plane, the chocks being spaced from one another.
• FIG. 6 is a view of the chocks of the two working rolls and of the bending devices in section through a plane perpendicular to the rolling plane and passing through the axes of the bending cylinders.
• FIG. 7 gives a hydraulic diagram of the balancing device in a more improved embodiment.

In Figure 1, there is shown schematically a quarto rolling mill comprising two working rolls (1) and (1ʹ) and two support rolls (2) and (2ʹ) .The axes of the cylinders are parallel and arranged along a clamping plane P1 passing through the contact generatrices.

The rolled product 20 passes between the working rolls (1) and (1ʹ) and its median plane corresponds substantially to the transverse plane of symmetry P2 of the whole of the rolling mill stand and in particular of the support rolls (2) and ( 2ʹ). Normally, the cylinders are all aligned and centered on the same median plane P2. However, for the reasons indicated above, the working rolls (1) and (1ʹ) can be moved axially relative to the centering position so that their respective transverse plane of symmetry is offset by one side or by one. other with respect to the median plane P2. To this end, an axial displacement force F1 is applied in one direction or the other to the working cylinders (1) and (1ʹ).

On the other hand, according to another known arrangement, cambering forces F2 are applied to the ends of the shafts of the working cylinders (1) and (1ʹ), by means of their chocks so as to camber the cylinder. corresponding.

Thanks to the arrangements according to the invention, the working rolls (1) and (1ʹ) can be subjected at the same time to an axial displacement force F1 and to the bending forces F2.

FIG. 2 shows an end of a working cylinder with a chock, and an axial displacement device. The working cylinder (1) is provided at its two ends with centered pins, by means of bearings , inside chocks (3) forming a body bearing and sliding mounted, parallel to the clamping plane P1, in windows (40) formed in the two uprights (4) of the rolling stand.

To this end, as shown in FIG. 5, each chock (3) of the working cylinder 1 is provided with sliding faces (31) parallel to the clamping plane P1 and which can slide along corresponding faces ( 51) arranged inwards on support blocks (5) fixed in the windows (40) of the stand (4) of the rolling mill.

In this way, each chock (3) guided between the two vertical faces (51) can move in two directions, on the one hand vertically under the action of the bending device and on the other hand parallel to the axis (10 ) of the cylinder under the action of the axial adjustment device.

Various devices are known for axial displacement of the cylinders which do not constitute the subject of the invention and which it is therefore not useful to describe in detail.

In general, the axial displacement force which is applied to one of the chocks must be exerted exactly in the axis of the cylinder and, for this purpose, one can use, for example, a single jack supported on a lifting beam making it possible to apply the axial displacement force on the two sides of the chock.

However, if the displaced cylinder is a driving cylinder, it is also possible, as shown in FIG. 2, to use displacement cylinders (42) supplied in synchronism and placed symmetrically on either side of the means (43 ) driving the cylinder in rotation (1), the chock (3) being provided, on each side of the axis (10), hooking lugs (35) which engage in corresponding hooking heads integral with the rod of each jack (42). This attachment can advantageously be carried out in a removable manner by lateral displacement of the displacement cylinder (42) as shown in FIG. 2 for the right cylinder.

On the other hand, each chock (3) of a cylinder (1) is secured to the latter in the axial direction by means of a cap (13) for closing the bearing cage, the latter being made of so as to be able to withstand axial forces, for example tapered bearings In this way, the axial displacement force applied by the jacks (42) on one of the chocks (3) is transmitted to the working cylinder and to the second chock placed at the other end of the latter.

Each chock (3) is also associated with a cambering assembly which, as shown schematically in Figure 6, generally consists of two pairs of jacks (6ª, 66ª) and (6 b , 66 b ) placed respectively on either side of the clamping plane P1 on which the axis of cylinder 1 is centered.

We know that we can achieve either a so-called "positive" bending in which the opposite chocks of the two working rolls deviate from each other, or a "negative" bending for which the opposite chocks are close together . However, it is generally necessary to oppose the approximation of chocks which results in crushing of the edges of the sheet relative to the central part and this is why, in the most current shown in the figures, only positive bending is carried out, that is to say in the direction of spacing of the chocks with respect to the plane of passage of the sheet, according to the arrows F₂ in FIG. 1.

To this end, as can be seen in FIG. 6, each chock 3 is extended beyond the sliding faces (31) by bearing parts (32) in the form of ears which extend above the block. support (5) in which are housed the camber cylinders (6). However, the bending force is not applied directly to the chocks (3), but to intermediate pieces (7) which are interposed between the bending cylinders (6) and the corresponding bearing parts (32).

Each support block (5) is common for the two working cylinders (1) and (1ʹ) and comprises, at each end, at the top and at the bottom, a transverse recess (52) limited by two spaced parallel faces (54) at the clamping plane. Each intermediate piece (7) is provided with an external horizontal part (70) housed in the recess (52) and guided in translation along corresponding sliding faces on the two opposite faces (54) of the housing (52).

Preferably, each intermediate part (7) has the shape of a T, the external part (70) forming two horizontal wings (75) which extend symmetrically on either side of a vertical central part (73) centered in the median plane P3 of the support block (5) perpendicular to the clamping plane P1 that is to say the vertical plane of symmetry of the two pairs of camber cylinders in which the chock (3) of each is centered of two working cylinders (1 and 1ʹ) when the latter are themselves aligned and centered on the median plane P2 of the cage.

The two camber cylinders (6ª, 66ª) symmetrical with respect to the plane P3, each consist of a piston (62) slidably mounted vertically in a bore (67) formed in the support block (5).

The vertical central part (73) of the intermediate piece (7) extends vertically between the two cylinders (6ª, 66ª) and engages in a machining (53) forming a central well formed in the support block (5) between the bores (67) of the two cylinders (6a, 66ª) and which extends the transverse recess (52) in which extend the two wings (75) of the intermediate piece (7) to pass over the two cylinders (6ª, 66ª).

The central part (73) constitutes a foot for guiding the intermediate part (7) mounted to slide vertically between two guide faces (55) parallel to the plane P3 and symmetrically spaced apart on either side of it and which constitute the two opposite sides of the central machining (53).

The same arrangement is adopted for the cylinders (6ʹª, 66ʹª) for bending the lower cylinder (1ʹ). The support block (5) which is common for the two working cylinders (1 and 1ʹ) is therefore symmetrical, on the one hand, with respect to the vertical plane P3 and on the other hand, with respect to a horizontal plane.

To make the cambering assemblies (6 and 6ʹ) associated with the two cylinders, there are therefore housed in the block (5), on each side of the plane of symmetry P3, two bores (67 and 67ʹ) separated by a central partition (68) and opening in the transverse recesses (52, 52ʹ) formed on the two faces, respectively upper and lower, of the block (5) and in which engage the upper parts (70, 70ʹ) of the two intermediate parts (7, 7ʹ) on which the chocks (3 and 3ʹ) of the two working rolls (1 and 1ʹ) are supported respectively. Each bore (67) is sealed by a partition (63) which constitutes the bottom of the transverse recess (52) and limits the chamber of the jack (6) closed, on the opposite side, by the partition 68 and inside which slides the piston (61) extended by a rod (62) which crosses the partition (63) to rest on the corresponding wing (75) of the intermediate piece (7).

The two pairs of jacks (6ª, 66ª) (6ʹª, 66ʹa) thus formed on the two faces of the support block (5) can be supplied by hydraulic circuits as shown in FIG. 7, the support part (5) thus constituting a real fixed hydraulic block.

Furthermore, the support lug (32) of the chock (3) is supported, by means of a thrust grain (33) on a smooth face (76) formed on the external part (70) of the intermediate piece (7) and along which the thrust grain (33) can therefore slide continuously following the axial displacements of the cylinder 1.

The thrust grain (33) is placed in the transverse plane of symmetry of the chock (3) and is therefore centered in the plane P3 in the position shown in FIG. 4 for which the working rolls (1) and (1ʹ ) are aligned and centered in the median plane P2 of the cage.

Because the support block (5) is common for the two cambering systems (6 and 6ʹ) of the two working cylinders (1 and 1ʹ), the central parts forming the guide foot (73, 73ʹ) of the two intermediate parts (7, 7ʹ) engage in the same machining (53) which completely crosses the support block (5), in the axis thereof, connecting between them the transverse recesses (52 and 52 entre) and passing between the chambers of the four camber cylinders.

As shown in FIG. 5, the guide foot (73) of each intermediate part (7, 7ʹ) is provided, at its end opposite to the external part (70), with an L-shaped notch which spares a thinned part (74) offset laterally so that the two guide feet (73, 73ʹ) can overlap in the middle part of the central machining (53). In this way, each guide foot (73, 73ʹ) can be guided practically all along the guide faces (55) formed over the entire height of the central machining (53).

Furthermore, in the axial direction, the two support parts (33) of each chock are also centered in thrust planes P4 parallel to the clamping plane P1 and passing through the axes of the two corresponding camber cylinders.

As can be seen in FIG. 5, the thrust planes P4, Pʹ4 of the two cambering assemblies associated with the chocks (3 and 3ʹ) and placed in the same support block 5 are offset on either side of the plane of symmetry of the support block 5 on which the machining is centered (53).

When, by means of the jacks (42), an axial displacement of one of the cylinders is controlled, by example the working cylinder (1), the corresponding thrust grain (33) slides on the smooth face (76) of the intermediate piece (7) on one side or the other of the plane of symmetry P3. If, at the same time, a cambering force is exerted on the cylinder, each sliding part (7) moves vertically thanks to its guide foot (73) which opposes the moment of overturning resulting from the shifting of the thrust grain (33) relative to the plane of symmetry of the forces exerted by the jacks.

The invention therefore makes it possible to carry out at the same time the axial adjustment and the bending of a working cylinder and, if the axial displacements remain reduced, as is most often the case, the moment of overturning of the intermediate part ( 7) which results can be easily collected by the embedding effect of the guide foot (7).

This avoids increasing the pressures on the vertical guide surfaces which could increase friction and penalize the performance of the thickness regulation.

However, if it is desired to make greater axial displacements, the resulting overturning moment can result in excessive friction forces liable to disturb the movement of the chock. It is then preferable to add to the embedding effect of the guide foot other provisions making it possible to reduce friction by balancing the applied forces.

Various means can be used for this purpose.

Thus, in the embodiment shown in Figure 3, the intermediate parts (7) and (7ª) corresponding to the two chocks (3) and (3ª) of each cylinder (1) and which are placed at the same level with respect to the axis of the cylinder, are integral with a beam (77) extending along the cylinder, parallel to its axis. This beam (77) can be dimensioned so as to absorb the moments of overturning of the parts (7) and (7a) due to the movement of the chocks (3) and (3a).

This simple arrangement can however have a drawback insofar as the four beams (77) extend between the two uprights of the cage, near the working rolls, that is to say in a space which is has an interest in clearing.

This is why, in a preferred embodiment, a balancing of the forces applied by the bending cylinders is carried out as a function of the position of the corresponding chock.

According to one of the essential characteristics of the invention, the offset of the displaced cylinder (1) is measured relative to the median plane P2 of the cage by means of a displacement sensor (44) consisting of two sliding parts, one relative to the other, fixed, for example on the two parts of one of the jacks (42) and providing an analog or digital signal proportional to the offset of the working cylinder relative to the centering position in the median plane P2 and of sign corresponding to the direction of the shift. This signal is used for balancing the pressures in the camber cylinders by means of a dis positive (8) shown diagrammatically in FIG. 7.

In this figure, there is shown by way of example a displaceable cylinder (1) and its two bending devices each consisting of two sets of jacks placed in hydraulic blocks (5a, 5b, 5ʹc, 5ʹd) each set comprising two jacks (6a, 66ª), (6b, 66b), (6ʹa, 66ʹa) (6ʹb, 66ʹb).

By convention, the reference 6 is assigned to the camber cylinders, placed on the side of the cylinder, that is to say towards the inside of the cage and the reference 66 to the cylinders placed towards the outside.

The four jacks associated with each chock are arranged in the manner described above and are centered in two transverse planes R3 and R4 spaced from each other by a distance e.

The hydraulic blocks (5a, 5b) and (5c, 5d) of the two chocks are connected by a single supply circuit (80) to a source of pressurized fluid not shown but the circuit (80) is divided into two branches ( 81) and (82) allowing the cylinders placed on the same side of the chock in the direction of axial displacement to be supplied at the same pressure. The branch (81) therefore supplies the jacks (6ª, 6 b ,) and (66 c , 66 d ) in parallel of the two rows R3 and Rʹ4 placed on the right in FIG. 7 while the branch 82 supplies the jacks in parallel (66ª, 66 b ,) and (6 c , 6 d ) of the two rows R4 and Rʹ3 placed on the left.

The hydraulic circuit is designed so that, whatever the pressures, all the cylinders are supplied with the same flow rate so as to determine equal displacements at the same speed.

Each branch (81), (82) of the supply circuit (8) is provided with a pressure regulator (83) which, depending on the signals received on its input (84) regulates the pressure in the corresponding circuit but in maintaining a constant flow.

Each cylinder (1) is associated with an axial displacement sensor (44) providing an analog or digital signal proportional to the displacement and which is applied to a calculation unit (85).

On the basis of the signals received, the latter develops the pressure setpoints S1 and S2 applied to the inputs (84) of the pressure regulators (83) of the two branches (81) and (82) according to a law programmed in the advance to ensure a distribution of pressures P1 and p2 such that the sum of the moments resulting from the thrust forces applied by the camber cylinders in the planes P4 and the reaction of the support part 32 of the corresponding chock on the T-shaped part is zero. In this way, even in the centering position of the cylinders (1) in the median plane P2 of the cage, the two rows of cylinders R3 and R4 may not be symmetrical with respect to the median plane P5 of the chock roll and this allows the cylinders to be arranged in the most adequate manner inside the hydraulic blocks (5) whose plane of symmetry does not necessarily coincide with that of the bearing.

Of course, the invention is not limited to the details of the embodiment which has just been described, variants which can be imagined by employing in particular equivalent means without departing from the protective framework defined by the claims.

In particular, the various members used for balancing the pressures could be replaced by means fulfilling the same functions, these means being able to be hydraulic, electric or even mechanical (cam, lever arm, etc.). In general, any technology for measuring displacements, calculating corrections and balancing pressures can be used to obtain the desired result.

It will also be noted that, as indicated on the left-hand side of FIG. 6, the fixed bending devices according to the invention can adapt to different diameters of cylinders and / or adapt to a variation in the diameter due wear, within the limit of the cylinder stroke.

Finally, the invention has been described in the case of a rolling mill with positive bending alone, but the same arrangements could be used to bend each cylinder in both positive and negative directions.

Without appreciably modifying the embodiment described above, it would suffice, for example, to use double-acting jacks whose rods are fixed to the support ears of the chocks to act in one direction or the other.

But we could also, in another arrangement, use single-acting cylinders placed in pairs on either side of the support part of the chock, each pair of cylinders being associated with a T-shaped sliding part.

The reference signs inserted after the technical characteristics mentioned in the claims, have the sole purpose of facilitating the understanding of the latter, and in no way limit their scope.

Claims (17)

1. Rolling mill with axially displaceable cylinders comprising, inside a support cage (4), at least two working rolls (1,1ʹ) resting on a clamping plane P1, on at least two cylinders d 'support (2,2ʹ) and whose ends are carried, by means of bearings in chocks (3,3ʹ) slidably mounted in the support cage, parallel to the clamping plane, at least one of the cylinders of work (1) being associated, on the one hand with means (42) for moving said cylinder (1) along its axis (10) on either side of a position for centering the working cylinders on the median plane P2 of the cage (4) and on the other hand means (6) for bending said cylinder (1) comprising, for each chock (3) two symmetrical assemblies of at least two bending cylinders (6) spaced apart 'from each other in the axial direction, and acting respectively on support parts (32) formed on each side of the chock (3), said sets of jacks being placed inside a support block (5) secured to the cage,
characterized in that each set (6) of cambering cylinders bears in the direction of the cambering force on a sliding part (7) slidably mounted vertically between two pairs of guide faces (54) (55) respectively parallel, and perpendicular to the clamping plane (P1), formed in a machining (52) (53) produced inside the support block (5) and that the corresponding support part (32) of the chock ( 3) is supported with the possibility of sliding on a flat and smooth face (76) mena gée on said sliding part (7) on the side opposite to the camber cylinders (6) and parallel to the axis of the cylinder (1). 2. Rolling mill according to claim 1, characterized in that the sliding part (7) comprises parts (75) of support, in the direction of the bending, of each bending cylinder (6) extending horizontally au- above each cylinder (6) and at least one guide portion (73) in the form of a foot extending vertically, engaging between two spaced apart guide faces (55) for sliding guide of said foot (73), perpendicular to the clamping plane (P1) and formed on two opposite faces of the machining (53) produced inside the support block (5). 3. Rolling mill according to claim 2, characterized in that each bending assembly (6) comprising two jacks (6,66) spaced from one another and centered in a plane (P4) parallel to the rolling plane (P1), the sliding part (7) has the shape of a T comprising a central part (73) forming the guide foot inside the support block (5) extending vertically between the two jacks ( 6, 66), and an enlarged external part (70) forming two wings (75) extending horizontally on either side of the foot (73), each above one of said jacks (6) and ( 66). 4. Rolling mill according to one of claims 1 to 3, characterized in that the two guide faces (54) formed in the support block (5) parallel to the clamping plane (P1) are symmetrically spaced apart and d 'another of a thrust plane (P4) passing through the axes of the camber cylinders (6) and in which is also centered the support part (32) of the chock (3), all the forces applied for the bending thus passing through said thrust plane (P4). 5. A rolling mill according to claims 3 and 4, characterized in that the machining carried out in the support block (5) comprises a transverse part (52) passing over the two camber cylinders (6) and in which is guided the enlarged external part (70) comprising the two wings (75) of the sliding part (7) in the shape of a T and a central part (53) forming a well in which the internal part forming the foot is guided (73) for guiding the sliding part (7). 6. Rolling mill according to one of the preceding claims, characterized in that, in each upright (4) of the rolling mill stand, the cambering assemblies (6) (6ʹ) of the two working rolls (1) (1ʹ) are mounted in a single support block (5) comprising, on its two opposite faces, two transverse recesses (52) (52ʹ) connected by a single central machining (53) passing between bending cylinders (6) (6ʹ). 7. Rolling mill according to claim 6, characterized in that the guide foot (73) of each sliding part (7) forms, on the side of the chock (3) corresponding, a mounting head of sufficient width for absorb the effects of overturning the sliding part (7) during bending and that its internal end, on the side opposite to the chock (3) has, in cross section by a plane parallel to the rolling plane (P1), a L-shaped notch providing a tapered portion (74) laterally offset from the thrust plane (P4) so that the two thinned parts (74,74ʹ) of the two sliding parts (7) and (7ʹ) associated respectively with the two working rolls (1) (1ʹ) overlap in the central part of the machining single (53) formed in the center of the support block (5). 8. Rolling mill according to one of claims 5, 6 and 7, characterized in that the two thrust planes (P4) (Pʹ4) of the cambering assemblies (6) (6ʹ) associated respectively with the two working rolls (1 ) (1ʹ) are offset laterally on either side of the median plane of the central machining (53) of the support block (5). 9. Rolling mill according to one of the preceding claims, characterized in that it comprises a balancing device (10) of the camber cylinders (6) comprising a means (44) for measuring the displacement of the cylinder (1) considered , relative to the centering position and means (83) for individual adjustment, at each instant of the pressure exerted on each cambering cylinder (6), as a function of the measured offset and of the position of the cylinder (6) considered by relative to the median plane of the sliding part (7) so that the sum of the moments resulting from the application of the cambering forces and the moment of the reaction of the chock on the sliding part (7) is zero. 10. Rolling mill according to one of claims 1 to 9, characterized in that the sliding parts (7,7ª) of the two chocks (3, 3ª) of the same cylinder (1) placed at the same level relative to the axis of the cylinder (1) are formed at the two ends of a continuous beam (77) extending parallel to the axis of the cylinder (1) between the two corresponding uprights of the cage (4). 11. A rolling mill according to claim 9, characterized in that the two chocks (3) (3a) of each cylinder being each associated with two symmetrical sets of camber cylinders, arranged on either side of the clamping plane P1, the cylinders (6a and 6b) (66c and 66d) placed respectively, in each of the assemblies, in the same relative positions relative to the median plane P5 of their respective bearings are connected in parallel to the same branch (81) (82) of a common circuit (80) for supplying pressurized fluid comprising as many branches as there are jacks (6,66) in each assembly, each branch being provided with means (83) for individual adjustment of the pressure of the fluid, with maintaining equal flows in all branches. 12. A rolling mill according to claim 11, characterized in that the means for individually adjusting the pressures in the jacks comprise, a servo-valve (83) on each branch (81) (82) of the supply circuit, said servo-valves being controlled by a calculation means (85), on the basis of a programmed law of corrections to be made to the pressures as a function of the offset measured and displayed by the calculation means and of the respective positions of the jacks supplied by the branch considered to ensure a correct distribution of the pressure force. 13. Method for adjusting the profile of axially displaceable rolls in a rolling mill comprising, inside a support cage (4) at least two working rolls (1,1ʹ) bearing, in a rolling plane P1, on at at least two support cylinders (2,2ʹ), the ends of which are carried, by means of rolling bearings, in chocks (3) mounted mobile in the support cage (4), parallel to a clamping plane P1 , process in which an axial displacement of at least one working cylinder (1) is carried out simultaneously relative to a centering position for which the two working cylinders (1,1ʹ) are symmetrical with respect to the median plane P2 of the cage (4) and on the other hand a bending of the cylinder displaced by application on its ends of a bending effort, said effort being exerted on each chock (3) by two sets of at least two jacks camber axially spaced apart, characterized in that the cambering force is exerted by means of fixed cylinders bearing, on one side on a support block (5) integral with the cage (4) and the other on an intermediate piece (7) kept slidingly guided on the support block (5) in the direction of application of the bending force, so as to resist the effects of overturning in the direction of axial displacement of the cylinders, said part being provided on the side of the chock (5) corresponding with a sliding surface (76) on which slides the support part (32) of the chock (3) in the event of axial displacement of the corresponding cylinder. 14. The method of claim 13, characterized in that, to achieve the camber of the displaceable cylinder relative to the centering position, the individual pressure exerted by each cylinder (6) is continuously adjusted. , 6ʹ) as a function of the measured offset and the position at the same instant of the jack considered (6.6ʹ) with respect to the median plane of the sliding part (7), so that the sum of the moments resulting from the application of the cambering forces and the moment of the reaction of the chock on the part slip (7) is zero. 15. Rolling mill with axially displaceable rollers comprising, inside a support cage (4), at least two working rolls (1,1ʹ) bearing along a rolling plane P1, on at least two rolls d support (2,2ʹ) and the ends of which are carried, by means of bearings in chocks (3,3ʹ) capable of being displaced, in the support cage, parallel to the clamping plane P1, at least l 'one of the working cylinders (1) being associated, on the one hand with means (42) for moving said cylinder (1) along its axis (10) on either side of a centering position of the working rolls on the median plane P2 of the rolled product (20), and on the other hand means (6) for bending said roll (1) comprising, for each chock (3) two symmetrical sets of at least two jacks of bending (6,6ʹ) spaced from each other in the axial direction, characterized in that the bending cylinders (6) of each chock are mounted on a fixed support solida ire (5) of the cage, that these jacks are supplied using a common hydraulic pressure and that these jacks are supported in the direction of the cambering force on sliding parts (7,7 7) in shape of T, that the part forming the foot of the T is arranged so as to allow guiding in translation, in the vertical direction, along a machining (53) read in the same blocks (5) which already contain the camber cylinders, that the chocks of the working cylinders are each supported on a part (7) thereby receiving the cambering force and can move on these parts by sliding when the cylinders are to be moved axially and the sliding parts (7) are guided in the vertical plane using a low friction system of the rolling type or of the hydrostatic support type so allow operation of the system causing little friction loss in the vertical plane. 16. Rolling mill according to one of the preceding claims, characterized in that it is of the sexto type and that the bending force and the movement of movement apply to the intermediate rolls. 17. Rolling mill according to one of claims 1 to 15, characterized in that it is of the sexto type and that the bending force and the movement of movement apply to the working rolls.

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