EP1005923B1 - Rolling mill provided with means for bending the work rolls - Google Patents

Abstract

A rolling mill comprises respectively positive (5,5') and negative (6,6') cambering rams supported on lugs (7,7') of chocks (4,4') of the two working cylinders. Each lug of a chock (4) has a staged section comprising at least one support part (73) and a clearance (74). The negative cambering rams (6) of a first chock (4) are arranged on the same side of the rolling plane (P1) than the positive cambering rams (5') of the second chock (4') crossing the rolling plane through the clearance (74). The chocks of the two working cylinders are similar and can be mounted on either cylinders (2,2').

Description

Rolling metal products in the form of tape is normally carried out in a train of rolling mills each consisting of a cage comprising two support columns spread apart and connected by sleepers, between which is mounted a set of superimposed cylinders having parallel axes and placed substantially in the same clamping plane substantially perpendicular to the direction of displacement of the product.

You can make rolling mills of different kinds. Generally, in a rolling mill, the product to be rolled passes between two cylinders of work which define the rolling plan; these cylinders are generally relatively large in diameter reduced with regard to the efforts to which they are subjected, they are therefore generally based respectively on at least two support cylinders between which is applied the rolling force.

The so-called "quarto" rolling mills, therefore have four superimposed cylinders, respectively two associated working cylinders, respectively, with two more supporting cylinders large diameter.

In the "sexto" rolling mills, cylinders intermediaries are interposed between each cylinder and the corresponding support cylinder.

Other types of rolling mill, including a plus or fewer cylinders are known and used in industry.

The cylinders are supported one on the others along substantially support lines parallel, and directed along a generator whose the profile, normally straight, depends on the forces applied and resistance of the cylinders. Generally the clamping force is applied by screws or cylinders interposed between the cage and the support cylinder shaft ends upper, the lower support cylinder taking support by these ends directly on the cage. AT apart from the latter, the other cylinders must therefore ability to move relative to the cage and at this effect, are carried by mounted support members sliding vertically in two windows in the two columns of the cage.

Clamping means such as screws or jacks, leaning on the cage, exert a vertical force in the direction of tightening of the cylinders for the rolling of the product passing between the cylinders of job.

Generally, each cylinder is mounted rotatable, around its axis, on bearings carried by two support members called chocks and this one are slidably mounted, parallel to the plane of clamping passing through the axes of the working cylinders, each between two flat guide faces provided respectively on either side of said plane of clamping on both sides of the window corresponding from the cage.

The clamping forces are applied between the two ends of the two support cylinders. Since the rolled product, of variable width does not fully cover the length of the work, each cylinder can flex under the action applied efforts.

This results in a thickness variation of the space of passage of the strip between the cylinders of working, the edges of the strip can thus be more thinner than the central part.

For a long time, we have tried to correct these thickness defects on the cross section of the rolled product and used for this purpose different means.

For example, it has been proposed to compensate for the deformation of the rolls due to the rolling force by a bulging of their surface obtained by machining according to a particular profile. This presents the disadvantage of not being perfectly suited to all widths of the rolled product. In addition, the thickness defect on the cross section of the product laminate is complex because it is the result of all the deformations of all the cylinders, which are different diameters, and the deformation of all the constituent parts of the rolling stand under the effort.

This is why, we also proposed to realize a continuously adjustable correction, by cambering effects of working cylinders, which are usually small diameters, applying controlled bending forces on both ends from their tree.

For this purpose, we usually use hydraulic cylinders placed on either side of each chock and bearing in one direction on a fixed part and in the other on side parts protruding forming support ears of the chock.

We can thus achieve a so-called cambering negative, by tightening the chocks of the two working rolls, to compensate for excess thickness edges of the product or a so-called positive camber, by spacing the same chocks from the two cylinders to compensate for an excess thickness of the central part of the product.

To reduce the number of cylinders, you can consider using double acting cylinders realizing, in a sense the positive cambering and in the other the negative camber. However, then the rods of the cylinders are connected, in both sense, to the chalkboard. However, the cylinders must be replaced periodically and, for this purpose, are withdrawn of the cage by displacement parallel to their axis in sliding or rolling on rails. We must then remove the camber cylinders at the same time as the chocks, or apply the bending effort to intermediate pieces on which the chocks are supported with the possibility of axial sliding.

Such an assembly is quite complicated and, generally we prefer to use single cylinders effect acting in opposite directions on chocks, respectively for the positive camber and for the negative camber of the cylinder. For this, the cylinders of positive camber can be simply interposed between the chocks of the two working rolls, respectively upper and lower by taking support in opposite directions on them. However, we do not can then have only a symmetrical effect on the two cylinders on either side of the rolling plane.

It is therefore preferable to use cylinders associated with each chock to apply individually specific bending efforts on each of the working cylinders. However, a such an arrangement obviously increases the number of cylinders and complicates their installation, in particular for positive camber cylinders which are placed between the chocks.

In addition, it must be taken into account that, working cylinders having a fairly large diameter weak, their chocks are smaller than those support cylinders. So it seems natural, for adjust the levels of the work chocks, take support on the support chocks, which can, in addition, be extended by guide legs between which the work chocks are mounted sliding.

However, the level of support chocks may vary and, to ensure precise control of the profile of the working cylinders, it is preferable that the cambering cylinders bear directly on the cage.

For this purpose, it is therefore more advantageous to mount the camber cylinders in two pieces of support fixed respectively on the two sides of each window of the cage at the level of the cylinders of work and in which the circuits are arranged hydraulic, these support parts being, for this reason, sometimes called "hydraulic blocks".

Usually, positive camber cylinders and negative are housed in support parts projecting inward from the window and provided with guide faces at their ends lateral of the chock, the ears thereof extending outwardly between said parts in projection.

For this reason, each support block usually has three projecting parts, respectively a central part placed at the level of the rolling plan, in which the cylinders are housed of positive bending of the two chocks and two parts support placed, respectively, above and in below the rolling plane and in which are housed the negative camber cylinders of both cylinders, respectively upper and lower.

As seen in Figure 1 which shows, at as an example, a provision like this, each support block, therefore has an E shape comprising, on either side of the projecting part central, two notches in which extend, respectively, the ears of the two chocks. These notches must therefore have a sufficient height to allow the relative levels to be varied cylinders.

However, the rolls of a rolling mill and, in particular, the working cylinders, wear enough quickly and their diameter can therefore vary, as well that, of course, the relative positions of cylinders applied to each other. The figure 1 shows, for example, the relative positions of the new and used cylinders, respectively on the right and to the left of the clamping plane. As a result, the heights of the guide faces and the strokes of the cylinders should be increased depending on the range wear to allow height adjustment necessary cylinders.

In addition, disassembly of the cylinders cannot be do that in a determined position that matches at the level of fixed chutes sliding rails and, in this position, the cylinders must be all separated from each other. Now usually the camber cylinders are used to balance the weight working rolls and their chocks and must therefore withstand these throughout the race of adjustment between disassembly position and position the tightest of the chocks.

For all these reasons, the central part of the support blocks in which the cylinders are placed positive camber, as well as the notches in which extend the ears of the chocks, must have each a minimum height to ensure the necessary stroke.

As a result, the total height of the blocks hydraulic must be relatively large and it's therefore necessary to have a sufficient interval between the chocks of the support cylinders to place the hydraulic blocks. This complicates the implementation of the system arching in case of modernization of an existing cage and in the case of a new cage, these requirements increase the dimensions of the cage and therefore the cost thereof.

Document JP-A-1.005612 solves such a problem thanks to to a special arrangement in which each ear of a chock has a stepped profile comprising a support part for the camber cylinders, positive and negative respectively of this first chock and a free space of passage of the positive camber cylinders of the other chock.

Thus, the central part of the support block can be removed the cylinders positive camber of a chock that can be placed next to the cylinders of negative arching of the other chock.

Such an arrangement therefore makes it possible to reduce the height of the blocks of support and simplify their implementation.

In addition, to determine the dimensions and the installation of hydraulic blocks, cylinders and support ears, a set of parameters related to operating conditions. For example, the rolling plan should normally be placed at a substantially constant level and one is brought like the shows, Figure 1, to perform, respectively for the upper working cylinder and for working cylinder lower, special chocks having guide faces side extended downward to provide guidance correct over all the necessary height, taking into account the wear range.

Such an arrangement cannot be symmetrical and we must therefore have two types of chocks, respectively for the upper cylinders and the lower cylinders. When replacing, the cylinders new ones must be fitted with adequate chocks in advance according to their position in the cage, respectively at above or below the rolling plane.

This problem is also solved thanks to the arrangement described in the document JP-A-1.005612, which allows to use, for working rolls, chocks of a single model, these can be adapted either to an upper cylinder or to a lower cylinder, by simple turning.

However, in such an arrangement, the camber cylinders are placed in two diagonal planes which intersect along a vertical axis of symmetry. he as a result that the forces applied to each chock, respectively to left and right of the clamping plane passing through the axes of the cylinders work are axially offset on either side of the median plane of the chock, orthogonal to the axis of the cylinder. Such an axial offset can present disadvantages for the centering of the rolling effort.

It therefore appears that, in the design of a new rolling stand or for adapting systems bending to an existing cage, you must take into account set of sometimes contradictory requirements while seeking, obviously, to reduce the overall cost of the cage and to allow as precise adjustment as possible of the profile of the cylinders.

The object of the invention is therefore to solve the whole of these problems avoiding the drawbacks mentioned upper.

The invention therefore generally applies to a rolling mill comprising, inside a holding cage having two spaced apart columns, a set of cylinders comprising at least two working cylinders, mounted rotary, around axes substantially parallel to a rolling plane, each on two chocks strung respectively in windows of the two columns of the cage and sliding mounted along fixed guide faces parallel to a clamping plane, each by means of lateral holding faces, the rolling mill being equipped with means for applying bending forces on the chocks from the two working rolls comprising, for each column of the cage, a set of cylinders arranged on either side of the clamping plane and acting respectively on support ears of each chock extending projecting, respectively, relative to the lateral retaining faces of the chock and each having an internal bearing face facing the plane of rolling and an external bearing face turned to the opposite side, each set bending cylinders comprising at least two positive bending cylinders bearing, respectively, on the internal faces of the ears of the two chocks and at least two negative cambering cylinders supported, respectively on the external faces of the ears of the two chocks, rolling mill in which each ear of a first chock has a stepped profile with at least one support part and at least one element free passage space mobile of at least one positive camber cylinder of the second chock, the stepped profiles of the ears, respectively, of the two chocks being inverted by so that a support part of a first chock corresponds to a free space of the second chock.

According to the invention, on each side of the clamping plane, the ear a first working chock placed on a first side of the plane of rolling comprises a single support part centered on a median plane of said chock perpendicular to the axis of the cylinder and two free spaces, arranged on either side of said single support part and the ear of the second chock placed on the second side of the rolling plane has only one free space centered on the median plane and two support parts arranged on either side of said single space, each set of jacks comprising, on the one hand a positive camber cylinder and a negative camber cylinder supported respectively on the internal and external faces of the single support part of the ear of the first working chock and, on the other hand, two cylinders of positive cambering and two negative cambering cylinders arranged on both sides of the median plane and bearing respectively on the internal faces and external of the two support parts of the second working chock.

According to another characteristic particularly advantageous, the fixed elements of the cylinders of bending, respectively positive and negative of the two chocks are mounted respectively in parts in projection of two support blocks respectively fixed on each column of the cage, on either side of the plane of tightening, each support block being symmetrical about in the rolling plane and comprising, between said parts in projection, a unique central notch in which extend the support ears of the chocks of the two cylinders, respectively upper and lower, and each chock is provided, on each side of the clamping plane, with a single lateral holding face extending on the side opposite to rolling plane with respect to the support ear and sliding along a fixed guide face arranged at the end of a corresponding projecting part of the block of support.

Preferably, the support ears of each chocks are offset towards the rolling plane with respect to the axis of the corresponding cylinder so that the faces internal support for positive camber cylinders are almost in contact with each other in the wear position maximum of the working cylinder.

In a preferred embodiment, the the two ears of a first working choke extending, respectively, on either side of the clamping plane comprise, one, a support part one framed by two free spaces and the other, a single framed free space by two support parts, the arrangement being reversed for the ears of the second work chock.

According to another advantageous characteristic of the invention, in the case a rolling plant comprising at least two stands operating in tandem, the chocks of the working cylinders and the support blocks of all the cages are identical.

The invention applies to new rolling mill stands but it is particularly advantageous for the modernization of existing cages, for which the dimensional constraints of columns and chocks of existing support cylinders can complicate or prevent installing a design arching system classic.

• la figure 1 est une vue en coupe transversale de la partie centrale d'une cage de laminoir quarto de type connu.
• la figure 2 est un schéma de principe d'une disposition des empoises et des vérins de cambrage des cylindres de travail, analogue à celle du document JP-A-1.005612.
• La figure 3 est un schéma de principe, en vue de dessus selon la ligne III-III de la figure 2.
• La figure 4 montre schématiquement, en perspective, la disposition des vérins de cambrage.
• La figure 5 est une vue partielle de côté des empoises de travail.
• La figure 6 est une vue en coupe transversale selon la ligne VI-VI de la figure 5.
• La figure 7 est une vue de dessus schématique de la disposition selon l'invention.

The invention will be better understood from the description which follows of certain particular embodiments, given by way of example and represented in the appended drawings in which:

• Figure 1 is a cross-sectional view of the central part of a quarto rolling stand of known type.
• Figure 2 is a block diagram of an arrangement of chocks and camber cylinders of the working rolls, similar to that of document JP-A-1.005612.
• Figure 3 is a block diagram, seen from above along line III-III of Figure 2.
• Figure 4 shows schematically, in perspective, the arrangement of the camber cylinders.
• Figure 5 is a partial side view of the working chocks.
• FIG. 6 is a cross-sectional view along line VI-VI of FIG. 5.
• Figure 7 is a schematic top view of the arrangement according to the invention.

In Figure 1, there is shown in section transverse, the classic layout of a rolling mill type quarto comprising, inside a cage having two spread columns 1, two working cylinders, respectively upper 2 and lower 2 ', which take support, respectively, on two support cylinders, upper 21 and lower 21 'and define an air gap for the passage of an M strip to be laminated, passing along a rolling plan P1.

Figure 1 shows the central part of a window of a column 1 of the cage, in cross section at the axis of the cylinders, the second column being identical.

Each working cylinder 2, 2 'is rotatably mounted, at its ends, on trunnions turning in bearings housed in chocks 4, 4 '. Likewise, support cylinders 21, 21 'are carried by chocks 41, 41 '.

The axes of the cylinders are parallel and must be held substantially in a clamping plane P2 perpendicular to the rolling plane P1. Usually the latter is horizontal, the plane of clamp P2 being substantially vertical.

In the rolling position shown on Figure 1, the cylinders are tight, and their levels may vary depending on their wear. AT As an example, the half view on the right represents the relative positions of the new cylinders and the half view left represents the positions of used cylinders smaller diameter.

It is therefore necessary to be able to adjust the relative levels of the cylinders and that's why the cylinder chocks are strung in a window 10 from column 1 of the cage and can slide parallel to the clamping plane P2.

The chocks 41, 41 'of the support cylinders 21, 21 'which have a large diameter, are mounted sliding along guide faces 11a, 11b formed directly along the two uprights 1a, 1b which frame window 10 of column 1.

However, the chocks 4, 4 ′ of the cylinders of work 2, 2 'smaller diameter are less wide that the chocks 41, 41 ′ of the support cylinders 21, 21 'and their guide faces must therefore be less apart. Therefore, according to a provision conventional, the guide faces 12a, 12b of the chocks are arranged on the faces opposite two machined blocks 3a, 3b which are mounted respectively on the two uprights 1a, 1b of the column and extend inwardly projecting from window 10.

It is advantageous, in a rolling mill, that the rolling plan P1 is maintained at a level substantially constant, especially when the band to laminate M passes successively in several rolling mills operating in tandem.

In the example shown in Figure 1, to adjust the level of the rolling plan, we act on wedges 16 of adjustable height, by corners or by cylinders, which are placed on the bottom bottom of each column 1 of the cage and on which take support the chocks 41 'of the support cylinder lower 21 '; the level of the lower holds 16 is adjusted according to the diameters of the cylinders for that, taking into account the diameter of the working cylinder lower 2 ', the upper generator thereof located substantially at the plane of rolling P1.

Level of upper support cylinder 2 is adjusted by clamping means not shown, such as screws or cylinders, which are mounted at the upper part of the two columns 1 of the cage for build on chocks 41 and which allow, in addition, to apply the necessary rolling force thickness reduction.

Of course, other provisions may be used to adjust the relative levels of cylinders inside the cage.

As indicated, the cylinders, in especially the working cylinders, must be periodically removed from the cage for maintenance or replacement and, for this, their chocks roll or slide on fixed guide rails. These rails (not shown in the figure) are mounted on the cage columns and placed at a constant level for which all the cylinders are spread apart others. To place the cylinders in the position replacement, lower the support cylinder lower 21 'to its lower level by means of lower wedges and the cylinder is raised higher support 21 at its higher level through clamping means and possibly cylinders auxiliaries 15 mounted in the support blocks 3a, 3b and bearing on the chocks 41 of the cylinder of upper support 21. In service, these cylinders 15 also serve to balance the weight of cylinder 21 and its chocks 41.

The supporting cylinders being thus spaced of a large opening, the relative levels of working cylinders 2, 2 'can be adjusted by cylinders housed in the support blocks 3a, 3b. Of the as indicated above, these jacks also serve, in service, to apply bending efforts, respectively positive or negative, on chocks working cylinders.

Figure 1 shows the most classic in which each chock 4, 4 'is associated with two sets of cylinders placed respectively on either side of the clamping plane P2 and comprising, for each working cylinder, respectively upper 2 or lower 2 ', at least a positive cambering cylinder 5, 5 'and at least one 6,6 'negative camber cylinder.

Usually, these cylinders act on support parts provided on either side of each chocks and which form opposite ears 7, 7 ' each projecting from the side corresponding side 42 of the chock.

Therefore, each support block 3 has a E-shape comprising three holding parts in projection, respectively an upper part 32, a central part 33 and a lower part 32 ', which frame two notches, respectively upper 31 and lower 31 ′, into which the ears 7, 7 'of the working chocks, respectively upper 4 and lower 4 '. Camber cylinders resting on the ears of the chock are housed in these three holding parts whose ends facing each other form the guide faces 12a, 12b the along which the lateral sides 42a slide, 42b, 42'a, 42'b, of the two chocks 4, 4 '.

So the two positive camber cylinders, respectively 5 of the upper working cylinder 2 and 5 'from the lower working cylinder 2', are housed in the central part 33 of the support block 3 and are supported, respectively, on the internal faces 71, 71 ', tours towards the rolling plane P1, ears 7, 7 ', both working chocks 4, 4 '. Negative camber cylinders 6, 6 'are housed, respectively, in the projecting part upper 32 and in the lower projecting part 32 'of each support block 3 and bear on the faces external 72, 72 'of the ears 7, 7' of the two chocks 4, 4 ', turned on the opposite side to the rolling plane P1.

As seen in Figure 1, to house the positive cambering cylinders 5, 5 'in the central part 33 with the stroke necessary to adjust the level of the working cylinders it is necessary to give a relatively large thickness at the central part support 33 of the support block 3 whose end 34 must constitute, over a sufficient height, a guide face for the corresponding lateral sides of chocks 4, 4 '.

In addition, in the closed position of the cylinders of work represented on the left half-view and for which used cylinders have the smallest diameter, the two chocks 4, 4 ′ come practically into contact one from the other. The dimensioning of the different parts support blocks 3 and working chocks must therefore take the wear range into account, especially when you want to keep the rolling plan at a level constant. For example, in the cage shown on the Figure 1, the underside 43 of the chock 4 is located below the rolling plane in the wear position Max.

These different imperatives complicate the implementation places cambering means in the cage and lead, the more often, to an asymmetrical arrangement compared to the rolling plan, the chocks being necessarily different for the two working cylinders.

As we will see now, the disposition of document JP-A-1.005612 allows to avoid such disadvantages, and to simplify the installation of hydraulic blocks.

The principle of this provision is shown schematically in Figures 2 and 3 and in more detail on Figures 5 and 6.

This arrangement is described, by way of example, in the case of a quarto type rolling mill as shown in the Figure 1 and therefore comprising all the provisions usual. In Figures 2 and 3, only schematically the two uprights 1a, 1b of the column between which are arranged the two working cylinders 2, 2 'which are carried by chocks 4, 4' mounted sliding between support blocks 3a, 3b.

As can be seen, in FIG. 2, each block of support 3a, 3b has a single notch 35a, 35b which extends on either side of the rolling plane P1, the part protruding center 33 of the known arrangement being, therefore, deleted. Thus, each support block has a section in C and not in E.

As a result, in each support block 3, the camber cylinders must all be housed in two support parts, respectively upper 32 and lower 32 'framing a central notch 35. The arrangement of negative camber cylinders 6, 6 'remains unchanged but, in however, each 5, 5 'positive camber cylinder must necessarily be housed in the holding part in projection of the support block which is on the side opposite to the chock on which it must act, compared to the plan of rolling P1.

This is why the positive camber cylinders 5a, 5b bearing on the internal faces 71a, 71b of the two ears 7a, 7b of the upper chock 4 are housed in the lower protruding parts 32'a, 32'b of the blocks of support 3a, 3b, with cylinders 6'a, 6'b of negative bending of the lower chock 4 '.

Therefore, the body 51 of each camber cylinder positive 5 must be placed next to the body 61 'of the actuator 6 'negative camber, in the lower projection 32 ', and the rod 52 of the jack 5 must cross the ear 7 'of the lower chock 4' to pass to the other side of the rolling plane P1 and lean on the internal face 71 of the ear 7 of the top working chock 4.

In addition, in order not to increase the overhang projecting support parts 32, the jacks camber are placed next to each other and centered, respectively in two planes Pa, Pb parallel to the clamping plane P2 and spaced apart symmetrically on either side of it.

Figure 3 schematically shows a mode of realization of the ears of the chocks allowing to get this result. We see, in fact, that each side of the chock, the camber cylinders, respectively, positive 5 and negative 6 'are placed one next to the other and offset axially, respectively on either side of the median plane P3 of the chock 4 'on which the bearings 40' are centered rotary support for the working cylinder 2 '. Each 7 'ear of the chock therefore has a stepped profile comprising a part 73 ′ for supporting the cambering cylinder negative 6 'which covers only part of the length of the chock, in the longitudinal direction of the axis of the cylinder, so as to leave a free space 74 'allowing passage of the cylinder rod 5 of positive camber.

In addition, this provision is reversed, one part between the opposite sides of the same chock 4 ', on either side of the clamping plane P2 and on the other hand, between the same sides of the two chocks respectively lower 4 'and upper 4, placed on either side of the rolling plane P1.

For example, we see in Figure 3 that the ear 7'a of the lower chock 4 'lying at left of clamping plane P2, has a stepped profile comprising a portion 73'a for supporting the actuator 6'a negative camber which is placed in front of the plane median P3 of the bearings, and extends at most over the half the length (L) of the chock, so that leave a free space 74 'placed behind the same median plane P3, for the passage of the rod of the jack 5a positive camber of the upper chock 4. On the other hand, the ear 7'b of the lower chock 4 'placed to the right of the clamping plane P2 has a reverse stepped profile comprising a part 73'b for supporting the cambering cylinder negative 6'b, which is placed behind the median plane P3 and leaves a free space 74'b placed in front of the same plane median P3 for the passage of the cylinder rod 5b for bending positive of the upper chock 4.

In the embodiment shown in FIGS. 5 and 6, the bodies 51, 61 of the different cylinders, which are single acting, can be made simply bores in opposite angles of the corresponding projecting parts 32, 32 ′, of the blocks of support 3. Figure 6, which is a cross section, by a plane passing through the axes of the cylinders, of the support block 3a placed to the left of the clamping plane P1 in FIG. 5, shows that the lower holding part 32 ′ of said block 3a has two bores placed side by side, respectively 61 'forming the body of the negative camber cylinder 6' and 51 forming the body of the cylinder 5 for positive cambering of the chock superior 4.

As shown in Figure 3, the cylinders of positive camber 5a, 5b of the upper working cylinder 2 are thus placed in two opposite angles parts of lower support 32'a, 32'b of the two support blocks 3a, 3b and are therefore centered on a first diagonal plane Q1 inclined at a non-right angle to the clamping plane P2. It is the same with the free spaces 74'a, 74'b provided in the ears 7'a, 7'b of the lower chock 4 '. From this done, the negative camber cylinders 6'a, 6'b of the cylinder lower work 2 'are placed on either side of the plane P2, in the other two angles of the holding parts 32'a, 32'b of the two support blocks 3a, 3b and centered in a second diagonal plane Q2, as well as the support parts 73'a, 73'b of the two ears 7'a, 7'b.

In Figure 4 which shows schematically, in perspective, the set of two chocks 4, 4 ', we see that the layout is reversed for the working chock upper 4 and upper holding parts 32a, 32b support blocks 3a, 3b; the positive camber cylinders 5'a, 5'b of the lower cylinder 2 'are centered in the second diagonal plane Q2 while the camber cylinders negative 6a, 6b of the upper working cylinder 2 are centered in the first diagonal plane Q1.

The entire arrangement therefore includes an axis central symmetry 10 placed at the intersection of the plane of clamping P2 with the median plane P3 of the chocks and by which pass the two diagonal planes Q1 and Q2.

Because of this, although the camber cylinders acting on two opposite ears of a chock, are offset axially on either side of the median plane P3, the action of camber exerted on the chock remains well centered by relation to turnover, in the positive direction as in the negative sense.

The arrangement shown in the figures is particularly simple and can be easily adapted to an existing cage. One could, however, imagine other provisions making it possible to pass through the center of chock the result of bending efforts exercised in the positive or negative sense. In particular, the bending effort could be applied, on each side of chock, by a greater number of cylinders arranged so as to ensure the centering of the result of the efforts applied.

FIG. 7 shows an arrangement according to the invention in which the bending force is applied on one side of the chock by a single jack and on the other by two jacks supplied in parallel. In this case, each ear of a chock has a stepped profile having two free spaces on either side of a support part or else two support parts on either side of a free space. Thus, the ear 7'a of the lower working chock 4 ', placed to the left of the clamping plane P2, comprises a support part 73'a which is centered on the median plane P3 of the bearings, on which take support the positive 5'a and negative 6'a camber cylinders. This support portion 73'a is framed by two free spaces 74'a ₁ , 74'a ₂ through which pass the rods of two jacks 5a ₁ , 5a ₂ of positive bending of the upper working cylinder which are supplied in parallel. On the right side of the clamping plane P2, the ear 7'b comprises two support parts 73'b ₁ , 73'b ₂ symmetrically spaced apart on either side of the median plane P3, on which two pairs of cylinders operating in parallel, respectively 5'b ₁ , 5'b ₂ of positive bending and 6'b ₁ , 6'b ₂ of negative bending of the lower cylinder 2 '. Between these two support parts 73'b ₁ , 73'b ₂ is placed a central recess 74'b for the passage of the rod of the jack 5b for positive bending of the upper chock 4.

The support ears 7a, 7b of the upper working chock 7 shown in phantom in Figure 7 are arranged in reverse and therefore comprise, on the left, two parts 73a ₁ , 73a ₂ , for supporting the two jacks of positive camber 5a ₁ , 5a ₂ and, on the right, a support part 73b framed by two free spaces 73b ₁ , 73b ₂ for passage of the rods of the jacks 5'b ₁ , 5'b ₂ of positive camber of the lower cylinder 2 '.

Thus, the bending efforts applied to each chock, in the positive direction or in the direction negative have a resultant directed along the axis center of symmetry OO 'which passes through the center of each level.

Since the support ears 7, 7 'of the two chocks 4, 4 ′ penetrate into the same notch central 35 of each support block 3, the faces of lateral support 42, 42 'of each chock 4, 4' extend on one side of the ear 7, 7 'of so as to slide along the guide faces 36, 36 ' formed at the ends of the holding parts in projection 32, 32 '. Therefore, the two chocks can be symmetrical with respect to the rolling plane P1. As a result, chocks can be used identical for the two working cylinders, the chock being simply turned 180 ° according to whether it is placed above or below the plane of rolling P1.

It should be noted that, to allow the disassembly of the cylinders, the cylinder rods must be fully retracted so as to release entirely the central notch 35. As a result, as shown in figures 5 and 6, the height of each holding part, respectively upper 32 or lower 32 ', from a support block 3 is determined based on the stroke of the cylinder positive camber which itself depends on the length that we have to give to the cylinder rod to make it lean on the ear of the chock placed from the other side of the rolling plane P1, the cylinders of negative camber with a lower stroke.

The invention has the advantage of allowing a reduction in the overall height of each block of support compared to usual arrangements since we remove the protruding central part which was previously necessary to house the positive camber cylinders. This results in a decrease in height of the area that should remain available between chocks 41, 41 'of the cylinders support to allow the implantation of the blocks of support. This provision is particularly interesting in the case of the modernization of a existing rolling stand because it allows facilitate the installation of the cambering system positive and negative between the support cylinders without notable modification of the cage columns.

Furthermore, the fact that the faces of support 42 extend on one side of the ears 7, these can be brought closer possible of the rolling plan, which allows minimize the length of the rods 52 positive camber cylinders. The internal faces 71a, 71b of the two ears 7a, 7b are then placed substantially at the level of the internal face 43 of chock 4 facing the rolling plane. This one is itself separated from the axis of the cylinder by a distance a little less than the smallest radius of the working cylinder 2. In this way, when the cylinders are in their maximum state of wear, the internal faces 71, 71 'of the ears 7, 7' of the two chocks 4, 4 'being almost in contact with one of the other, in the rolling plane P1, taking into account the necessary adjustments for negative bending.

But the invention still presents other benefits.

For example, the number of guide faces fixed and lateral chock holding faces is decreased. Now, we know that the surfaces of slip must be fitted with attachments made of a material with a coefficient of friction suitable for use and which constitute parts wear. The decrease in their number, through the adoption of all the arrangements according to the invention, reduces the cost of installation as well as production costs by simplifying operations maintenance and by reducing the necessary duration of interventions.

Furthermore, we know that in a rolling mill tandem, it is desirable to maintain the plan of rolling to a substantially constant level.

Thanks to the invention, because the height overall hydraulic blocks and chocks is lower, it is possible to insure without difficulty the necessary adjustment ranges and use for all cages of support blocks of the same height and even identical.

Of course, the invention is not limited to details of the embodiments which have not been described as an example, other provisions equivalents that can be imagined without deviating from the defined protection framework by the claims. In particular, it would possible to use a greater number of cylinders arranged in the parts support so that the result of the efforts passes always by the center of the chock.

Furthermore, the invention has been described in the case of a quarto rolling mill but could be applied to any type of a rolling mill, for example quinto or sexto, whenever it It is useful to make a camber of the working cylinders.

The reference signs inserted after the technical characteristics mentioned in the claims are intended only to facilitate the understanding of them and in no way limit them the scope.

Claims (5)

1. A rolling mill comprising, inside a holding frame with two spaced standards (1a, 1b), a set of rolls containing at least two work rolls (2, 2'), mounted to rotate, around axes substantially parallel to a rolling plane (P1), each on two chocks attached respectively in windows (10) of both standards of the frame and mounted to slide along fixed guiding faces (12) parallel to a clamping plane (P2), each via lateral holding faces (42), whereas the rolling mill is provided with means for applying bending loads onto the chocks (4, 4') of both work rolls (2, 2') comprising, for each standard (1a, 1b) of the frame, a set of actuators arranged on either side of the clamping plane (P2) and acting respectively on resting ears (7a, 7'a, 7b, 7'b) of each protruding chock (4, 4'), respectively, with respect to the lateral faces (42) holding the chock and having each an internal resting face (71) directed to the rolling plane (P1) and an external resting face (72) directed toward the opposite side, whereas each set of bending actuators comprising at least two positive bending actuators (5, 5') resting, respectively, on the internal faces (71, 71') of the ears (7, 7') of both chocks (4, 4') and at least two negative bending actuators (6, 6') resting, respectively on the external faces (72, 72') of the ears (7, 7') of both chocks (4, 4'), a rolling mill wherein each ear (7') of a first chock (4') exhibits a staggered profile with at least one resting part (73'a) and at least one free space (74'a) for letting through said mobile element (52a) of at least one positive bending actuator (5a) of the second chock (4), the staggered profiles of the ears (7a, 7'a), respectively, of both chocks (4, 4') being reverted so that a resting section (73'a) of a first chock (4') corresponds to a free space (74a) of the second chock (4).
      characterised in that, on each side of the clamping plane (P2), the ear (7'a) of a first work chock (4') situated on a first side of the rolling plane (P1) comprises a single resting section (73'a) centred on a median plane (P3) of said chock (4') perpendicular to the axis of the roll and two free spaces (74'a1, 74'a2), provided on either side of said single resting section (73'a) and the ear (7a) of the second chock (4) situated on the second side of the rolling plane (P1) comprises a single free space (74a) centred on the median plane (P3) and two resting sections (73a, 73b) provided on either side of said single space (74a), each set of actuators comprising, on the one hand a positive bending actuator (5'a) and a negative bending actuator (6'a) resting respectively on the internal and external faces of the single resting section (73'a) of the ear (7'a) of the first work chock (4') and, on the other hand, two positive bending actuators (5a1, 5a2) and two negative bending actuators (6a1, 6a2) provided on either side of the median plane (P3) and resting respectively on the internal and external faces of both resting sections (73a, 73b) of the second work chock (4).
2. A rolling mill according to claim 1, characterised in that the fixed elements (51, 51', 61, 61') of the bending actuators, respectively positive (5, 5') and negative (6, 6') of both chocks (4, 4') are mounted respectively in protruding sections (32, 32') of two supporting blocks (3a, 3b) fixed respectively on each standard (1a, 1b) of the frame (1), on either side of the clamping plane (P2), and in that each supporting block (3a, 3b) is symmetrical with respect to the rolling plane (P1) and comprises, between said protruding sections (32, 32'), a single central notch (35a, 35b) wherein extend the resting ears (7a, 7'a) (7b, 7'b) of the chocks (4, 4') of both rolls, respectively upper (2) and lower (2'), whereas each chock (4, 4') is provided, on each side of the clamping plane (P2), with a single lateral holding face (42) extending on the side opposite to the rolling plane (P1) with respect to the resting ear (7) and sliding along a fixed guiding face (12) provided at the end of a corresponding protruding section (32) of the supporting block (3).
3. A rolling mill according to claim 2, characterised in that the resting ears (7, 7') of each chock (4, 4') are offset toward the rolling plane (P1) with respect to the corresponding axis of the roll so that the internal resting faces (71, 71') of the positive bending actuators (5, 5') are almost in contact with another in the maximum wear position of the work rolls (2, 2').
4. A rolling mill according to any one of the previous claims, characterised in that both ears (7'a, 7'b) of a first work chock (4') extending, respectively on either side of the clamping plane (P2) comprise, for the one, a single resting section (73'a) surrounded by two free spaces (74'a₁, 74'a₂) and for the other, a single free space (74'b) surrounded by two resting sections (73'b₁, 73'b₂), whereas the arrangement is reverted for the ears (7a, 7b) of the second work chock.
5. A rolling mill according to one of the previous claims, applicable to a rolling assembly comprising at least two tandem-operating frames, characterised in that the chocks (4, 4') of the work chocks (2, 2') and the supporting blocks (3) of all the frames are identical.

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