EP1044736B1 - Rolling mill with hydraulic adjustment - Google Patents

Abstract

A device measures the position of the adjustable roll, comprising, at each end (42) of the roll, a measuring shaft (4) passi with play into a tubular sheath (5) for maintaining the sealing of the pressure chamber (33). A rolling mill incorporates a hydraulic tightening device acting on at least one roll (2) of adjustable level. A device measures the position of the adjustable roll, comprising, at each end (42) of the roll, a measuring shaft (4) passing with play into a tubular sheath (5) for maintaining the sealing of the pressure chamber (33). The tightening jacks (3) are single effect. The sea sheath (5) associated with each jack is extended by a linking component (53) crossing the column of the cage up to an external e on which thrusts a recall device for the jack (3), in the sense opposite to that of the tightening, by thrusting on the column o the cage.

Description

The invention relates to improvements hydraulic rolling mills comprising, in particular, means of locating positions relative of the cylinders.

We know that, in general, a rolling mill includes, inside a fixed cage, at least two working cylinders defining an air gap of passage of the product along a rolling plan. For maintain the spacing of the working cylinders, which determine the reduction in product thickness, these the latter are supported, generally by through larger diameter cylinders said support or support cylinders, on means clamping bearing themselves on the cage.

A rolling mill called "quarto" type, for example, includes two supporting working cylinders respectively on two support cylinders. In one "sexto" type rolling mill an intermediate cylinder is interposed between each working cylinder and the corresponding support cylinder. But we know also other types of rolling mills.

The rolling mill stand normally includes two vertical columns connected by a crosspiece and on which are mounted clamping means taking support, respectively, on each end of a adjustable level cylinder, usually a cylinder Support. Each cylinder is carried by a shaft of rotating rotation, at its two ends, in bearings each mounted in a support block called "chock" and able to slide, according to a plan of clamping passing through the axes of the working cylinders, in a window inside the column corresponding from the cage.

All of these provisions are well known and do not require a detailed description.

Previously, the tightening of the cylinders was produced by mechanical devices of the screw-nut type, comprising, for example, a screw supported, by an internal end, on the chock corresponding support cylinder and meshing in a fixed nut bearing, in the opposite direction, on the column, the screw being rotated back and forth to tighten or loosen the cylinders.

However, for several years, we have preferred use hydraulic clamping devices comprising, on each column, two elements sliding one inside the other, respectively a mobile element resting on the cylinder chock and a fixed element bearing on the column.

The use of hydraulic cylinders allows, in particular, to facilitate effort control rolling and ensuring thickness regulation of the laminated product. For this it is necessary to allow a dynamic response of the system and, by Therefore, to know precisely the position of the cylinder adjustable relative to the cage, from which we can determine the positions of others cylinders.

To this end, the depositing company has already proposed, in French Patent No. 2,645,051, a device for marking the position of the cylinders comprising, in each column, a measuring rod extending along the axis of the clamping cylinder between a internal end facing the window and fixed on the movable element of the jack and passing through the column to an external end connected to a position. This rod must therefore pass through the cylinder pressure and, for this purpose, it is passed in a sealing sleeve having one end internal fixed on the movable element of the jack and a sealing part slidably mounted relative to the fixed element, with the interposition of a sliding joint allowing the pressure in the chamber to be maintained the cylinder without interfering with the movement of the element mobile of it.

The measuring rod passes with play in the tubular sheath so as to avoid any measurement disturbance, the rod having no contact with no other part of the rolling mill than the element mobile of the jack on which it is fixed.

Thanks to such an arrangement, it is possible to know at all times, with precision, the position relative to the cage of the movable element of the cylinder and cylinder on which the force is applied tightening, in order to make the corrections necessary, for example, to take into account yielding and other deformations due to the application of tightening force or correcting faults thickness or flatness detected downstream.

In addition, you must also have the possibility of moving the cylinders over a large area amplitude to adapt to the different thicknesses of the product and variations in cylinder diameter which are subject to fairly significant wear. These cylinders must, moreover, be replaced periodically and for that, you have to place them in a disassembly position for which they are away from each other.

These cylinder operations can be performed by auxiliary cylinders but it is also possible to use clamping cylinders double-acting, working in both directions. Usually the cylinder body is fixed and takes support on the column is fixed, the piston movable bearing on the cylinder to be adjusted and limiting two bedrooms, respectively a master bedroom for the application of the clamping force and a annular cylinder return chamber in the direction opposite. The result, however, is a complication of the cylinder oil supply circuit, which is not not symmetrical. In addition the tightness in both cylinder chambers is not easy to realize, account held the necessary high pressures, and generates friction harmful to the thickness regulation.

It is therefore easier to use cylinders single acting that have only one room, the application of pressure determining the displacement of the piston only in the direction of Tightening. However, it is then necessary to provide means for returning the piston in the opposite direction.

During rolling, the restoring force is provided by the product itself. When stopped, in however, only auxiliary cylinders are available usually used for weight balancing cylinders and, if necessary to exercise cambering efforts to compensate for bending cylinders. However, these balancing cylinders act on the chocks of the cylinders and cannot therefore not be used to hold the clamping cylinders in raised position, in the phases of change of cylinders for maintenance operations.

Therefore, when using single acting cylinders, these are sometimes associated with clamp locking devices, operated by auxiliary cylinders, which hold at least cylinders under their own weight during operations disassembly. However, such devices are not not intended to operate as part of a normal sequence of operation and can be destroyed during false operations because they are obviously not designed to withstand the thrust of the cylinders Tightening. Such accidents cause stoppages for repair that significantly disrupt the production.

The invention makes it possible to remedy such disadvantages in proposing a reminder device particularly simple, applicable to cylinders of advantageous single acting clamping to use the existing provisions, without complicate the rolling stand.

In addition, the invention is particularly useful for the modernization of existing cages.

The invention therefore applies, in a way general, to a rolling mill of the type described above, in which the means for clamping the cylinders include two mounted hydraulic cylinders respectively on the two columns of the cage and each comprising two sliding mounted elements one inside the other and delimiting a room of pressure supplied with pressurized fluid, respectively, a movable support element on the block supporting the corresponding end of the cylinder adjustable and a fixed element resting on the cage column, said rolling mill being equipped with means for measuring the position of the adjustable cylinder comprising, at each end of the cylinder, a rod measuring device having an internal end connected to the movable member of the clamping cylinder and extending successively through the pressure chamber, the fixed element of the jack and the column of the cage, to an outer end placed outside of the cage, said rod passing with play in a sheath tubular extending into the pressure chamber of the cylinder for maintaining the tightness thereof, said sheath having an integral internal end axially of the movable element of the jack and a part sealing sliding mounted in relation to the fixed element.

According to the invention, the sheath tubular seal associated with each cylinder is extended outwards, beyond the part sliding sealing, by a connecting member elongated extending along the measuring rod and crossing the column of the cage to one end placed outside the cage on which is fixed a support part of an element return means movable from the jack to the fixed element, said means of booster resting on the cage column and acting on the movable element through the connecting member and the sealing sleeve, in the opposite direction to the tightening direction.

Particularly advantageously, the connecting member is fixed, at its end placed at the outside of the column, on at least one arm extending transversely and the return means is consisting of at least one cylinder having a fixed element leaning on the column in an offset position transversely to the measuring rod and a mobile element resting on said arm transverse.

Preferably, the link member is associated with at least two transverse arms extending symmetrically and forming a spreader on which are supported by at least two offset return cylinders on either side of the measuring rod.

Advantageously, a joint is arranged between the sleeve and the connecting member in order to allow misalignments.

In a preferred embodiment, the elongated connecting member consists of a sleeve tubular extending in the extension of the sheath sealing and having a central bore of sufficient diameter for passage with rod clearance of measurement.

In a first embodiment, the jack clamp includes a fixed hollow body supported on the cage column and a movable piston taking support on the cylinder support block.

In another embodiment, the cylinder clamping includes a fixed piston resting on the cage column and a movable hollow body taking support on the cylinder support block.

But the invention will be better understood by the following description of certain embodiments, given by way of example, and represented on the attached drawings.

Figure 1 shows schematically a first embodiment of the invention.

Figure 2 shows a second mode of realization of the invention adapted, in particular, to the modernization of an existing rolling stand.

As indicated above, the invention can be applied to any type of rolling mill including several cylinders superimposed inside a cage comprising two separated columns fixed on a solid foundation and connected by a cross.

In Figure 1 which applies to a rolling mill quarto or sexto having a support cylinder 2 of adjustable level, only the part is shown top of a column 1 in which is provided a window 11 for guiding a chock 21 of the cylinder 2. The column normally has the form of a closed frame comprising two uprights 12, 12 'and one top rail 13. Both sides of the window 11 form guide faces 14, 14 'of the chocks cylinders.

Between the chock 21 and the cross 13 of the column 1 is interposed a hydraulic cylinder of clamping 3 comprising a cylindrical body 31 in which is slidably mounted a piston 32 limiting a pressure chamber 33 which can be supplied with fluid under pressure by a hydraulic circuit not represented.

In the embodiment shown in the Figure 1, the body 31 constitutes the fixed element of the cylinder which rests on the cross member 13 of the column 1, the piston 32 constituting the movable element which takes support on the chock 21 by a front part 34 forming the cylinder rod. The rolling mill is equipped with a device for measuring the position of cylinder 2 which is of the type described in French patent 2,645,051 of the same company and therefore includes a measuring rod 4 having an internal end 41 secured axially with the movable element 32 of the cylinder and which passes through the fixed element 31 and the column 1 up to an external end 42 connected to a measuring device 43 placed outside the column 1. The rod 4 therefore passes successively through a bore 44 formed in the bottom of the body 31 of the jack and in a bore 45 formed in the cross member 13 of the column 1.

To seal the chamber pressure 33, a tubular sheath 5 is interposed between the movable element 32 and the fixed element 31 of the cylinder 3. This sheath 5 is hooked by its end internal 51, to piston 32 and is slidably mounted, its opposite end 52, along the bore 44 of the cylinder body 31, with interposition of a seal sliding seal. In this way, the sheath 5 can follow the movements of the piston 32, the part sliding 52 now sealing the chamber pressure 33.

The sleeve 5 is provided with a central bore of diameter greater than that of the rod 4 which passes thus with play in this bore, without contact with the scabbard. In this way, the measurement does not risk to be disturbed by due misalignments, by example, to deformations of the various parts of the cage.

In particular, cylinder 2 can be subjected to a bending during the passage of the product and it is necessary to leave clearances between the faces of guide 14, 14 'of the column and chock 21 which can therefore be slightly offset from the cage.

In the arrangement of Figure 1, the piston 32 rests directly on the chock 21 and can therefore be itself subject to misalignments by relation to the fixed body 31 which rests on the column 1. These misalignments can be cashed by the sheath 5 which, in the provision of the patent French 2.645.051 already cited, is connected respectively to the piston 32 and to the fixed body 31 of the jack by articulated joints 51, 52. Of course, the game left between the measuring rod 4 and the tubular sleeve 5 must be sufficient to allow these misalignments without risk of contact between the two parts.

All these provisions are described in detail in the patent already cited but other arrangements are possible.

For example, as mentioned schematically in Figure 1, we can arrange a swivel seal between piston 32 and actuator body 31 to admit misalignments of one item relative to the other but it's more difficult to seal the chamber ring placed between the rod 34 of the jack and the body cylindrical 31.

When using a double acting cylinder, so it's best to keep the alignment of the two elements of the cylinder, but it is then necessary to spare, between the movable element of the jack and the chock a support swivel which allows to admit misalignments. A such a provision determines, however, a concentration of stresses at the fulcrum.

It is therefore preferable, as shown in the Figure 1, to use a single-acting cylinder, the movable element 32, 34 is supported directly on the chock 21 by a flat face allowing to distribute constraints but whose piston can pivot slightly in relation to the cylinder body, the sheath tubular allowing, as we have seen, to admit misalignments. However, if a cylinder is used simple effect, it is necessary to provide means cylinder return in the opposite direction to the force of Tightening.

The present invention resolves so particularly simple this problem using, for the recall, the tubular sheath 5 which is necessary, anyway, to seal the pressure chamber 33.

For this purpose, the sheath 5 is extended, from opposite side to cylinder 2, by a connecting member elongated 53 which extends along the measuring rod 4, without contact with it and passes through bore 45 to lead to the outside of the cage, on the other side of cross member 13 of column 1. At its outer end 54, the connecting member 53 is provided two transverse arms 55 which extend symmetrically on either side of axis 40 of the measuring rod 4, so as to form a spreader on which are supported by two cylinders 56 mounted on the external face 13 ′ of the cross member 13.

In the preferred embodiment shown in the figures, the connecting member is a tubular sleeve 53 defining a central bore in which the measuring rod 4 passes with clearance and which extends in the extension of the sealing sleeve 5 to the outside of the cage 1.

As already indicated, the sleeve 5 is secured, in axial displacement, with the piston 32 of the cylinder, by its lower end 51 which forms a ball joint.

Consequently, the cylinders 56 bearing on cross member 13 and, on the opposite side, on spreader 55, allow, via the sleeve 53, to retract the piston 32 in the direction opposite the clamping force, the pressure chamber 33 being, obviously, covered.

The previously known arrangement can thus fulfill a new function thanks to the addition of extension sleeve 53 and cylinders 56 which serve as return means for the single-acting cylinder 3. Of course, bore 45 should simply have sufficient dimensions to allow passage with sleeve clearance 53.

Likewise, the measuring rod 4 passes with clearance to the inside of the sleeve 53 which constitutes a simple extension of the tubular sheath 5 for holding sealing.

If the tightness of the pressure chamber 33 is ensured by the sliding seal 52 of the sleeve tubular 5, the sleeve 53 can pass freely in bore 45. However, it is preferable to place, at the outlet of bore 45, a sliding seal 15 for guiding the sleeve 53 which is then held laterally by the two seals sliding 52 and 15.

If the sliding joint 15 is susceptible sealing the fluid pressure in the cylinder chamber 33, we can consider removing the ball joint 52, the ratio between the length and the transverse dimensions of the sleeve 53 giving this one sufficient flexibility to allow possible misalignments of its opposite end 51 with piston 32.

Moreover, the extension sleeve 53 does not not necessarily form a single piece with the sleeve 5 but can be connected to it by a articulation allowing misalignments.

The whole of the spreader 55 and the cylinders of reminder 56 can be placed in a cover 16 on which is fixed the measuring device 43 connected to the end 42 of the measuring rod 4.

In the example of FIG. 1, the body 31 of the cylinder is fixed and is therefore arranged in the part top of window 11. However, the angles of window 11 are normally rounded to ensure continuous transmission of the clamping forces on the uprights 12, 12 'of the column and it can be difficult to accommodate the body of a cylinder having a sufficient section. Therefore, it can be interesting to reverse the arrangement of figure 1, the piston 32 of the jack being fixed while the body cylindrical 31 is movable and rests on the chock 21 of cylinder 2, the body 31 of the jack being able to have an upper side adapted to the profile of the face crosspiece 13 while providing a internal chamber 33 of sufficient section to exercise the clamping force required without increasing excessively pressure.

Such a provision is particularly interesting when you want to modernize a cage existing.

Indeed, the old cages are provided, usually from mechanical clamps to screw-nut comprising, on each column, a screw driven in rotation, in one direction or the other, by external means, and whose internal end rests on the chock of the cylinder to be moved, the screw rotating in a fixed rotating nut which is supported, in the opposite direction, on the column.

The invention allows, without replacing cage columns, to adapt a clamping system hydraulic to a rolling mill of this type.

In Figure 2, only the central part of the cross member 13 of a column which, at was originally fitted with a screw nut. As a result, the column was equipped with a bore 6 having a relatively large diameter to allow the passage of the screw and opening, outwards, in a recess 61 making it possible to accommodate the means for driving the screw in rotation and, towards the inside, i.e. on the side of the window 11, in a recess 62 making it possible to house the nut, fixed in rotation, resting on the column. The recess 62 therefore has dimensions greater than the bore 6 for the passage of the screw and limits an annular bottom which can be machined to form a counterbore 63 for supporting the nut.

If you want to replace the screw-nut with a hydraulic cylinder, it is interesting to take support on the column through this face machined 63 but the housing 62 is normally insufficient to place the cylinder body there hydraulic with sufficient dimensions to exert the clamping force.

Therefore, it is particularly advantageous to reverse the arrangement of FIG. 1, the piston 32 being fixed while the cylinder body 31 is mobile.

As in the case of Figure 1, the piston 32 ', on which the body is slidably mounted cylindrical 31 'of the jack, is extended by a part support 34 which, in this case, extends towards the rear of the cylinder. To adapt to the usual dimensions of the housing 62 of the nut, the rear part 34 'of the piston is associated with a spacer piece 35 which slides into the housing 62 to come to bear on the machined face 63.

In the opposite direction, the body of the jack 31 ′, which is housed at the top of the window 11, rests on the chock 21 by its bottom 30 which has sufficient seating area for the transmission of the clamping force.

As before, the measuring rod 4 extends inside a tubular sheath 5 having a lower end 51 secured in the direction axial, from the bottom of the cylindrical body 31 and a upper end 52 which slides in a bore 44 'formed in the piston 32' and its rear part 34. The bore 44 'can advantageously be covered a shirt along which the joint slides sliding 52.

The sheath 5 is extended upwards by a sleeve 53 which loosely surrounds the measuring rod 4 until the exit of it outside the crosspiece 13. The sleeve 53 can be maintained at its upper part 54, by a sliding joint 15 'which can consist of a simple friction sleeve soft mounted on a closing plate 64 of bore 6.

As mentioned, this was planned large enough for the passage of the screw and so we can pass there, for example, a oil supply pipe 36 which is connected on a bore of the piston 32, 34 opening into the pressure chamber 33 and which passes through the plate 64 up to a fitting allowing the connection of a supply hose.

Advantageously, the piston 32 'is held applied by its rear part 34 'against the face support 63 by bolts 65 regularly distributed around the axis and bearing on the plate 64.

As indicated above, the part outer 54 of sleeve 53 carries a spreader 55 on which are supported by the lifting cylinders 56. The assembly is covered by a cover 16 on which the measuring device, not shown, is fixed, associated with the rod 4.

We see that the means according to the invention allow without excessive complication, to modernize an existing cage by replacing each clamping screw by a single-acting hydraulic cylinder associated with a means of recall.

But the invention is not limited to the details of the embodiments which have just been described in title of simple example and who could do subject to variations without departing from the scope of protection defined by the claims.

For example, the link between the sealing sleeve 5 and the return means could consist of two rods extending along the measuring rod 4 and fixed by joints, to their ends, respectively on the sleeve 5 and on the lifting beam 55.

On the other hand, the invention has been described in measuring device frame according to patent French 2,645,051 from the same company, but it could apply to any tracking device using a measuring rod connected to the movable element of the jack and passing through a holding sleeve of the sealing of the pressure chamber. As we have indicated above, if a spherical support is provided between the movable element of the jack and the chock of the cylinder to be actuated, the sealing sleeve can be slidably mounted in the bore in the cage column, which ensures more easily sealing. In such a provision, the sleeve surrounding the measuring rod can be extended to the outside of the cage by a sleeve carrying a lifting beam or even a single transverse arm of one or more lifting cylinders. In this case, there is no need to provide ball joints between the sleeve and the elements of the jack.

Furthermore, the recall means could also be changed. For example, the sleeve of extension 53 could be actuated by a cylinder annular threaded on its external part 54.

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

Claims (8)

1. A roll mill comprising a supporting stand with two separate roll standards (1), at least two superimposed rolls delineating an air-gap for the passage of a product to be rolled along a rolling plane, and having each two ends each rotating inside a supporting block (21) mounted to slide, parallel to a clamping plane passing through the axes of the rolls, between two guiding faces (14, 14') provided on two sides of a window (11) of each roll standard (1), means for clamping the rolls and acting on at least one roll (2) with adjustable level, comprising two clamping jacks (3) mounted respectively on both standards (1) of the stand and each comprising two elements mounted to slide one into the other and delineating a pressure chamber (33) connected to pressurised fluid supply means, respectively, a mobile back-up element (32) on the supporting block (21) of the corresponding end of the adjustable roll (2) and a fixed element resting on the roll standard of the stand, and means for measuring the position of the adjustable roll comprising, at each end of the roll, a measuring rod (4) having an internal end (41) connected to the mobile element (32) of the clamping jack (3) and extending successively through the pressure chamber (33), the fixed element (31) of the jack and the roll standard (1) of the stand, up to an opposite end (42) located outside the standard (1), whereas the said rod (4) goes through a tubular sleeve (5) with a certain clearance that extends into the pressure chamber (33) of the jack in order to preserve the tightness thereof, whereas the said sleeve (5) has an internal end (51) axially integral with the axis of the mobile element (32) of the jack (3) and exhibits an insulating section (52) mounted to slide axially with respect to the fixed element (31),
      characterized in that the tubular sleeve (5) connected to each jack (3) is extended to the outside, beyond the sliding insulating section (52), by an oblong linking member (53) extending along the measuring rod (4) without any contact with the said rod and going through the roll standard (1) of the stand up to an end (54) located outside the stand (1) and on which is fixed a back-up section (55) of restoring means (56) of the mobile element (32) of the jack toward the fixed element (31), whereas the said restoring means (56) act onto the mobile element (32) via the linking member (53) and the tubular sleeve (5), in the direction opposite the clamping direction, while resting on the roll standard (1) of the stand.
2. A roll mill according to claim 1, characterized in that the linking member (53) is fixed, at its external end (54), on at least one arm (55) extending transversally and the restoring means comprise at least one jack (56) having a fixed element (31) resting on the roll standard (1) in a transversally offset position with respect to the measuring rod (4) and a mobile element resting on the said transversal arm (55).
3. A roll mill according to claim 2, characterized in that the linking member (53) is connected to at least two transversal arms extending symmetrically and forming a joystick (55) on which rest at least two restoring jacks (56) offset on either side of the measuring rod.
4. A roll mill according to any one of the previous claims, characterized in that a joint is arranged between the sleeve (5) and the linking member (53) in order to allow for misalignments.
5. A roll mill according to any one of the previous claims, characterized in that the oblong linking member is a tubular sheath (53) extending along the insulating sleeve (5) and comprising a central bore with sufficient diameter for the measuring rod (4) to pass through it with a certain clearance.
6. A roll mill according to claim 5, characterized in that each standard (1) is provided with sliding guiding means (15) of the sheath (53).
7. A roll mill according to any one of the previous claims, characterized in that each clamping jack (3) comprises a hollow fixed body (31) resting on the roll standard (1) of the stand and a mobile piston (32) resting on the supporting block (21) of the roll (2).
8. A roll mill according to any one of claims 1 to 6, characterized in that each clamping jack (3) comprises a fixed piston (32') resting on the roll standard (1) of the stand and a hollow mobile body (31') resting on the supporting block (21) of the roll (2).

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