EP1552892B1 - Machine for straightening metal bands - Google Patents

Abstract

The machine has two leveling equipments with respective active cylinders (A, 2). Maintaining units (4, 4`) at the ends of the cylinder (2) are associated to springs, to apply the cylinder (2) on intermediate rollers. The cylinder (2) drives the rollers and support rollers, when the equipments are in rest position. The machine is stopped while placing the equipments in leveling position, when synchronous speed of the tape is reached. An independent claim is also included for a method of leveling a metallic tape by tape movement.

Description

The subject of the invention is a leveling machine that can be used, in particular, in a tensile planing installation of a metal strip and also covers the process used.

The document JP-A-63-149017 discloses a machine and a planing method described in the preamble of claims 1 and 22.

In the different sectors of metallurgy and, in particular, for the production of metal sheets, planing machines are usually used to eliminate as much as possible the unevennesses appearing as a result of rolling.

As schematically shows figure 1 , a leveling machine comprises, in a general manner, a certain number of rollers rotatably mounted about axes orthogonal to a running direction of the band to be hovered and offset longitudinally and vertically, so as to define a corrugated path of the strip which, in addition, is under tension and thus undergoes traction-bending effects in opposite directions to homogenize the stresses. For this purpose, such a machine comprises, inside a frame not shown on the figure 1 at least two longitudinally offset planing crews, respectively an upper crew E 'and a lower crew E, placed respectively above and below the band M and mechanical or hydraulic means for controlling the vertical displacements of each crew plane, transversely to the strip travel plane, between a planing position and a rest position spaced from the strip.

As shown in figure 1 such a machine may comprise, for example, two bending units F1, F2, each comprising an upper planing unit E 'and a lower unit E, a bending unit T carrying a so-called "tile corrector" roller vertically adjustable by a mechanical system and, often, another bending unit carrying a "hanger" or decambering correction roll.

Other configurations of installations may, however, be used depending on the field of application.

Each leveling unit comprises a transverse frame, movable vertically in the frame and carrying a leveling cylinder, called active cylinder, rotatably mounted about an axis transverse to the scroll direction. For leveling, the active cylinder is of small diameter, and must therefore be supported on support members consisting, in most cases, of two intermediate rollers themselves resting on three rows of rollers.

The transmission of the forces and the centering in rotation are done by application of the active cylinders on the intermediate rollers and the support rollers which are only fixed on the transverse frame.

Indeed, to achieve the desired effect of flexion-traction, the active planishing cylinders must have a relatively small diameter and therefore rotate at a very high speed, resulting in relatively rapid wear of their outer faces. The active cylinders and possibly the intermediate rollers must therefore be replaced periodically.

For this purpose, a disassembly device is usually used which makes it possible to remove the assembly of the planing unit requiring maintenance and to spread it laterally on one side of the machine, the metal strip being able to remain in the machine, ie 'stop, either while scrolling. Indeed, for a simple change of the active cylinders or any other short-term maintenance, it is preferable to stop only the planeuse to open it and replace the cylinders without stopping the running of the band in the processing section.

Such operations must therefore be performed quickly and that is why, usually, the active cylinders and the intermediate rollers are simply held at their ends by axial abutments, usually made of ceramic material, which take up the axial thrusts occurring during the planing of the band. The assembly must however be mounted so as to remain attached to the transverse frame in the opening and closing phases of the machine, out of planing, as well as during the handling of the chassis.

Previously, the planing was done in separate machines, the band running from a coil placed upstream to be rewound downstream. However, it is now necessary to install planing machines in continuous lines used, in particular, for annealing or hot-dip galvanizing the strip.

In such lines, the coils are welded end to end at the line entrance, the strip being cut into coils at the outlet. Tape accumulators are therefore placed, respectively, upstream and downstream to ensure a constant speed of travel of the strip in a central processing section during the stop required for the inlet for welding or the exit for shearing. . The planers are normally installed in this central section at a substantially constant speed in order to obtain the desired regularity of the quality parameters of the product.

However, the welding between two successive coils is usually an extra thickness that may deteriorate the planing rolls. To avoid this disadvantage, it is preferable to open the planer by spreading the planing rolls at the time of the passage of the weld and then bringing them into contact with the strip. The set of active cylinders, intermediate rollers and support rollers is then again dragged by friction during the docking of the equipment on the belt and this inevitably results in slippage due to inertia. rotation of the various cylinders and rollers for a few seconds which may, however, correspond to several tens of meters of tape, given the speed of scrolling.

Generally, in a continuous annealing or hot-dip galvanizing line, such slippage is tolerated because the defects by scratching, pitting or roughness defects that may result therefrom are not very visible or at least not prohibitive for ordinary steels.

However, it is now sought to treat in continuous lines other types of steels for which the surface is more fragile and its more important appearance, such as stainless steels. In addition, such steels often have a reduced coefficient of friction, that is to say a lower ability to frictionally drive all cylinders and rollers, which increases the risk of slipping.

To avoid this inconvenience, it was proposed in the document JP-A-63-149017 , to give the active cylinder in advance, in the position separated from the planing equipment, a corresponding angular velocity substantially at the speed of travel of the band, which prevents skidding at the time of docking. For this purpose, the document JP-A-63149017 provides for rotating the central row of support rollers, the latter being mounted on a splined shaft connected to a motor by a clutch. The rotational movement is then transmitted by friction to the intermediate rollers and then to the active roll, the rotational speed of the driven rollers being adjusted so as to give the active roll an angular velocity corresponding to the running speed of the roll, which allows avoid skating at the time of docking.

Such an arrangement makes it possible to place the motor and the clutch on the chassis of the leveling equipment in a position separated from the plane of travel of the band but presents certain drawbacks.

Indeed, the torque is transmitted to the active cylinder only by friction and this effect depends on the application pressure of the rotating members on each other. For the lower crew, this application pressure is simply the weight of the active cylinder and the intermediate rollers, as long as the active cylinder is not applied to the belt.

On the other hand, for the upper crew, the active cylinder must be carried at its ends by two bearings suspended from the chassis of the crew by springs which pull up the active cylinder in order to apply it to the intermediate rollers. and the support rollers.

To allow disassembly of the active cylinder, the springs are connected to the bearings by removable hooks.

Such an arrangement is quite complex and may not guarantee sufficient application pressure for the friction drive of the active rolls at the desired speed.

On the other hand, the angular velocity of the support rollers on which the torque is applied must be adjusted according to the ratio of diameters of said rollers, intermediate rollers and the active cylinder so that the angular velocity of the latter corresponds exactly to the speed of the tape. However, the diameters of these different members may vary slightly due to wear and must be taken into account for the adjustment of angular velocities. Moreover, this wear is not evenly distributed over the length of the rolls and there may therefore be a slight difference in diameter and, consequently, in peripheral speed between the successive rollers of the row driven in rotation. This difference results in increased wear of parts of the intermediate rollers and active rolls which can result in defects on the web. The objective sought may therefore not be achieved.

The invention overcomes these various drawbacks with a new arrangement allowing, by very simple means, to surely drive the active cylinders at an angular speed corresponding to the speed of travel of the product, while maintaining a possibility easy and quick disassembly and reassembly of the active cylinders and, if necessary, intermediate rollers.

The invention is defined in independent claims 1 and 22.

The invention therefore applies, in a general manner, to a leveling machine comprising at least two leveling equipments placed on either side of the strip and each comprising an active cylinder and a set of support members. mounted rotatably about their axes on a transverse frame, the assembly being movable parallel to itself between a rest position for which the active cylinder is spaced from the strip and a leveling position for which the active cylinder is applied to the band bearing on the support side, on the opposite side, each active cylinder can be rotated, before its application on the band, at an angular speed corresponding substantially to the speed of travel of the band.

According to the invention, the rotational drive of each active cylinder is determined by direct application of a rotational torque on one end of said cylinder, at an angular speed controlled by the running speed of the strip.

For this purpose, each active cylinder is carried at each of its ends by a centering pin rotatably mounted about the axis of the cylinder, on a support member slidably mounted on the transverse frame of the crew parallel to a plane. radial axis passing through the axis of said active cylinder, the positions relative to said frame of the two support pieces being adjustable by radial sliding for the displacement of the active cylinder, parallel to its axis, between a application position on its support members and a spaced position, and one of the centering pins of each active cylinder is connected to a means for direct application of a rotational torque on said pin.

Particularly advantageously, each support part of an active cylinder comprises a first portion in the form of a cylindrical housing, in which is mounted a rotatable support bearing of the active cylinder, centered on a radial plane passing through the axis of said cylinder. , and a second portion forming an arm slidably mounted on a slide formed on a guide foot fixed to the transverse frame of the leveling crew. In addition, each piece of sliding support is associated with a return means bearing in one direction on the support piece and in the other on the transverse frame, for the application of the active cylinder on its support members.

Preferably, each support member comprises a support means on the frame, advantageously constituted by a cam mounted rotatably between at least two positions, respectively a position spaced from the frame, allowing the application of the active cylinder on its support members , thanks to the biasing means bearing on said support member and a bearing position on the frame to push the support member against the action of the biasing means.

In a preferred embodiment, each support member comprises a bearing portion provided with at least one through hole of at least one guide rod fixed by a first end to the transverse frame and extending, on the other side of the support portion of the support piece, to a second end on which is formed a support flange of a resilient means compressed between said flange and the support portion of the support piece .

According to another preferred feature, each support part of an active cylinder carries a centering bearing with a rotating internal cage in which is threaded a support pin fixed on the end of the active cylinder, in the axis thereof. , one of the two journals being extended outwardly by a drive end connected to a means for controlling the rotation of the journal with the active cylinder, about its axis.

Advantageously, each of the two support journals of the active cylinder forms a shaft end provided, on the side of the active cylinder, with a detachable connecting means with the active cylinder, said shaft end being axially displaceable between a constricted position of connection with the cylinder, for the rotary support of the latter and a spaced apart position, disengaged from the end of the cylinder, for disassembly of the latter, the connecting means being able to consist of two parts of conjugate forms formed respectively on the trunnion; and the end of the cylinder and engaging one another by axial displacement of the journal from a spaced apart position to a constricted position.

According to another particularly advantageous arrangement, at least the support member of the driving pin of each active cylinder is slidably mounted parallel to a radial plane passing through the axis of said cylinder, on a guide foot integral with a sliding mounted base on the transverse frame, parallel to the axis of the active cylinder, between a constricted position of the two support pieces for engaging the ends of the active cylinder on the centering bearings and a spaced apart position of the ends of the active cylinder, for the disassembly of the latter, the transverse frame being provided with means for fixing the base of the guide foot of each support piece in the constricted position of engagement of the ends of the active cylinder on the centering bearings.

Thanks to the provisions according to the invention, in the rest position of the planing equipment, the active cylinder can be separated from its support rollers by the two cams, in order to be disassembled and, after reassembly between the two journals, it is pushed back by the two support pieces in the opposite direction so as to bear in advance on its support members. In this position, it is rotated at a peripheral speed corresponding to the running speed of the strip, also driving the support members, so that the contact with the strip, in the planing position, can occur without risk of slippage and, therefore, deterioration of the surface quality of the product.

However, this application of the active cylinder on its support members can be maintained in the rest position of the flight crew. planing, the active cylinder being removed from its support members only in case of need for disassembly and / or replacement.

Moreover, because the rotational torque is applied directly to the active cylinder, the angular speed of rotation thereof around its axis can be slaved to the running speed of the tape and this, not only in the position rest of the planing crew but also, during the planing, in the working position of the crew.

This avoids the risk of skidding, not only when docking after a stop planing, but also during the planing, for example in case of abrupt variation of the speed of travel in the planing section, the inertia of the rollers and support rollers being compensated because the slave speed rotational torque is applied directly to the active cylinder which frictionally drives its support members.

Other advantageous features within the scope of protection of the invention will appear in the following description of a particular embodiment, given by way of example and shown in the accompanying drawings.

The figure 1 is a schematic view of the assembly of a leveling installation.

The figure 2 is an overview, from the side, of a superior planing crew.

The figure 3 is a detail view, in axial section, of one end of the upper planing crew.

The figure 4 is a side view of the two planing crews.

The figure 5 is a horizontal sectional view along line VV of the figure 4 .

As mentioned above, the figure 1 schematically shows the conventional layout of a leveling installation comprising for example two flexion units F1-F2 and a tile correction device T, associated with deflection rollers D and adjustable in height, in order to define a corrugated path of the strip M that runs between the successive rollers in a longitudinal direction parallel to the plane of the figure 1 .

To achieve planing, the strip is put under tension by known means such as so-called "S-roll" tensioning rollers placed upstream and downstream. The figure 1 shows, for example, the downstream tensioner device S.

Each bending unit comprises two planing crews, respectively lower E and upper E 'longitudinally offset and each having, usually, an active cylinder A associated with two intermediate rollers I which are supported on three rows of support rollers G when the cylinder active A is applied to the strip in the planing position shown on the figure 1 by vertical displacement of the frame C, for example, by means of jacks or screws not shown.

On the figure 2 it is shown, in side view, all the upper planing equipment E 'mounted on a transverse frame 1 forming a strong beam extending in a direction orthogonal to the tape running axis and provided support portions 10 for jacks or thrust screws of the leveling equipment in its application position on the belt.

Advantageously, in the example shown on the figure 2 , the transverse frame of the upper crew E 'is rotatably mounted about a horizontal axis, according to a provision subject to the FR-A-2,659,254 from the same company, which makes it possible to turn up the entire crew to facilitate disassembly and replacement of cylinders and rollers.

As indicated above, in the arrangements usually used, the active cylinder A and the intermediate rollers I, bear on each other and on the rollers G only in the planing position and that is why they are carried with play by the transverse frame C and are only held laterally by axial stops.

In the invention, on the contrary, as shown by the figures 2 and 3 , the active cylinder 2 is provided, at its opposite ends, with two journals 3, 3 'centered on the axis 20 of the cylinder and rotatably mounted, by means of bearings 30, 30', on two support pieces 4, 4 'in the way shown in more detail on the figures 3 , 4 and 5 .

In this arrangement, each support piece 4 forms a sort of chock centered on a radial plane P passing through the axis 20 of the active cylinder 2 and comprises an arm 41 mounted to slide radially on a guide foot 5 extending towards the strip from the frame 1, and a box-shaped portion 40 fixed to the end of the arm 41 opposite the frame, and in which is inserted the bearing 30 of the pin 3.

On the other hand, each support piece 4 of one end of the active cylinder 2 is associated with return means 6 for applying the active cylinder 2 to its support members which consist, in the example shown, of two intermediate rollers 7, 7 ', held axially between the two guide feet 5, 5' and resting on three rows of support rollers 70 rotatably mounted on the transverse frame 1.

For this purpose, each support piece 4, 4 'is provided, on the side of the frame 1, with a sole 44 on which at least two springs 6 spaced apart symmetrically on either side of the radial plane P and bearing , in the opposite direction, on the chassis 1.

As shown by Figures 4 and 5 each spring 6 is threaded onto a bushing 61 passing through an orifice of the soleplate 44 of the chock 4 and fixed on the chassis 1 by an axial screw 62, the bushing 61 comprising a compression flange 63 of the spring 6.

Each chock 4, 4 'is thus mounted to slide radially on at least two bushes 61 and pushed towards the frame 1 by the springs 6 compressed between the flanges 63 and the flange 44 which extends parallel to the base 51, at a low distance from it.

The two chocks 4, 4 'supporting the ends of the active roller 2 are thus pushed towards the transverse frame 1 by applying the active cylinder on the intermediate rollers 7, 7' which bear on the rollers 70.

As usual, the intermediate rollers 7 are not carried by bearings but simply held laterally between two axial abutments each consisting of a ceramic chip 71 mounted in a housing 72 fixed by a rear extension 73 on the guide foot 5. A this effect, the guide foot 5 comprises two spaced apart amounts 52 carrying the slides 50, between which extends a crossbar 54 provided with two recesses 53 in which are threaded the extensions 73 of the two stops 71 of centering, respectively, of the two intermediate rollers 7, 7 '.

Each housing 72 is held by a clamping screw engaging in a threaded bore of the extension 73 which is slidably mounted in the housing 53 parallel to the bisecting plane of the two rows of rollers 70 on which it is supported, with a clearance allowing slight adjustments of the intermediate roll.

Thus, when the active cylinder 2 is applied by the springs 6 to the support rollers 7, the latter can move slightly, parallel to themselves so as to be applied on the support rollers 70.

Moreover, as indicated above, the active cylinder 2 is subject to wear and must be replaced. For this, the bases 51 of the two guide feet 5 carrying the two support pieces 4 are slidably mounted on the transverse frame 1, parallel to the axes of the cylinders.

For this purpose, as shown by Figures 4 and 5 each base 51 is provided with a central groove which engages on a rectilinear boss 11 of the transverse frame 1. In addition, it is provided with two longitudinal housings 12 inside which are mounted sliding, respectively, two strips 13 connected to the base 51 by screws 14 which, after sliding, to block the base 51 in the chosen position.

Furthermore, each pin 3 of the active cylinder consists of two parts engaging one in the other and secured by a screw 34, respectively a pivot 31 fixed to the end of the active cylinder 2, in the axis of this, and a shaft end 32 threaded into the bearing 30 and, therefore, axially secured to the support part 4 and the guide foot 5.

In the preferred embodiment shown in the figure 3 , the pivot 31 and the shaft end 32 are provided with conical conical portions respectively formed recessed and projecting, and engaging one into the other to ensure both the centering and the rotational drive of the active cylinder 2, one of the shaft ends 32, for example the one on the left on the figure 3 , being provided with a tip 33 on which is applied a rotational torque produced by a motor means not shown.

However, to allow disassembly of the active cylinder 2, it is necessary to suppress the application pressure thereof on the intermediate rollers 7, 7 '.

For this purpose, each chock 4, 4 'of a trunnion 3, 3' of the active cylinder 2 is equipped with a cylinder spacing means constituted, in the embodiment shown in the drawings, of a cam 8 to eccentric profile rotatably mounted on the central rib 41 of the chock 4 about an axis 80. Thus, as shown in FIG. figure 4 , a rotation of the eccentric cam 8 about its axis 80 makes it possible to push the sole 44 of each support piece 4, 4 'by increasing the compression of the springs 6. The active cylinder 2 thus being slightly spaced from the intermediate rollers 7, 7 ', it is possible to spread laterally the two guide feet 5, 5' with the support pieces 4, 4 'to release the pivots 31 at both ends of the cylinder 2.

Thus, after having unlocked the bases 51 by unscrewing the screws 14 and disconnected the two parts 31, 32 of each pin 3 by unscrewing the screws 34, the two guide feet 5 can be moved axially apart with the support pieces 4, 4 ' and the bearings 30, 30 'which drive the shaft ends 32, 32'.

In the case of the lower planing crew E, shown in figures 3 , 4 and 5 , the active cylinder 2 thus disengaged from its bearings 30, 30 'simply rests on its support rollers 7, 7'. It can therefore be easily removed and replaced.

If necessary, it is also possible to remove and replace the intermediate rollers 7, 7 'which rest on the support rollers 70.

In the case of the upper planing unit E 'shown in FIG. figure 2 , it is particularly interesting that the transverse frame 1 is rotatably mounted about a horizontal axis 15, according to a provision which is the subject of the French patent FR 2,659,254 already cited. Indeed, before any disassembly operation, it is thus possible to return 180 ° the upper leveling unit E 'so that the active cylinder 2 is placed above its support members and is based on these last when one discards the two ends of the shaft 32, 32 'with the chocks 4, 4'.

After replacing the active cylinder 2 and possibly the intermediate rollers 7, 7 ', the chocks 4, 4' are tightened so that the conical portions of the pivot 31 and the shaft end 32 engage one into the other. other. The cylinder 2 can then be applied to the intermediate rollers 7, 7 'by rotating in the opposite direction the eccentric cams 8 which are provided with a flat face 81, in order to allow the springs 6 to push the sole 44 towards the base 51.

To prevent jamming of the cam 8, the spacing (e) between the sole 44 and the base 51 is kept at a minimum value by adjustable stops 64 consisting of screws engaging in threaded bores of the sole 44.

As usual, these operations can be performed on each leveling unit, in a maintenance position spaced from the machine and the entire crew, with the transverse frame, is then returned to the working position inside the machine. frame.

Furthermore, as indicated above, one of the two journals of each active cylinder 2, for example the left trunnion 3 on the figure 2 , is extended by a drive end 33, for example fluted, which can be removably connected to a motor means such as geared motor, pulley and belt or other motion transmission member, according to the general arrangement selected for the machine . For example, a motor means 9, indicated schematically on the Figures 1 and 2 , can be arranged on the fixed frame or on the frame of each planing equipment E, E 'and removably connected to the active cylinder 2, 2', by a telescopic double cardan extension 36 for transmitting the torque to following all the positions of the axis of the active cylinder, according to the diameters of all its support members.

On the other hand, easy to design means to adjust the rotational speed of the active cylinders of the two planing crews, taking into account their diameters, so as to slave their peripheral speeds to the linear speed of the moving strip. This speed of movement can be measured at any moment by a sensor 92, for example from the speed of rotation of the rollers of one of the tensioning units S which, as currently, are placed on either side of the leveling machine in order to put the band in tension.

The arrangements just described make it possible to provide a simple and relatively economical solution to all of the problems set out above and, in particular, to avoid the effects of skidding which could deteriorate the surface condition of the product. while facilitating the maintenance of planing crews.

Indeed, because a rotational torque can be applied directly to one of the journals of each active cylinder, the angular velocity thereof can be adjusted precisely and, in particular, slaved to the scroll speed of the band, so that the two speeds are kept identical at each moment.

Furthermore, the direct drive in rotation of each cylinder by a pin connected detachably to the cylinder 2 facilitates disassembly and reassembly of the cylinder.

Indeed, after placing the assembly of a leveling unit in its rest position, separated from the band, it is possible, by simple rotation of the cams 8, to push the two support pieces 4, 4 'with the cylinder 2. The two support pieces 4, 4 'are then spaced axially to release the cylinder 2 which, in this position, is spaced from the intermediate rollers 7, 7' and can be removed without risk of deterioration of its surface.

After reassembly of the active cylinder 2, it is applied again on the intermediate rollers 7 and the rollers 70 by rotation of the two cams 8. The assembly is tightened under a force adjusted by the setting of the springs 6.

The active cylinders 2 can then be started in rotation and they frictionally drive the intermediate rollers and the support rollers. When the speed of synchronism with the band is reached, one can proceed to the closing of the machine by placing the two crews E, E 'in their planing positions, the docking of the active cylinders on the band being done thus without skating and without risk of marking the product.

Moreover, even during leveling, because of the precise control and the possibility of servocontrolling the angular velocities of the active cylinders, the latter can be driven permanently at an angular speed corresponding to the running speed of the strip, which makes it possible to absorb variations in the planing speed without risk of slipping, even for low friction bands.

Of course, the invention is not limited to the details of the embodiment that has just been described as a simple example, other variants that can be imagined in the context of protection of the invention, as defined by the revendicatiions.

Thus equivalent means could be used for the removable mounting of the journals of an active cylinder in their bearings, the sliding assembly thereof, both in the axial direction and in the radial direction and the application of said cylinder on his support organs.

In particular, the springs 6 could be replaced by other means. In addition, it should be noted that the application forces of the active cylinder are not the same for the lower equipment E and for the upper equipment E 'whose weight must be compensated. This is why, as shown in figure 4 , the chocks of the upper active cylinder are advantageously associated with two pairs of springs symmetrical with respect to the radial plane P, on the one hand the springs 60 which exert only the application pressure necessary for the rotational drive of the cylinder and rollers intermediate, and secondly, two springs 65 which are tared so as to take up the weight of the active cylinder 2 with its two chocks 4, 4 ', its drive means 36 and, in a general manner, all the organs which are not worn directly by the chassis.

Moreover, in a simpler embodiment, only the drive trunnion 3 could be removably connected to the end of the cylinder, the other trunnion remaining fixed on the cylinder and can simply engage axially in the cage internal of the corresponding bearing for the reassembly of the cylinder, the guide foot of the piece 4 'bearing support is then fixed on the frame.

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

Claims (24)

1. Machine for straightening metal bands

   • comprising control means of the travel under tension of the strip along a longitudinal direction and along a travel plane, at least two straightening trains (E, E') located on both sides of the strip (M) and each comprising an active cylindrical roll (A, 2) and a set (I, 7) of support units assembled rotating on a transverse frame (C, 1), around rotation axes parallel to each other and orthogonal to the direction of travel, and control means of the movement of each straightening train (E, E'), in a parallel to itself, between an at rest position wherein the active roll (A, 2) is spaced out from the strip and a straightening position wherein the active roll rests on the strip by leaning, on the opposite side, against its support units (I, 7), each roll (2) able to be driven spinning, before its resting on the strip (M), at an angular speed corresponding more or less to the travel speed of the strip,

   • characterized by the fact that

   - each active roll (2, 2') is carried, at each of its ends, by a centring spindle (3, 3') assembled spinning on the axis of the cylindrical roll, on a bearing chock (4, 4') assembled sliding on the transverse frame (1) of the train (E, E') in a parallel to a radial plane (P) going through the axis of said active roll (2),

   - the positions in relation to said frame of the two bearing chocks (4, 4') can be set through radial sliding for the moving of the active roll (2), in a parallel to its axis, between a position of leaning against its support units (7, 7') and a spaced out position,and that

   - each active roll (2, 2') can be driven spinning on its axis by direct exertion of a rotation torque to one of its centring spindle (3).
2. Machine for straightening metal bands according to claim 1, characterized by the fact that each bearing chock (4, 4') of an active roll (2) comprises a part (40) shaped like a casing, wherein is assembled a rotating support bearing (30) of the corresponding spindle (3, 3') of the active roll (2), centered on a radial plane (P) going through the axis (20) of said roll (2) and an arm (41) assembled sliding on a guide (50) located on a guiding stand (5) fixed on the transverse frame (1) of the straightening train.
3. Machine for straightening metal bands according to anyone of claims 1 and 2, characterized by the fact that each sliding bearing chock (4, 4') is associated to a return mean (6) resting in one direction on the bearing chock (4) and, in the opposite direction, on the transverse frame (1), for the leaning of the active roll (2) against its support units (7, 7').
4. Machine for straightening metal bands according to claim 3, characterized by the fact that each bearing chock (4, 4') comprises a mean (8) of resting on the frame (1) to push back the active roll (2), against the action of the return mean (6), in a position of dismantling and of reassembly wherein the active roll (2) is spaced out from its support units (7, 7') or rests freely on them.
5. Machine for straightening metal bands according to claim 4, characterized by the fact that the resting mean (8) is a cam assembled spinning on an axis (80) and comprising

   • a side resting on the frame (1) by spinning on the axis (80), in order to push back the bearing chock (4, 4') against the action of the return mean (6) and

   • a flat side (81) putting itself, by rotation of the cam (8), into a spaced out position from the frame (1) to allow the leaning of the active roll (2) against its support units (7) thanks to the return means (6).
6. Machine for straightening metal bands according to anyone of claims 1 to 5, characterized by the fact that each bearing chock (4) comprises a support part (44) provided with at least one opening giving way to at least one guiding rod (61) fixed by a first end on the transverse frame (1) and stretching, on the other side of the support part (44) of the bearing chock, up to a second end on which is located a thrust flange (63) for a springy return mean (6) compressed between said thrust flange (63) and the support part (44) of the bearing chock (4).
7. Machine for straightening metal bands according to claim 6, characterized by the fact that each bearing chock (4) is assembled sliding radially along at least two guiding rods (61) each going through an opening in the support part (44) and each associated to a spring (6) slipped on said rod (61) and compressed between the support part (44) and a thrust flange (63) located at the end of the guiding rod (61).
8. Machine for straightening metal bands according to claim 7, characterized by the fact that each guiding rod is made of a bush (61) slipped on a screw (62) fixed on the support part (44) of the bearing chock (4) and resting on a thrust flange (63) located at the end of the bush (61) opposite to the support part (44), a spring (6) being slipped on the bush (61) and compressed, thanks to a screwing down of the screw (62), between the thrust flange (63) and the support part (44).
9. Machine for straightening metal bands according to claim 8, characterized by the fact that the two bearing chocks (4, 4') of the ends of each active roll (2) are each associated to return means (6) which are tared in order to make the active roll (2) lean against its support units (7, 70) under just enough a pressure to ensure the friction drive of said support units (7, 70) by the active roll (2).
10. Machine for straightening metal bands according to claim 9, characterized by the fact that the two bearing chocks of the active roll (2) of the upper train (E') are each associated to a first return mean (60) tared to make the active roll (2) lean against its support units (7, 70) and, furthermore, associated to a second return mean (65) tared in order to compensate the weight of the active roll, of its bearing chocks (4, 4') and of machine parts (36) that are not directly carried by the supporting frame (1).
11. Machine for straightening metal bands according to anyone of the previous claims, characterized by the fact that each bearing chock (4) carries a rotating bearing (30) for centring one end (3) of an active roll (2), comprising at least an antifriction bearing with an external cage (30a) fixed on the bearing chock (4) and a rotating internal cage (30b), wherein is inserted a centring spindle (3), fixed on the corresponding end of the active roll (2) and centered on the rotation axis (20) of the latter.
12. Machine for straightening metal bands according to anyone of the previous claims, characterized by the fact that one (3) of the two spindles fixed respectively to both ends of the active roll (2), is continued outside by a driving rod end (33) linked to a mean (36) of exertion of a rotation torque on the spindle (3), for the spinning of the cylindrical roll (2), on its axis (20), at a wished angular speed.
13. Machine for straightening metal bands according to anyone of the previous claims, characterized by the fact that at least the bearing chock (4) of the driving spindle (3) is assembled sliding along a guiding stand (5) which is itself assembled sliding on the transverse frame (1), in a parallel to the axis of the active roll (2), between a tight position of the two bearing chocks (4, 4') for the full insertion of each end (31, 31') of the active roll (2) inside the corresponding bearing chock (4, 4') and a spaced out position for the release of the ends (31, 31') of the active roll (2), in order to dismantle the latter.
14. Machine for straightening metal bands according to anyone of the previous claims, characterized by the fact that at least the driving spindle , (3) on which is exerted the rotation torque, is linked a removable way to the corresponding end (31) of the active roll (2).
15. Machine for straightening metal bands according to claim 14, characterized by the fact that at least the driving spindle (3) comprises a piece of a shaft (32) assembled rotating on the bearing chock (4) and provided with a removable linkage mean with the end (31) of the active roll, said piece of shaft (32) being movable axially , with the bearing chock (4), between a tight position of linkage with the roll (2), for the rotating support of the latter, and a spaced out position separated from the end (31) of the cylindrical roll (2), for the dismantling of the latter.
16. Machine for straightening metal bands according to claim 15, characterized by the fact that the linkage mean (34) between the spindle (3) and the roll (2) is made of two twin-shaped parts, located respectively on the piece of shaft (32) and on the corresponding end (31) of the roll (2), and fitting into each other by axial moving of the piece of shaft (32) from a spaced out position to a tight position.
17. Machine for straightening metal bands according to claim 16, characterized by the fact that at least the guiding stand (5) of the bearing chock (4) of the driving spindle (3) is fixed on a base (51) assembled sliding on the frame (1) in a parallel to the radial plane (P) and associated to removable means for the fastening of the guiding stand (5) on the frame (1) in the tight position of full insertion of the ends (31) of the active roll (2) inside the bearing chocks (4, 4').
18. Machine for straightening metal bands according to anyone of the previous claims, characterized by the fact that the support units of the active roll comprise at least two cylindrical rolls (7, 7') assembled spinning on their axis, each between two aligned centring machine parts (71), located respectively on two guiding stands (5) fixed on the transverse frame and on which are assembled sliding, respectively, the two bearing chocks (4, 4') of the active roll (2), in a parallel to a radial plane (P) going through the axis (20) of said active roll (2).
19. Machine for straightening metal bands according to claim 18, characterized by the fact that the centring machine parts of each support roll (7) are made of two axial thrust rolling bearings (71) assembled respectively on the guiding stands (5) of the two bearing chocks (4, 4') of the active roll (2).
20. Machine for straightening metal bands according to anyone of the previous claims, characterized by the fact that the support units (7) of the active roll (2) of each train (E) comprise at least two intermediate rolls (7, 7') held laterally each between two axial thrust rolling bearings (71) and each leaning against at least two rows of rollers (70) assembled spinning on the transverse frame (1).
21. Machine for straightening metal bands according to claim 20, characterized by the fact that each end of an intermediate roll (7) is centered on an axial thrust rolling bearing (71) assembled in a casing (72) with an extension (73) housed in a hollowing (53) located on a part (52) of the guiding stand (5), with a clearance allowing an adjustment of the position of the intermediate roll (7) depending on the diameters of the active roll (2) and of the support units (7, 70).
22. Process for straightening a strip (M) thanks to its travel, along a longitudinal axis, between at least two straightening trains (E, E') comprising each an active roll (2) spinning on an axis (20) orthogonal to the travel axis of the strip (M) and associated to at least two rotating support units (7) spinning on axes parallel to the one of the active roll (2), the whole set being carried by a support transverse frame (1) able to be moved, transversally to the travel plane of the strip (M), between a straightening position wherein the active roll (2) is resting on the strip (M) and leans, on the opposite side, against its support units (7, 70), with a spinning drive of said active roll (2) and support units (7), and an at rest position wherein the active roll (2) is spaced out from the strip,
    process wherein each roll (2, 2') is driven spinning on its axis, in its position spaced out from the strip, at an angular speed corresponding to the travel speed of the strip,
    characterized by the fact that the spinning drive of each active roll (2) is determined by direct exertion of a rotation torque on an end (31) of the roll (2) with an automatic control system to make the angular speed of the active roll (2) match the speed travel of the strip (M).
23. Straightening process according to claim 22, characterized by the fact that each active roll (2) can be driven spinning not only in its position spaced out from the strip (M) but also in its position of resting on the strip, with an automatic control system to make, all the time, the angular speed of the roll (2) match the travel speed of the strip (M) for its landing on the strip and during the straightening.
24. Straightening process according to anyone of claims 22 and 23, characterized by the fact that the active roll (2) is permanently leaning against its support units (7), in the at rest position of the straightening train (E), and is spaced out from said support units (7) when needed, for the dismantling and the replacement of said active roll (2).

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