EP0277846A1 - Ladle turret - Google Patents

Abstract

PCT No. PCT/FR88/00006 Sec. 371 Date Sep. 6, 1988 Sec. 102(e) Date Sep. 6, 1988 PCT Filed Jan. 5, 1988 PCT Pub. No. WO88/04969 PCT Pub. Date Jul. 14, 1988.The pivoting device for ladles used in continuous casting comprises at least one arm extended overhanging from a rotary barrel and comprised of a parallelogram-shaped deformable and articulated assembly comprising two supporting uprights connected to the barrel by parallel rods hinged to the uprights about upper and lower movable pins, and to the barrel (2) about upper and lower fixed pins. The uprights form an outer side movable vertically while remaining parallel to itself by deformation of the parallelogram under the action of at least one lifting jack. The articulations defining the movable pin of the upper rods are provided on a transverse frame extended horizontally and passing outside the ladle between the latter and the barrel, and the two supporting uprights are secured to the transverse frame and form with the latter a rigid fork-shaped seat wherein the ladle is nested.

Description

The present invention belongs to the field of the steel industry and relates to a ladle swivel, used in particular in continuous steel casting plants.

In this type of installation, the pockets containing the molten metal and coming from the steelworks are brought close to the casting installation by means of a transport trolley or an overhead crane and placed above a distributor-container into which the molten metal is poured through a tap hole. The molten metal then passes from the distributor to the bottomless ingot mold where the continuous strip of metal is formed: slab or bar.

In order to facilitate the replacement of the pockets and to reduce downtime as much as possible, a device called a "pocket swivel" is often used as pocket support.

Such devices are known. They comprise at least one arm extending in overhang from a barrel rotatably mounted about a vertical axis on a fixed base, for example the support frame of the installation. Each arm can support a pocket and bring it by rotation, from a loading and unloading position to a casting position above the dispenser.

The pivoter is often provided with two diametrically opposite arms so that, while a pocket, placed above the distributor, pours the steel it contains, one can remove from the other arm the pocket previously emptied for replace it with a new full pocket.

Generally, the tap hole, closed by a nozzle, is extended downwards by a pouring tube, the role of which is to protect the steel jet, between pocket and distributor, from contact with air and therefore from oxidation.

The protective devices are generally, either a refractory tube attached or held under the pocket, or a skirt made of asbestos or similar materials in which a neutral atmosphere is maintained.

Since the bag is brought above the dispenser and then evacuated by rotation of the support arm around its vertical axis, it has been necessary to equip the pocket supports with lifting devices which allow the pouring tube to be released during the pocket or dispenser changes. Lifting is also necessary when, to unblock the closing nozzle of the taphole, it is necessary to breathe in it using a lance, pressurized oxygen which burns the steel frozen in the orifice of the nozzle.

The devices for lifting the known pocket support arms can be of the hydraulic or electromechanical type.

In mechanical type devices, the lifting is generated by elements of the winch and hauling type, screws and nuts, connecting rods, cranks. These devices are heavy and bulky, they sweep a large space during the rotation of the pivot, which creates dangerous areas at workstations. In addition, generally, they comprise a certain number of articulations and guides exposed to steel projections and therefore frequent and delicate maintenance.

In addition, the protruding guides above above the arms require a higher lift height at the bridge and therefore a building height in relation.

In hydraulic type devices, lifting is generated by jacks. These devices are simpler and create less stress than mechanical devices.

In this case, the lifting of the pocket is controlled by at least one hydraulic cylinder bearing on the support arm, the latter being pivotally mounted on the barrel about a horizontal axis.

The pocket is provided with two pins engaging in suspension members which allow maneuvering by the overhead crane and which rest on support parts provided at the end of the support arm and which often have the shape of a bowl trapezoidal in which are embedded the lower parts, of corresponding shapes, of the suspension members. Therefore, if the support parts are rigidly fixed to the end of the support arms, the pivoting of the latter during lifting determines a change in orientation of the support members and therefore an oscillation of the pocket around its journals. This is why it is often considered preferable to provide the support parts on two support uprights connected to the barrel by an articulated system forming a deformable parallelogram of which they constitute an external side which can be moved parallel to itself. For this purpose, each support post is articulated around horizontal axes on the one hand on the end of the support arm and on the other hand on a connecting rod parallel to the support arm and articulated on the so key, the top of the deformable parallelogram being constituted by the respectively fixed and movable articulation axes of the support arm and of the connecting rod respectively on the base and on the two support uprights.

In such arrangements, which are described, for example, in documents EP-A-0206169 or FR-A-2234946, the lifting force is applied to the support arm which therefore works in bending and the force required for cylinder is greater than the weight of the load. For this reason and to better support the articulated assembly during lifting, it is generally carried out by means of two spaced apart and synchronized jacks each acting on one side of the support arm.

The subject of the invention is a device of the deformable parallelogram type, but simpler, lighter and less bulky than most known devices. In addition, the rigidity of the elements supporting the pocket is increased and it is possible to carry out the lifting by means of a single lifting cylinder, the effort developed being better used. In addition, the device according to the invention promotes protection against steel projections of the various mechanical and hydraulic members while having total accessibility which allows easy and effective maintenance.

The pocket pivot according to the invention is therefore of the type comprising a barrel rotatably mounted on a fixed base and at least one arm extending in overhang and constituted by an articulated assembly in the form of a deformable parallelogram comprising two uprights of support placed on hand and on the other side of the pocket and connected to the barrel by a set of parallel rods, respectively upper and lower, connected respectively to the two uprights and to the barrel by articulations defining four horizontal axes constituting the vertices of the deformable parallelogram whose said uprights constitute an outer side mobile capable of moving vertically while remaining parallel to itself by deformation of the parallelogram under the action of at least one levare cylinder.

According to the invention, the joints defining the movable axis of the upper connecting rods are formed on a transverse frame extending horizontally and passing outside the pocket between the latter and the barrel and the two support uprights are fixed. rigidly on said transverse frame and form with the latter a rigid chair in the form of a fork into which the pocket fits.

Compared to other known arrangements with a deformable parallelogram, the invention therefore has the particularity of placing the movable upper axis outside the pocket, between the latter and the barrel, the two lateral, fixed and mobile sides of the parallelogram , being oriented at an angle so that the upper movable axis of the parallelogram is substantially vertical to the lower fixed axis. Thanks to this arrangement, the support chair can bear directly on the lifting jack (s), the latter being interposed between the barrel and the transverse frame and directed along a substantially vertical axis, bearing respectively on the nearby transverse frame. of the axis upper mobile and on the barrel near the lower fixed axis.

Such an arrangement allows in particular to raise the pocket by means of a single jack placed in the vertical median plane of the chair and bearing on the center of the transverse frame of the support chair.

Furthermore, because the weight of the chair supporting the pocket is applied directly to the jack (s), the upper and lower connecting rods which constitute the substantially horizontal sides of the parallelogram have only a stabilizing role in order to hold the chair in accordance the three axes and are subjected only to compression or tensile forces. In addition, the size of the jack or jacks is directly conditioned by the mass of the pocket and its stroke is substantially equal to the required lifting stroke.

In addition, the load can be directly measured, either by means of a load cell interposed between the lifting cylinder and the drum, or by simple measurement of the cylinder pressure.

• Fig. 1 représente un bras de pivoteur de poche conforme à l'invention, vu de côté.
• Fig. 2 représente, dans sa partie supé­rieure, une demi-vue de dessus du pivoteur et, dans sa partie inférieure, une demi-coupe selon A-A de la figure 1.
• Figs. 3 et 4 représentent deux exemples de réalisation différents du pivoteur selon l'invention.

However, the invention also has other advantages which will appear during the following description of a preferred embodiment and of certain variants shown schematically in the accompanying drawings.

• Fig. 1 shows a pocket pivot arm according to the invention, seen from the side.
• Fig. 2 represents, in its upper part, a half-view from above of the pivoter and, in its lower part, a half-section along AA of FIG. 1.
• Figs. 3 and 4 represent two examples different embodiments of the pivot according to the invention.

The pocket pivot shown in Figures 1 and 2 comprises a barrel (2) rotatably mounted about a vertical axis on a frame or base (1) anchored to the foundation. The rotation of the barrel is controlled by a motor and is transmitted by gears not shown to a slewing ring with rollers (21) integral with the barrel (2).

This pivoter is of the type comprising two arms (4) (4ʹ) of pocket support extending in overhang from the barrel (2), symmetrically on either side of the axis (3) of the rotating barrel (2). As can be seen, however, in the figure, each support arm (4) is constituted by a massive support chair (4) spaced from the barrel and connected to the latter simply by two pairs of parallel rods, respectively upper (5) and lower (6). The chair (40) for supporting the ladle (16) consists of two uprights (41) placed on each side of the ladle (16) and rigidly connected to each other by a horizontal beam or transverse frame (42) so to constitute a rigid block in the form of a fork having two free ends (43).

At each of these free external ends (43) are provided lateral support members (44) forming a cradle on which the pocket rests by means of two diametrically opposed axes or pins (17).

According to a known arrangement, the pins (17) engage in suspension members (19) provided at their lower part with a support surface of trapezoidal shape which fits into a surface of the same formed shape recessed on the corresponding cradle (44) so as to secure the pocket (16).

On the external side, the upper (5) and lower (6) rods for guiding and holding the chair (40) are articulated respectively on the transverse frame (42) and on the free ends (43) of the two uprights (41). around joints 45, 46 respectively defining an upper mobile axis (52) and a lower mobile axis (62).

On the internal side, the upper (5) and lower (6) connecting rods are articulated on the barrel (2), around two fixed axes respectively upper (51) and lower (61). The two fixed articulation axes (51) and (61) are defined by bearings carried by the barrel (2) and formed respectively on flanges (22) fixed to the upper part and in the axis of the barrel (2). and on flanges (23) fixed to the lower part, at the level of the rotation ring (21).

The different joints (45, 46, 22, 23) are an integral part of the connecting rods and the barrel, the added parts being simple short bearings.

The four axes (51), (52), (61), (62) are placed at the vertices of a deformable parallelogram, each upright (41) of which therefore constitutes a movable external side opposite to the fixed internal side defined by the upper axes (51) and lower (61). The upper (5) and lower (6) connecting rods form the other two upper and lower sides respectively of the parallelogram.

The other two sides are formed on the one hand by the lower connecting rods (6) forming the lower side and on the other hand by the upper connecting rods lines (5) forming the upper side of the parallelogram.

It can be seen that the orientation of the lateral sides of the parallelogram and the length of the connecting rods are determined so that the movable upper axis (52) of the parallelogram is placed substantially vertical to the lower fixed axis (16).

In the preferred embodiment shown in the drawings, the lifting movement of the pocket is generated by a single hydraulic cylinder (7) bearing on the one hand on the barrel (2), between the two lower connecting rods (6) and on the other hand on the pocket support chair (40), in the middle of the transverse frame (42).

In such an arrangement, the lifting cylinder can therefore be oriented in a substantially vertical direction. The necessary changes of orientation during the lifting are authorized by interposing between the two elements of the jack (7) and, respectively, the barrel (2) and the chassis (42), articulated support members (71, 72) . We can use ball bearings but an articulation around an axis parallel to the axes of the parallelogram would be sufficient.

As can be seen, the jack (7) thus directly supports the weight of the pocket (16) to which is added that of the chair (40).

No reduction effect therefore increases the load applied to the jack whose displacement is substantially equal to that of the pocket and this is what makes it possible, in particular, to use a single jack whose size and stroke are directly conditioned by the mass to be lifted and the lifting stroke requested.

The hydraulic circuit is simplified because the lifting cylinder can be a simple plunger, the downhill return being ensured in a safe manner, even without load, by the dead weight of the chair (40) and connecting rods (5) and (6 ).

The support chair (40) can be constituted by a mechanically welded block forming a very rigid fork simply held by the connecting rods (5) and (6) so as to move parallel to itself. The connecting rods (5) and (6) work only in traction or in compression and can moreover be relatively short even if the fixed upper axis (51) is placed very close to the axis of the barrel (2). The chair (40) is, itself, little stressed in bending.

The horizontal support of the two supports (44) of the pins (17) is ensured by the transverse frame (42) associated with a torsion box (15) extending horizontally between the two upper connecting rods (5) to which it is rigidly attached. The two lower connecting rods (6) can, moreover, also be secured by a connecting bar (63).

Thus, any imbalance is absorbed by an element not subject to wear or maintenance as would be the conventional dynamic devices such as pinions, racks, hydraulic distributors, screws, nuts, etc ....

Maintaining the parallelism of the corresponding elements on the two sides of the parallelogram generates a torque which can be made to bear essentially by the box (15) by adapting the dimensional characteristics of the latter accordingly, as well as for the transverse frame. (42) which supports the lifting effort, in particular when using a single cylinder.

Of course the second arm (4ʹ) of the pivot extending symmetrically on the other side of the axis (3) of the rotary barrel (2) would be produced in the same way and that is why it did not seem necessary to represent it completely on the drawings.

Figure 3 shows a different embodiment of the pivot according to the invention.

The difference compared to the previously described pivot lies in the fact that the jack (7) is rigidly fixed directly on the rotary barrel (2). The thrust of this jack (7) is then transmitted to the support chair (40) by a compression rod (9), articulated at its two ends respectively on the chair (40) and on the jack (7).

This particular embodiment of the lifting device causes a better distribution for the transmission of forces in the elements of the pivot. The hydraulic circuits can then be in rigid piping and the entire hydraulic lifting device, in particular the rod (12) of the jack, the seals and the weighing equipment, can be particularly well protected from steel projections.

Figure 4 shows another variant. The compression rod (9) is articulated at its upper end on the transverse frame (42) and at its lower end, directly on the piston (10) of the jack (7) passing through an axial bore formed in the rod (12 ) and leaving the clearance necessary for the orientation of the connecting rod (9). The rod 12 is then used only for guiding and sealing and is very little stressed, the load being applied directly to the piston (10).

In Figure 4, there is also shown a weighing device comprising on each side of the pocket, two sets of scales (14). However, given the proportionality between the weight of the pocket and the compression force directly applied to the cylinder, this weighing device can very well, in a new way be directly applied to the level of the lifting cylinder (7).

For example, as shown diagrammatically in FIG. 1, load cells (73) could be interposed between the body of the jack (7) and the barrel (2) at the level of the lower support member (71) .

But one could also determine the weight of the pocket simply from a measurement of the hydraulic pressure applied to the jack (7) taking into account the dead weights.

It will be noted that the arrangement in accordance with the invention has the advantage of freeing, in the middle of the rotary barrel (2), a free space in which the main hydraulic control equipment can be installed on a simple floor well worn by the barrel ( 2). Other elements: tank, drawers, can be installed in overhang under the footbridges provided for circulation on the side of the pivoter but it is also possible to house the entire hydraulic control in the barrel.

Variants can be made in the embodiment of the pivot which has just been described without departing from the protective framework defined by the claims.

For example, it is particularly advantageous to use a single jack for lifting the pocket support arm, which makes it possible to overcome all the hydraulic synchronization problems present in all hydraulic devices with several jacks. However, it would also be possible to act on two jacks (7) at the two ends of the transverse frame (42).

We could also interpose between the drum (2) and the chair (40) a shock absorber coming to reduce the effects of the shocks of deposit on the whole structure, the compact and rigid shape of the chair allowing, moreover, to better absorb such shocks.

It can be seen that all of the characteristics that have just been described allow a simple pivot to be obtained, where the mounting and changing of the pockets is easy, and whose weight is less than that of most known pivoters .

The weight of the ladle and of the elements which support it are supported directly without gear reduction effect by the lifting means, the latter can be constituted by a single jack placed in the vertical median plane of the pivot and directed vertically so that the load to be lifted and the lifting force are substantially parallel, in opposite directions and of equal intensity, except for dead masses.

Thus, the inevitable external forces are not converted into greater internal forces, as is the case with the classic lever devices.

In addition, total accessibility to all delicate areas (cylinders, connecting rods, torsion boxes), allows easy and efficient maintenance of the installation and all sensitive equipment can be easily protected, for example by covers and / or gunite protections.

Claims (11)

1. Pivot of pockets comprising a barrel (2) rotatably mounted on a fixed base (1) and at least one arm (4) extending in overhang and constituted by an articulated assembly in the form of a deformable parallelogram comprising two support uprights (41) placed on either side of the pocket (16) and connected to the barrel (2) by a set of parallel rods, respectively upper (5) and lower (6) connected respectively to the two uprights (41 ) by joints (45) (46) defining two movable axes, respectively upper (52) and lower (62) and in the barrel (2) by joints (22) (23) defining two fixed axes respectively upper (51) and lower (61), the four axes of articulation constituting the vertices of the deformable parallelogram whose said uprights (41) constitute a movable outer side capable of moving vertically while remaining parallel to itself by deformation of the parallelogram under the action of at least one lifting cylinder (7) characterized by the fact that the articulations (45) defining the movable axis (52) of the upper connecting rods (5) are formed on a transverse frame (42) extending horizontally and passing outside the pocket (16) between it ci and the barrel (2) and that the two support uprights (41) are rigidly fixed on said transverse frame (42) and form with the latter a rigid chair (40) in the form of a fork in which the pocket fits (16). 2. Pivot of pockets according to claim 1, characterized in that the support chair (40) bears directly on the lifting cylinders or (7), the latter being interposed between the barrel (2) and the transverse frame (42). 3. Pivot of pockets according to claim 2, characterized in that the or the lifting cylinders (7) are directed along a substantially vertical axis. 4. Pivot of pockets according to claim 3, characterized in that the lifting jack (s) (7) bear on the transverse frame (42) near the upper movable axis (52) and on the barrel (2 ) near the lower fixed axis (61). 5. Pivot of pockets according to claim 1, characterized in that the lifting of the pocket is carried out by a single jack (7) placed in the vertical median plane of the chair (40) and bearing on the center of the transverse frame ( 42). 6. Pivot pocket according to one of the preceding claims, characterized in that each lifting cylinder (7) is associated with a weighing means of the pocket (16). 7. Pivot of pockets according to claim 6, characterized in that the weighing means of the pocket (16) consists of at least one load cell (73) interposed between the lifting cylinder (7) and the barrel (2) . 8. Pivot pocket according to claim 6, characterized in that the weighing of the pocket (16) is carried out from a direct measurement of the pressure of the lifting cylinder (7). 9. Pivot of pockets according to one of the preceding claims, characterized in that the two elements of each lifting cylinder (7) bear respectively on the barrel (2) and on the transverse frame (42) of the support chase (40) by means of support members (71) (72) articulated at least around an axis parallel to the axes of articulations ( 51, 52, 61, 62) of the deformable parallelogram. 10. Pivot of pockets according to one of claims 1 to 8, characterized in that each lifting cylinder (7) comprises a first element (11) rigidly fixed on the barrel (2) and a second element (10, 12 ) bearing on the chase (40) by means of a compression rod (9) articulated at its two ends. 11. Pivot of pockets according to claim 10, characterized in that the compression rod (9) passes with clearance in a bore formed in the axis of the rod (12) of the jack (7) so as to bear directly on the piston (10) of the jack (7).

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