Rolling station and rolling mill plant

Abstract

Rolling station intended to couple with a respective rolling cartridge or stand provided with two rolling cylinders, wherein the rolling station has a supporting frame of the transmissions suitable for housing a pair of transmission devices of which a first transmission device is intended to couple with a first rolling cylinder and a second transmission device is intended to couple with a second rolling cylinder, the first rolling cylinder being put in rotation by a first motor via the first transmission device and the second rolling cylinder being put in rotation by a second motor via the second transmission device.

Claims

1. An assembly comprising: a rolling stand having a first rolling cylinder and a second rolling cylinder that rotate in opposite directions, said first rolling cylinder being driven by a first motor by way of a first transmission, said second rolling cylinder being driven by a second motor by way of a second transmission; and a rolling station comprising: a supporting frame that houses said first and second transmissions and supports said first and second transmissions without a universal joint adapter, said first transmission having a chain of gears directly coupled to an output shaft of said first motor without a universal adapter, said second transmission having a chain of gears directly coupled to an output shaft of said second motor without a universal adapter, each of said first transmission and said second transmission having a first output pinion with a transmission slot, said transmission slot engaging a hub of one of the first and second rolling cylinders, said first and second rolling cylinders positioned in side-by-side relationship, said first output pinion being controlled in rotation by a first torque division pinion that is integral with a first crown, said first output pinion also controlled in rotation by a second torque division pinion that is integral with a second crown, a combined and coordinated action of said first and second torque division pinions controlling the rotation of said first output pinion, said first and second crowns being rotatable by a fourth pinion, said fourth pinion having a first toothed band that is a first gear that transmits motion to said first crown and a second toothed band that is a second gear that transmits motion to said second crown.

2. The assembly of claim 1, wherein said first motor and said second motor are controllable independently of each other.

3. The assembly of claim 2, wherein said first motor and said second motor are controllable independently of each other with different rotation speeds, a rotation speed difference of said first motor and said second motor corresponding to a rotation speed difference of said first rolling cylinder with respect to a rotation speed of said second rolling cylinder.

4. The assembly of claim 3, wherein the rotation speed difference of said first motor and said second motor is controllable in a manual or automatic manner according to rolling parameters.

5. The assembly of claim 1, wherein said first gear and said second gear are respectively a first helical gear shaped with a first screw and a second helical gear shaped with a second screw, wherein the first screw has a shape opposed to a shape of the respective teeth of said first helical gear being oriented at an opposite orientation with respect to an orientation of teeth of said second helical gear.

6. The assembly of claim 1, wherein said fourth pinion receives the rotational motion from one of said first motor and said second motor with an interposition of an epicyclic reduction gear.

7. The assembly of claim 6, wherein said epicyclic reduction gear has a first stage on which a first input shaft engages, said first input shaft acting on first planetary gears of said first stage, which are rotationally supported by a first planetary gear support which provides rotation to a second shaft, said second shaft transmitting a rotational motion from said first stage to a second stage, said second shaft acting on second planetary gears of said second stage, said second planetary gear being rotationally supported by a second planetary gear support which rotates a third shaft, said third shaft coupled to said fourth pinion.

8. The assembly of claim 1, wherein said first and second transmissions are mobilized by a sliding movement on said supporting frame by guides of said first and second transmissions.

9. The assembly of claim 8, said first transmission and said second transmission are suspended from said supporting frame, wherein a supporting compensator self-balances a movement of said first transmission with respect to said second transmission.

10. The assembly of claim 9, wherein said supporting compensator comprises three levers, of which: a central lever is hinged on said supporting frame in correspondence to a midpoint between a first end and a second end of said central lever; a first transmission lever is hinged at the first end of said central lever and on which a first element of a locking devices acts; and a second transmission lever is hinged at the second end of said central lever and on which a second element of the locking device acts, an adjustment of position of said first transmission and said second transmission being reciprocally coordinated by said supporting compensator, said first transmission and said second transmission being suspended from said supporting frame by said supporting compensator.

11. The assembly of claim 10, wherein locking device is a hydraulic lock.

12. The assembly of claim 8, wherein a hydraulic actuator drives the movement of said first transmission or said second transmission.

13. The assembly of claim 8, wherein a mechanical actuator drives the movement of said first transmission or said second transmission.

14. The assembly of claim 1, wherein an anchorage frame has frame guides cooperative with said supporting frame so as to allow movement of said supporting frame.

15. The assembly of claim 14, wherein said frame guides are movable in relation to a driven condition of said rolling stand.

16. A rolling process using the assembly of claim 1, wherein said first rolling cylinder has a rotational speed and said second rolling cylinder has another rotational speed, the rolling process comprising: adjusting a rotational speed difference between the rotational speeds of said first rolling cylinder and said second rolling cylinder; and independently controlling the rotation of said first rolling cylinder and said second rolling cylinder by said first transmission and said second transmission.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following a solution is described with reference to the enclosed drawings to be considered as a non-exhaustive example of the present invention in which:

(2) FIG. 1 schematically shows a front view of a rolling station made according to the present invention relating to a rolling stand with a horizontal axis.

(3) FIG. 2 schematically shows the rolling station of FIG. 1 in which the rolling station has been partially represented in section to let catch sight of the internal transmission device.

(4) FIG. 3 schematically shows a front three-quarter view of the rolling station of FIG. 1.

(5) FIG. 4 schematically shows a back three-quarter view of the rolling station of FIG. 1.

(6) FIG. 5 schematically shows the rolling station of FIG. 3 in which the rolling station has been partially represented in section to let catch sight of the internal transmission device.

(7) FIG. 6 schematically shows a perspective view of the transmission device relating to one of the cylinders of the rolling stand.

(8) FIG. 7 schematically shows a side view of the rolling station made according to the present invention relating to a rolling stand with a horizontal axis.

(9) FIG. 8 schematically shows a sectional view of the rolling station of FIG. 7 in which the sectional views indicated with A-A and B-B have been placed next to each other.

(10) FIG. 9 schematically shows a front three-quarter view of a different embodiment of the rolling station according to the present invention.

(11) FIG. 10 schematically shows a front view of a rolling station made according to the present invention relating to a rolling stand with a horizontal axis, in a first adjustment configuration.

(12) FIG. 11 schematically shows a sectional view of the rolling station of FIG. 10.

(13) FIG. 12 schematically shows a front view of a rolling station made according to the present invention relating to a rolling stand with a horizontal axis, in a second adjustment configuration.

(14) FIG. 13 schematically shows a sectional view of the rolling station of FIG. 12.

(15) FIG. 14 schematically shows a front view of a rolling station made according to the present invention relating to a rolling stand with a horizontal axis, during the coupling with the corresponding rolling cartridge.

(16) FIG. 15 schematically shows a sectional view of the rolling station of FIG. 14.

(17) FIG. 16 schematically shows a perspective view of a rolling station of the prior art relating to a rolling stand with a horizontal axis.

(18) FIG. 17 schematically shows a sectional view of the initial portion of transmission from the motor to the transmission device of a rolling station made according to the present invention.

(19) FIG. 18 schematically shows a front view of a rolling station made according to the present invention relating to a rolling stand with a vertical axis.

DETAILED DESCRIPTION OF THE INVENTION

(20) With reference to the figures (FIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG. 5) the present invention relates to the control system of a rolling stand. In the solution according to the present invention the rolling cartridge (9) remains advantageously the same, with the additional advantage that the present solution can be implemented independently of the type of rolling cartridge adopted on the plant and with the advantage that the application of the present invention is advantageous in the case of existing plants as well.

(21) The oblong metal product is worked to obtain a determined size or surface area in section and a determined profile, which can be, for instance, circular, ovoid or elliptic, quadrangular, hexagonal, L-shaped, C-shaped, etc.

(22) According to the invention, each of the cylinders (31) is controlled by a respective high-speed electric motor, indicatively but not exclusively between 3000 and 5000 RPM. The first motor (1) and the second motor (11) are preferably of the AC type. The cylinders (31) consist of a first rolling cylinder and a second rolling cylinder rotating opposite to each other, that is to say, according to opposite rotational directions. Each motor is provided with a respective control inverter that allows for the independent control of the first motor (1) with respect to the second motor (11) and vice versa. A first rolling cylinder is controlled by a first electric motor (1) and a second rolling cylinder is controlled by a second electric motor (11). Each of the first electric motor (1) and second electric motor (11) is coupled with the respective rolling cylinder (31) by means of a transmission device, that is to say, a first transmission device (3) for the first motor (1) and a second transmission device (33) for the second motor (11). The transmission device (3, 33) is provided (FIG. 2, FIG. 5, FIG. 6, FIG. 7, FIG. 8) with a shaft or first output pinion (17) equipped with a transmission slot (19) for the engagement of the hub (18) of the respective cylinder of the two cylinders (31) of the stand or cartridge (9). The shaft or first output pinion (17) is controlled in rotation by means of the combined and coordinated action of a second torque division pinion (16) integral with a first crown (15) by which it is put in rotation and of a third torque division pinion (22) integral with a second crown (21) by which it is put in rotation, the first crown (15) and the second crown (21) being put in rotation by means of a fourth self-balanced pinion (14) provided with a first gear (23) of transmission of the rotational motion to the first crown (15) and further provided with a second gear (24) of transmission of the rotational motion to the second crown (21). The fourth self-balanced pinion (14) in its turn receives the rotational motion from the motor (1, 11) with the interposition of an epicyclic reduction gear (13).

(23) The first output pinion (17) is controlled by a pair of pinions, that is to say, a second torque division pinion (16) and a third torque division pinion (22). As a consequence, with equal sizes of the overall gear (diameter, band, module) it is possible to transmit twice the torque with respect to the use of one pinion only. However, each of the two cylinders (31) must be controlled by one respective motor only, that is to say, the first motor (1) for a first of the two cylinders (31) and a second motor (11) for a second of the two cylinders (31). Therefore, for each of the two cylinders (31) a device is necessary, which divides the torque of the respective motor in an exactly equal way onto two different chains of gears to transmit it to the only first output pinion (17) of the respective cylinder. For this purpose a fourth self-balanced pinion (14) is used, which is provided with a double toothed band with opposite screws, that is to say, provided with a first helical gear (23) and with a second helical gear (24) wherein the screw constituting the first helical gear (23) is made according to one shape opposed to the screw constituting the second helical gear (24). Therefore the first gear (23) transmitting the rotational motion and the second gear (24) transmitting the rotational motion are respectively a first helical gear (23) shaped with a first screw and a second helical gear (24) shaped with a second screw, wherein the first screw constituting the first helical gear (23) is made according to one shape opposed to the second screw constituting the second helical gear (24). That is to say, the first screw has the respective teeth of the first helical gear (23) oriented according to an opposite orientation with respect to the orientation of the teeth of the second screw of the second helical gear (24). The division of the torque into an exactly equal value between the first helical gear (23) and the second helical gear (24) is guaranteed by the fact that the fourth self-balanced pinion (14) is not axially locked and, in order to keep in dynamic balance, the axial components of the meshing forces on the first helical gear (23) and on the second helical gear (24) must be exactly identical and contrary. Therefore, also the tangential meshing force on the first helical gear (23), to which the torque is directly linked, will be equal to the tangential meshing force on the second helical gear (24) and as a result the transmitted torques will be equal too.

(24) The epicyclic reduction gear (13) is preferably made up (FIG. 17) of a first stage (36) onto which a first input shaft (35) engages that can be directly the output shaft of the motor (1, 11) or a shaft of connection with the output shaft of the motor. The preferred solution is the one in which the first input shaft (35) is directly the output shaft of the motor (1, 11), because the weight and rotating masses of the transmission system are minimized to the advantage of greater reliability and lower costs. The first input shaft (35) acts on first planetary gears (37) of the first stage (36), which are rotationally supported by a first planetary-gears support (38) which in its turn puts in rotation a second shaft (39). The second shaft (39) transmits the rotational motion from the first stage (36) to a second stage (40). The second shaft (39) acts on second planetary gears (41) of the second stage (40), which are rotationally supported by a second planetary-gears support (42) which in its turn puts in rotation a third shaft (43). The third shaft (43) in its turn is coupled with the fourth self-balanced pinion (14) of the first transmission device (3) in the case of the first motor (1) or of the second transmission device (33) in the case of the second motor (11).

(25) The present invention provides the use of two transmission devices (3, 33) with divided torque for the purpose of reducing their weight and sizes. The application of transmission devices (3, 33) with divided torque determines a weight reduction, with respect to the current solutions, by about 30-35% only of the part related to the transmission devices themselves, without considering the elimination (FIG. 16) of the adapters (28) of the prior art systems and the lower cost of the electric motors, that is to say, of the first electric motor (1) and of the second electric motor (11) with respect to the single motor (25) of the prior art solutions. Further benefits derive from the fact that, by adopting a more compact and lighter structure for the realization of the stand, thanks to the previously mentioned size and weight reductions, there is also a significant reduction in the construction needs of the plant and in particular as to the realization of the (FIG. 16) foundations (32) that may be reduced if not even eliminated. Furthermore, the plant as a whole will be considerably more compact, as is evident also from the comparison between the prior art solutions (FIG. 16) and the solution according to the present invention (FIG. 4) and considering that a rolling mill plant usually requires the presence of 14-16 rolling stands plus, if necessary, further finishing machines. The two transmission devices (3, 33), that is to say, the first transmission device (3) and the second transmission device (33), are supported by a supporting frame (7) of the transmissions. The two transmission devices (3, 33) are sliding on the supporting frame (7) of the transmissions by means of guides of the transmissions (4), which allow for their movement on the basis of the positioning of the rolling stand, for the purpose of adapting the position of the two transmission devices (3, 33) to the rolling line. For example in the case of a rolling station (20) suitable for housing a cartridge (9) according to a horizontal cylinders (31) configuration (FIG. 12), the two transmission devices (3, 33) will be vertically sliding. For example in the case of a rolling station (20) suitable for housing a cartridge (9) according to a vertical cylinders (31) configuration (FIG. 18), one or both transmission devices (3, 33) will be horizontally sliding. The sliding of the two transmission devices (3, 33) can be locked by means of respective locking means (5) of the transmission preferably of the hydraulic type. For example the described adjustment can be used for the adjustment of the reciprocal distance between the cylinders (31) depending on the wear conditions of the latter. As a consequence, in case of need for adjustment, the procedure provides that: one unlocks the locking means (5) of the transmission; one controls the adjustment of the position of the transmission devices (3, 33), during this phase the transmission devices (3, 33) being suspended with a supporting compensator (6) of the transmission that allows for a self-balance in such a way that the transmission devices (3, 33) may be moved by some drives that can be hydraulic or mechanical, but that must overcome only the friction of the guide mechanism (4) of the transmission; one locks the locking means (5) of the transmission.

(26) For example (FIG. 10, FIG. 11), from a reciprocally close position of the two cylinders (31), acting as previously described, one can reach (FIG. 12, FIG. 13) a reciprocally spaced position of the two cylinders (31). The supporting compensator (6) preferably consists of three levers, of which: a central lever hinged on the supporting frame of the transmissions (7) in correspondence of a midpoint between a first end and a second end of said central lever; a first transmission lever hinged in correspondence of the first end of the central lever and on which a first element of locking means of the reduction gear (5) acts; a second transmission lever hinged in correspondence of the second end of the central lever and on which a second element of locking means of the reduction gear (5) acts.

(27) In this way, therefore, one can control the adjustment of the position of the transmission devices (3, 33), with the transmission devices (3, 33) which are suspended by means of the supporting compensator (6) of the transmission. The adjustment of the position of the first transmission device (3) and of the second transmission device (33) is reciprocally coordinated by means of the supporting compensator (6), the first transmission device (3) and the second transmission device (33) being suspended from the supporting frame (7) of the transmissions by means of said supporting compensator (6) of the transmission.

(28) Furthermore, adjustments are provided to allow to carry out the channel change. In fact, each rolling cylinder can be provided with several rolling channels for the purpose of enabling a fast channel change for example in case of wear of the channel in use with a new channel or to change the channel in use with another channel having different characteristics. For example it may be provided that the supporting frame of the transmissions (7) is mobile with respect to the anchorage frame (10) for the adjustment of the position of the rolling channel obtained on the cylinders (31). Furthermore (FIG. 14, FIG. 15) the rolling cartridge (9) can be sliding on own guides of the cartridge (34) to enable its insertion (FIG. 12) or extraction (FIG. 14) with respect to the rolling station (20). As a consequence, the rolling station (20) is preferably provided with an anchorage frame (10) for its fixing to the floor. The anchorage frame (10) is provided with guides of the frame (8) suitable to allow for the movement of the supporting frame (7) of the transmissions. Furthermore, guides of the stand (34) may be present. The guides of the frame (8) and the guides of the stand (34), can be made in the superimposed configuration (FIG. 3) or in line (FIG. 9) or according to other configurations, according to the plant layout.

(29) The two cylinders (31) are controlled in an independent way, and through the inverter and management system the necessary adjustments can be made to obtain a perfect synchronism of the system. This is observed to be a big advantage with respect to the present state of the art, which is bound by a single transmission of the two cylinders.

(30) With the present invention it is not necessary to realize the foundation for the support of the reduction gear and of the motor, obtaining a considerable saving in the realization of the civil works. Moreover, the necessary space is considerably reduced and therefore the sizes of the shed can be reduced as well. Therefore, the saving achieved with the application of the present invention is not only linked to the transmission system, but in particular to the simplification that is introduced to the whole structure of the plant.

(31) In particular the use of two motors, that is to say, a first electric motor (1) for a first rolling cylinder and a second electric motor (11) for a second rolling cylinder of the rolling stand allows to use motors of a smaller size with respect to the single motor used in the prior art solutions, with lower costs, better performances from the point of view of control. Furthermore, the possibility to control in an independent way the rotation of each of the two rolling cylinders allows to obtain benefits from the point of view of the quality of the material. In fact, in this way one obtains the possibility to modify the peripheral speeds of the rolling cylinders in a reciprocally independent way also during the rolling process, that is to say in loading conditions. For example one can change the rotation speed of one cylinder with respect to the other according to the load and to the effort detected on each rolling cylinder to compensate for possible differences which may be the symptom of the wear of one cylinder with respect to the other or of the unevenness of the material, such as unevenness in the section, unevenness in the temperature, unevenness in correspondence of the head and/or of the tail of the oblong metal material, etc. In this way such problems can be solved by varying the speed of a cylinder with respect to the speed of the other cylinder of the same rolling stand, obtaining on the oblong metal material a condition of balance between sliding and a different mechanical action of deformation in correspondence of the portion in contact with the first rolling cylinder controlled by the first motor (1) with respect to the conditions in correspondence of the portion in contact with the second rolling cylinder controlled by the second motor (11), in favour of the quality and of the mechanical characteristics of the finished product. For example, in addition to the compensation for the wear of the channel of the cylinders that is obtained by the variation in the reciprocal distance of the cylinders, there may be a compensation for the wear of the channel of the cylinders obtained by means of the introduction of a difference in the rotation speed of a cylinder with respect to the other, which is not possible with the rolling stands of the prior art, provided with one single motor, and which is instead possible with the solution according to the present invention in which each cylinder is controllable in an independent way by means of the respective motor. As a consequence there may also be an extension of the useful life cycle of the rolling cylinders thanks to the increased possibilities of compensation provided by the solution according to the present invention.

(32) Therefore, the solution according to the present invention provides the supply of a rolling station (20) intended to couple with a respective rolling cartridge or stand (9) that is provided with two rolling cylinders (31) identical to each other, a first cylinder being provided with at least one first semi-channel and a second cylinder being provided with at least one second semi-channel, the reciprocal placing side-by-side of the cylinders (31) involving the reciprocal placing side-by-side of the at least one first semi-channel and of the at least one second semi-channel whose ensemble constitutes at least one rolling channel of the cartridge or stand (9), wherein the rolling station (20) includes a supporting frame of the transmissions (7) intended to house a pair of transmission devices of which a first transmission device (3) is intended to couple with a first rolling cylinder of the cartridge or stand (9) and a second transmission device (33) is intended to couple with a second rolling cylinder of the cartridge or stand (9), the first rolling cylinder being put in rotation by a first motor (1) by means of the first transmission device (3) and the second rolling cylinder being put in rotation by a second motor (11) by means of the second transmission device (33).

(33) The first motor (1) and the second motor (11) can be controllable in an independent way of each other and/or in a coordinated way with each other. For example one can provide an independent control of a motor with respect to the other, or one can provide the control of one motor only with the other motor that follows the control performed on the first motor with the introduction of a possible speed difference between the first motor (1) and the second motor (11), which can be null or assume a determined difference value calculated in an absolute way or in a percentage way with respect to the speed of the first motor (1). In general the first motor (1) and the second motor (11) are controllable in an independent way of each other with different rotation speeds, the rotation speed difference of the first motor (1) and of the second motor (11) corresponding to a rotation speed difference of the first cylinder with respect to the rotation speed of the second cylinder of the two cylinders (31) of the stand or cartridge (9). For example the rotation speed difference of the first motor (1) and of the second motor (11) is controllable in a manually and/or automatically controlled way according to rolling parameters, such as: temperature of the oblong metal material; temperature differences between a first oblong metal material rolled in the rolling line and a second oblong metal material rolled in the rolling line after the first; temperature differences of the cylinders following the progressive heating of the latter following the rolling process; temperature of a portion of the oblong metal material detected by means of temperature detection means in order to compensate for the greater rolling effort required in correspondence of portions having a lower temperature and/or the lower rolling effort required in correspondence of portions having a greater temperature with respect to adjacent portions along a same oblong metal material bar; unevenness of the oblong metal material, such as temperature, section, mechanical structure unevenness, etc.; unevenness of the oblong metal material detected by means of the input from the first motor (1) and/or second motor (11) and/or differences between them; physical and/or mechanical characteristics of the head and/or of the tail of the oblong metal material material constituting the oblong metal material that is rolled; material for making the cylinders (31); wear of the rolling channel; one or more measurements of the section of the oblong metal material taken in one or more points of the rolling line; tension applied to the oblong metal material between a pair of rolling stations (20); combination of one or more of the described parameters.

(34) In correspondence of the first motor (1) a first safety joint (2) is installed and in correspondence of the second motor (11) a second safety joint (12) is installed.

(35) The safety joints have the function of protecting the mechanical transmission in case of cobbles, that is to say, when the rolled product gets blocked inside the rolling cartridge due to operation errors or to problems of various nature that can occur above all during the starting of the plant, that is to say, when the plant is in a test phase. In case of a sudden block of the stand, the mechanical transmission may undergo such high shocks as to damage some components. For this reason a joint with a device is usually introduced, set at a predetermined torque value, which is released when the safety threshold is reached disconnecting the motor from the rest of the transmission. The release device can be of various nature, such as with elements that break, with friction discs, of the hydraulic type, etc. In the prior art solutions said function is performed (FIG. 16) by the toothed joint (26). Advantageously in the solution according to the present invention the application of the safety joint is carried out in a more protected position.

(36) The present invention also relates to a rolling mill plant for the production of oblong metal products comprising at least one rolling station (20) as previously described.

(37) Furthermore, this invention relates to a rolling process for the production of oblong metal products by means of successive passages within a sequence of rolling cartridges or stands (9) of a rolling line comprising rolling stations (20) each of which is intended to house a rolling cartridge or stand (9), in which at least one rolling cartridge or stand (9) is provided with two rolling cylinders (31), a first cylinder of the two cylinders (31) being provided with at least one first semi-channel and a second cylinder of the two cylinders (31) being provided with at least one second semi-channel, the reciprocal placing side-by-side of the two cylinders (31) involving the reciprocal placing side-by-side of the at least one first semi-channel and the at least one second semi-channel which together in their side-by-side configuration form at least one rolling channel of the cartridge or stand (9) intended for the mechanical working by rolling of an oblong metal product passing in said at least one rolling channel in which the rolling process comprises at least one phase of adjustment of the rotation speed difference between the first cylinder and the second cylinder of these two cylinders (31) installed on a same rolling cartridge or stand (9), the first cylinder and the second cylinder of these two cylinders (31) being controllable in rotation in an independent way of each other by means of a pair of transmission devices of which a first transmission device (3) is intended to couple with the first rolling cylinder of the cartridge or stand (9) and a second transmission device (33) is intended to couple with the second rolling cylinder of the cartridge or stand (9), the first rolling cylinder being put in rotation by a first motor (1) by means of the first transmission device (3) and the second rolling cylinder being put in rotation by a second motor (11) by means of the second transmission device (33). Furthermore, said rotation speed difference between the first cylinder and second cylinder is controllable in a manually and/or automatically controlled way according to rolling parameters.

(38) Of course all this must be understood as further advantageous as it is well known that the wear of the materials, in particular of the opposed cylinders, occurs even if imperceptibly in a different way. Therefore, even very small variations in the diameter between the cylinders due to the natural and continuously variable wear implies different peripheral speeds, therefore by the present invention by obtaining the possibility of variation in the angular speed of a cylinder with respect to the other an extremely optimal rolling is obtained with an increase in quality, profitability and productivity.

(39) The description of the present invention has been made with reference to the enclosed figures in a preferred embodiment, but it is evident that many possible changes, modifications and variations will be immediately clear to those skilled in the art in the light of the previous description. Thus, it must be underlined that the invention is not limited to the previous description, but includes all the changes, modifications and variations in accordance with the appended claims.

(40) Nomenclature Used

(41) With reference to the identification numbers in the enclosed figures, the following nomenclature has been used: 1. First electric motor 2. First safety joint 3. Transmission device 4. Guide of the transmission 5. Locking means of the transmission 6. Supporting compensator of the transmission 7. Supporting frame of the transmissions 8. Guides of the frame 9. Rolling cartridge 10. Anchorage frame 11. Second electric motor 12. Second safety joint 13. Epicyclic reduction gear 14. Fourth self-balanced pinion 15. First crown 16. Second torque division pinion 17. First output pinion 18. Hub 19. Transmission slot 20. Rolling station 21. Second crown 22. Third torque division pinion 23. First helical gear 24. Second helical gear 25. Single motor 26. Toothed joint 27. Reducer with two output shafts 28. Adapter 29. Adapters support 30. Adjustment reducer of the cylinders 31. Cylinder 32. Foundations 33. Second transmission device 34. Guides of the stand 35. First input shaft 36. First stage 37. First planetary gear 38. First planetary-gears support 39. Second shaft 40. Second stage 41. Second planetary gear 42. Second planetary-gears support 43. Third shaft