Rolling mill for rod-shaped bodies

Abstract

A rolling mill for rolling rod-shaped bodies, defining a rolling axis and comprising a rolling train provided with at least two rolling stands (1, 2), each rolling stand (1, 2) comprising three working rollers (3, 3') arranged at 120° from one another so as to define a passage (5) for said rod-shaped bodies; wherein the rolling mill is provided with a frame (4) to contain the rolling stands (1, 2) along said rolling axis, designed so that the odd-numbered rolling stands (1) can be inserted into said frame and extracted from said frame exclusively from a first side of the rolling mill, along a direction transverse to the rolling axis, while the even-numbered rolling stands (2) can be inserted into said frame and extracted from said frame exclusively from a second side of the rolling mill, along a direction transverse to the rolling axis.

Description

[0001] P024269WO-01 -eng Notarbartolo & Gervasi S.p.A.

[0002] ROLLING MILL FOR ROD-SHAPED BODIES

[0003] ************

[0004] Field of the invention

[0005] The present invention belongs to the technical field of production, by rolling, of rodshaped products, such as rods, bars or similar products, but also of hollow tubular products, and therefore, in particular, of pipes. In particular, the present invention relates to a rolling mill for producing the aforesaid products and to a method for replacing at least one rolling stand in said rolling mill.

[0006] Background art

[0007] Various types of rolling mill are known. Among these there are, for example, the sizing mill, the stretch reducing mill, the extracting-sizing mill.

[0008] In some rolling mills, rolling can be performed by means of rolling stands with three motorized rollers, each roller being rotatable about a rotation axis and inclined by 120° with respect to the other rollers. Conventionally, one of the rollers has a horizontal rotation axis actuated by a horizontal axis adapter. The other two rollers are instead actuated by corresponding adapters, one of which is operatively installed below the support surface of the rolling stands.

[0009] There are also known rolling stands with three rollers, one of which has a horizontal rotation axis actuated by a horizontal axis adapter while the other two rollers are instead actuated by inner conical gears connecting the horizontal rotation axis of the first roller with each of the two inclined rotation axes of the other two rollers.

[0010] With this type of rolling stands, each pair of subsequent and adjacent stands comprises a stand of the "even-numbered" type and a stand of the "odd-numbered" type, in which the arrangement of the rollers of the odd-numbered stand corresponds to that of the even-numbered stand when subjected to a 180° rotation about the horizontal axis passing through the rolling center.

[0011] Disadvantageously, it has been shown that the operation of replacing the stands is particularly complex, due to the configuration of the three-roller stands conventionally used. In fact, the use of a horizontal axis roller motorized by a horizontal adapter makes it difficult to replace the stand from the rolling line. At the same time, the arrangement of the other rollers and of the related actuation adapters requires a complex support structure and an equally complex foundation system, P024269WO-01 -eng Notarbartolo & Gervasi S.p.A. below the support surface of the stands, necessary to house the motorization means of one of the adapters in the case of individually controlled rollers.

[0012] To simplify the operation of replacing the stands, rolling mills have been designed with rolling stands having three motorized rollers, each roller rotating about a rotation axis and inclined by 120° with respect to the other rollers, but with a first roller having a vertical rotation axis actuated by a vertical axis adapter, positioned above the stand. A second roller is operatively placed above a horizontal reference plane onto which the rolling axis lies; while a third roller is operatively placed below said horizontal reference plane. The adapters of the second roller and of the third roller are operatively installed below the support surface of the rolling stands.

[0013] With this type of rolling stands, instead, each pair of subsequent and adjacent stands comprises a stand of the "even-numbered" type and a stand of the "odd- numbered" type, in which the arrangement of the rollers of the odd-numbered stand corresponds to that of the even-numbered stand when subjected to a 180° rotation about the vertical axis passing through the rolling center.

[0014] However, even this last configuration of rolling stands has some disadvantages relating to the replacement of the stands.

[0015] A first disadvantage is that the insertion of all the rolling stands into the rolling mill and the extraction thereof from the rolling mill occurs, along a direction transverse to the rolling axis, only from one side of the rolling mill itself. This involves that for half of the rolling mill stands, the extraction occurs on the side opposite to that in which the corresponding vertical-axis adapter is located, whereby the release strokes of the adapters inclined with respect to the vertical direction are quite long and, in particular, the adapter on the stand extraction side requires a universal joint to ensure the degree of rotation required to reach a position of non-interference.

[0016] A second disadvantage is that, since the insertion and extraction of the rolling stands occur exclusively from a same side of the rolling mill, a longitudinal platform for the stand change is provided, laterally external to the rolling mill and parallel thereto, having a length at least double that of the length of the rolling train, since a first portion of the platform, provided with housings or stations supporting the group of new rolling stands to be inserted, is followed longitudinally by a second empty portion, provided with housings or stations to receive the respective rolling stands P024269WO-01 -eng Notarbartolo & Gervasi S.p.A. to be replaced. Therefore, the large size of the stand change area requires considerable engineering works and high capital and operating costs for the line.

[0017] A third disadvantage is that some known rolling mills, although they overcome the issue of stand locking through an axial compression (along the rolling axis), require excessive times for changing the product, since the stands cannot be unlocked and / or replaced individually and the filling of the entire rolling train, possibly with transport stands, is constantly required even where rolling would require a limited amount thereof. In solutions which instead allow the individual replacement of the rolling stands, there is a risk that, once the axial locking has been released, the extraction of the single rolling stand can generate friction with the adjacent, previous and / or subsequent stands, and therefore a displacement of the latter. To avoid this problem, US2018 / 304327A1 provides for the use of releasing thrust actuators arranged at the entry side of the rolled body in the rolling mill, and adapted to push the rolling stands one on the next one in rolling direction, in order to return the rolling stands to their original insertion position. However, this solution is complex and not always effective.

[0018] A fourth disadvantage is that the known solutions for the side locking of the rolling stands inside the rolling mill, i.e., the locking along a direction orthogonal to the rolling axis, do not ensure that the rolling position is always repetitive and never affected by the wear of the runners or of the wheels used for extracting and inserting the stands during the change procedure.

[0019] From the considerations reported above, the need emerges to create an innovative rolling mill that overcomes the aforesaid drawbacks.

[0020] Summary of the invention

[0021] It is the primary object of the present invention to provide a rolling mill in which, once the axial locking of the rolling train stands has been released, friction is automatically avoided, during the extraction of the single rolling stand, with the adjacent, previous and / or subsequent, stands, and therefore a displacement of the latter is also avoided.

[0022] It is another object of the present invention to provide a rolling mill with an extremely compact stand change area, substantially the same size as the rolling train, thus requiring less engineering works and low capital and operating costs for the line. P024269WO-01 -eng Notarbartolo & Gervasi S.p.A.

[0023] It is a further object of the present invention to provide a rolling mill with three-roller stands, having a working roller with a vertical rotation axis, capable of minimizing the release strokes of the adapters and limiting the downward rotation of the adapter on the stand exit side to a few degrees, thus allowing the use of adapters even without cardans.

[0024] It is another object of the present invention to provide a rolling mill with a more efficient side locking system of the rolling stands therein, which ensures that the rolling position is always repetitive and never affected by the wear of the runners or wheels used for extracting and inserting the stands during the change procedure.

[0025] It is a further object of the present invention to provide a more efficient method for replacing the rolling stands.

[0026] The present invention achieves at least one of such objects, and other objects which will become apparent in the light of the present description, by means of a rolling mill for rolling rod-shaped bodies, defining a rolling axis and comprising a rolling train provided with at least two rolling stands, each rolling stand comprising three working rollers arranged at 120° from one another so as to define a passage for said rod-shaped bodies; wherein said rolling stands are arranged in sequence along the rolling axis so that the respective passages are aligned to define a rolling path along said rolling axis, wherein in each of said rolling stands the rotation axis X, X’ of a working roller is vertical, wherein said rolling stands are arranged, one adjacent to the next one, along said rolling axis, and the position of the working rollers of an odd-numbered rolling stand corresponds to the position of the working rollers of the adjacent even-numbered rolling stand rotated by 180° about a vertical axis V passing through the center of said passage, wherein the odd-numbered rolling stands of said rolling stands have the working roller with a vertical rotation axis X at a first side of the rolling mill, parallel to the rolling axis, while the even-numbered rolling stands of said rolling stands have the working roller with a vertical rotation axis X’ at a second side of the rolling mill, parallel to the rolling axis and opposite to said first side, P024269WO-01 -eng Notarbartolo & Gervasi S.p.A. wherein the rolling mill is provided with a frame to contain the rolling stands along said rolling axis, designed so that the odd-numbered rolling stands can be inserted into said frame and extracted from said frame exclusively from said first side of the rolling mill, along a direction transverse to the rolling axis, while the even-numbered rolling stands can be inserted into said frame and extracted from said frame exclusively from said second side of the rolling mill, along a direction transverse to the rolling axis; wherein odd-numbered compartments for the odd-numbered rolling stands and even-numbered compartments for the even-numbered rolling stands are provided in the frame; wherein at least two thrust actuators are provided in the frame, at an exit side of a rolled body from the rolling mill, which are adapted to push the rolling stands one on the next one in a direction opposite to a rolling direction, to lock in said frame, along the rolling axis, the rolling stands against at least one fixed abutment arranged at an entry side of the body to be rolled in the rolling mill; wherein elastic means are provided in the frame, arranged between an odd- numbered compartment and an even-numbered compartment and adapted to transmit a thrust produced by said thrust actuators by transferring the thrust from one rolling stand to the next one until the entire rolling train is locked against said at least one fixed abutment; and wherein said elastic means are designed so that, once the thrust actuators are deactivated, the rolling stands return to the original insertion position thereof in the frame.

[0027] A further aspect of the invention relates to a method for replacing at least one rolling stand in the aforesaid rolling mill, wherein the odd-numbered rolling stands, having a working roller thereof with a vertical rotation axis X at a first side of the rolling mill parallel to the rolling axis, are inserted into the frame and extracted from said frame exclusively from said first side of the rolling mill; and wherein the even-numbered rolling stands, having a working roller thereof with a vertical rotation axis X’ at a second side of the rolling mill parallel to the rolling axis and opposite to said first side, are inserted into said frame and extracted from said frame exclusively from said second side of the rolling mill; P024269WO-01 -eng Notarbartolo & Gervasi S.p.A. wherein, after the insertion of the odd-numbered rolling stands in the respective odd- numbered compartments and the insertion of the even-numbered rolling stands in the respective even-numbered compartments, the at least two thrust actuators push the rolling stands one on the next one in a direction opposite to the rolling direction, to lock in said frame, along the rolling axis, the rolling stands against the at least one fixed abutment arranged at the entry side of the body to be rolled in the rolling mill, thus defining a blocking position of the rolling stands; wherein the elastic means transmit the thrust produced by said thrust actuators by transferring said thrust from one rolling stand to the next one until the entire rolling train is locked against said at least one fixed abutment; and wherein, before replacing at least one rolling stand, the thrust actuators are deactivated and the rolling stands return to the original insertion position thereof in the frame by means of said elastic means.

[0028] Further features and advantages of the invention will become more apparent in light of the detailed description of exemplary but non-exclusive embodiments.

[0029] The dependent claims describe particular embodiments of the invention.

[0030] Brief description of the Figures

[0031] In the description of the invention, reference is made to the attached drawing tables, provided by way of explanation and not of limitation, in which:

[0032] Figure 1 shows a perspective view of a rolling mill according to the invention; Figure 2 shows a side view, partially in section, of the rolling mill of Figure 1 ;

[0033] Figure 3 shows a top view of a diagram for extracting the rolling stands in a first variant of the rolling mill according to the invention;

[0034] Figure 3a shows a top view of a diagram for extracting the rolling stands in a second variant of the rolling mill according to the invention;

[0035] Figure 4 shows a side view, partially in section, of a first variant of rolling stand inside the rolling mill of Figure 1 ;

[0036] Figure 5 shows an enlargement of the lower part of Figure 4;

[0037] Figure 6 shows an enlargement of the upper part of Figure 4;

[0038] Figure 7 shows a side view, partially in section, of a second variant of rolling stand inside the rolling mill of Figure 1 ;

[0039] Figure 8 shows an enlargement of part of a further variant of rolling stand; P024269WO-01 -eng Notarbartolo & Gervasi S.p.A.

[0040] Figure 9 shows a side view of part of a system for translating a rolling stand transversely to the rolling axis;

[0041] Figure 10 shows a partial side view of the rolling mill according to the invention;

[0042] Figures 1 1 and 12 show a side view of a rolling stand compartment, respectively with adapters in the extended position, i.e., connecting with the respective rollers, and with adapters in the retracted position to allow the rolling stand to be extracted; Figure 13 shows a perspective view of a first variant of elastic means used in a rolling mill according to the invention;

[0043] Figure 14 shows a cross-section of a second variant of elastic means used in a rolling mill according to the invention;

[0044] Figure 15 shows a partial side view of a rolling mill according to the invention in which there is provided a plurality of the elastic means of Figure 14.

[0045] The same numbers and the same reference letters in the Figures identify the same elements or components.

[0046] Description of exemplary embodiments of the invention

[0047] With reference to the Figures, some examples are shown of a rolling mill for rodshaped bodies, such as rods, bars or similar products, but also hollow tubular products, and therefore, in particular, pipes. The rolling mill of the invention is a rolling mill with at least two rolling stands.

[0048] Exclusively by way of explanation, the rolling mill according to the invention can be a sizing mill, a stretch reducing mill, or an extracting-sizing mill.

[0049] In all embodiments of the invention, the rolling mill defines a rolling axis and comprises a rolling train provided with at least two rolling stands 1 , 2, each rolling stand 1 , 2 comprising three working rollers 3, 3’ arranged at 120° from one another so as to define a passage 5 for the rod-shaped body (Figure 4).

[0050] Each rolling stand 1 , 2 has a working roller 3’ having a vertical rotation axis X, X’, while the other two working rollers 3 have rotation axes inclined by +30° and -30°, respectively, with respect to a horizontal reference perpendicular to the vertical axis passing through the center of said passage 5.

[0051] The rolling stands 1 , 2 are of the type capable of withstanding the separation force thereon, i.e., the force due to rolling, without the aid of external actuators, such as, P024269WO-01 -eng Notarbartolo & Gervasi S.p.A. for example, hydraulic capsules or screwdowns. Therefore, they are rolling stands without a roller-holder cartridge.

[0052] The rolling stands 1 , 2 are arranged in sequence along the rolling axis so that the respective passages 5 are aligned to define a rolling path along said rolling axis.

[0053] In particular, the rolling stands 1 , 2 are arranged, one adjacent to the next one, along said rolling axis, and the position of the working rollers 3, 3’ of an odd-numbered rolling stand 1 corresponds to the position of the working rollers 3, 3’ of the adjacent even-numbered rolling stand 2 rotated by 180° about a vertical axis V passing through the center of said passage 5.

[0054] Therefore, the odd-numbered rolling stands 1 of said rolling stands 1 , 2 have the working roller 3’ with a vertical rotation axis X at a first side of the rolling mill, parallel to the rolling axis, while the even-numbered rolling stands 2 of said rolling stands 1 , 2 have the working roller 3’ with a vertical rotation axis X’ at a second side of the rolling mill, parallel to the rolling axis and opposite to said first side.

[0055] Advantageously, the rolling mill is provided with a frame 4, preferably a single frame, to contain the rolling stands 1 , 2 along the rolling axis, which is designed so that the odd-numbered rolling stands 1 can be inserted in the frame 4 and extracted from said frame 4 exclusively from said first side of the rolling mill, along a direction transverse to the rolling axis, while the even-numbered rolling stands 2 can be inserted into said frame 4 and extracted from said frame 4 exclusively from said second side of the rolling mill, along a direction transverse to the rolling axis. In a preferred variant, these transverse directions coincide.

[0056] In the frame 4, odd-numbered compartments for the odd-numbered rolling stands 1 and even-numbered compartments for the even-numbered rolling stands 2 are provided. In particular, the odd-numbered compartments are adapted to receive odd-numbered rolling stands 1 in an original insertion position thereof, and the even- numbered compartments are adapted to receive even-numbered rolling stands 2 in an original insertion position thereof.

[0057] The aforesaid configuration of frame and rolling stands allows, for all the stands, to minimize the release strokes of the adapters 34, 35, 36 and to limit the downward rotation of the adapter 36 on the stand exit side to a few degrees, thus ensuring the use of adapters even without a universal joint. Figures 1 1 and 12 show, for a frame P024269WO-01 -eng Notarbartolo & Gervasi S.p.A. compartment represented without a stand therein, the adapters 34, 35, 36 in the extended position, i.e., connecting the respective working rollers, and the adapters 34, 35, 36 in the retracted position, allowing the extraction of the rolling stand, respectively.

[0058] Preferably, as for example diagrammatically shown in Figure 3, the frame 4 comprises, along said first side of the rolling mill, first side openings 6 for inserting and extracting the odd-numbered rolling stands 1 , said first side openings 6 alternating with first vertical columns 7 which laterally close a compartment of respective even-numbered rolling stands 2.

[0059] Similarly, the frame 4 comprises, along said second side of the rolling mill, second side openings 8 for inserting and extracting the even-numbered rolling stands 2, said second side openings 8 alternating with second vertical columns 9 which laterally close a compartment of respective odd-numbered rolling stands 1 .

[0060] Thereby, each first side opening 6 on the first side corresponds to a second vertical column 9 on the second side, while each second side opening 8 on the second side corresponds to a first vertical column 7 on the first side.

[0061] In a variant, the frame 4 is unique for the entire rolling mill and further comprises a system of upper beams 10 and a system of lower beams 1 1 , said systems 10, 1 1 being arranged parallel to each other, perpendicular to the first vertical columns 7 and to the second vertical columns 9, and connecting both above and below said first vertical columns 7 to said second vertical columns 9.

[0062] In other words, the frame 4 for containing the rolling stands consists of the first vertical columns 7 and second vertical columns 9, arranged alternating between one stand and the other along the rolling axis, and of upper longitudinal beams 10 and lower longitudinal beams 1 1 connecting said vertical columns 7, 9 together, leaving the entry / exit slots of the stands open on the two sides, also said slots being arranged alternately along the rolling axis. This type of structure, also lightened by holes for the passage of the adapters, does not undergo high bending loads, such as, for example, in conventional rolling mills with one horizontal adapter and the other two adapters inclined by +30° and -30°, respectively, with respect to a horizontal reference, since no overhangs or suspended parts are present.

[0063] The frame 4 further comprises (Figures 1 and 10) a first end wall 42 which is P024269WO-01 -eng Notarbartolo & Gervasi S.p.A. transverse, for example orthogonal, to the rolling axis and configured for the entry of the body or product to be rolled, and a second end wall 43 which is opposite, and for example parallel, to the first end wall 42 and configured for the exit of the rolled body or product. Both end walls can be arranged perpendicular to the rolling axis, to the system of upper beamsl 0 and to the system of lower beams 11 .

[0064] The upper beams 10 and the lower beams 11 are longitudinally arranged, parallel to each other and to the rolling axis, and connect both above and below said first end wall 42 to said second end wall 43 and also said first vertical columns 7 to said second vertical columns 9.

[0065] In a further variant, not shown, the frame 4 is unique for the entire rolling train, but it is not provided with the vertical columns 7, 9 alternating between one stand and the other, along the rolling axis.

[0066] In this case, the frame 4 for containing the rolling stands comprises a first end wall 42 which is transverse, for example orthogonal, to the rolling axis and configured to allow the entry of the body to be rolled; a second end wall 43, which is opposite, and for example parallel, to the first end wall 42 and configured to allow the exit of the rolled body; a system of upper beams 10 and a system of lower beams 1 1 parallel to the rolling axis and connecting both above and below said first end wall 42 to said second end wall 43; a single first side opening, between the first end wall 42 and the second end wall 43, on said first side of the rolling mill for inserting and extracting the odd-numbered rolling stands 1 transversely to the rolling axis; and a single second side opening, between the first end wall 42 and the second end wall 43, on said second side of the rolling mill for inserting and extracting the even-numbered rolling stands 2 transversely to said rolling axis.

[0067] In a preferred embodiment of the rolling mill of the invention (Figures 1 -3a), in order to change one or more rolling stands, the following is provided:

[0068] - a first side platform 12 at said first side of the rolling mill, arranged laterally outside the frame 4 and parallel thereto, suitable for receiving at least one odd-numbered rolling stand 1 extracted from said frame 4 and for supporting at least one new odd- numbered rolling stand T to be inserted into said frame 4;

[0069] - and a second side platform 13 at said second side of the rolling mill, arranged laterally outside the frame 4 and parallel thereto, suitable for receiving at least one P024269WO-01 -eng Notarbartolo & Gervasi S.p.A. even-numbered rolling stand 2 extracted from said frame 4 and for supporting at least one new even-numbered rolling stand 2' to be inserted into said frame 4.

[0070] In a first variant, diagrammatically shown in Figure 3, the first side platform 12 is slidable parallel to the rolling axis and is provided with first empty housings 14, configured to receive a respective odd-numbered rolling stand 1 of the rolling train to be replaced, and alternating along the rolling direction with second housings 15 that support the new odd-numbered rolling stands 1 ' to be inserted into the frame 4. Each first housing 14 is adjacent to a second housing 15, whereby the first side platform 12 is configured to pass from an extraction position, in which the first empty housings 14 are at respective odd-numbered rolling stands 1 to be replaced, to an insertion position, in which the second housings 15 supporting the new odd- numbered rolling stands 1 ’ are at a respective odd-numbered compartment of the rolling train, left vacant by the corresponding odd-numbered rolling stand 1 that has just been extracted.

[0071] Similarly, the second side platform 13 is slidable parallel to the rolling axis and is provided with third housings 16, configured to receive a respective even-numbered rolling stand 2 of the rolling train to be replaced, and alternating along said rolling direction with fourth housings 17 to support the new even-numbered rolling stands 2' to be inserted into the frame 4.

[0072] Each third housing 16 is adjacent to a fourth housing 17, whereby the second side platform 13 is configured to pass from an extraction position, in which the third empty housings 16 are at respective even-numbered rolling stands 2 to be replaced, to an insertion position, in which the fourth housings 17 supporting the new even- numbered rolling stands 2’ are at a respective even-numbered compartment of the rolling train, left vacant by the corresponding even-numbered rolling stand 2 that has just been extracted.

[0073] Advantageously, to move from the extraction position to the insertion position or vice versa, each side platform 12, 13 only has to slide by a single stand step, i.e., to slide the distance between the centerline planes, transverse to the rolling axis, of two adjacent rolling stands located inside the frame 4. This allows for the creation of an extremely compact stand change area, substantially the same size as the rolling P024269WO-01 -eng Notarbartolo & Gervasi S.p.A. train, thus requiring less engineering works and low capital and operating costs for the line.

[0074] In particular, the first side platform 12 has a plurality of housings or stations 14, 15 for odd-numbered rolling stands 1 , 1 ’ equal to the total number of rolling stands 1 , 2 of the entire rolling train; while the second side platform 13 has a plurality of housings or stations 16, 17 for even-numbered rolling stands 2, 2’ equal to the total number of rolling stands 1 , 2 of said rolling train.

[0075] When it is necessary to replace one or more odd-numbered rolling stands 1 of the rolling train, one or more new spare odd-numbered rolling stands 1 ' are arranged on the first side platform 12 so that, when each first station 14 is laterally arranged at a respective odd-numbered rolling stand 1 of the train, said one or more new odd- numbered rolling stands 1 ' are in the second stations 15 at a respective even- numbered rolling stand 2 adjacent to the odd-numbered rolling stand 1 to be replaced, the first stations 14 remaining vacant at the respective odd-numbered rolling stand 1 to be replaced.

[0076] Similarly, when it is necessary to replace one or more even-numbered rolling stands 2 of the rolling train, one or more new spare even-numbered rolling stands 2' are arranged on the second side platform 13 so that, when each third station 16 is arranged laterally at a respective even-numbered rolling stand 2 of the train, said one or more new even-numbered rolling stands 2' are in the fourth stations 17 at a respective odd-numbered rolling stand 1 adjacent to the even-numbered rolling stand 2 to be replaced, the third stations 16 remaining vacant at the respective even- numbered rolling stand 2 to be replaced.

[0077] The empty space of the first stations 14 and of the third stations 16 on the two side platforms 12, 13 (Figure 3) also allows to facilitate the operations of removing and placing the stands on the relative platform by means of a span crane, also protecting the safety of the operator. Depending on the crane capacity and the required productivity, lifting devices can be provided to lift the stands individually or in groups. In a second variant, diagrammatically shown in Figure 3a, the first side platform 12 is fixed and provided with first housings 18, each first housing 18 being placed at a respective odd-numbered rolling stand 1 of the rolling train and suitable both for receiving said odd-numbered rolling stand 1 , once extracted from the frame 4, and P024269WO-01 -eng Notarbartolo & Gervasi S.p.A. for receiving a respective new odd-numbered rolling stand 1 ’ to be inserted into the frame 4, once the extracted odd-numbered rolling stand 1 has been removed from said first housing 18.

[0078] Similarly, the second side platform 13 is fixed and provided with second housings 19, each second housing 19 being at a respective even-numbered rolling stand 2 of the rolling train and suitable both for receiving said even-numbered rolling stand 2, once extracted from the frame 4, and for receiving a respective new even-numbered rolling stand 2’ to be inserted into the frame 4, once the extracted even-numbered rolling stand 2 has been removed from said second housing 19.

[0079] Preferably, at least one crane is provided, such as a span crane, for

[0080] - removing the odd-numbered rolling stands 1 from said first housings 18 which have been previously extracted from respective odd-numbered compartments of the rolling mill, and positioning the new odd-numbered rolling stands 1 ’ in said first housings 18,

[0081] - and removing the even-numbered rolling stands 2 from said second housings 19 which have been previously extracted from respective even-numbered compartments of the rolling mill, and positioning the new even-numbered rolling stands 2’ in said second housings 19.

[0082] For extracting and inserting the rolling stands in the frame 4 of the rolling mill of the invention, the following can, for example, be provided (Figures 1 -2):

[0083] - first actuators 20 at the odd-numbered compartments of the frame 4, therefore at the first side openings 6 when the vertical columns 7 are provided, for inserting and extracting the odd-numbered rolling stands, and

[0084] - second actuators 21 at the even-numbered compartments of the frame 4, therefore at the second side openings 8 when the vertical columns 9 are provided, for inserting and extracting the even-numbered rolling stands.

[0085] These actuators 20, 21 can be, for example, hydraulic or electromechanical actuators.

[0086] First actuators 20 and second actuators 21 are preferably configured to hook, individually or in a group, the respective rolling stands 1 , 2 to be extracted from the frame 4 and move them towards the relative side platform 12, 13, and configured to subsequently hook, individually or in a group, the new rolling stands 1 ’, 2’ to be P024269WO-01 -eng Notarbartolo & Gervasi S.p.A. inserted into the frame 4 and move them from the relative side platform 12, 13 towards said frame 4.

[0087] In more detail, considering the aforesaid first variant in the stand change sequence, the stand or stands to be replaced 1 , 2 are hooked and automatically dragged out of the rolling train by means of the actuator 20, 21 , associated with the stand itself, and positioned on the corresponding side platform 12, 13 in one of the respective empty stations 14, 16. Once the extraction is complete, the side platform translates by a single stand step to position the new stand or stands 1 ’, 2’ of the stations 15, 17 at the respective empty rolling compartment to be loaded. The actuator 20, 21 hooks and automatically pushes the new stand into the respective frame compartment.

[0088] Considering instead the aforesaid second variant in the stand change sequence, the stand or stands to be replaced 1 , 2 are hooked and automatically dragged out of the rolling train by means of the actuator 20, 21 , associated with the stand itself, and positioned on the corresponding side platform 12, 13 in one of the respective empty stations 18, 19. Once the extraction is completed, the extracted stand or stands are removed from the stations 18, 19, the new stand or new stands 1 ’, 2’ are again positioned in the respective stations 18, 19, and the actuator 20, 21 hooks and automatically pushes the new stand into the respective frame compartment. Figure 9 shows, as an example of an actuator 20, 21 for extracting and inserting the rolling stands into the frame 4, a carriage 37 suitable to translate in a direction transverse to the rolling axis from a first position, distal with respect to the frame 4 and placed beyond the relative platform 12, 13 (considering the rolling axis as a reference), to a second position proximal with respect to the side opening 6, 8 of the respective compartment of the frame 4.

[0089] The carriage 37, in a variant thereof, is provided with a hook 38 configured to hook a protrusion 39 provided on the vertical side of each rolling stand which is proximal to the working roller 3' thereof with a vertical rotation axis.

[0090] The tracks or runners or rails along which the rolling stands and relative carriages 37 slide are not described herein, as they are of a known type. P024269WO-01 -eng Notarbartolo & Gervasi S.p.A.

[0091] In the rolling mill of the present invention, there can be provided side locking means for the rolling stands inside the frame 4, i.e., means for locking the rolling stands transversely to the rolling axis.

[0092] Preferably, each compartment of the frame 4 is provided with at least one central abutment 22, suitable to define an end-of-stroke for the respective rolling stand during a step of insertion into the frame 4.

[0093] Said at least one central abutment 22 is positioned along a vertical plane proximal to the rolling axis, preferably positioned at a distance from the rolling axis which is shorter than the distance between a vertical plane containing the rolling axis and a vertical plane containing the vertical rotation axis X, X’ of one of the working rollers. In the example of Figures 4-7, only one central abutment 22 is visible on both the upper inner surface and the lower inner surface of the frame compartment.

[0094] It is not excluded that two or more central abutments 22 can be provided on both the upper inner surface and the lower inner surface of the compartment.

[0095] The structure of each rolling stand, for example, has a recess 40 at the top delimited by a shoulder 41 (Figure 6) to advance the stand inside the compartment until the shoulder 41 abuts against the central abutment 22.

[0096] In a first variant of the side locking means, in order to complete said side locking of the stand, each compartment of the frame 4 is further provided with (Figures 4-6):

[0097] - at least one lifting and locking actuator 23, arranged at the lower inner surface of the compartment, for lifting a corresponding rolling stand after having reached said at least one central abutment 22;

[0098] - and at least one upper abutment 24, arranged at the upper inner surface of the compartment, adapted to define a lifting end-of-stroke of the rolling stand.

[0099] The rolling stand is therefore lifted and brought in abutment on said at least one upper abutment 24 so that the rolling position is always repetitive and never affected by wear of the tracks or wheels or runners used for extracting and inserting the stands during the change procedure.

[0100] For example, two lifting and locking actuators 23 and two upper abutments 24 can be provided, which are arranged on two sides with respect to a vertical plane containing the rolling axis (Figure 4). Alternatively, four lifting and locking actuators 23 and four upper abutments 24 can be provided. P024269WO-01 -eng Notarbartolo & Gervasi S.p.A.

[0101] By way of explanation, these lifting and locking actuators 23, for example hydraulic cylinders, can be operated by a valve for each rolling stand so as to ensure better synchronization control.

[0102] Preferably, said at least one lifting and locking actuator 23 is a cylinder, for example a hydraulic cylinder, provided with a stem with a wedge-shaped end 31 (Figure 5). Each rolling stand is in turn provided in the base thereof with at least one recess 32 of a shape complementary to the wedge-shaped end 31 of a respective stem. The wedge-shaped end 31 of the stem and the corresponding recess 32 are shaped so that the reception of said wedge-shaped end 31 in the recess 32 produces, in addition to lifting, also a lateral translation of the rolling stand to keep it abutting against the at least one central abutment 22. For this purpose, an appropriate clearance exists between the width of the wedge-shaped end 31 and the width of the recess 32.

[0103] In a second variant of the side locking means, in order to complete said side locking of the stand, each compartment of the frame 4 is further provided with (Figures 7- 8):

[0104] - at least one first locking actuator 25, for example a hydraulic cylinder, arranged at the upper surface of the compartment, preferably at a corner of the compartment and inclined by an angle smaller than 90° and greater than 0°, for example 45°, with respect to a horizontal plane, to push downwards a corresponding rolling stand after having reached the at least one central abutment 22, keeping it in contact with said at least one central abutment 22;

[0105] - and preferably at least one second locking actuator 26, for example a hydraulic cylinder, arranged at a closed side surface of the compartment, i.e., the vertical column 7, 9, and suitable to act in traction on the rolling stand in the direction of insertion of the rolling stand into the frame 4 to keep it further in contact with said at least one central abutment 22.

[0106] By way of explanation, the at least one second locking actuator 26 comprises a piston or jack 27 translatable in two translation directions opposite each other along a direction perpendicular to the rolling axis, while the rolling stand comprises a seat 28 in which said piston or jack 27 is adapted to engage to pull the rolling stand against said at least one central abutment 22. The seat 28 is provided on the vertical P024269WO-01 -eng Notarbartolo & Gervasi S.p.A. side of each rolling stand which is distal from the working roller 3' thereof having the vertical rotation axis.

[0107] In this second variant, therefore, the side locking of the stands occurs without lifting them, by means of a vertical or inclined thrust exerted by the first locking actuator 25, to generate a force with at least a downward lateral component to impart the locking action against the central abutments 22.

[0108] One or two second locking actuators 26 can also be provided, for example one or two cylinders with a hammer head, also rotating, engaging the stand in the seat 28 and pulling it against the central abutments 22.

[0109] Furthermore, in the rolling mill of the present invention, there can be provided axial locking means for locking the rolling stands inside the frame 4, i.e., means for locking the rolling stands along the rolling axis.

[0110] Advantageously, as shown in Figure 10, at least two thrust actuators 29 are provided in the frame 4, at the exit side of the rolled body from the rolling mill, i.e., arranged on the second end wall 43, said thrust actuators being adapted to push the rolling stands one on the next one, preferably in a direction opposite to the rolling direction (indicated by arrow A), to lock in said frame 4 along the rolling axis the rolling stands against at least two fixed abutments 33 arranged at the entry side of the body to be rolled in the rolling mill, i.e., arranged on the first end wall 42. In particular, there can be provided three thrust actuators 29 adapted to push the rolling stands one on the next one, preferably in the direction opposite to the rolling direction, to lock in said frame 4 along the rolling axis the rolling stands against three corresponding fixed abutments 33. However, it is not excluded to provide a single fixed abutment 33.

[0111] Advantageously, elastic means 30 are provided in the frame 4, arranged between an odd-numbered compartment and an even-numbered compartment of said frame 4 and adapted to transmit the thrust produced by said thrust actuators 29 by transferring it from one rolling stand to the next one until the entire rolling train is locked against the fixed abutments 33.

[0112] Such elastic means 30 are designed so that, once the thrust actuators 29 are disabled, the rolling stands return to the original insertion position thereof in the frame 4, so that no friction is generated between adjacent rolling stands 1 , 2 during the step of extracting a rolling stand from the frame 4. P024269WO-01 -eng Notarbartolo & Gervasi S.p.A.

[0113] In particular, in a first variant, the elastic means 30 can comprise (Figures 10-13) a system of elastic plates or sheets, for example including first elastic plates or sheets fixed in a cantilever manner on the upper inner surface of the frame and second elastic plates or sheets fixed in a cantilever manner on the lower inner surface of the frame. For example, the elastic plates or sheets can be screwed onto the respective surface in a cantilevered position. As shown in Figures 11 and 12, the elastic plates or sheets, for example grouped in packs, are arranged transversely to the rolling axis, in particular on a vertical plane perpendicular to the vertical plane containing the rolling axis when they are in a rest configuration.

[0114] The thrust actuators 29, for example hydraulic cylinders, pack the rolling stands 1 , 2 from the exit side of the rolling mill towards the entry side. Each stand pushes the next one through the system of elastic plates or sheets which allow, once the axial locking is released, to extract a single stand without generating friction, and therefore without generating a displacement of the previous stand or next stand. Preferably, both said first elastic plates, or sheets, and said second elastic plates, or sheets, are respectively two plates 47, or two packs of plates, vertically projecting from the respective inner surface of the frame 4 and linked to each other by means of a horizontal shoe 48, in which said plates are inserted and fixed, and against which the rolling stands rest during the locking operation (Figure 13).

[0115] As shown in the example of Figure 13, the assembly of two first plates 47 and the first horizontal shoe 48 is fixed in a cantilever manner on the upper inner surface of the frame 4. Similarly, the assembly of two second plates 47 and the second horizontal shoe 48 is fixed in a cantilever manner on the lower inner surface of the frame 4 (not shown).

[0116] In a second variant, the elastic means 30 can comprise (Figures 14-15) a system of components 49 arranged transversely to the rolling axis, whereby, when the thrust actuators 29 are activated, each rolling stand pushes the next one through said system of components 49.

[0117] Preferably, each component 49 is composed by a fixed body 50 and a movable body 51 arranged coaxially inside the fixed body 50, protruding from both sides of said fixed body and slidable, parallel to the said rolling axis, with a predetermined stroke inside the fixed body 50; whereby, when the thrust actuators 29 are activated, P024269WO-01 -eng Notarbartolo & Gervasi S.p.A. each rolling stand pushes the next one through the movable bodies 51 of the system, resting against said movable bodies 51 during the locking operation. Once the axial locking is released, the rolling stands return to the original insertion position thereof thanks to the movable bodies 51 , allowing to extract a single stand without generating friction, and therefore without generating a displacement of the previous stand or next stand.

[0118] For example, said component 49 can be cylindrical or prismatic in shape. In particular, both said fixed body 50 and said movable body 51 can be hollow, cylindrical or prismatic in shape.

[0119] Said components 49 are arranged along a vertical plane perpendicular to the vertical plane containing the rolling axis.

[0120] In a first example (not shown), first components 49 of said system of components are fixed in a cantilever manner on an upper inner surface of the frame 4, and second components 49 of said system of components are fixed in a cantilever manner on a lower inner surface of the frame 4.

[0121] In a second example, shown in Figure 15, said components 49 are inserted directly in a wall 52 separating an odd-numbered compartment 53 from an even-numbered compartment 54. The movable bodies 51 always protrude from both sides of said wall 52.

[0122] A further variant, which is not part of the present invention and corresponds to the solution disclosed in US2018 / 0304327A1 , instead of using the aforementioned elastic means, provides for at least two auxiliary thrust actuators, arranged in the frame at the entry side of the rolled body in the rolling mill, for pushing the rolling stands onto each other in the rolling direction, causing the rolling stands to return to their original insertion position. However, this solution is less effective and more complex.

[0123] In all the embodiments of the rolling mill of the invention, for each rolling stand, a motor 44, 45, 46 and a relative transmission shaft or adapter 34, 35, 36 are provided for each working roller (Figure 2), or a single motor and relative single transmission shaft are provided for the working roller having a vertical rotation axis X, X', the other two working rollers being driven by gears inside the rolling stand (solution not shown). P024269WO-01 -eng Notarbartolo & Gervasi S.p.A.

[0124] The individual drive configuration, with upper vertical adapters 34 and inclined adapters 35, 36 on the two sides at an angle of 30° with respect to the horizontal direction, shown in Figure 2, has the advantage of simplifying maintenance and accessibility to the controls as well as significantly reducing the exposure of the lower motors 45, 46 to the cooling water.

[0125] The single drive configuration, with only upper vertical adapters, significantly reduces installation space and engineering works as well as the capital and operating costs for the line.

[0126] In general, for small and medium-sized rolling mills, the motors can be directly flanged-mounted on the gearboxes; in other cases, the motors can be of the footmounted type.

[0127] In all the embodiments of the rolling mill of the invention, the rolling stands 1 , 2 are configured so that the position of the rotation axes of the working rollers 3, 3’ can be adjusted by a few millimeters in the radial direction (with respect to the rolling axis), optionally by means of an eccentric system.

[0128] Preferably, mechanical actuation means, for example motorized means, for actuating said eccentric system are provided, which are external to some or each rolling stand and, for example, are arranged on the top, at the working roller 3' with a vertical rotation axis.

[0129] A further advantage can be obtained by providing said mechanical actuation means as remotely operatable, so as to control the position of the rotation axes of the working rollers in the radial direction even with the rolling stands inside the frame 4, and not only in the workshop.

[0130] A method is described below for replacing at least one rolling stand 1 , 2 in a rolling mill according to the invention.

[0131] Advantageously, the odd-numbered rolling stands 1 , having a working roller 3' thereof with a vertical rotation axis X at a first side of the rolling mill parallel to the rolling axis when inserted in a respective odd-numbered compartment, are inserted into the frame 4 and extracted from said frame 4 exclusively from said first side of the rolling mill; while the even-numbered rolling stands 2, having a working roller 3’ thereof with a vertical rotation axis X’ at a second side of the rolling mill parallel to the rolling axis and opposite to said first side, when inserted in a respective even- P024269WO-01 -eng Notarbartolo & Gervasi S.p.A. numbered compartment, are inserted into said frame 4 and extracted from said frame 4 exclusively from said second side of the rolling mill.

[0132] After the insertion of the odd-numbered rolling stands 1 in the respective odd- numbered compartments in the original insertion position thereof and the insertion of the even-numbered rolling stands 2 in the respective even-numbered compartments in the original insertion position thereof, the at least two thrust actuators 29 push the rolling stands one on the next one in a direction opposite to the rolling direction, to lock in the frame 4, along the rolling axis, the rolling stands against the at least one fixed abutment 33 arranged at the entry side of the body to be rolled in the rolling mill, thus defining a blocking position of the rolling stands.

[0133] Advantageously, the elastic means 30 transmit the thrust produced by said thrust actuators 29 by transferring said thrust from one rolling stand to the next one until the entire rolling train is locked against said at least one fixed abutment 33. Before replacing at least one rolling stand, the thrust actuators 29 are deactivated and the rolling stands return to the original insertion position thereof in the frame 4 by means of said elastic means 30.

[0134] Considering the variant of the rolling mill with the side platforms 12, 13, sliding parallel to the rolling axis, the first side platform 12 slides by a single stand step, passing

[0135] - from an extraction position (Figure 3), in which the first housings 14 are at a respective odd-numbered compartment of the rolling train while the second housings 15 are at a respective even-numbered compartment of said rolling train,

[0136] - to an insertion position in which the second housings 15 are at a respective odd- numbered compartment while the first housings 14 are at a respective even- numbered compartment, and vice versa.

[0137] In the extraction position of said first side platform 12, the first housings 14, which are empty, receive respective odd-numbered rolling stands 1 to be replaced, extracted from the respective odd-numbered compartment, while in the insertion position new odd-numbered rolling stands 1 ’ supported by the second housings 15 are inserted into the respective odd-numbered compartment, left vacant by the corresponding odd-numbered rolling stand 1 previously extracted. P024269WO-01 -eng Notarbartolo & Gervasi S.p.A.

[0138] Similarly, the second side platform 13 slides by a single stand step, passing

[0139] - from an extraction position, in which the third housings 16 are at a respective even- numbered compartment while the fourth housings 17 are at a respective odd- numbered compartment,

[0140] - to an insertion position in which the fourth housings 17 are at a respective even- numbered compartment while the third housings 16 are at a respective odd- numbered compartment.

[0141] In the extraction position of said second side platform 13, the third housings 16 receive respective even-numbered rolling stands 2 to be replaced, extracted from the respective even-numbered compartment, while in the insertion position new even-numbered rolling stands 2' supported by the fourth housings 17 are inserted into the respective even-numbered compartment, left vacant by the corresponding even-numbered rolling stand 2 previously extracted.

[0142] More in detail, to replace at least one odd-numbered rolling stand 1 of the rolling train, the following steps are provided:

[0143] - providing the first side platform 12 in the extraction position with the first empty housings 14 and with at least some second housings 15 provided with new odd- numbered rolling stands 1 ’;

[0144] - extracting, from the respective odd-numbered compartment of the frame 4, the odd-numbered rolling stands 1 to be replaced and receiving them in the respective first housing 14;

[0145] - sliding, by a single stand step, the first side platform 12 to pass from the extraction position to the insertion position;

[0146] - inserting the new odd-numbered rolling stands 1 ’ present in the second housings 15 in the respective odd-numbered compartment.

[0147] Similarly, to replace at least one even-numbered rolling stand 2 of the rolling train, the following steps are provided:

[0148] - providing the second side platform 13 in the extraction position with the third empty housings 16 and with at least some fourth housings 17 provided with new even- numbered rolling stands 2’; P024269WO-01 -eng Notarbartolo & Gervasi S.p.A.

[0149] - extracting, from the respective even-numbered compartment of the frame 4, the even-numbered rolling stands 2 to be replaced and receiving them in the respective third housing 16;

[0150] - sliding, by a single stand step, the second side platform 13 to pass from the extraction position to the insertion position;

[0151] - inserting the new even-numbered rolling stands 2’ present in the fourth housings 17 in the respective even-numbered compartment.

[0152] Instead, considering the variant of the rolling mill with the fixed side platforms 12, 13, to replace at least one odd-numbered rolling stand 1 of the rolling train the following steps are provided:

[0153] - extracting, from the respective odd-numbered compartment, the odd-numbered rolling stands 1 to be replaced and receiving them in the respective first housing 18;

[0154] - removing the odd-numbered rolling stand 1 from the respective first housing 18, preferably by means of a crane;

[0155] - receiving, in the respective first housing 18, corresponding new odd-numbered rolling stands 1 ’, preferably by means of a crane;

[0156] - inserting said new odd-numbered rolling stands 1 ’ into the respective odd- numbered compartment.

[0157] Similarly, to replace at least one even-numbered rolling stand 2 of the rolling train, the following steps are provided:

[0158] - extracting, from the respective even-numbered compartment, the even-numbered rolling stands 2 to be replaced and receiving them in the respective second housing 19;

[0159] - removing the even-numbered rolling stands 2 from the respective second housing 19, preferably by means of a crane;

[0160] - receiving, in the respective second housing 19, corresponding new even- numbered rolling stands 2’, preferably by means of a crane;

[0161] - inserting said new even-numbered rolling stands 2’ into the respective even- numbered compartment.

Claims

P024269WO-01 -eng Notarbartolo & Gervasi S.p.A.CLAIMS1 . A rolling mill for rolling rod-shaped bodies, defining a rolling axis and comprising a rolling train provided with at least two rolling stands (1 , 2), each rolling stand (1 , 2) comprising three working rollers (3, 3’) arranged at 120° from one another so as to define a passage (5) for said rod-shaped bodies; wherein said rolling stands (1 , 2) are arranged in sequence along the rolling axis so that the respective passages (5) are aligned to define a rolling path along said rolling axis, wherein in each of said rolling stands (1 , 2) the rotation axis (X, X’) of a working roller (3’) is vertical, wherein said rolling stands (1 , 2) are arranged, one adjacent to the next one, along said rolling axis, and the position of the working rollers (3, 3’) of an odd-numbered rolling stand (1 ) corresponds to the position of the working rollers (3, 3’) of the adjacent even-numbered rolling stand (2) rotated by 180° about a vertical axis (V) passing through the center of said passage (5), wherein the odd-numbered rolling stands (1 ) of said rolling stands (1 , 2) have the working roller (3’) with a vertical rotation axis (X) at a first side of the rolling mill, parallel to the rolling axis, while the even-numbered rolling stands (2) of said rolling stands (1 , 2) have the working roller (3’) with a vertical rotation axis (X’) at a second side of the rolling mill, parallel to the rolling axis and opposite to said first side, wherein the rolling mill is provided with a frame (4) to contain the rolling stands (1 , 2) along said rolling axis, designed so that the odd-numbered rolling stands (1 ) are inserted into said frame and extracted from said frame exclusively from said first side of the rolling mill, along a direction transverse to the rolling axis, while the even- numbered rolling stands (2) are inserted into said frame and extracted from said frame exclusively from said second side of the rolling mill, along a direction transverse to the rolling axis; wherein odd-numbered compartments for the odd-numbered rolling stands (1 ) and even-numbered compartments for the even-numbered rolling stands (2) are provided in the frame (4);24P024269WO-01 -eng Notarbartolo & Gervasi S.p.A. wherein at least two thrust actuators (29) are provided in the frame (4), at an exit side of a rolled body from the rolling mill, which are adapted to push the rolling stands one on the next one in a direction opposite to a rolling direction, to lock in said frame (4), along the rolling axis, the rolling stands against at least one fixed abutment (33) arranged at an entry side of the body to be rolled in the rolling mill; wherein elastic means (30) are provided in the frame (4), arranged between an odd- numbered compartment and an even-numbered compartment and adapted to transmit a thrust produced by said thrust actuators (29) by transferring it from one rolling stand to the next one until the entire rolling train is locked against said at least one fixed abutment (33); and wherein said elastic means (30) are designed so that, once the thrust actuators (29) are deactivated, the rolling stands return to the original insertion position thereof in the frame (4).

2. A rolling mill according to claim 1 , wherein said frame (4) comprises, along said first side, first side openings (6), for inserting and extracting said odd-numbered rolling stands (1 ) in / from the respective odd-numbered compartments, which alternate with first vertical columns (7) that laterally close a respective even- numbered compartment, and wherein said frame (4) comprises, along said second side, second side openings (8), for inserting and extracting said even-numbered rolling stands (2) in / from the respective even-numbered compartments, which alternate with second vertical columns (9) that laterally close a respective odd-numbered compartment, whereby each first side opening (6) on the first side corresponds to a second vertical column (9) on the second side, while each second side opening (8) on the second side corresponds to a first vertical column (7) on the first side.

3. A rolling mill according to claim 2, wherein said frame further comprises a first end wall (42) transverse to the rolling axis and configured to allow the entry of the body to be rolled; a second end wall (43), opposite to the first end wall (42) and configured to allow the exit of the rolled body; a system of upper beams (10) and a system of lower beams (11 ) parallel to each other and to the rolling axis and connecting, both above and below, said first end wall (42) to said second end wall (43) and said first vertical columns (7) to said second vertical columns (9).P024269WO-01 -eng Notarbartolo & Gervasi S.p.A.

4. A rolling mill according to claim 1 , wherein said frame (4) comprises a first end wall (42) transverse to the rolling axis and configured to allow the entry of the body to be rolled; a second end wall (43) opposite to the first end wall (42) and configured to allow the exit of the rolled body; a system of upper beams (10) and a system of lower beams (1 1 ) parallel to each other and to the rolling axis and connecting, both above and below, said first end wall (42) to said second end wall (43); wherein a single first side opening is provided, between the first end wall (42) and the second end wall (43), on said first side of the rolling mill to insert and extract said odd- numbered rolling stands (1 ); and wherein a single second side opening is provided, between the first end wall (42) and the second end wall (43), on said second side of the rolling mill to insert and extract said even-numbered rolling stands (2).

5. A rolling mill according to any one of the preceding claims, wherein a first side platform (12) is provided at said first side of the rolling mill, arranged laterally outside the rolling train and parallel thereto, suitable for receiving at least one odd-numbered rolling stand (1 ) extracted from said frame (4) and for supporting at least one new odd-numbered rolling stand (1 ') to be inserted into said frame (4); and wherein a second side platform (13) is provided at said second side of the rolling mill, arranged laterally outside the rolling train and parallel thereto, suitable for receiving at least one even-numbered rolling stand (2) extracted from said frame (4) and for supporting at least one new even-numbered rolling stand (2') to be inserted into said frame (4).

6. A rolling mill according to claim 5, wherein said first side platform (12) is slidable parallel to the rolling axis and is provided with first housings (14), configured to receive respective odd-numbered rolling stands (1 ) of the rolling train to be replaced, alternating along said rolling direction with second housings (15) configured to support the new odd-numbered rolling stands (T); wherein each first housing (14) is adjacent to a second housing (15); whereby the first side platform (12) is configured to pass from an extraction position, in which the first empty housings (14) are at respective odd-numbered rolling stands (1 ) to be replaced, to an insertion position, in which the second housings (15) supporting the new odd-numbered rolling stands (1 ’) are at a respective odd-P024269WO-01 -eng Notarbartolo & Gervasi S.p.A. numbered compartment of the rolling train, left vacant by the corresponding odd- numbered rolling stand (1 ) that has been extracted; and wherein said second side platform (13) is slidable parallel to the rolling axis and is provided with third housings (16), configured to receive respective even- numbered rolling stands (2) of the rolling train to be replaced, alternating along said rolling direction with fourth housings (17) to support the new even-numbered rolling stands (2’); wherein each third housing (16) is adjacent to a fourth housing (17); whereby the second side platform (13) is configured to pass from an extraction position, in which the third empty housings (16) are at respective even-numbered rolling stands (2) to be replaced, to an insertion position, in which the fourth housings (17) supporting the new even-numbered rolling stands (2’) are at a respective even- numbered compartment of the rolling train, left vacant by the corresponding even- numbered rolling stand (2) that has been extracted.

7. A rolling mill according to claim 5, wherein said first side platform (12) is fixed and provided with first housings (18), each first housing (18) being placed at a respective odd-numbered rolling stand (1 ) of the rolling train and suitable both for receiving said odd-numbered rolling stand (1 ), once extracted from the frame, and for receiving a respective new odd-numbered rolling stand (1 ’) to be inserted into the frame, once the extracted odd-numbered rolling stand (1 ) has been removed from said first housing (18); and wherein said second side platform (13) is fixed and provided with second housings (19), each second housing (19) being at a respective even-numbered rolling stand (2) of the rolling train and suitable both for receiving said even- numbered rolling stand (2), once extracted from the frame, and for receiving a respective new even-numbered rolling stand (2’) to be inserted into the frame, once the extracted even-numbered rolling stand (2) has been removed from said second housing (19); preferably wherein at least one crane is provided for removing the extracted odd- numbered rolling stands (1 ) from said first housings (18) and positioning the new odd-numbered rolling stands (1 ’) in said first housings (18), and for removing the27P024269WO-01 -eng Notarbartolo & Gervasi S.p.A. extracted even-numbered rolling stands (2) from said second housings (19) and positioning the new even-numbered rolling stands (2’) in said second housings (19).

8. A rolling mill according to any one of claims 2 to 7, wherein the following is provided- first actuators (20) at odd-numbered compartments of the frame (4) for inserting and extracting the odd-numbered rolling stands, and- second actuators (21 ) at even-numbered compartments of the frame (4) for inserting and extracting the even-numbered rolling stands.

9. A rolling mill according to claim 8, wherein said first actuators (20) and said second actuators (21 ) are actuators, preferably hydraulic or electromechanical actuators, configured to hook, individually or in a group, the rolling stands (1 , 2) to be extracted from the frame (4) and move them towards the relative side platform (12, 13), and configured to hook, individually or in a group, the new rolling stands (1 ’, 2’) to be inserted into the frame (4) and move them from the relative side platform (12, 13) towards said frame (4).

10. A rolling mill according to any one of the preceding claims, wherein odd- numbered compartments for the odd-numbered rolling stands and even-numbered compartments for the even-numbered rolling stands are provided in the frame (4); preferably wherein each compartment is provided with at least one central abutment (22), adapted to define a stroke end for the respective rolling stand during a step of insertion into the frame (4); wherein said at least one central abutment (22) is positioned along a vertical plane proximal to the rolling axis, preferably positioned at a distance from the rolling axis which is shorter than the distance between a vertical plane containing the rolling axis and a vertical plane containing the vertical rotation axis (X, X’) of one of the working rollers.1 1 . A rolling mill according to claim 10, wherein each compartment is provided with:- at least one lifting and locking actuator (23), arranged at the lower inner surface of the compartment, for lifting a corresponding rolling stand after having reached said at least one central abutment (22);- and at least one upper abutment (24), arranged at the upper surface of the compartment, adapted to define a lifting end-of-stroke of the rolling stand.28P024269WO-01 -eng Notarbartolo & Gervasi S.p.A.

12. A rolling mill according to claim 11 , wherein said at least one lifting actuator (23) is a cylinder provided with a stem with a wedge-shaped end (31 ), and wherein the rolling stand is provided, in the base thereof, with at least one recess (32) with a shape complementary to the wedge-shaped end (31 ) of a respective stem so as to receive said wedge-shaped end (31 ) thus generating, in addition to the lifting, also a lateral translation of the rolling stand to keep it abutting against said at least one central abutment (22).

13. A rolling mill according to claim 10, wherein each compartment is provided with at least one first locking actuator (25), arranged at the upper surface of the compartment and preferably inclined at an angle smaller than 90° and greater than 0° with respect to a horizontal plane, to push downwards a corresponding rolling stand after having reached the at least one central abutment (22), keeping it abutting against said at least one central abutment (22); preferably, wherein each compartment is further provided with at least one second locking actuator (26), arranged at a respective vertical column (7, 9) and adapted to act in traction on the rolling stand in the direction of insertion of said rolling stand into the frame (4) to further keep it abutting against said at least one central abutment (22); preferably, wherein said second locking actuator (26) comprises a piston or jack (27) translatable in two translation directions opposite to each other along a direction perpendicular to the rolling axis, and wherein the rolling stand comprises a seat (28) in which said piston or jack is adapted to engage to pull the rolling stand against said at least one central abutment (22).

14. A rolling mill according to any one of the preceding claims, wherein said elastic means (30) comprise a system of elastic plates or sheets, preferably grouped in packs, arranged transversely to the rolling axis, whereby, when the thrust actuators (29) are activated, each rolling stand pushes the next one through said system of elastic plates or sheets; preferably wherein said elastic plates or sheets are arranged, in a rest configuration thereof, along a vertical plane perpendicular to the vertical plane containing the rolling axis;29P024269WO-01 -eng Notarbartolo & Gervasi S.p.A. preferably wherein first elastic plates or sheets of said system of elastic plates or sheets are fixed in a cantilever manner on an upper inner surface of the frame (4), and second elastic plates or sheets of said system of elastic plates or sheets are fixed in a cantilever manner on a lower inner surface of the frame (4).

15. A rolling mill according to claim 14, wherein both said first elastic plates and said second elastic plates are respectively two plates (47), or two packs of plates, vertically projecting from the respective inner surface of the frame (4) and linked to each other by means of a horizontal shoe (48) against which the rolling stands rest during the locking operation; preferably wherein the assembly of said two plates (47) and said sliding shoe (48) is fixed in a cantilever manner on the respective inner surface of the frame (4).

16. A rolling mill according to any one of the claims from 1 to 13, wherein said elastic means (30) comprise a system of components (49) arranged transversely to the rolling axis, whereby, when the thrust actuators (29) are activated, each rolling stand pushes the next one through said system of components (49); wherein each component (49) is composed by a fixed body (50) and a movable body (51 ) arranged coaxially inside the fixed body (50), protruding from both sides of said fixed body and slidable, parallel to said rolling axis, with a predetermined stroke inside the fixed body (50); whereby, when the thrust actuators (29) are activated, each rolling stand pushes the next one through the movable bodies (51 ) of the system, resting against said movable bodies (51 ) during the locking operation; preferably wherein said components (49) are arranged along a vertical plane perpendicular to the vertical plane containing the rolling axis.

17. A rolling mill according to claim 16, wherein first components (49) of said system of components are fixed in a cantilever manner on an upper inner surface of the frame (4), and second components (49) of said system of sliding components are fixed in a cantilever manner on a lower inner surface of the frame (4); or wherein said components (49) are inserted directly in a wall (52) separating an odd- numbered compartment (53) from an even-numbered compartment (54).

18. A method for replacing at least one rolling stand (1 , 2) in a rolling mill according to any one of the preceding claims, wherein the odd-numbered rolling stands (1 ), having a working roller (3') thereof with a vertical rotation axis (X) at a first side of30P024269WO-01 -eng Notarbartolo & Gervasi S.p.A. the rolling mill parallel to the rolling axis, are inserted into the frame (4) and extracted from said frame (4) exclusively from said first side of the rolling mill; and wherein the even-numbered rolling stands (2), having a working roller (3’) thereof with a vertical rotation axis (X’) at a second side of the rolling mill parallel to the rolling axis and opposite to said first side, are inserted into said frame (4) and extracted from said frame (4), exclusively from said second side of the rolling mill; wherein the at least two thrust actuators (29) push the rolling stands one on the next one in a direction opposite to the rolling direction, to lock in said frame (4), along the rolling axis, the rolling stands against the at least one fixed abutment (33) arranged at the entry side of the body to be rolled in the rolling mill, thus defining a blocking position of the rolling stands; wherein the elastic means (30) transmit the thrust produced by said thrust actuators (29) by transferring said thrust from one rolling stand to the next one until the entire rolling train is locked against said at least one fixed abutment (33); and wherein, when the thrust actuators (29) are deactivated, the rolling stands return to the original insertion position thereof in the frame (4) by means of said elastic means (30).

19. A method according to claim 18, wherein a first side platform (12) is provided, arranged at said first side of the rolling mill outside the rolling train and provided with first housings (14) alternating with second housings (15) along said rolling direction; wherein each first housing (14) is adjacent to a second housing (15); and wherein a second side platform (13) is provided, arranged at said second side of the rolling mill outside the rolling train and provided with third housings (16) alternating with fourth housings (17) along said rolling direction; wherein each third housing (16) is adjacent to a fourth housing (17); wherein said first side platform (12) slides parallel to the rolling axis by a single stand step, passing from an extraction position, in which the first housings (14) are at a respective odd-numbered compartment of the rolling train while the second housings (15) are at a respective even-numbered compartment of said rolling train, to an insertion position, in which the second housings (15) are at a respective odd- numbered compartment while the first housings (14) are at a respective even- numbered compartment;31P024269WO-01 -eng Notarbartolo & Gervasi S.p.A. wherein, in the extraction position of said first side platform (12), the first housings (14) receive respective odd-numbered rolling stands (1 ) to be replaced, extracted from the respective odd-numbered compartment, while in said insertion position new odd-numbered rolling stands (1 ’) supported by the second housings (15) are inserted into the respective odd-numbered compartment, left vacant by the corresponding odd-numbered rolling stand (1 ) previously extracted; and wherein said second side platform (13) slides parallel to the rolling axis by a single stand step, passing from an extraction position, in which the third housings(16) are at a respective even-numbered compartment while the fourth housings (17) are at a respective odd-numbered compartment, to an insertion position, in which the fourth housings (17) are at a respective even-numbered compartment while the third housings (16) are at a respective odd-numbered compartment; wherein, in the extraction position of said second side platform (13), the third housings (16) receive respective even-numbered rolling stands (2) to be replaced, extracted from the respective even-numbered compartment, while in said insertion position new even-numbered rolling stands (2') supported by the fourth housings(17) are inserted into the respective even-numbered compartment, left vacant by the corresponding even-numbered rolling stand (2) previously extracted.

20. A method according to claim 18, wherein a first fixed side platform (12) is provided, arranged at said first side of the rolling mill outside the rolling train and provided with first housings (18) at respective odd-numbered compartments of the rolling train; wherein a second fixed side platform (13) is provided, arranged at said second side of the rolling mill outside the rolling train and provided with second housings (19) at respective even-numbered compartments of the rolling train; wherein, to replace at least one odd-numbered rolling stand (1 ) of the rolling train, the following steps are provided:- extracting, from a respective odd-numbered compartment, the at least one odd- numbered rolling stand (1 ) to be replaced and receiving it in the respective first housing (18);- removing said at least one odd-numbered rolling stand (1 ) from the respective first housing (18), preferably by means of a crane;32P024269WO-01 -eng Notarbartolo & Gervasi S.p.A.- receiving, in the respective first housing (18), at least one respective new odd- numbered rolling stand (1 ’), preferably by means of a crane;- inserting said at least one respective new odd-numbered rolling stand (1 ’) into the respective odd-numbered compartment; and wherein, to replace at least one even-numbered rolling stand (2) of the rolling train, the following steps are provided:- extracting, from a respective even-numbered compartment, the at least one even- numbered rolling stand (2) to be replaced and receiving it in the respective second housing (19); - removing said at least one even-numbered rolling stand (2) from the respective second housing (19), preferably by means of a crane;- receiving, in the respective second housing (19), at least one respective new even- numbered rolling stand (2’), preferably by means of a crane;- inserting said at least one respective new even-numbered rolling stand (2’) into the respective even-numbered compartment.33

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