Device and method for guiding and directing a metal sheet in a curving calender

Abstract

Herein described is a device (1; 1') and a method for guiding and directing a metal sheet (2) curving calender (3) for continuously forming a frustoconical structure. The device (1; 1') comprises resting and contrasting means (4; 4') supported by a support unit (6; 6) and adapted to restingly receive a longitudinal edge (5) of the metal sheet (2) and contrasting a movement of the edge (5) in a direction which is transverse to an advancement trajectory (T) of the metal sheet (2) so as to determine a continuous rotation of the metal sheet. The resting and contrasting means comprise rolling elements (4; 4') arranged to roll along the edge (5) upon the movement of the metal sheet (2) along the advancement trajectory (T). The resting and contrasting means provide for a pair of rolling elements (4; 4') that are rotatably free to roll along the edge (5) upon the movement of the metal sheet (2) along the advancement trajectory (T), the support body (6, 6') being freely oscillatable around an axis (S3; S3') so as to allow an orientation of the rolling elements (4; 4') so as to maintain the latter in contact with the edge (5).

Description

DEVICE AND METHOD FOR GUIDING AND DIRECTING A METAL SHEET IN A CURVING CALENDERBackground of the invention

[0001] The present invention relates to the field of metal sheets curving calenders and more particularly it relates to a device and a method for guiding and directing the metal sheet through a curving calender, for continuously forming frustoconical structures.State of the art

[0002] As known, in order to obtain frustoconical structures (or simply "conical", as conventionally referred to in the industry), a metal sheet is subjected to a curving operation using special roller calenders.

[0003] In order to obtain a truncated cone section, the metal sheet must be cut into an appropriate shape with internal and external longitudinal edges provided with an appropriate curvature.

[0004] The curved sides correspond to the two bases of the final truncated cone, and the mutually inclined straight sides are designed to be longitudinally joined and mutually welded so as to form an apothem with it and complete the truncated cone.

[0005] The metal sheet is driven by the rotation of the rollers of the calender and, at the end of the curving in the calender, it is closed on itself so as to take the desired truncated cone shape.

[0006] In order for the metal sheet to be curved correctly in the frustoconical shape, it has to precisely pass through a pre-established trajectory, besides being curved driven and bent by the rollers of the calender, also rotating continuously around a determined rotation centre.

[0007] In order to impart the rotation to the advancing metal sheet, there is currently used pivot or wheel element, positioned in the calender, between the rollers thereof, on which there rests the internal curved concave edge of the advancing metal sheet.

[0008] The metal sheet, drawn by the action of the calender orthogonally to the rollers, presses with the internal curved edge thereof on such wheel or pivot element, which acts as a rotation fulcrum for the metal sheet.

[0009] Clearly, being very localised, the pressing forces that the edge and the pivot or wheel element exchange are significant and this may unfortunately damage the edge.

[0010] Other prior art systems provide for the use of guide slide, still within the calender, between the rollers thereof, on which there rests and relatively slides the internal curved edge of the metal sheet. In this case, although on the one hand there is attained a more extensive contact area between the slide and the edge of the sheet, there is also a relative slidingbetween them which not only complicates the process due to the sliding frictions which occur but once again risk to irremediably damage the geometry of the edge. Furthermore, the invariable geometric shape of the guide slide does not ensure the attainment of an extensive area of contact when processing metal sheets with different curving values, therefore this raising the problems relating to concentration of stresses addressed above regarding the pivot devices.

[0011] As mentioned, when forming the conical or frustoconical structure, the metal sheet being processed must be oriented with respect to the calender so that the generatrixes of the cone are parallel to the longitudinal axes of the curving rollers.

[0012] Due to the strong frictions that are generated between the metal sheet and parts of the devices and / or due to their positioning in an area inside the calender, the prior art devices very frequently cause a displacement of the metal sheet along the longitudinal axis of the rollers therefore losing the correct orientation of the metal sheet with respect to the curving rollers. Therefore, in order to appropriately direct the metal sheet, one is forced to carry out numerous, extremely complex, difficult, long, and expensive (and on large cones like the wind energy ones which are also dangerous for the safety of the operator) continuous repositioning of the metal sheet to recover the correct geometric orientation thereof.In order to overcome drawbacks outlined above, the proprietor under this document proposed an innovative solution even considering the fact that it is “outside” the calender, which operates upstream with respect thereto, and which guides the metal sheet “before” the latter enters between the rollers of the calender, with a positive arm which also reduces the load on the edge of the sheet, disclosed in EP3638432B1, which allows to guide the metal sheet in a faster, safer, and more efficient manner, particularly aims at maintaining the geometry of chamfered edges of the metal sheet and ensure high levels of safety to which the operators are subjected.

[0013] However, for the construction of significantly large frustoconical structures, such as for example the ones used for marine foundations of wind energy towers, there are used metal sheets having thicknesses that may range between 50 mm and 150 mm and above of thickness and lengths of the longitudinal edges of the order of tens of metres. Such metal sheets for example for foundations, being processed would exert on the prior art guide devices pressure values that are so high that they would damage them irremediably. This forces to waive the use of guide devices in favour of bending equipment other than the calender. In addition, this equipment is often cumbersome and difficult to handle, with abending process that is extremely complex, difficult, long and also dangerous in terms of safety of the operators who perform them. Furthermore, the solution disclosed in EP3638432B1- which envisages the use of resting and contrasting means movable along a closed path - may be not cost-effective due to the structural complexity that a dimensioning appropriate to a metal sheets with high thickness as indicated above would involve, making the device of EP3638432B1 significantly large, making it almost unusable.

[0014] Therefore, there is large room for improvement in the guide systems for curving metal sheets for obtaining conical structures and the need to identify an effective technical solution, that is sustainable both in terms of dimensions and cost-effectiveness for processing significantly large metal sheets.Objects of the invention

[0015] An object of the invention is to provide a technical solution that allows to simplify the device in terms of construction and make it useable in terms of size in a calender, while simultaneously improving the resistance thereof to stresses and operating versatility, for example upon the variation of the geometry of the sheet to be processed; in particular, an object is to provide a device that can adapt to the curvature of the longitudinal edges of the sheet.

[0016] A further object of the invention is to provide a device that is capable of guiding a metal sheet so as to evenly distribute the stresses imparted by the sheet being processed to the device.

[0017] A further object of the invention is to improve the current guide devices of the metal sheet and provide a technical solution which, while being cost-effective, allows to process significantly large metal sheets effectively and precisely.

[0018] Another object of the invention is to obtain a conical curving process that is continuous, easy and effective, protecting the shape of the edge against deformations.

[0019] A further object is to improve the geometric precision and the processing tolerances.Summary of the invention

[0020] These and other objects are attained by a system as defined by the attached claims.

[0021] In particular, thanks to the invention, the metal sheet is driven to rotate continuously while it advances without excessive concentrated loads or unwanted sliding actions which would irremediably damage the edge of the metal sheet jeopardising its subsequent use, being generated thereon.

[0022] Furthermore, the invention allows to maintain continuous contact between the guide device and the edge of the metal sheet so that the metal sheet follows the pre-established advancement trajectory without generating off-tolerance defects or imprecisions in the bent metal sheet.

[0023] Further characteristics and advantages will be apparent from the dependent claims and from the description.Brief description of the drawings

[0024] The invention will be clearer and implemented with reference to the attached drawings, which show some exemplifying and non-limiting embodiments thereof, wherein: Figure 1 is a perspective view of a device for continuously guiding and directing a metal sheet in a curving calender according to a first embodiment;Figure 1 A is a top view of the device according to a second embodiment of the invention;Figure 2 is a perspective view of the device of Figure 1, operating on a metal sheet shown schematically;Figure 3 is a lateral elevational view of the calender on which the device according to the invention is fitted;Figure 4 is a top view of the device according to the invention with some parts removed to show the others better;Figure 5 is an interrupted lateral view of the device of Figure 1;Figure 6 is a perspective view of a part of the device of Figure 1 comprising rolling elements held by a portion of a support unit;Figure 7 is a front elevational view of the part of the device of Figure 6;Figure 8 is a section taken along the plane VIII- VIII of Figure 7;Figure 9 is a section taken along the plane IX-IX of Figure 7;Figure 10 is a section taken along the plane X- X in Figure 7;Figure 11 is a top view of the part of device represented in Figure 6 in which the concealed portions of the support unit were indicated with a dashed line;Figure 12 is a schematic lateral partial section - passing through a rotation axis of a rolling element - which shows a cylindrical rolling element of the device according to the invention associated with a chamfered edge of the metal sheet;Figure 13 is a section like that of Figure 12 in which a reel rolling element of the device according to the invention is associated with a second chamfered edge;Figure 14 is a section like that of Figure 12 in which a reel rolling element of the deviceaccording to the invention is associated with a third chamfered edge.Detailed description

[0025] With reference to Figures 1, 1A, 2 and 3, there is shown a device 1, 1’ according to the invention appropriate to be fitted on a curving calender 3 for processing metal products, in particular for curving metal sheets 2. The curving calender 3 may be provided with two or more (for example from 2 to 4) curving rollers 3b.

[0026] The device 1, 1’ is used to direct and guide a metal sheet 2, in particular a sheet 2 having curved longitudinal edges, in the curving calender 3 for obtaining a conical structure through a continuous curving process. Such conical structure comprises, in particular and by way of non-limiting example, a frustoconical structure designed to be used in the wind energy industry, such as a conical part of a foundation structure of a wind energy tower or of a conical part of a wind energy tower.

[0027] The device 1, 1’ may be fitted on a structure of the curving calender 3 or on a support plane 3a for supporting and advancing the metal sheet 2, for example a support plane of the roller unit type or on another support arranged upstream of the curving rollers 3b of the calender 3. Additionally, or alternatively, the device 1, 1’ may be fitted on support means other than the calender 3. For example, the device 1, 1’ may be fitted on a support connected to a floor or to the ground.

[0028] In the embodiment of the curving calender 3 shown in Figure 3, there is provided for a first device 1, 1’ arranged on a side of the curving calender 3. The device 1 , 1’ is configured to be fitted in an area outside the processing (curving) area occupied by the curving rollers 3b of the calender 3. Precisely, the device 1, 1’ is configured to be positioned upstream of said processing area - with respect to the advancement trajectory of the metal sheet. In an embodiment, the device 1, 1’ is arranged upstream, in the proximity of the curving rollers 3b. This first device is positioned so as to lie on the internal curved edge of the metal sheet 2.

[0029] Additionally to the first device 1, 1’, in order to guide the metal sheet more precisely during the continuous rotation thereof during the advancement and / or distribute the load more evenly on the edge of the metal sheet, there may be provided for a second device positioned upstream of the first device (in an area farther from the processing area) and configured, in particular, to lie on the internal edge of the sheet 2; such second device may be smaller than the first device given that - being farther from the calender 3 - it is subjected to support a lower processing force.

[0030] Furthermore, there may be provided for a further device (positioned on the opposite side with respect to the first and the second device) which can be positioned to interact with an outer curved edge of the metal sheet 2 to assist the first and the second device in guiding and directing the metal sheet 2 even more precisely.

[0031] It cannot be ruled out that one or more devices 1, 1’ can be fitted in one or more different positions, upstream and / or downstream, of the rollers 3b mentioned above, or even in a position aligned with the rollers 3b, that is on the plane coplanar to the axes of such rollers, in proximity of a head area of such rollers 3b.

[0032] The device 1, 1’ comprises a support unit 6, 6’ adapted to be fitted on a structure of the calender 3, and resting and contrasting means 4, 4’ supported by the support unit 6 and adapted to restingly receive an longitudinal curved edge 5 of the metal sheet 2 and contrast a movement of the edge 5 exerting an action in a direction that is transverse with respect to a pre-established advancement trajectory T of the metal sheet 2, the movement being generated by the curving rollers 3b of the calender 3 and orthogonal thereto. In other words, the movement of the transversal edge 5 to be contrasted through the resting and contrasting means 4, 4’ is driven by the curving rollers 3b and it is substantially orthogonal with respect to the rotation axes of the curving rollers 3b. In particular, such movement is substantially orthogonal to a rotation axis of an upper curving roller positioned above the metal sheet 2 being processed during the operation.

[0033] In the event of a continuous conical curving operation, the advancement trajectory T is a curved trajectory. The resting and contrasting means 4, 4’ are configured to continuously guide the metal sheet 2 during the advancement thereof along an advancement trajectory T. In particular, the resting and contrasting means 4, 4’ are configured to allow the rotation of a metal sheet 2 around a curving axis oriented depending on the inclination of the generatrix of the conical structure to be obtained.

[0034] The resting and contrasting means comprise rolling elements 4a, 4b, 4c, 4d that are rotatably free to roll along the edge 5 upon the movement of the metal sheet 2 along the advancement trajectory T. The support unit 6, 6’ is freely tiltable around an axis S3, S3’ (Figures 1A, 4, 7 and 11).

[0035] In the embodiment shown in Figures, 1, 2-14 (first embodiment), the resting and contrasting means 4 comprise a first pair of rolling elements 4a, 4b rotatably supported by a first support part 6a and at least one second pair of rolling elements 4c, 4d rotatably supported by a respective second support part 6b. However, there may be provided for alarger number of pairs of suitably sized rolling elements.

[0036] The rolling elements 4a, 4b, 4c, 4d are arranged to roll along the edge 5 upon the movement of the metal sheet 2 along the advancement trajectory T.

[0037] The first support part 6a and the second support part 6b are supported in a freely oscillatable manner by a base part 6c of the support unit 6 so as to allow an orientation of the resting and contrasting means 4 (that of the pairs of rolling elements 4a, 4b, 4c 4d) such to keep the latter in contact with the edge 5 of the metal sheet 2 adapting to the longitudinal curved profile of the edge 5 and exerting a load distributed on the edge 5. In this embodiment shown in Figures 1, 2-14, the support unit 6 comprises the first support part 6a, the second support part 6b and the base part 6c.

[0038] With reference to the embodiment of the device indicated with reference numeral 1’ (second embodiment), there may be provided for a single pair of rolling elements (Figure 1A).

[0039] Furthermore, two (or more) devices 1 ’ (each comprising a single pair of rollers) may be arranged close to each other - along the advancement direction of the metal sheet - so as to provide for four (or more) approached resting points for the metal sheet 2.

[0040] Furthermore, the support unit 6 may comprise a connection part 6d in particular configured to support the base part 6c in a freely oscillating manner so as to contribute to the orientation of the resting and contrasting means 4.

[0041] The rolling elements 4a, 4b, 4c, 4d are freely rotatable around respective rotation axes Rl, R2, R3, R4 which are parallel to each other. Such rolling elements 4a, 4b, 4c, 4d may be mutually positioned so as to define respective external contact surfaces distributed and arranged to roll (without sliding) in contact with the edge 5.

[0042] In the first shown embodiment, there are provided for four rolling elements 4a, 4b, 4c, 4d divided into two pairs of rolling elements.

[0043] In an alternative embodiment of the device not shown, there may be provided for three pairs, or four pairs, or an even larger number of pairs. Providing for multiple rolling elements in contact with the edge 5 of the metal sheet 2 allows a distribution of the force exerted by the metal sheet during the advancement thereof and simultaneous rotation rolling on each of the rolling elements reducing a concentration effect of the stresses both on the edge of the metal sheet and on the contact surface / s of the device.

[0044] As mentioned, in the second shown embodiment (Figure 1 A), there are provided for two rolling elements in a single pair.

[0045] Each of the rolling elements, 4b, 4c, 4d in particular comprises a roller element having an outer contact surface for the edge 5 which is substantially cylindrical.

[0046] The outer contact surface may be cylindrical (Figures 1, 2, 4, 6, 7, 8, 9, 10, 11 and 12). In other words, the rolling elements 4a, 4b, 4c, 4d are provided with a cylindrical contact surface and they may be used to support metal sheets with relatively high thickness of the edge, for example in a range comprised between 50 and 120 mm. As a matter of fact, in such metal sheets with relatively high thickness, the rounding on the edges of the metal sheet due to the chamfering may extend for a relatively small height of the thickness of the sheet, (for example for an overall vertical extension of the rounding smaller than half of the thickness of the metal sheet). As a result, the edge of the metal sheet, which has taken a substantially vertical arrangement (that is substantially orthogonal to the advancement trajectory T) following the chamfering, may resist to a force exerted on the contact surface through a relatively large edge surface, reducing a concentration effect of the stresses and therefore the risk of damaging or deforming the edge.

[0047] With this type of edges, such as the first edge 5a (Figure 12) there may be associated a device 1, 1 ’ provided with rolling elements with cylindrical outer contact surface.

[0048] The device 1, 1’ may also be used for processing (that is for curving) metal sheets 2 from the edges 5b, 5c made thinner by the chamfering, where the rounding on the edge of the metal sheet due to a chamfering processing are generally more extensive. In particular, for this type of metal sheets with relatively thin edge (or however in the presence of an extensive chamfered edge) each of the rolling elements of the device may be conformed with a shaped profile (“reel-like”) adapted to be engaged with a conjugate caulking profile for the base 5. The shaped profile is conformed to allow to distribute the contact between the edge of the metal sheet and the rolling element also, or only, on an inclined area of such shaped profile, reducing the concentration of the stresses in the edge and the resulting deformations or damage.

[0049] In particular, there may be provided for a shaped profile 4a’ provided with a circumferential groove and conformed to house a metal sheet 2 having a conjugated profiled 5b in which the vertical portion of the edge 5 is extended for a height smaller than half of the total thickness of the sheet 2 (Figure 13), or a further shaped profile 5c in which the edge 5 does not provide for a vertical portion (that is a chamfered edge for the entire thickness of the metal sheet 2, up to reaching to “zero” - in a condition referred to as “X-shaped chamfer”).

[0050] The first support part 6a and the second support part 6b may be respectively pivoted on a first oscillation axis SI and on a second oscillation axis S2. The first oscillation axis SI and the second oscillation axis S2 may be parallel to each other.

[0051] The base part 6c may be pivoted on a third oscillation axis S3 parallel both to the first oscillation axis SI and to the second oscillation axis S2.

[0052] With reference to Figures 7, 12 and 13, in the shown embodiment, there are provided for rotatable support pivots - at the rotation axes Rl, R2, R3, R4 mentioned above - which are coupled with clearance to the rolling elements and fixedly to the respective support parts so as to allow the rolling elements to freely rotate upon the contact action of the edge when the sheet 2 proceeds in the advancement trajectory T.

[0053] Furthermore, there are provided for swinging support pivots (Figure 9) - at the oscillation axes SI and S2 - which are fixedly coupled to the base part 6c and with clearance to the respective support parts so as to allow the independent and free oscillation of the support parts (and therefore of the pairs of rolling elements) with respect to the base part 6d. Similarly, a further swinging support pivots, provided for at the third oscillation axis S3, is fixedly connected to the connection part 6d and with clearance to the base part 6c so as to allow an oscillation (which is limited angularly as described below) of the latter with respect to the base part 6c.

[0054] Each support part 6a, 6b of the support unit 6 comprises at least two mutually parallel and spaced apart plate-shaped portions (along a vertical direction); each pair of rolling elements 4a, 4b, 4c, 4d is fitted in a position interposed between the respective plate-shaped portions (therefore forming two stacked structures).

[0055] Similarly, the base part 6c comprises at least two further mutually parallel and spaced apart plate-shaped portions; each support part 6a, 6b is fitted in a position interposed between the two further plate-shaped portions. In other words, the base part 6c forms a stacked structure together with the two support parts 6a, 6b, in which the first support part 6a and the second support part 6b are arranged one adjacent to the other so as to be substantially aligned along a direction parallel to the advancement direction of the metal sheet 2.

[0056] The connection part comprises a fork element 6d in particular configured to be coupled on opposite sides with the further plate-shaped portions of the base part 6c.

[0057] The connection part 6d (or equivalently the fork element) is supported by a slide unit 6f slidable - transversely to the advancement trajectory T of the metal sheet 2 - on a guide element 8a appropriate to be fitted to the structure of the calender 3. In the shownembodiment, the guide element 8a is part of a frame 8 of the device configured to be fixed to the structure of the calender 3, in particular to the support plane 3a. In an alternative embodiment not shown, the guide element may be fixed on the side of the calender. In a further embodiment not shown, the guide element may be provided for on a support fixed to the floor.

[0058] The device 1 may comprise an actuator device 7 in particular configured to move the support unit 6 and support a thrust of the edge 5 transversely to the advancement trajectory T. The actuator device 7 is provided with a projectable end, or stem 7a, which is movable transversely to the advancement trajectory T and it is coupled to the connection part 6d.

[0059] The device 1 may further comprise oscillation limitation means (not shown) in particular configured to limit an oscillating movement of the base part 6c with respect to the connection part 6d and therefore allow a directed guide of the metal sheet 2 along the advancement trajectory T. Such oscillation limitation means may in particular comprise two mechanical stops.

[0060] The described device 1 is used to implement a method for guiding and directing a metal sheet 2 in a curving calender 3 for continuously forming a conical structure, in particular a frustoconical structure.

[0061] The method comprises the steps of: providing for rolling elements 4a, 4b, 4c, 4d comprising a first pair of rolling elements 4a, 4b rotatably supported by a first support part 6a, and at least one second pair of rolling elements 4c, 4d rotatably supported by a respective second support part 6b, the first support part 6a and the second support part 6b being supported in a freely oscillating manner by a base part 6c; carrying a longitudinal edge 5 of the metal sheet 2 restingly on the rolling elements 4a, 4b, 4c, 4d; contrasting a movement of the edge 5 in a direction that is transverse to the advancement trajectory T of the sheet 2 through the resting and contrast action of the rolling elements 4a, 4b, 4c, 4d, the movement being generated by curving rollers 3b of the calender 3 and being orthogonal with respect to rotation axes of said rotation axes curving rollers 3b; running the edge 5 of the metal sheet 2 on the freely rotatable rolling elements 4, 4’ during the advancement of the metal sheet 2 along the advancement trajectory T;continuously guiding the metal 2 through the rolling elements 4a, 4b, 4c, 4d during the advancement of said metal sheet 2 along the advancement trajectory T; and allowing the oscillation of the first support part 6a, and the oscillation of the second support part 6b so as to allow said rolling elements 4a, 4b, 4c, 4d to be oriented and maintain a contact with the edge 5 adapting to the longitudinal curved profile of the edge 5 and exerting a load distributed on the edge 5.

[0062] In the light of the above, the device and method according to the present invention allow to overcome the limits and drawbacks of the devices and methods of the prior art, successfully attaining the pre-established objects.

[0063] The specific swinging configuration of the resting and contrasting means 4, 4’ allows to continuously guide the metal sheet so as to evenly distribute on each rolling element 4a, 4b, 4c, 4d the stresses imparted by the metal sheet 2 being processed by the device 1, 1’.

[0064] In particular, the configuration of the resting and contrasting means 4, 4’ and of the support unit 6, 6’, enables the metal sheet 2 to be driven to rotate while continuously advancing without excessive concentrated loads or unwanted sliding actions which would irremediably damage the edge 5 of the metal sheet 2 jeopardising its subsequent use, being generated thereon.

[0065] Furthermore, the use of easily available components, such as plate-like elements and rolling rollers, allows to constructively simplify the device with respect to those of the prior art reducing the dimensions thereof making it efficiently usable on the calenders, while simultaneously reducing the manufacturing costs of the device.

[0066] Owing to the possibility of the support unit 6, 6’ to take various geometric configurations, particularly thanks to the freely oscillating connections of the various parts 6a, 6b, 6c, 6d which form the support unit 6, 6’ allows to obtain a device 1 that is versatile in the operation, for example upon the variation of the geometry of the metal sheet 2 to be processed; in particular there may be provided for a device 1 capable of adapting to the curving (for example at different curvature radii) of the longitudinal edge of the metal sheet 2.

[0067] Therefore, the device and the method described allow to attain a conical curving process that is continuous, quick, easy and efficient, protecting the shape of the edge 5 of the metal sheet 2 and the resting and contrasting means 4, 4’ of the device 1, 1’ from damage and deformations.

[0068] The device according to the present invention is a technical solution that is simultaneously relatively small in size to make it adapted to be used effectively upstream of a calender, cost-effective and capable of processing significantly large metal sheets effectively and precisely.

Claims

CLAIMS1. Device (1) for guiding and directing a metal sheet (2) in a curving calender (3) for continuously forming a conical structure, in particular a frustoconical structure, said device (1) comprising: a support unit (6) suitable for being fitted to a structure of said calender (3), or to support means distinct from said calender (3) in a region upstream of curving rollers (3b) of said calender (3), and resting and contrasting means (4) supported by said support unit (6) and suitable for restingly receiving a curved longitudinal edge (5) of said metal sheet (2) and contrasting a movement of said edge (5) exerting an action in a direction which is transverse with respect to a pre-established advancement trajectory (T) of said metal sheet (2), said movement being generated by said curving rollers (3b) and being orthogonal with respect to the rotation axes of said curving rollers (3b), said resting and contrasting means (4) being configured to continuously guide said metal sheet (2) during the advancement of said metal sheet (2) along said advancement trajectory (T), said support unit (6) being freely oscillatable around an axis (S3), characterised in that said resting and contrasting means (4) comprise a first pair of rolling elements (4a, 4b) supported rotatably free by a first support part (6a), and at least one second pair of rolling elements (4c, 4d) supported rotatably free by a respective second support part (6b), said rolling elements (4a, 4b, 4c, 4d) being arranged to roll along said edge (5) upon the movement of said metal sheet (2) along said advancement trajectory (T), said first support part (6a) and said second support part (6b) being supported in a freely oscillatable manner by a base part (6c) of said support unit (6) so as to enable an orientation of said rolling elements (4a, 4b, 4c, 4d) such to maintain the latter in contact with said edge (5) adapting to the longitudinal curved profile of said edge (5) and exerting a load distributed on said edge (5).

2. Device (1) according to claim 1, wherein said support unit (6) comprises a connection part (6d) configured to support said base part (6c) in a freely oscillating manner so as to contribute to said orientation of said resting and contrasting means (4).

3. Device (1) according to claim 1 or 2, wherein said rolling elements (4a, 4b, 4c, 4d) of said first pair of rolling elements (4a, 4b) and of said second pair of rolling elements (4c, 4d) are freely rotatable around respective rotation axes (Rl, Rl, R2, R3) parallelto each other and they are mutually positioned so as to define respective external contact surfaces of said rolling elements (4a, 4b, 4c, 4d) distributed and arranged to roll in contact with said edge (5).

4. Device (1) according to any one of claims 1 to 3, wherein said first support part (6a) is hinged on a first oscillation axis (SI) and said second part of support (6b) is hinged on a second oscillation axis (S2), said first oscillation axis (SI) and said second oscillation axis (S2) being parallel to each other.

5. Device (1) according to claim 4, wherein said base part (6c) is hinged on a third oscillation axis (S3) parallel to said first oscillation axis (SI) and to said second oscillation axis (S2).

6. Device (1) according to claim 4 or 5 as claim 4 is appended to claim 3, wherein said first oscillation axis (SI) and said second oscillation axis (S2) are parallel to said rotation axes (Rl, R2, R3, R4) of said rolling elements (4a, 4b, 4c, 4d).

7. Device (1) according to any one of claims 1 to 6, wherein each support part (6a, 6b) comprises at least two mutually parallel and spaced apart plate-shaped portions, and wherein each pair of rolling elements (4a, 4b, 4c, 4d) is fitted in a position interposed between the respective plate-shaped portions.

8. Device (1) according to claim 2 or according to any one of claims 3 to 7 as appended to claim 3, wherein said base part (6c) comprises at least two further mutually parallel and spaced apart plate-shaped portions, wherein said connection part comprises a fork element (6d) configured to be coupled on opposite sides with said further plate-shaped portions of the base part (6c), and wherein each support part (6a, 6b) is fitted in a position interposed between said two further plate-shaped portions, said first support part (6a) and said second support part (6b) being arranged alongside one another so as to be substantially aligned along a direction parallel to the advancement direction of said metal sheet (2).

9. Device (1) according to claim 2 or according to any one of claims 3 to 8 as appended to claim 3, wherein said connection part (6d) is supported by a slide unit (6f), said slide unit (6f) being slidable on a guide element (8a) so as to be movable transversely to said advancement trajectory (T) of said metal sheet (2), said guide element (8a) being suitable for being fitted to said structure of said calender (3).

10. Device (1) according to any one of claims 1 to 9, comprising an actuator device (7) configured to move said support unit (6) and support a thrust of said edge (5)transversely to said advancement trajectory (T), said actuator device (7) being provided with a projectable end (7a) movable transversely to said advancement trajectory (T) and coupled with said connection part (6d).

11. Device (1) according to any one of the preceding claims, wherein each of said elements (4a, 4b, 4c, 4d) comprises a roller element having an outer contact surface for said edge (5) that is substantially cylindrical.

12. Device (1) according to any one of the preceding claims, wherein each of said rolling elements (4a, 4b, 4c, 4d) has a shaped profile that is suitable for being engaged with a conjugate caulking profile for said edge (5).

13. Curving calender (3) for processing a metal sheet (2) for continuously forming a conical structure, in particular a frustoconical structure, said curving calender (3) comprising a support plane (3a) for supporting and advancing said metal sheet (2) along said advancement trajectory (T), a series of curving rollers (3b), and at least one device (1) according to one of the preceding claims.

14. Curving calender (3) according to claim 13, comprising a first device (1) provided for adjacent to said support plane (3a) and positioned upstream of and near said curving rollers (3b), and a second device (1) positioned upstream of said first device, with respect to said advancement trajectory (T).

15. Method for guiding and directing a metal sheet (2) in a curving calender (3) for continuously forming a conical structure, in particular a frustoconical structure, the method comprising the following steps: provide for rolling elements (4a, 4b, 4c, 4d) comprising a first pair of rolling elements (4a, 4b) rotatably supported by a first support part (6a), and at least one second pair of rolling elements (4c, 4d) rotatably supported by a respective second support part (6b), said first support part (6a) and said second support part (6b) being supported in a freely oscillating manner by a base part (6c), taking a curved longitudinal edge (5) of said sheet (2) to rest on said rolling elements (4a, 4b, 4c, 4d), contrasting a movement of said edge (5), in a direction that is transverse to a pre-established advancement trajectory (T) of said metal sheet (2) through the resting and contrast action exerted by said rolling elements (4a, 4b, 4c, 4d), said movement being generated by curving rollers (3b) of the calender(3) and being orthogonal with respect to the rotation axes of said curving rollers (3b), running the edge of said metal sheet (2) on said freely rotatable rolling elements (4a, 4b, 4c, 4d), during the advancement of said metal sheet (2) along said advancement trajectory (T), continuously guiding said metal sheet (2) through said rolling elements (4a, 4b, 4c, 4d) during the advancement of said metal sheet (2) along said advancement trajectory (T), allowing the oscillation of said first support part (6a) and the oscillation of said second support part (6b) so as to allow said rolling elements (4a, 4b, 4c, 4d) to be oriented and maintain a contact with said edge (5) adapting to the longitudinal curved profile of said edge (5) and exerting a load distributed on said edge (5).

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