Roll bending machine

Abstract

A roll bending machine (1) for metal plates and / or sheets comprises an upper bending roll (2) and two side bending roll (3); a supporting structure (5) to support opposite ends (2a, 2b, 3a, 3b) of upper and side bending rolls; moving means (6) to move the upper bending roll (2) and / or the side bending rolls (3) and adjust their position and / or orientation; the moving means (6) comprises for each bending roll (2, 3) a linear moving unit (10, 40) that includes a hydraulic cylinder (11, 11') having a piston (12) provided with a rod (13) connected to and acting on an end of the bending roll (2, 3), a hydraulic pump (15) to supply the hydraulic cylinder (11, 11') with pressurized hydraulic fluid and driven by a rotary electric motor (16), a tank (17) for said hydraulic fluid and a hydraulic circuit (20) provided with ducts (21-25) and valves (26-30) to connect hydraulic cylinder (11, 11'), hydraulic pump (15) and tank (17).

Description

[0001] Roll bending machine

[0002] The invention relates to machines for bending and / or curving metal plates and sheets and in particular to a roll bending machine, commonly referred to as a calender.

[0003] Roll bending machines or calender machines comprise a plurality of rotating bending rolls or cylinders, typically three or four, through which a plate or sheet of generally metallic material to be suitably bent, in particular to be curved, is passed. Typically the bending rolls are arranged with respective longitudinal rotation axes parallel to each other and in such a way that a product, plate or sheet, passing through them according to an advancement direction that is orthogonal to the said rotation axes, is generally bent with a set radius of curvature (for example to form a cylindrical element).

[0004] The three-roll bending machines comprise an upper roll and two side bending rolls arranged below and to the sides of the upper roll. The latter is motorized, that is, driven in rotation during the bending process by a suitable driving unit so as to exert a torque suitable for dragging and bending the plate. The side rolls can be idle, i.e. free to rotate about the respective rotation axes, or they can also be motorized by respective driving units.

[0005] The vertical position of the upper roll and / or the positions of the side rolls can be adjusted in order to change the mutual distances between said rolls according to the size and / or thickness of the plate or sheet and the bending / curving to be carried out.

[0006] The four-roll bending machines comprise an upper roll, an underlying lower roll and two side rolls, all rotating about their respective longitudinal rotation axes parallel to each other. The upper and lower rolls are motorized and allow the plate or sheet to be gripped or “pinched” when moved along the advancement direction, while the side rolls keep the plate or sheet square, i.e. they support the sheet or plate at the bottom and guide it in a controlled manner as it enters and leaves the upper and lower rollers. The latter ones are generally rotated by separate and respective driving units so as to exert corresponding bending torques on the plate or sheet. The side rolls are idle, i.e. free to rotate about their respective rotation axes.

[0007] The lower roll can be moved vertically towards / away from the upper roll, whose position is instead generally fixed. The side rolls can be moved with respect to the upper and lower rolls, along an inclined direction or according to an arcuate trajectory. The positions of the lower roll and the side rolls are adjusted according to size and / or thickness of the plate or sheet and the bending / curving to be carried out thereon. In both types of bending machines, with three or four rolls, in order to rotate the bending rolls and / or move them to adjust their position, hydraulic actuators are used that can provide the high torques and / or compression / traction forces necessary to bend and curve plates and sheets that can have high thicknesses and dimensions.

[0008] In particular, hydraulic rotary motors are used to rotate the motorized rolls about their respective longitudinal rotation axes, while hydraulic cylinders or jacks are used to linearly move the rolls so as to adjust their position relative to one another.

[0009] A hydraulic cylinder is also used to rotate and disengage a supporting element (yoke) from one end of the upper roll to allow the curved product to be laterally removed from the bending machine.

[0010] Consequently, the known roll bending machines include a hydraulic system suitable to supply and control the rotary motors and hydraulic cylinders. Such a hydraulic system typically comprises one or more hydraulic pumps operated by respective rotary electric motors provided with speed reducers, a tank for the hydraulic fluid, a plurality of valves for controlling the flow of hydraulic fluid under pressure to and from the actuators and a hydraulic circuit formed by a plurality of ducts and pipes adapted to connect and convey the high-pressure hydraulic fluid from the pump to the actuators and vice versa.

[0011] A disadvantage of such known roll bending machines is that the respective hydraulic systems are rather complex and expensive and require large electric motors and pumps in order to be able to supply the plurality of hydraulic actuators. In addition, the size of the hydraulic circuit connecting all the actuators requires a large amount of hydraulic fluid.

[0012] The hydraulic system is also complex to install and adjust and is quite cumbersome.

[0013] Finally, due to the power of the electric motor or motors required to drive the large hydraulic pump(s), hydraulic systems of this type consume a lot of energy even when only one hydraulic actuator has to be operated.

[0014] It is an object of the present invention to improve the known roll bending machines, in particular of the three or four roll type, suitable for bending and / or curving metal sheets and plates.

[0015] Another object is to provide a roll bending machine capable of bending and curving plates and sheets with great precision and accuracy and which at the same time allows a significant reduction in the energy consumption required for its operation.

[0016] Another object is to provide abending machine that is easy to assemble and mount, equipped with a modular and simplified hydraulic system.

[0017] These and further objects are achieved by a roll bending machine according to one or more of the claims set out below.

[0018] The invention can be better understood and implemented with reference to the attached drawings which show exemplary and non-limiting embodiments, wherein: figure 1 is a perspective view of the roll bending machine of the invention of the four- roll or bending cylinder type, showing in particular a first side of the bending machine; figure 2 is another perspective view of the roll bending machine of figure 1, showing in particular a second opposite side of the bending machine; figure 3 is a front view of the bending machine of figure 1; figure 4 is a projection view of the first side of the bending machine of figure 1; figure 5 is a projection view of the second side of the bending machine of figure 2; figure 6 is a hydraulic diagram of a first linear moving unit of the bending machine of the invention; figures 7 and 8 are perspective views from respective opposite sides of a three-roll type roll bending machine of the invention; figures 9 and 10 are perspective views from respective opposite sides of a variant of the roll bending machine of the invention of the three-roll type.

[0019] With reference to figure 1, a roll bending machine 1 according to the invention is shown, suitable for bending and / or curving metal plates and / or sheets, of the so-called four-roll type and comprising an upper bending roll or cylinder 2, two side bending rolls or cylinders 3, the latter ones positioned on both sides of the upper roll 2, and a lower bending roll 4 positioned under the upper roll 2 and between the side rolls 3. The upper roll 2, lower roll 4 and side rolls 3 are mounted rotatably about respective longitudinal and parallel rotation axes XI, X2, X3. In particular, the upper roll 2 is rotatable about a first rotation axis XI, the side rolls 3 are rotatable about respective second rotation axes X2 and the lower roll 4 is rotatable about a third rotation axis X3.

[0020] The machine 1 also comprises a supporting structure 5 configured to support respective opposite ends 2a, 2b, 3a, 3b, 4a, 4b of upper roll 2, lower roll 4 and side rolls 3 and moving means 6 associated with said supporting structure 5 and configured to move the lower roll 4 and the side rolls 3 in order to adjust their position and / or orientation with respect to the upper roll 2. In particular, the moving means 6 comprise for each roll 3, 4 two first linear moving units 10 acting on the respective ends 3a, 3b, 4a, 4b of the roll.

[0021] With reference to the embodiment of the four-roll bending machine of figures 1 to 5, the moving means 6 comprise two first linear moving units 10 associated with each side roll 3 to move the latter along an arcuate trajectory so as to approach and lift it or move it away and lower it with respect to the upper 2 and lower 4 rolls.

[0022] The moving means 6 further comprise at least a second linear moving unit 40 acting on the lower roll 4 to move the latter linearly, in particular vertically, so as to lift it and bring it closer to the upper roll 2 or lower it and move it away from the upper roll 2. In particular, the second linear moving unit 40 acts on the ends 4a, 4b of the lower roll 4 by means of suitable transmission mechanisms, of known type and not illustrated in the figures.

[0023] Alternatively, in a variant of the bending machine 1 not illustrated in the figures, the moving means 6 may comprise a pair of second linear moving units 40 each acting on a respective end 4a, 4b of the lower roll 4.

[0024] With particular reference to the hydraulic diagram of figure 6, each linear moving unit 10, 40, in particular of the electro-hydraulic type, includes a hydraulic cylinder or jack 11, I T, a hydraulic pump 15 to supply pressurized hydraulic fluid, for example oil, the hydraulic cylinder 11, I T, a rotary electric motor 16 arranged to drive the hydraulic pump 15 and a tank 17 of the hydraulic fluid.

[0025] It should be noted that the first and second linear moving units 10, 40 differ from each other only in the dimensions of the hydraulic cylinder, since the hydraulic cylinder I T of the second linear moving unit 40 must be able to exert on the lower roll 4 very high compression / traction forces, greater than those required to move the side rolls 3.

[0026] Each cylinder 11, 11' comprises a piston 12 provided with a rod 13 connected to and acting on a respective end of a bending roll. The piston 12 forms inside a casing 14 of the hydraulic cylinder 11, 1 T a first chamber 18 and a second chamber 19 fed by the pump 15.

[0027] Each linear moving unit 10, 40 further includes a respective hydraulic circuit 20 provided with ducts 21-25 and valves 26-30 for connecting the hydraulic cylinder 11, 11', the pump 15 and the tank 17 in flow connection.

[0028] The hydraulic pump 15, of known type and not described in further detail, is of a reversible type that is suitable for pumping pressurized hydraulic fluid selectively into the first chamber 18 or into the second chamber 19 of the hydraulic cylinder 11, I T so as to allow the controlled moving of the piston 12 in the two opposite directions or linear moving directions. The hydraulic pump 15 comprises for this purpose two supply / suction ports 31, 32 each of which is connected to a respective chamber 18, 19 of the hydraulic cylinder 11, 1 T by means of a first duct 21 and a second duct 22 of the hydraulic circuit 20, respectively. In particular, a first supply / suction port 31 is connected by means of the first duct 21 to the first chamber

[0029] 18 of the cylinder 11, I T not crossed by the rod 13 of the piston 12, while a second supply / suction port 32 is connected by means of the second duct 22 to the second chamber

[0030] 19 of the cylinder 11, I T crossed by the rod 13 of the piston 12.

[0031] Each supply / suction port 31, 32 of the hydraulic pump 15 is also connected to the tank 17 by means of a respective third duct 23 and a respective fourth duct 24 of the hydraulic circuit 20.

[0032] The hydraulic circuit 20 also comprises two check valves 26, each of which is inserted in a respective third duct 23 to allow the hydraulic fluid to flow only from the tank 17 to the pump 15 (under suction), and two relief valves 27, each of which is inserted in a respective fourth duct 24 to allow the hydraulic fluid to flow only from the pump 15 to the tank 17 upon reaching a defined pressure (maximum pressure) at the respective port 31, 32 of the pump 15, thus ensuring that in the hydraulic circuit 20 the pressure does not exceed a set maximum value.

[0033] A filter 33 is inserted in a common end section of the two third ducts 23 to filter any impurities present in the hydraulic fluid sucked from the tank 17.

[0034] The hydraulic circuit 20 also comprises a first sequence valve 28 and a second sequence valve 29 inserted respectively in the first duct 21 and in the second duct 22. More precisely, the first sequence valve 28 is interposed in the first duct 21 between the first chamber 18 of the cylinder 11, I T and the pump 15 and is configured to allow the hydraulic fluid to flow freely from the pump 15 to the first chamber 18 and the hydraulic fluid to flow from the first chamber 18 to the pump 15 only when the pressure in the first chamber 18 is substantially equal to the pressure in the second duct 22, downstream and almost at the second supply / suction port 32 of the pump 15. Similarly, the second sequence valve 29 is interposed in the second duct 22 between the second chamber 19 of the cylinder 11, I T and the pump 15 and is configured to allow the hydraulic fluid to flow freely from the pump 15 to the second chamber 19 and the hydraulic fluid to flow from the second chamber 19 to the pump 15 only when the pressure in the second chamber 19 is substantially equal to the pressure in the first duct 21, downstream and almost at the first supply / suction port 31 of the pump 15. The hydraulic circuit 20 also includes a discharge valve 30 inserted in a fifth duct 25 that connects the first duct 21 to the tank 17, and in particular put in flow connection a section of the first duct 21, which is interposed between the pump 15 and the first sequence valve 28, with a section of a fourth duct 24 located downstream of the respective relief valve 27. The discharge valve 30 can be selectively operated to open or close the fifth duct 25 and thus to allow or prevent the hydraulic fluid flowing from the first duct 21 to the tank 17.

[0035] The discharge valve 30 is for example a hydraulic valve of the known type, a two-way two- position electrically operated valve.

[0036] The hydraulic circuit 20 further comprises two pressure sensors 34 positioned respectively on the first duct 21, near the first chamber 18 of the cylinder 11, I T and on the second duct 22, near the second chamber 19 of the cylinder 11, I T. The two sensors 34 are connected to a control unit 50 of the bending machine 1 to transmit to the control unit values of the pressure inside the two chambers of the cylinder so as to feedback-control the cylinder 11 and adjust a force exerted by the roll on the sheet or plate to be bent.

[0037] The supporting structure 5, of known type and therefore not described in detail, comprises a first portion 51 and a second portion 52 parallel to each other and spaced apart which support the opposite ends of the bending rolls. The first portion 51 and the second portion 52 are connected and linked to each other by a base 53.

[0038] The supporting structure 5 further comprises a supporting element 54, so-called yoke, configured to rotatably support a respective end 2a of the upper roll 2 in an operating position W. The supporting element 54, of known type, is rotatably fixed about an oscillation axis Y, in particular it is rotatably coupled to the second portion 52 of the supporting structure 5 so as to be rotatable between the operating position W, in which it is engaged and supports the end 2a of the upper roll 2, and a non-operating position, not illustrated in the figures, in which said supporting element 54 is disengaged from the respective end 2a of the upper roll 2, in particular to allow a curved product, i.e. a plate or sheet, to be laterally removed from the bending machine.

[0039] The oscillation axis Y is almost horizontal and orthogonal to rotation axes XI, X2, X3 of bending rolls.

[0040] The moving means 6 are configured to rotate the supporting element 54 between the operating position and the non- operating position and comprise for this purpose a respective linear moving unit 10 associated with the supporting structure 5 and acting on the supporting element 54. In particular, the casing 14 of the cylinder 11 is rotatably fixed to the second portion 52 of the supporting structure 51, while a free end 13a of the rod 13 of the piston 12 of the cylinder 11 is rotatably fixed to the supporting element 54.

[0041] The control unit 50 of the roll bending machine 1 is also connected to, and configured to control, the linear moving units 10, 40 and adjust a position and / or an orientation of the bending rolls 2, 3, 4.

[0042] The roll bending machine 1 also comprises driving means 7 arranged to rotate the upper roll 2 and the lower roll 4, in particular about the respective rotation axes XI, X3.

[0043] The driving means 7 include two driving units 8 associated to the supporting structure 5, in particular fixed to the first portion 41 thereof and configured to rotate respectively the upper roll 2 and the lower roll 4 separately and independently.

[0044] Each driving unit 8, in particular of the electric type, comprises a respective rotary electric motor 36 connected to and acting on the respective bending roll 2, 4 by means of a speed reducer device 37.

[0045] The control unit 50 is also connected to, and configured to control, the driving units 8 of the driving means 7 to adjust and control the angular position and / or rotation speed of the upper 2 and lower 4 rolls.

[0046] The operation of the roll bending machine 1 of the invention comprises to rotates the upper bending roll 2 and lower bending rolls 3 about their respective longitudinal rotation axes XI, X3 in order to pinch and drag a plate or sheet to be bent / curved. The plate is inserted between the two upper 2 and lower 4 rolls, in particular by resting it on one of the side rolls 3, in particular the one upstream with reference to an advancement direction, which is substantially orthogonal to the rotation axes XI, X2, X3 of bending rolls.

[0047] In order to rotate the upper 2 and lower 4 rolls the two driving units 8 of the driving means 7 are activated and controlled by the control unit 50.

[0048] The relative position of the lower roll 4 is adjusted before the bending procedure, based on the thickness of the plate, by suitably operating the moving means 6, in particular the second linear moving unit 40.

[0049] Likewise, positions of side rolls 3 with respect to the upper 2 and lower 4 rolls can be modified separately and independently before and / or during operation to bend and / or curve the plate in the required manner.

[0050] To this end, the pairs of first linear moving units 10 associated with the respective side rolls 3 are operated by the control unit 50 to vary a position and / or an orientation of each side roll 3 with respect to the upper 2 and lower 4 rolls.

[0051] The operation of each linear moving unit 10, 40 provides that the respective rotary electric motor 16 is activated to drive the corresponding hydraulic pump 15, in particular with such a rotation direction as to allow the pump 15 to supply the pressurized hydraulic fluid into the desired hydraulic cylinder chamber 11, 1 T in order to move the piston 13 as required.

[0052] More specifically, the rotary electric motor 16 is rotated in a first direction so that the pump 15 dispenses the pressurized fluid from the first port 31 to supply through the first duct 21 the first chamber 18 of the cylinder 11, I T causing the extension of the piston 12 and its rod 13, for example to lift the corresponding bending roll (the lower roll 4 or a side roll 3).

[0053] In this step the first sequence valve 28 allows free passage of hydraulic fluid from the pump 15 to the first chamber 18.

[0054] During rotation the pump 15 also sucks, through the second supply / suction port 32, the hydraulic fluid exiting from the second chamber 19 of the cylinder 11, I T and sends the hydraulic fluid to the first chamber 11. To this end, the second sequence valve 29 allows the hydraulic fluid to flow from the second chamber 19 to the pump 15 and therefore to the first chamber 18 only when the pressure in said second chamber 19 is substantially equal to the pressure in the first duct 21, in order to prevent the piston 13, for example under the weight of the relative bending roll, from being able to suddenly empty the second chamber 18 (pushing the pressurized fluid towards the tank 17), i.e. from moving in an uncontrolled and dangerous manner.

[0055] The check valve 26 located on the third duct 23 of the hydraulic circuit 20 connected to the second supply / suction port 32 in fact prevents the fluid from flowing from the second chamber 19 of the cylinder into the tank 17.

[0056] If the rotary electric motor 16 is rotated in an opposite second direction, the pump 15 delivers the pressurized fluid from the second port 32 so as to supply, through the second duct 22, the second chamber 19 of the cylinder 11, I T causing the retraction of the piston 12 and of the relative rod 13, for example to lower the bending roll 3, 4.

[0057] In this step, the second sequence valve 29 allows the free passage of hydraulic fluid from the pump 15 to the second chamber 19.

[0058] During rotation, the pump 15 also sucks, through the first supply / suction port 31, the hydraulic fluid exiting from the first chamber 18 of the cylinder 11, I T and sends the hydraulic fluid to the second chamber 11. For this purpose, the first sequence valve 29 allows the hydraulic fluid to flow from the first chamber 18 to the pump 15 and therefore to the second chamber 19 only when the pressure in the first chamber 18 is substantially equal to the pressure in the second duct 22, in order to prevent that, for example under the weight of the relative bending roll, the piston 13 can suddenly empty the first chamber 18 (pushing the pressurized fluid towards the tank 17) that is to say it can move in an uncontrolled and dangerous way.

[0059] Thus during rotation the pump 15 progressively sucks in a controlled manner, through the first supply / suction port 31, the hydraulic fluid exiting from the first chamber 18 of the cylinder 11 and sends it to the second chamber 19.

[0060] Also in this case, the check valve 26 located on the third duct 23 of the hydraulic circuit 20 connected to the first supply / suction port 31 prevents the fluid from flowing from the first chamber 18 of the cylinder 11 into the tank 17.

[0061] The discharge valve 30, which is in the normally open position when not activated, so as to connect the first duct 21 to the tank 17, ensures that the piston 12 cannot move, and in particular cannot extend by moving the bending roll, in the event of incorrect start-up of the hydraulic pump 15.

[0062] The roll bending machine 1 of the invention allows metal sheets and plates to be bent and curved with great precision and accuracy even when they have great thickness, and at the same time allows energy consumption during its operation to be significantly reduced.

[0063] The moving means 6 comprise in fact a plurality of first and second linear moving units 10, 40 of electro-hydraulic type, autonomous and operable separately and independently, able to move and displace the bending rolls in a precise and reliable manner. Such linear moving units 10, 40 have a limited energy consumption due to the small dimensions and powers of the respective electric motors 16 and pumps 15.

[0064] Similarly, the driving means 7 comprise a plurality of driving units 8 of the electric type, autonomous and separately and independently operable, capable of rotating the bending rolls in a precise and reliable manner and having a limited energy consumption as a result of the reduced dimensions of the respective electric motors 36.

[0065] Unlike known roll bending machines, the roll bending machine 1 of the invention therefore does not require a central hydraulic system, provided with one or more powerful electric motors to drive one or more large hydraulic pumps capable of supplying pressurized fluid to all linear and rotary actuators that move and rotate the bending rolls. In this way, during the operation of the machine of the invention, the energy consumed is only the energy required to drive the electric motors of reduced size and power of the only linear moving units 10, 40 and driving units 8 actually in use.

[0066] In addition, the absence of a central hydraulic system makes it possible to reduce the size and dimensions of the roll bending machine and, above all, to simplify and speed up assembly and maintenance procedures.

[0067] Finally, it should be noted that the simplification of the moving means 6 and the absence of a central hydraulic system reduces the risk of failure, in particular of leakage of the hydraulic circuit.

[0068] Figures 7 and 8 show a roll bending machine 1 of the invention of the so-called three-roll type, which differs from the machine above described and illustrated in figures 1 to 6 in that it comprises an upper bending roll 2 and two side bending rolls 3 placed on both sides of the upper roll 2. The upper roll 2 and the side rolls 3 are rotatable about respective longitudinal rotation axes XI, X2 parallel to each other and are supported at opposite ends 2a, 2b, 3a, 3b by the supporting structure 5.

[0069] The moving means 6 associated to the supporting structure 5 are configured to move the side rolls 3 to allow adjustment of their position and / or orientation with respect to the upper roll 2. The moving means 6 comprise for each side roll 3 two respective first linear moving units 10 acting on the corresponding ends 3 a, 3b of the aforementioned side rolls.

[0070] The first linear moving units 10 are the same as those described for the four-roll bending machine of figures 1 to 6.

[0071] The driving means 7 are arranged to rotate the upper roll 2 and the side rolls 3, and include three driving units 8 associated with the supporting structure 5 and configured to rotate the upper roll 2 and the side rolls 3 separately and independently.

[0072] The driving units 8 are the same as described for the four-roll bending machine of figures 1 to 6.

[0073] The supporting structure 5 of the machine 1 also comprises in this variant a supporting element 54, so-called yoke, configured to rotatably support a respective end 2a of the upper roll 2 in an operating position W.

[0074] The supporting element 54, of known type, is rotatably fixed about an oscillation axis Y (almost horizontal and orthogonal to the rotation axes XI, X2 of bending rolls), in particular fixed to the second portion 52 of the supporting structure 5, so as to be rotatable between the operating position W and the non-operating position, in which it is disengaged from the respective end 2a of the upper roll 2, in particular to allow a curved product, i.e. a plate or sheet, to be laterally removed from the bending machine. In particular, the supporting element 54 is rotated between the two operating and non-operating positions by a respective linear moving unit 10 of the moving means 6.

[0075] The operation of this variant of the three-roll bending machine of the invention provides rotating the upper rolls 2 and the side bending rolls 3 about the respective longitudinal rotation axes XI, X2 to drag and then bend a plate or sheet.

[0076] To rotate the upper 2 and side 3 rolls the respective driving units 8 of the driving means 7 are activated and controlled by the control unit 50 of the machine 1.

[0077] The positions and / or orientations of the side rolls 3 are changed separately and independently before and / or during operation to bend and / or curve the plate as required.

[0078] To this end, the pairs of first linear moving units 10 associated with the respective side rolls 3 are operated by the control unit 50 to vary a position and / or an orientation of each side roll 3 with respect to the upper roll 2. In particular, the ends 3a, 3b of the side rolls 3 are moved, for example linearly along an oblique or inclined adjustment direction, according to which the side roll can be lifted and brought closer to the upper roll 2 or lowered and spaced from the upper roll 2.

[0079] The specific operation of a first linear moving unit 10 has already been described with reference to the embodiment of the four-roll bending machine of figures 1 to 6.

[0080] With reference to figures 9 and 10, a variant of the roll bending machine 1 of the invention of the three-roll type is illustrated, which differs from the three-roll bending machine already described and illustrated in figures 7 and 8, in that the upper bending roll 2 can be moved by the moving means 6, in particular linearly and vertically, to adjust its position and / or orientation with respect to the side rolls 3.

[0081] For this purpose, the moving means 6 comprise at least a second linear moving unit 40 acting on the upper roll 2 to move it linearly, in particular vertically, so as to raise or lower it. In particular, the second linear moving unit 40 acts on the ends 2a, 2b of the upper roll 2 by means of suitable transmission mechanisms, of known type and not illustrated in the figures. Alternatively, in a variant of the bending machine 1 not shown in the figures, the moving means 6 may comprise a pair of second linear moving units 40 each acting on a respective end 2a, 2b of the upper roll 2.

[0082] The side rolls 3 can also be moved by the moving means 6 towards and away from the upper roll 2, in particular along a horizontal adjustment direction and orthogonal to the rotation axis X2 of the aforementioned side rolls 3.

[0083] The moving means 6 comprise for each side roll 3 two first linear moving units 10 acting on respective ends 3a, 3b of the side roll 3.

[0084] The first and second linear moving units 10, 40 are the same as described for the four-roll bending machine of figures 1 to 6.

[0085] The driving means 7 are arranged to rotate the upper roll 2 and include a driving unit 8 associated with the supporting structure 5.

[0086] The driving unit 8 is the same as described for the four-roll bending machine of figures 1 to 6.

[0087] The supporting structure 5 of the machine 1 comprises a supporting element 154, so-called yoke, configured to rotatably support a respective end 2a of the upper roll 2 in an operating position W.

[0088] In this variant, the supporting element 154 is rotatably fixed to a base element 155 slidably connected to the supporting structure 5, in particular to a second portion 52 thereof, and linearly and vertically moved by the second linear moving unit 40 of the moving means 6. The supporting element 154 is rotated about the oscillation axis Y (almost horizontal and orthogonal to the rotation axes XI, X2 of bending rolls) between the operating position W and the non-operating position by a respective first linear moving unit 10 of the moving means 6.

[0089] The operation of this variant of the three-roll bending machine of the invention provides to rotate the upper roll 2 about the respective first longitudinal rotation axis XI in order to drag and then bend a plate or sheet.

[0090] To rotate the upper roll 2 the respective driving unit 8 of the driving means 7 is activated and controlled by the control unit 50 of the machine 1.

[0091] Positions and / or orientations of the upper roll 2 and the side rolls 3 are modified separately and independently before and / or during operation to bend and / or curve the plate as required. For this purpose, the first and second linear moving units 10 associated with the upper 2 and side 3 rolls are operated by the control unit 50 to vary a position and / or an orientation of each roll 2, 3. The specific operation of a first and a second linear moving unit 10, 40 has already been described with reference to the embodiment of the four-roll bending machine of figures 1 to 6.

Claims

CLAIMS1. Roll bending machine (1) for bending and / or curving metal plates and / or sheets, comprising:- an upper bending roll (2) and two side bending rolls (3) positioned on both sides of said upper bending roll (2), said upper and side bending rolls (2, 3) being rotatable about respective longitudinal rotation axes (XI, X2) parallel to each other;- a supporting structure (5) suitable to support respective opposite ends (2a, 2b, 3a, 3b) of said upper bending roll (2) and side bending rolls (3);- moving means (6) associated with said supporting structure (5) and configured to move said upper bending roll (2) and / or said side bending rolls (3) in order to adjust their position and / or orientation, said moving means (6) comprising for each bending roll (2, 3) at least one linear moving unit (10, 40);- a control unit (50) connected to, and configured to control, said at least one linear moving unit (10, 40) and to adjust a position and / or an orientation of the bending roll (2, 3); characterized in that each linear moving unit (10, 40) includes:- a hydraulic cylinder (11, 11') having a piston (12) provided with a rod (13) connected to and acting on an end of the bending roll (2, 3);- a hydraulic pump (15) to supply said hydraulic cylinder (11, 11') with pressurized hydraulic fluid;- a rotary electric motor (16) arranged to drive said hydraulic pump (15);- an tank (17) for said hydraulic fluid;- a hydraulic circuit (20) provided with ducts (21-25) and valves (26-30) to connect said hydraulic cylinder (11, 11'), said hydraulic pump (15) and said tank (17).

2. Roll bending machine (1) according to claim 1, wherein said hydraulic pump (15) is of the reversible type and suitable for delivering pressurized hydraulic fluid selectively into a first chamber (18) or into a second chamber (19) that are formed by said piston (12) inside a casing (14) of said hydraulic cylinder (11, 11').

3. Roll bending machine (1) according to claim 2, wherein said hydraulic pump (15) comprises two supply / suction ports (31, 32), each of which being connected to the first chamber (18) and to the second chamber (19) of said hydraulic cylinder (11, 11') by respectively a first duct (21) and a second duct (22) of said hydraulic circuit (20).

4. Roll bending machine (1) according to claim 3, wherein each supply / suction port (31, 32) of said hydraulic pump (15) is connected to the tank (17) by means of a respective third duct (23 ) and a respective fourth duct (24) of said hydraulic circuit (20), wherein the hydraulic circuit comprises check valves (26), each inserted in a respective third duct (23) and capable to allow the hydraulic fluid to flow only from the tank (17) to the pump (15), and relief valves (27), each inserted in a respective fourth duct (24) and capable to allow the hydraulic fluid to flow only from the pump (15) to the tank (17) upon reaching a defined pressure at the respective port (31, 32) of the pump (15).

5. Roll bending machine (1) according to claim 3 or 4, wherein said hydraulic circuit (20) comprises a first sequence valve (28) inserted in said first duct (21) that is connected to said first chamber (18) of said hydraulic cylinder (11, 11'), said first sequence valve (28) being configured to allow the hydraulic fluid to flow freely from the pump (15) to the first chamber (18) and the hydraulic fluid to flow from the first chamber (18) to the pump (15) only when a pressure in said first chamber (18) is substantially equal to a pressure in said second duct (22).

6. Roll bending machine (1) according to any of claims 3 to 5, wherein said hydraulic circuit (20) comprises a second sequence valve (29) inserted in said second duct (22) that is connected to said second chamber (19) of said hydraulic cylinder (11, 11'), said second sequence valve (29) being configured to allow the hydraulic fluid to flow freely from the pump (15) to the second chamber (18) and the hydraulic fluid to flow from the second chamber (19) to the pump (15) only when a pressure in said second chamber (19) is substantially equal to a pressure in said first duct (21).

7. Roll bending machine (1) according to any of claims 3 to 6, wherein said hydraulic circuit (20) comprises a discharge valve (30) that is inserted in a fifth duct (25), which connects said first duct (21) with said tank (17) and can be selectively driven to open or close said fifth duct (25).

8. Roll bending machine (1) according to any preceding claim, wherein said moving means (6) are configured to move said side bending rolls (3) to adjust their position and / or orientation with respect to said upper bending roll (2) and comprise for each side bending roll (3) two first linear moving units (10) acting on respective ends (2a, 2b, 3a, 3b) of said side bending roll (3).

9. Roll folding machine (1) according to any preceding claim, wherein said moving means(6) are configured to move said upper bending roll (2), in particular linearly, to adjust its position and / or orientation with respect to said side bending rolls (3) and comprise at least one respective second linear moving unit (40) acting on said upper bending roll (2).

10. Roll folding machine (1) according to any preceding claim, further comprising a lower bending roll (4) rotatable about a respective longitudinal rotation axis (X3), said lower bending roll (4) being under said upper bending roll (2) and interposed between said side bending rolls (3).

11. Roll bending machine (1) according to claim 10, wherein said moving means (6) are configured to move said lower bending roll (4) in particular linearly, to adjust its position and / or orientation with respect to said upper bending roll (2) and comprise at least one respective second linear moving unit (40) acting on said lower bending roll (4).

12. Roll bending machine (1) according to claim 11, wherein said control unit (50) is further connected to, and configured to control, said second linear motion unit (40) and adjust a position and / or an orientation of said lower bending roll (4).

13. Roll bending machine (1) according to any preceding claim, comprising driving means(7) arranged for rotating said upper bending roll (2) and / or said side bending rolls (3), said driving means (7) including for each bending roll (2, 3) to be rotated a driving unit(8) associated with said supporting structure (5) and configured to rotate separately and independently said bending roll (2, 3).

14. Roll bending machine (1) according to claim 10 or 11, comprising driving means (7) arranged for rotating said upper bending roll (2) and / or said lower bending roll (4), said driving means (7) including for each bending roll (3, 4) a driving unit (8) associated with said supporting structure (5) and configured to rotate separately and independently said bending roll (2, 4).

15. Roll bending machine (1) according to claim 13 or 14, wherein said driving unit (8) comprises a respective rotary electric motor (36) connected to, and acting on, the respective bending roll (2, 3, 4) by means of a speed reducer device (37).

16. Roll bending machine (1) according to any preceding claim, wherein said supporting structure (5) comprises a supporting element (54; 154) suitable to rotatably support a respective end (2a) of said upper bending roll (2) in an operating position (W), saidsupporting element (54; 154) being rotatable about an oscillation axis (Y) in a nonoperating position in which it is disengaged from said respective end (2a) of said upper bending roll (2), in particular in order to allow a bent product to be laterally removed from the roll bending machine, said moving means (6) being configured to rotate said supporting element (54; 154) between said operating position and said non-operating position and comprising a respective first linear moving unit (10) associated with said supporting structure (5) and acting on the supporting element (54).

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