WO2011148059A2

WO2011148059A2 - Press brake, press brake beam and table, and edging method

Info

Publication number: WO2011148059A2
Application number: PCT/FI2011/050484
Authority: WO
Inventors: Hannu Alitalo
Original assignee: Aliko Oy Ltd
Priority date: 2010-05-27
Filing date: 2011-05-26
Publication date: 2011-12-01
Also published as: FI20105602A0; FI20105758A0; FI20105758A; WO2011148059A3

Abstract

The invention relates to a press brake, press break beam, press brake table, and an edging method. The press brake (1) comprises a body (2), lower beam (4), upper beam (3) and powered members (6a, 6b) for moving the upper beam relative to the lower beam during edge pressing. The press brake comprises several adjusting units (11) for bend compensation of support surfaces (9) on the beams. The adjusting units are each separately controllable and comprise an eccentric mechanism (12). The adjusting units may bend the support surface or act on the support of the support surface. The adjusting units may reside on the beam, table (17), or between the beam and table.

Description

Press brake, press brake beam and table, and edging method

Background of the invention

[0001] The invention relates to a press brake that comprises at least a body, first and second elongated beams supported to the body, with at least one beam movable relative to the body by means of powered members. Between the beams, there is a gap into which the piece to be edged is arranged for bending, in which the beams are moved relative to each other. The opposite, gap-side edges of the beams have support surfaces, to which edging tools may be fastened. Further, the press brake has means for compensating for the bending of the beams and for setting the support surfaces in parallel.

[0002] The invention also relates to a press brake beam and table, and an edging method.

[0003] The field of the invention is described in more detail in the preambles of the independent claims of the application.

[0004] It is possible to manufacture various products of sheet material by bending. A press brake can be used for rectilinear bending, in which the bending axis is straight. In a press brake, sheet material is bent in one direction between edging tools. The edging tools include a male die and a female die. Typically, bending in a press brake is done as a free bend, in which the sheet is bent so that it is not pressed against the entire surface of the tool and adjusting the distance between the tools affects the angle of the formed edge. The structure of a press brake is made as robust as possible but, in spite of this, deformations occur in the structure and especially in the long beams, because the compressive forces are great and the distances between support points are long. Therefore, various devices are known, with which beams may be bent in advance into the opposite direction to the bend caused by edging forces. Without bend compensation, the male die remains further away from the female die in the middle of the gap than in the area of the ends and, therefore, the bending angle of the piece being bent remains larger in the middle. The purpose of bend compensation is to maintain the support surfaces of the upper and lower beams parallel during edging.

[0005] One known solution is to bend the beam directly by means of a hydraulic cylinder. Drawbacks of the cylinder are its high price, need for space, and the limitations this causes in the bending work. Further, because the pressure in the utilized cylinder is extremely high, the cylinder is very prone to malfunction.

[0006] Publication JP-61099523 discloses a press brake table with several interconnected eccentric mechanisms that are all turned simultaneously by means of a manually operated turning wheel. A drawback of this solution is its poor adjustability.

Brief description of the invention

[0007] It is an object of this invention to provide a novel and improved press brake, press brake beam, press brake table, and edging method.

[0008] The press brake of the invention is characterised in that the press brake is equipped with several independently controllable adjusting units and the turning positions of the eccentric mechanisms of these are separately controllable with a control unit to produce a local effect on the bend of a support surface.

[0009] The beam of the invention is characterised in that the beam comprises several separately controllable adjusting units and that each adjusting unit comprises at least one eccentric mechanism, the turning position of which affects the bend of the support surface.

[0010] The table of the invention is characterised in that the table comprises several independently controllable adjusting units, and the turning position of each eccentric mechanism in these is separately settable to produce a local effect on the bend of the support surface.

[0011] The method of the invention is characterised by affecting a support surface with several individually controllable adjusting units and their eccentric mechanisms and by adjusting bend compensation locally by turning the eccentric mechanism with an actuator in the adjusting unit.

[0012] The idea of the invention is that the bend of one or both support surfaces of the press brake is affected by means of several adjusting units which each have an eccentric mechanism. An actuator acts on the turning position of the eccentric. The turning position of each eccentric acts locally on the bend of the support surface. Each adjusting unit may be controlled separately by means of the control unit of the press brake.

[0013] The invention provides the advantage that with the eccentric mechanism, it is possible to obtain precise control of the bend compensation. Because the adjusting units may be controlled independently, they may be used to act locally on the bend of the support surface. The eccentric may also be used to transmit extremely high forces. In addition, the structure of the adjusting unit based on an eccentric is simple, inexpensive to manufacture, and requires little maintenance.

[0014] The idea of an embodiment is that one or both beams of the press brake are equipped with several independently controllable adjusting units, and the eccentric mechanisms in them are arranged to affect the bend of the beam. This way, the beam can be bend-compensated locally by means of the eccentric mechanism.

[0015] The idea of an embodiment is that at least one beam comprises at least two horizontal beam parts arranged vertically on top of each other. Further, several eccentric mechanisms are arranged between the beam parts.

[0016] The idea of an embodiment is that at least one beam comprises two or more horizontal beam parts arranged vertically on top of each other. The beam parts are connected at both ends to diagonal pull bars, in which case the connection point has a force node. During edging, a vertical compressive force is transmitted through the force node to the beam part and causes a local support force to the supporting surface. The adjusting units with eccentric mechanisms are arranged at these connection points. The control unit of the press brake adjusts by means of the actuator the turning positions of the eccentric mechanisms so that local supporting forces are transmitted through the force nodes to the support surface, which makes the support surface straight under the influence of the edging forces.

[0017] The idea of an embodiment is that the lower beam comprises two or more horizontal beam parts arranged vertically on top of each other and connected at both ends to diagonal pull bars. At the connection points of the diagonal pull bars and beam parts, there are force nodes, through which vertical compressive force is transmitted to the beam part during edging. At least the connection points affecting the support surface ends are equipped with eccentric mechanisms. The eccentric mechanisms of the adjusting units affecting the support surface ends are turned into a turning position with a clearance. The clearance reduces the support of the support surface ends in the beginning of edge pressing, whereby the support surface ends can bend away from the gap. The size of the clearance may be adjusted by turning the eccentric. Thanks to the clearance, no compressive force is transmitted to the sup- port surface through the force node. Only when the beam has bent and the clearance disappeared will compressive force transmit to the support surface through the force node.

[0018] The idea of an embodiment is that the lower beam of the press brake is equipped with a table. The adjusting units are arranged between the frame of the beam and table.

[0019] The idea of an embodiment is that the lower beam of the press brake is equipped with a table that comprises first and second table parts. The first table part, that is the lower table part, is fixed to the beam frame. The second table part, that is the upper table part, is parallel to the first table part and on the side of the gap. The eccentric mechanisms of the adjusting units are arranged between the first and second table parts, whereby it is possible to act on the bend of the gap-side second table part and the support surface thereon with the eccentrics.

[0020] The idea of an embodiment is that the press brake comprises at least one measuring device for measuring the deformation of the piece being edged. The measuring information is transmitted to the control unit of the press brake. The control unit is arranged to adjust one or more independently controllable adjusting units on the basis of the measuring results so as to produce a local bend compensation on the support surface.

[0021] The idea of an embodiment is that pre-compensation is performed before edge pressing. In such a case, the edging forces and the bend of the support surface caused thereby are taken into consideration in advance in the turning position of the eccentric mechanisms. For pre-compensation, the control unit of the press brake may have a calculation feature that takes into consideration, among other things, the dimensions, material and edging angle of the piece being edged, and defines the size of the required bend compensation on the basis thereof.

[0022] The idea of an embodiment is to measure the size of the actual angle created in the piece after the first edge pressing step and performing bend compensation before the next edge pressing step on the basis of the measuring results. Thanks to this embodiment, it is possible to take into consideration the changes occurring in the dimensions and material of the piece being edged and their effect on the size of the angle being created.

[0023] The idea of an embodiment is to perform bend compensation actively during edge pressing. The control unit of the press brake may have, for bend compensation, adaptive control, that is control based on measurement, in which the bending angle of the piece being edged is measured during edge pressing and one or more adjusting units are adjusted on the basis of the measuring results.

[0024] The idea of an embodiment is to perform bend compensation by moving the support surface ends away from the gap. The support surface can be kept unchanged on the section between the ends, or it may be moved in the opposite direction to the ends, that is toward the gap. When the ends and mid-part of the support surface are moved into opposite directions, the necessary bend compensation may be produced with very small moves. The control unit of the press brake may have a control strategy for moving the support surface ends by controlling the adjusting units.

[0025] The idea of an embodiment is that the eccentric mechanism of the adjusting unit comprises a turning axle with several eccentrics at an axial distance from each other. Between the eccentrics, there are bearing sections which support the eccentric mechanism. Further, at each eccentric, there is a separate support piece with a cup-like support face, on which the eccentric acts when turning.

[0026] The idea of an embodiment is that the eccentric mechanism comprises at least one bearing section with a circular outer circumference, and at least one force transmission section also with a circular outer circumference. The bearing section and force transmission section are arranged axially one after the other, and they both comprise their own centre axles located at a transverse distance from each other as seen in the axial direction. The eccentric mechanism is turned with an actuator around the centre axle of the bearing section, whereby the position of the force transmission section located eccentrically to it changes.

[0027] The idea of an embodiment is that the eccentric has a point, where the eccentric transmits the edging force through itself without a turning torque directed to the eccentric. The eccentric can be set into a "top dead point", in which the motion provided thereby is at its greatest. This position corresponds to the situation where force is transmitted by means of a rigid piece.

[0028] The idea of an embodiment is that the eccentric mechanism comprises a rotationally asymmetric force transmission section. The force transmission and bearing sections may be coaxial, or their centre axles may reside at a transverse distance from each other. The force transmission section may be oval in shape or it may have other curved shapes.

[0029] The idea of an embodiment is that the eccentric mechanism is driven by means of a pressure medium cylinder. With a hydraulic cylinder, for instance, it is possible to produce very high forces. In addition, hydraulic cylinders are inexpensively priced, and they are relatively easy to control precisely to adjust the position of the eccentric.

[0030] The idea of an embodiment is that the eccentric mechanism is driven by means of a turning motor. Torque is transmitted from the turning motor over transmission gear to the eccentric mechanism. The turning motor may be an electric motor or hydraulic motor.

[0031] The idea of an embodiment is that, for the bend compensation of at least one support surface, adjusting units have been arranged on the entire length of the support surface, and the adjusting units can be controlled independently by means of the control unit of the press brake. The adjusting units may be arranged at 300 to 700 mm intervals, preferably at 500 mm intervals.

[0032] The idea of an embodiment is that the beam of the press brake comprises at least three parallel plate-like frame parts, and the gap-side edge of the middle frame part comprises a support surface, or it has a table furnished with a support surface fastened to it. The beam may have a crosswise opening which penetrates the frame plates and through which the eccentric mechanism is arranged. The bearing sections of the eccentric mechanism may be supported against the outermost frame plates, and the force transmission section may act on the middle frame plate.

[0033] By combining the above-mentioned embodiments and their features, it is possible to form different solutions suitable for each need.

Brief description of the figures

[0034] Some embodiments of the invention will be explained in greater detail in the attached drawings, in which

Figure 1 is a schematic front view of a press brake, the beam of which may be bent by means of eccentrics,

Figure 2 is a schematic front view of a press brake, the table of which may be bent by means of eccentrics, Figure 3 is a schematic front view of a press brake, the table ends of which may move away from the gap under the influence of eccentrics,

Figure 4 is a schematic front view of a press brake, the table of which comprises two table parts on top of each other, between which the eccentrics are arranged,

Figures 5a to 5c are schematic views of an eccentric mechanism in three different turning positions,

Figure 6 is a schematic side view of an eccentric mechanism with three force transmission sections arranged eccentrically relative to the turning axle,

Figure 7 is a schematic side view of an eccentric mechanism with one force transmission section arranged eccentrically relative to the turning axle,

Figure 8 is a schematic front view of the structure of an upper beam and the location of adjusting units at force nodes,

Figures 9a and 9b are schematic views of a detail of a connection point of Figure 8 at two different turning positions of the eccentric mechanism,

Figures 10a and 10b are schematic and cross-sectional views of details of Figures 9a and 9b,

Figure 11a is a schematic front view of the structure of a lower beam and the location of adjusting units along the sections of the beam ends,

Figures 11b and 11c show a cross-sectional detail of Figure 11a at the location of a adjusting unit,

Figures 12a and 12b illustrate by dashed lines the bend and straightening of a support surface,

Figure 13 is a schematic front view of the structure of an upper beam and the location of adjusting units between beam parts,

Figure 14 is a schematic and cross-sectional view of a detail pertaining to the positioning of the eccentric mechanism of Figure 13, and

Figure 15 is a diagram of features and characteristics related to the invention.

[0035] For the sake of clarity, the figures show some embodiments of the invention in a simplified manner. In the figures, like reference numerals identify like elements. Detailed description of some embodiments of the invention

[0036] The vertical press brake 1 shown in Figure 1 comprises a body 2 with at least ends 2a and 2b that may be supported against the floor. Between the ends 2a, 2b, an upper beam 3 and a lower beam 4 are supported, and the beams are elongated pieces. The beams 3 and 4 may be plate structures. The lower beam 4 may be connected by fastening pins 5 or corresponding connecting members to the ends 2a, 2b to make it stationary. The upper beam 3 may be moved in the vertical direction by means of powered members 6a and 6b. The powered members 6a, 6b may be hydraulic cylinders with which the upper beam 3 may be moved toward the lower beam 4 during edge pressing and, correspondingly, away from the lower beam 4 during the return movement. Between the upper beam 3 and lower beam 4, there is a gap 7, to which a piece 8 to be edged may be arranged. The opposite longitudinal edges of the beams 3, 4 have support surfaces 9, to which edging tools may be fastened. A male die is typically fastened to the upper beam 3 and a female die is fastened to the lower beam 4. For the sake of clarity, the edging tools are not shown in the figures of this application, and for the same reason, the support surfaces 9 are shown emphasized.

[0037] Figure 1 shows in an exaggerated way and by dashed line 10 the bending of the upper beam 3 support surface 9 under the effect of edging forces. The upper beam 3 is supported on its ends, but there is no support in the middle. Because the beam is typically several metres long, the beam 3 bends to some extent in the middle, even though its structure is constructed to be very rigid against bending. To compensate for this bend, the press brake 1 is equipped with several adjusting units 11 that may be arranged in the structure of the lower beam 4. The adjusting units 11 may be arranged along the entire length of the lower beam 4 at a predefined distance L from each other. The distance L may be 500 mm, for instance. Each adjusting unit 11 comprises an eccentric mechanism 12 and an actuator 13 to affect its turning position. The actuator 13 may be a hydraulic cylinder that may be connected through a crank or corresponding transmission element to act on the eccentric 12. With the adjusting units 11 the support surface 9 of the lower beam 4 may be bent into an arc as shown by dashed line 14 in the figure. The intention is then to bend the support surface 9 of the lower beam 4 so that it becomes parallel with the support surface of the upper beam 3 that bends during the edging. The size of the angle formed on the piece during edging is then equal along the entire edging length.

[0038] The eccentric mechanism 12 of the adjusting unit 11 transmits the force generated by the actuator 13 to the beam 4, and the beam 4 bends at said adjusting unit 11. Thus, the adjusting units 11 have a local effect on the bend of the support surface 9. The adjusting units 11 are independent devices that may be controlled autonomously. The operation of the press brake 1 may be controlled by one or more control units 15 that may also control the adjusting units 11. The control unit 15 may comprise a processor or it may be a programmable logic, for example. One or more control strategies may be set in the control unit 15 to control the adjusting units 11. Further, the press brake 1 may have one or more measuring devices 16 for measuring the deformation of the edged piece. The operation of the measuring device 15 may be based on non-contacting measurement, or it may comprise one or more sensors that may be in contact with the edged angle. Measuring data may be transmitted from the measuring device 16 to the control unit 15 that, on the basis of the measuring results, may determine the need for bend compensation and control the adjusting units 11 individually.

[0039] It is also possible that the upper beam 3 is equipped with adjusting units 11' of corresponding type, with which the bend compensation of the upper beam 3 can be done. Instead of a hydraulic cylinder, the actuator 13' of the adjusting unit 11' may be some other actuator that requires less space, or the turning motion may be transmitted from a distance by using suitable transmission elements, in which case the adjusting units 11' in the upper beam 3 may be positioned close to the support surface 9 without them hampering edging.

[0040] The lower beam 4 of the press brake 1 shown in Figure 2 is equipped with a table 17 with a support surface 9 on its top surface. Between the table 17 and lower beam 4 frame, there are several independently controllable adjusting units 11 , with which it is possible to affect the bend of the support surface 9 on the top surface of the table 17.

[0041] Figure 3 shows an embodiment, in which the table 17 ends may be lowered with the adjusting units 11. The ends of the table 17 may be bent downward by means of the adjusting units 11 or, alternatively, the support of the table 17 ends may be reduced with the adjusting units 11 , whereby the table 17 ends bend during edge pressing under the edging force. Adjusting units 11 in the middle of the table may be turned into what is known as the top dead point, the idea of which is presented later in connection with Figure 5c. It is further possible that the adjusting units 11 are arranged on the section of the table 17 ends only, and the middle section has rigid support.

[0042] In Figure 4, the lower beam 4 is equipped with a table 17 that comprises a first table part 17a and a second table part 17b arranged on top of each other. Several independently controllable adjusting units 11 are arranged between the table parts 17a and 17b. The first table part 17a comprises a fastening surface, at which it is fastened to the top surface of the lower beam 4 frame. The second table part 17b comprises on its gap-side longitudinal edge a support surface 9 for fastening edging tools. It is possible to bend the second table part 17b into an arc by means of the adjusting units 11. Alternatively, the support of the table part 17b ends may be reduced with the adjusting units 11 , whereby the table part 17b ends are allowed to bend during edge pressing under the edging force. Adjusting units 11 in the middle of the table 17 may be turned into what is known as the top dead point, the idea of which is presented later in connection with Figure 5c. It is also possible that the adjusting units 11 are arranged on the section of the table 17 ends only, and the middle section has rigid support.

[0043] In the embodiments of Figures 2 to 4, the upper beam 3 may also be equipped with adjusting units 11'.

[0044] Figures 5a to 5c show an eccentric mechanism 12 of a adjusting unit 11 in three different turning positions. The eccentric mechanism 12 may comprise one or more bearing sections 18 and one or more force transmission sections 19 that may have a circular outer circumference. The centre axles 20 and 21 of the sections 18 and 19 may reside at a transverse distance from each other. The centre axle 20 of the bearing section 18 may act as a turning axle, whereby the force transmission section 19 is located eccentrically to the turning axle 20. The bearing section 18 may be supported by a support piece 22 against a first support surface 23. At the force transmission section 19, there may be a pressing stem 24 with a cup-like surface on which the force transmission section 19 may act. With the pressing stem 24, load can be distributed to a larger surface area. The pressing stem 24 may move in the transverse direction during turning, as shown by an arrow in Figure 5b. The pressing stem 24 may be supported against a second support surface 25. A turning force F may be directed to the eccentric mechanism 12, whereby it may turn relative to the turning axle 20. The turning affects the distance L1 to L3 between the support surfaces 23 and 25, as seen in Figures 5a to 5c. In Figure 5c, the eccentric mechanism 12 is turned to the top dead point, in which the centre axles 20 and 21 are on the same vertical line. The vertical forces acting on the support surfaces 23, 25 are then transmitted through the eccentric mechanism 12 without causing a torque to the eccentric mechanism 12.

[0045] The eccentric mechanism 12 shown in Figures 5a to 5c may be as shown in Figure 6 or 7. Figure 6 shows an eccentric mechanism 12 with several bearing sections 18 and force transmission sections 19 alternately. This type of eccentric mechanism 12 may be arranged to the table 17, for instance, cross-wise to the longitudinal direction of the table 17. The eccentric mechanism 12 may then extend cross-wise from one edge of the table to the other. The eccentric mechanism 12 shown in Figure 7 is suitable for use in the openings between beam parts, for example.

[0046] Figure 8 shows an upper beam 3 that comprises four longitudinal beam parts 26a to 26d that are arranged vertically on top of each other. There may naturally also be fewer beam parts 26, two or three, for instance, or there may be more than four of them. The beam parts 26 may be fastened to each other at their longitudinal edges. The beam 3 further comprises diagonal pull bars 27a and 27b that are connected to connection points 28 at the ends of the beam parts 26. Corresponding diagonal pull bars also exist on the rear side of the beam 3. The edging force produced by the powered members 6a, 6b may be directed to the lowest beam part 26a, from which the force is transmitted through the diagonal pull bars 27 to the other beam parts 26b to 26d. There may be a pin or some other corresponding force-transmitting member in the connection points 28 between the beam part 26a and diagonal pull bars 27. In the connection points 28 between the other beam parts 26 to 26d and diagonal pull bars 27, there may be adjusting units 11 with their eccentric mechanisms, as is shown in detailed Figures 9a, 9b and 10a, 10b. When the beam 3 is pressed at its ends toward the gap 7, tensile stress is formed in the diagonal pull bars 27 which is transmitted through the connection points 28 to the beam parts 26b to 26d and on from the connection points 28 as compression stress vertically through the beam 3 until the support surface 9, as illustrated by arrows and dashed lines in Figure 9. The connection points 28 are thus force nodes of a certain type, through which edging forces are transmitted. When these force nodes are equipped with adjusting units 11 , it is possi- ble to affect the compression stress transmitted through them, which in turn affects the bend of the support surface 9 during edging. The beam 3 is then equipped with a force distribution system that is utilized in bend compensation. The intention is not to pre-bend the support surface 9 into an arc before edge pressing but to distribute the compressive force on the support surface 9 locally so that the support surface 9 is straight at the end of edge pressing. Independently controllable adjusting units 11 are used to affect the distribution of the compressive forces on the support surface 9. The eccentric mechanisms 12 of the adjusting units 11 may be adjusted to a predefined turning position before edge pressing, or alternatively they may be turned during edge pressing taking measuring results into consideration.

[0047] Figures 9a, 9b, 10a, and 10b show in more detail a connection point 28a and the operation of the adjusting unit 11 therein. In Figures 9a and 10a, the adjusting unit 11 is at its start position, when it does not generate stress to a node. In Figures 9b and 10b, the eccentric mechanism 12 of the adjusting unit has been turned into its maximum position with the powered member 13, whereby the force transmission surfaces 19 of the eccentric press the beam part 26d and generate stress to the force node. The beam part 26d may be between the diagonal pull bars 27b, in which case the bearing sections 18 of the eccentric mechanism 12 can be well supported to the openings in the diagonal pull bars 27b. The powered member 13 may be connected to the eccentric mechanism by means of a crank.

[0048] A beam structure and force distribution system of the type shown in Figures 8 to 10b may also be in the lower beam or, alternatively only in the lower beam.

[0049] Figure 11a shows a lower beam formed of beam parts 26a to 26d, diagonal pull bars 27a to 27b and connection points 28 and having a force distribution system and adjusting units 11. The bottom ends of the diagonal pull bars 27 are connected in the middle connection points 28 with pins 30 or corresponding force-transmitting members to the lowest beam part 26d. The other connection points 28 may be equipped with adjusting units 11 , the eccentric mechanisms of which may be used to influence when compressive force is transmitted vertically through the force nodes in the connection points to the support surface 9. When edging force acts on the top part of the beam 4, the pins 30 transmit the force to the diagonal pull bars 27 that transmit the force on to the frame 2. The eccentric mechanisms 12 of the adjusting units 11 at the ends of the beam 4 may be turned into a turning position, in which a clearance V is formed between the force transmission sections 19 and support surfaces. The turning position may be used to act on the size V1, V2 of the clearance. This is illustrated in Figures 11b and 11c. Due to the clearance V, the ends of the beam 4 are not supported in the beginning of edge pressing, as a result of which the ends may bend away from the gap 7. This is known as end-lowering compensation. The support surface 9 thus initially bends downward at the ends, as illustrated by dashed line 14a in Figure 12a. The beam 4 ends may bend downward to the extent allowed by the clearance V before force is transmitted through said force node to the diagonal pull bars 27. When the clearance V has disappeared as a result of the bending, the force node begins to transmit a supportive force which reduces the bending force directed to the middle part of the beam 4. When edge pressing progresses toward its end, the beam 4 and support surface 9 are pressed straight. This is illustrated by dashed line 14b in Figure 12b.

[0050] Figure 13 shows an upper beam 3 that may be formed of beam parts 26, diagonal pull bars 27 and connection points 28. In this embodiment, the connection points 28 do not have adjusting units 11 , but they are positioned between beam parts 26a and 26b. The beam part 26b may comprise two plate parts arranged at a distance from each other, and the beam part 26a may be arranged between these plates as shown in Figure 14. The bend of the support surface 9 may be affected by turning the eccentric mechanism 12. The solution of Figure 13 is also well suited for use in the lower beam 4.

[0051] Figure 15 is a simplified diagram illustrating the use of the independently controllable adjusting units and their eccentrics and various alternatives in bend compensation. The diagram also shows features and properties that have been described in other parts of this application.

[0052] In some cases, features disclosed in this application may be used as such, irrespective of other features. On the other hand, features disclosed in this application may, if required, be combined to form various combinations.

[0053] The drawings and the related description are only intended to illustrate the idea of the invention. Details of the invention may vary within the claims.

Claims

1. Press brake which comprises:

a frame (2) with at least ends (2a, 2b);

an elongated movable upper beam (3) and an elongated fixed lower beam (4) which are arranged vertically on top of each other and between which, there is a gap (7) for a piece (8) to be edged;

powered members (6a, 6b) for moving the upper beam (3) in relation to the lower beam (4);

and in which the opposite longitudinal edges of the beams (3, 4) are equipped with support surfaces (9) for fastening edging tools;

bend compensation means for compensating for the bend of the beams (3, 4) and for setting the support surfaces (9) in parallel regardless of the edging forces directed to the beams (3, 4);

and which bend compensation means have several adjusting units (11) with eccentric mechanisms (12) arranged to be turned by means of an actuator (13); and

at least one control unit (15) for controlling the operation of the press brake (1);

characterised in that

the press brake (1) is equipped with several independently controllable adjusting units (11), and the turning positions of the eccentric mechanisms (12) of these are separately controllable with the control unit (15) to produce a local effect on the bend of the support surface (9).

2. A press brake as claimed in claim 1, characterised in that at least one beam (3, 4) is equipped with several independently controllable adjusting units (11), and the eccentric mechanisms (12) in them are arranged to affect the bend of the beam (3, 4).

3. A press brake as claimed in claim 2, characterised in that at least one beam (3, 4) comprises at least two horizontal beam parts (26a to 26d) arranged vertically on top of each other; and

several eccentric mechanisms (12) are arranged between the beam parts (26a to 26d).

4. A press brake as claimed in claim 2, characterised in that at least one beam (3, 4) comprises at least two horizontal beam parts (26a to 26d) arranged vertically on top of each other; the beam parts (26a to 26d) are connected at both ends to diagonal pull bars (27a, 27b), and the connection point (28) has a force node, through which during edging a vertical compressive force is transmitted to the beam part and causes a local support force to the supporting surface (9);

at least one of said connection points (28) is equipped with a adjusting unit (11); and

the control unit (15) is arranged to adjust the eccentric mechanism (12) of the adjusting unit (11) for the purpose of adjusting the supportive force transmitted to the support surface (9) through the force node.

5. A press brake as claimed in claim 4, characterised in that the control unit (15) comprises a control strategy, according to which it is arranged to turn the eccentric mechanisms (12) of the adjusting units (11) acting on the ends of the lower beam (4) support surface (9) into a turning position, in which the connection point (28) comprises a clearance (V) which clearance (V) allows the ends of the support surface (9) to bend away from the gap (7).

6. A press brake as claimed in any one of the preceding claims, characterised in that

the lower beam (4) is equipped with a table (17); and

the eccentric mechanisms (12) of the adjusting units (11) are arranged between the lower beam (4) frame and table (17).

7. A press brake as claimed in any one of preceding claims 1 to 5, characterised in that

the lower beam (4) is equipped with a table (17);

the table (17) comprises a first table part (17a) and a second table part (17b);

the first table part (17a) is fixed to the lower beam (4) frame; and the eccentric mechanisms (12) of the adjusting units (11) are arranged between the first table part (17a) and second table part (17b).

8. A press brake as claimed in any one of the preceding claims, characterised in that

the press brake (1) comprises at least one measuring device (16) for measuring during edge pressing the deformation of the piece (8) being edged; and

during edge pressing, the control unit (15) is arranged to adjust at least one independently controllable adjusting unit (11) on the basis of the measuring results for the purpose of producing local bend compensation on the support surface (9).

9. A press brake as claimed in any one of the preceding claims, characterised in that

the control unit (15) comprises at least one control strategy, according to which at least one support surface (9) is bent into an arc by moving the support surface (9) at its ends away from the gap (7) by means of the adjusting units (11).

10. A press brake as claimed in any one of the preceding claims, characterised in that

the control unit (15) comprises at least one control strategy, according to which at least one support surface (9) is bent into an arc by moving the support surface (9) at its middle toward the gap (7) by means of the adjusting units (11).

11. A press brake as claimed in any one of the preceding claims, characterised in that

control unit (15) is arranged to act on the support of the support surface (9) ends by adjusting the adjusting units (11) at the ends of the support surface (9);

the ends of the support surface (9) have an allowed bend; and the control unit (15) is arranged to limit the bend of the support surface (9) ends by adjusting the turning position of the eccentric mechanisms (12).

12. A press brake beam that is an elongated piece and comprises: a support surface (9) on one longitudinal edge of the beam (3, 4) and against which support surface (9) an edging tool is supported;

fastening points on the ends of the beam, from which fastening points the beam (3, 4) is supported to the body (2) of the press brake; and

at least one adjusting unit (11) for bend compensation of the support surface (9), the adjusting unit (11) comprising at least one actuator (13) for adjusting the bend compensation;

characterised in that

the beam (3, 4) comprises several separately controllable adjusting units (11); and each adjusting unit (11) comprises at least one eccentric mechanism (12), the turning position of which affects the bend of the support surface (9).

13. A beam as claimed in claim 12, characterised in that the force generated by the actuator (13) is arranged for transmission by the eccentric mechanism (12) to the beam (3, 4) to produce a deformation on its support surface (9).

14. A beam as claimed in claim 12 or 13, characterised in that

at least one beam (3, 4) comprises at least two horizontal beam parts (26a to 26d) arranged vertically on top of each other;

the beam parts (26a to 26d) are connected at both ends to diagonal pull bars (27a, 27b), and the connection point (28) has a force node, through which vertical compressive force is transmitted during edging to the beam part and causes local support force to the supporting surface (9); and

at least one of said connection points (28) is equipped with a adjusting unit (11), and the turning position of the eccentric mechanism is arranged to affect the size of support force transmitted through the force node to the support surface (9).

15. A beam as claimed in any one of preceding claims 12 to 14, characterised in that

the beam (3, 4) is equipped with a table (17), a first surface of which is fastened to the beam (3, 4) and a second surface of which is equipped with a support surface (9) and fastening elements for fastening an edging tool; and between the beam (3, 4) frame and table (17), there are several adjusting units (11) equipped with eccentric mechanisms (12).

16. A press brake table that is an elongated piece and comprises: a fastening surface on the longitudinal edge of the table (17) and fastenable to the press brake (1);

a support surface (9) on the longitudinal edge opposite to the fastening surface and against which support surface (9) an edging tool is supportable; and

at least one adjusting unit (11) for bend compensation of the support surface (9), the adjusting unit (11) comprising an eccentric mechanism (12) and an actuator (13) for turning it;

characterised in that the table (17) comprises several independently controllable adjusting units (11), and the turning position of each eccentric mechanism (12) in these is separately settable to produce a local effect on the bend of the support surface (9).

17. A table as claimed in claim 16, characterised in that the adjusting units (11) are in connection with the fastening surface of the table (17), and the eccentric mechanisms (12) are arranged to generate a force effect between the table (17) and press brake beam (3, 4).

18. A table as claimed in claim 16, characterised in that the table (17) comprises a first table part (17a) and a second table part (17b) that are arranged on top of each other;

the first table part (17a) comprises a fastening surface;

the second table part (17b) comprises a support surface (9) and fastening elements;

several adjusting units (11) are arranged between the table parts (17a, 17b) at a longitudinal distance (L) from each other; and

the turning position of the eccentric mechanism (12) is arranged to affect the distance between the table parts (17a, 17b).

19. An edging method comprising:

using a press brake (1) for edging, the press brake having at least a body (2), a movable upper beam (3), fixed lower beam (4), and support surfaces (9) on the beams for fastening edging tools;

pressing a workpiece (8) between edging tools, which produces an elongated edge thereon; and

performing bend compensation, in which at least one adjusting unit (11) acts on at least one support surface (9) to compensate for the bend caused by edging forces;

characterized by

acting on the support surface (9) by means of several individually controllable adjusting units (11) and their eccentric mechanisms (12); and

adjusting bend compensation locally by turning the eccentric mechanism (12) with the actuator (13) of the adjusting unit.

20. A method as claimed in claim 19, characterized by transmitting from the actuator (13) of the adjusting unit to the support surface (9) a local force effect with the eccentric mechanism (12), whereby the support surface (9) bends at the adjusting unit.

21. A method as claimed in claim 19 or 20, characterized by adjusting with the eccentric mechanisms (12) support points away from the gap (7) at both ends of the support surface (9); and

performing edge pressing, in which the ends of the support surface (9) bend under edging forces away from the gap (7) to the extent of a distance limited by the support points.

22. A method as claimed in claim 19 or 20, c h a r a c t e r i z e d by performing pre-compensation, in which at least one support surface

(9) is bent before edge pressing.

23. A method as claimed in any one of preceding claims 19 to 22, characterized by

pressing a workpiece (8) between edging tools, which produces an elongated edge thereon;

releasing the pressure and measuring the angle of the edge formed on the workpiece (8);

performing bend compensation on the basis of the results from the angle measurement by turning the eccentric mechanism (12) of at least one adjusting unit (11); and

pressing the workpiece (8) again after the bend compensation, whereby the edge acquires its final form.

24. A method as claimed in any one of preceding claims 19 to 23, characterized by

adjusting with the eccentric mechanism (12) the bend compensation of the support surface (9) during edge pressing.

25. A method as claimed in any one of preceding claims 19 to 24, characterized by

performing bend compensation by moving the ends of the support surface (9) with the eccentric mechanisms (12) forcibly away from the gap (7).

26. A method as claimed in any one of preceding claims 19 to 25, characterized by

turning the eccentric mechanism (12) of each adjusting unit with its own actuator (13) individually and to the extent of a turning angle defined by the control unit (15) of the press brake (1).