EP2481492A2 - Bending tool for free-form bending of sheet metal and method for same - Google Patents

Abstract

The tool (4) has a workpiece support part (32) arranged in an end section (28) of a base body (26) on a side of a tool plane (30) and displaceable relative to the body. The end section forms a bending region (29). Another workpiece support part (33) is arranged on another side of the plane and fixed relative to the body. An end region (38) of the former support part facing towards the bending region is subjected with support force or automatically resettably designed against bending force acting on a workpiece (2) to be formed, where the support force acts against the bending force. An independent claim is also included for a method for free-form bending of workpieces to be manufactured from sheet.

Description

The invention relates to a bending tool, in particular a bending die, as described in claim 1.

The NL 1 014 810 A shows a bending device or a bending tool with a bending punch and a bending die. The bending die has a main body, in which one end section defines a bending region, wherein, viewed in the cross section of the main body, a tool plane passes through the bending region. In this end portion of the basic body forming the bending region, a first workpiece support part displaceable relative to the main body is arranged on one side of the tool plane, and a further workpiece support part fixed with respect to the main body is arranged or formed on the other side of the tool plane. The pivotally formed workpiece support member is pressed, starting from the punch during the bending operation of the sheet to a stop, so as to generate the necessary counterforce to carry out the bending operation. The disadvantage here is that with this bending die no free-form bending process can be performed.

The present invention has for its object to provide a bending tool and a method for free-form bending of sheet metal to be produced workpieces, in which a perfect bending result can be achieved.

This object of the invention is solved by the features of claim 1. The advantage resulting from the features of claim 1 lies in the fact that defined force relationships can be created throughout the bending process by the additional steady support and the associated supporting force counteracting the acting bending force. As a result of the supporting force applied to the displaceable workpiece support part, the portion of the metal sheet to be deformed which is adjacent to the bending area is pressed in the direction of the bending punch, whereby an exact and more accurate bending result can be achieved. Furthermore, however, a clear positional positioning of the displaceably formed workpiece support part is achieved even during the initial position. In addition, however, this is also still after completion of the Bending process achieved a guided return of the workpiece support member in the starting position. An additional advantage consists in the fact that thereby also the work safety for the operator himself can be increased, because that part of the sheet to be bent, which is facing the operator, is pivoted at a lower angular velocity. This leads to a reduction of the risk of injury.

Also advantageous is an embodiment according to claim 2, since such a guided pivoting or tilting of the displaceably formed workpiece support member is made possible relative to the main body of the bending tool.

A further advantage is an embodiment according to claim 3, since as a result of the arrangement of the pressure element a first possibility is provided to apply the workpiece support part during the entire bending process, starting from its initial position during the entire bending process with a defined compressive force or supporting force. Depending on the selected pressure element so that the support and thus constructed and the bending force counteracting support force can be better adapted to a variety of bending operations.

Due to the construction according to claim 4, it is possible to adapt the bending tool to a variety of bending conditions.

According to another embodiment variant according to claim 5, an additional possibility is created due to the lever arrangement to be able to bring either its own or an additional supporting effect for generating the supporting force on the workpiece support part.

Also advantageous is a development according to claim 6, since even the displaceable workpiece support member itself has elastically deformable properties, and is thus provided with a high own reset effect. This can be dispensed with additional components, such as the pressure element or the like. In addition, it would also be possible that during the bending process, the sheet to be bent along the leaf spring is deformed only elastically and so the remaining sheet metal portion of the metal sheet remains supported planar on a machine table.

In the embodiment according to claim 7, it is advantageous that the adjustment movement of the sheet to be bent from the workpiece support plane relative to the pivoting around the bending region can be kept low. As a result, large adjustment angles of the sheet in the region of the feed side relative to the workpiece support plane can be avoided. Furthermore, but also manipulation paths can be reduced during the bending process.

The development according to claim 8 ensures that a relatively large displacement region of the leg to be reshaped is thus created on the side facing away from the feed side. This large deformation is unproblematic with relatively short legs, since just with thin sheets due to the inertia no additional unwanted deformation is introduced into the workpiece to be produced. Due to the relatively steep orientation of the workpiece abutment surface with respect to the workpiece support plane, however, the pivot angle of the adjustably configured workpiece support member is minimized. This is for relatively elongated to be deformed sheets of advantage, even if they also have a small wall thickness, as an additional unwanted deformation of the sheet can be avoided in the supply side. The usually longer leg in the region of the feed side, however, adjusted relative to the workpiece support plane with a lower angular velocity due to the smaller adjustment path, whereby unwanted, additional deformation of the sheet can be avoided during the bending process.

The object of the invention is, however, independently solved by a method for free-form bending of sheet metal to be produced workpieces according to the features specified in claim 9. The advantages resulting from the combination of features of this claim are that, due to the different angular speeds of the legs of the sheet to be deformed or bent, those legs are deformed at the higher angular velocity, which has a shorter longitudinal extent starting from the bending area in its undeformed, vertical position , The usually longer leg in the region of the feed side, however, adjusted relative to the workpiece support plane with a lower angular velocity due to the smaller adjustment path, whereby unwanted, additional deformation of the sheet can be avoided during the bending process.

Finally, a procedure according to the features specified in claim 10 is advantageous because as an asymmetric orientation of the leg to be deformed in the final deformed position with respect to the workpiece support plane can be achieved. Thus, the leg turned away from the feed side in the bending region is deformed relatively quickly with respect to the leg located in the region of the feed side. But also manipulation ways, as they are necessary during the mounting and the execution of the bending process, can be minimized.

For a better understanding of the invention, this will be explained in more detail with reference to the following figures.

Fig. 1

eine Biegepresse mit einem Biegewerkzeug, in Ansicht und schematisch vereinfachter Darstellung;

Fig. 2

eine mögliche Ausbildung eines Teils des Biegewerkzeuges in seiner Ausgangsstellung vor dem Biegevorgang, in Seitenansicht geschnitten und vereinfachter schematischer Darstellung;

Fig. 3

das Biegewerkzeug nach Fig. 2, während des Biegevorganges;

Fig. 4

eine andere Ausbildung des Biegewerkzeuges, in Seitenansicht geschnitten und vereinfachter schematischer Darstellung.

Each shows in a highly schematically simplified representation:

Fig. 1

a bending press with a bending tool, in view and schematically simplified representation;

Fig. 2

a possible embodiment of a part of the bending tool in its initial position before the bending process, cut in side view and simplified schematic representation;

Fig. 3

the bending tool after Fig. 2 during the bending process;

Fig. 4

another embodiment of the bending tool, cut in side view and simplified schematic representation.

By way of introduction, it should be noted that in the differently described embodiments, the same parts are provided with the same reference numerals or the same component names, wherein the disclosures contained in the entire description can be mutatis mutandis to the same parts with the same reference numerals or component names. Also, the position information selected in the description, such as top, bottom, side, etc. related to the immediately described and illustrated figure and are to be transferred to a new position analogous to the new situation. Furthermore, individual features or combinations of features from the shown and described different Represent examples of their own, inventive or inventive solutions.

All statements on ranges of values in the description of the present invention should be understood to include any and all sub-ranges thereof, e.g. the indication 1 to 10 should be understood to include all sub-ranges, starting from the lower limit 1 and the upper limit 10, i. all subregions begin with a lower limit of 1 or greater and end at an upper limit of 10 or less, e.g. 1 to 1.7, or 3.2 to 8.1 or 5.5 to 10.

In the Fig. 1 is a manufacturing plant 1 for the free-form bending of sheet metal to be produced workpieces 2 shown in a highly schematically simplified representation.

The production plant 1 comprises a bending press 3, in particular a press brake, for producing the workpieces 2 or workpieces between relatively adjustable bending tools 4, such as bending punch 5 and bending die 6. These two parts of the bending tool 4 but can also be called upper tool and lower tool and are shown here only schematically simplified.

A machine frame 7 of the bending press 3 consists for example of a bottom plate 8 on the vertically upstanding, spaced from each other and mutually parallel side cheeks 9, 10 are arranged. These are preferably connected to each other by a solid, formed for example from a sheet metal part cross member 11 at their distance from the bottom plate 8 end portions.

The side cheeks 9, 10 are approximately C - shaped seen in side view to form a free space for forming the workpiece 2, wherein on front end faces 12 of bottom flanges of the side cheeks 9, 10 a fixed, on the bottom plate 8 upstanding press bar 13, in particular a table bar , is attached. At front end faces 14 of the bottom plate 8 remote legs is in linear guides 15 a to the table beam forming press bar 13 relatively adjustable further press bar 16, in particular a pressure bar, guided guided. On opposite, parallel to each other End surfaces 17, 18 of the two press beams 13, 16 can be arranged own tool holders 19, 20 for assembly with the bending tools or 4.

The bending press 3 shown has, as a drive arrangement 21 for the adjustable press beam 16, namely the pressure bar, here two powered by electrical energy drive means 22, which are line connected to a fed from a power grid 23 control device 24. By way of example, the operation of the bending press 3 can be controlled via a line-connected input terminal connected to the control device 24.

The drive means 22 may be electromotive spindle drives, as are well known, of which adjusting means 25 for a reversible actuating movement of the upper beam bar 16 formed by the pressure bar with this, for example, be drive-connected.

Further details required for the operation of such a bending press 3, such as safety devices, stop arrangements, control and measuring devices are omitted in the subject description to avoid unnecessary length of the description.

Furthermore, the manufacturing plant 1 may also include a manipulator not shown here, which at least takes a piece of it from a supply stack of sheets to be deformed or abzukantenden and spends in the workspace of the bending press 3. The manipulator in turn includes a gripping pliers, which in turn has gripping fingers. The gripping fingers each have clamping surfaces on the side facing the workpiece 2 to be produced. By a corresponding pivoting of the two gripping fingers against each other and applying a sufficient clamping force, the sheet or the workpiece to be manufactured 2 is held by the manipulator and moved accordingly positioned and positioned on the interaction of the clamping surfaces. With the gripper fingers of the gripping pliers, a corresponding gripping and, in a subsequent consequence, due to the clamping movement, a sufficient hold for the workpiece 2 to be produced from the sheet metal is ensured.

The here performed rough description of the bending press 3 with the cooperating or in operation bending tools 4 serves to general To improve understanding. The main focus, however, is directed to the formation of the bending tool 4, in particular of the bending die 6, as well as the actual bending process.

In the FIGS. 2 and 3 a first possible embodiment of the bending tool 4, in particular of the bending die 6 is shown, wherein it should be mentioned that this is a highly schematically simplified representation of the same.

For reasons of clarity, only the bending die 6 and only a portion of the cooperating bending punch 5 are shown schematically by the bending tool 4.

The bending die 6 or the lower tool formed by this comprises a main body 26, which can be used with its head part 27 in the previously described tool holder 19 of the lower press bar 13 and held there. In a distance from the head part 27 arranged end portion 28 of the base body 26, a bending portion 29 is formed or defined for the sheet to be bent. Seen in the cross section of the main body 26 - ie seen in the longitudinal extent of the press beams 13 and 16 - extends through the bending region 29, a tool plane 30th

The tool plane 30 preferably runs in vertical alignment between the parts of the bending tool 4 and is preferably spanned between a means of the head part 27 and the bending region 29.

In the Fig. 2 the bending punch 5 of the bending tool 4 is arranged distanced from the bending die 6, so that the sheet to be deformed can be placed in a corresponding position on the bending die 6 and positioned. For this purpose, not shown stop elements may be provided, with which the exact relative positioning of the sheet relative to the bending tool 4, in particular its tool level 30, takes place and so the production of the workpiece 2 can be performed from the usually undeformed metal sheet. Thus, the supernatant of the sheet can be set or fixed on both sides, particularly on the side turned away from a feed side 31. The supply side 31 is that region of the bending press 3 understood, from which the handling and manipulation of the sheet to the workpiece 2 by a manipulator and / or an operator takes place. Thus, the feed side 31 is in the region of a front side of the bending press. 3

In order to enable a support of the sheet to be deformed, in particular bending sheet during the bending process on Biegegesenk 6, it is provided here that the bending portion 29 is supported by at least two workpiece support members 32, 33, said workpiece support members 32, 33 either through the base body 26 and But also connected to the main body 26 or coupled, own components may be formed.

Thus, in this exemplary embodiment shown here, a first workpiece support part 32 is designed to be displaceable relative to the base body 26, and arranged on one side of the tool plane 30. On the other side of the tool plane 30, a workpiece support part 33 fixed with respect to the main body 26 is arranged or formed. In this embodiment, the first workpiece support member 32 is formed by its own pivot plate 34 and pivot lever. In order to allow the relative displacement of the pivot plate 34 relative to the base body 26, this is pivotally mounted about a parallel to a workpiece support plane 35 and parallel to the tool plane 30 aligned pivot axis 36. It is possible, the pivot axis 36 directly on or in the base body 26 or on a side of the body 26 arranged support plate 37 to store. A two-sided storage is to be preferred. Regardless of this, it would also be possible to make the pivotable work support member 32 longer in the direction of the press beams 13, 16, which increases the width with which workpieces 2 can be bent. Thus, an arrangement and design of a pivot axis 36 can no longer be effective. Thus, it would be conceivable to support the work support support part 32 in the direction of the press beams 13, 16 over a majority of its length or over its entire length continuously on the main body 26. Thus, e.g. the pivoting or tilting movement of the work support member 32 by a rocking about a continuous support line, a rolling or even mutual sliding on or on the base 26 done.

In order to be able to exert a defined reaction force or support force (F) on the first pivotable workpiece support part 32 during the bending process, an end region 38 of the first and displaceably formed workpiece support part facing the bending region 29 is formed 32 with this supporting force (F) acted upon. In this case, the supporting force (F) is oriented such that it counteracts the bending force (F _B ) acting on the workpiece 2 to be deformed. This ensures that the sheet to be deformed to the workpiece 2 is pressed with sufficient counterforce towards the bending punch 5 applying the bending force.

There are several possibilities for generating this support force (F). Thus, it is shown here that the first workpiece support part 32 is supported on at least one pressure element 40 in a section between the end region 38 facing the bending region 29 and the pivot axis 36. This builds or build the pressure elements 40 on the workpiece support member 32 acting supporting force (F) or generate them. Thus, the pressure element 40 from the group of components of gas spring, fluid-actuated cylinder, elastic pressure body such as compression springs, elastomer springs or the like may be selected.

Regardless of or in addition to this, it would also be possible for the first workpiece support part 32 to be connected to at least one tension element 42 in a section between the pivot axis 36 and a further end region 41 facing away from the bending region 29, the tension element 42 projecting onto the workpiece support part 32 acting supporting force (F) generated due to the leverage around the pivot axis 36. The tension member 42 is in the Fig. 3 shown in simplified form. Thus, the tension element 42 may be formed, for example, by a tension spring, pressure-actuated cylinder or elastic tension body. In this case, one end of the tension element 42 is connected to the workpiece support part 32 and the other end to the main body 26 or another part of the Biegegesenks 6, such as the support plate 37.

Regardless, it would also be possible to equip the pivotally mounted workpiece support member 32 with both the pressure element 42 and the tension member 42 together or to apply, so as to provide an even higher support force (F) for the bending operation can.

In order to achieve a parallel alignment of the support side of the pivotally mounted workpiece support member 32 in its rest position with respect to the workpiece support plane 35, is not on the side facing away from the pivot axis 36 side of the bending region 29 provided closer support member provided. This support member may be formed, for example, by a projection, a bar, a projection or the like. The pressure element 40 and / or the tension element 42 brings or bring the workpiece support part 32 into its starting position.

The workpiece support part 32, which is designed to be adjustable relative to the base body 26, is arranged on that side of the tool plane 30 which forms the feed side 31 for the sheet to be bent. Thus, it is possible to form the surface of the workpiece support member 32 facing the sheet metal or workpiece 2 to be produced as a workpiece abutment surface 43. As already described above, the tool plane 30 forms the plane in which the parts of the bending tool 4, namely the bending punch 5 and the bending die 6 cooperate with each other to perform the desired bending operation of the sheet toward the workpiece 2. Due to the arrangement and design of the press beams 13, 16 and the optionally held over the tool holder 19, 20 bending tool 4, the tool plane 30 has a mostly vertical or vertical orientation.

In the area of the feed side 31 is also responsible for a proper support of the sheet care. As already described above, this involves the workpiece support plane 35, which has an orientation which is preferably horizontal and perpendicular with respect to the tool plane 30. In the starting position of the bending tool 4 with the separate bending dies 5 and bending die 6 and the workpiece abutment surface 43 of the pivotally formed workpiece support member 32 is arranged parallel to the workpiece support surface 35 and in this. This makes it possible to support the sheet to be bent, starting from the feed side 31 on the workpiece support member 32 and, if necessary, push so far beyond the tool level 30 in the bending press 3 until the desired projection of the sheet is reached. This can, as already described above, take place by means of corresponding stop elements with which or the insertion path can be limited.

The bending die 6 of the bending tool 4 also has the workpiece support part 33 described above on the side of the tool plane 30 facing away from the adjustably configured workpiece support part 32. This workpiece support part 33 can either be an integral component of the main body 26 or else be designed as a separate component. If the workpiece support member 33 is formed as a separate component, this has the advantage that in a corresponding Wear or damage as well as changed bending conditions this can be easily replaced.

The fixed further workpiece support part 33 likewise has a further workpiece contact surface 44, which is preferably planar, and which is aligned in such a way that it encloses an angle 45 with the tool plane 30. This included between the workpiece abutment surface 44 and the tool plane 30 angle 45 can be in an angular range with a lower limit of 5 °, in particular 10 ° and an upper limit of 50 °, in particular 40 °. The angle range extends starting from the bending region 29 to the side or direction of the tool plane 30 which is averted from the feed side 31.

This makes it possible to perform an asymmetric bending operation of the sheet toward the workpiece 2 with respect to the tool level 30 in cooperation with the punch 5.

How best of the Fig. 3 can be seen here is the sheet metal to the workpiece 2 formed by the bending process. Thus, a first leg 46 is formed with respect to the tool plane 30 on the side of the tool plane 30 facing away from the feed side 31 and another leg 47 in the region of the feed side 31 with respect to the tool plane 30. Thus, the further or second leg 47 comes to the pivotally formed workpiece support member 32 and the first leg 46 on the other workpiece support member 33 and the trained there workpiece abutment surfaces 43, 44 to the plant.

Since the displaceably formed workpiece support member 32 is acted upon in its bending region 29 facing end portion 38 due to the additional arrangement of the pressure element 40 and / or tension member 42 with a sufficient support force (F), takes place here a constant support of the sheet during the forming process by the interaction of Bending punch 5 and bending die 6.

In this bending tool 4 described here, the geometry can be set so that between the bending punch 5, such as the upper tool, and the pivotable tool support member 32 together with the between them and be bent between them Share no sliding and thus no relative displacement must take place. The contact point or the contact line of the upper tool describes during the bending process approximately a short, flat circular arc in a vertical orientation with the pivot axis 36 as the center. The upper tool can still follow elastically the small deflection of a few tenths of a millimeter transverse to the feed direction, provided that its elasticity and the counterforce are sufficiently large. This creates a Kantung, which has only on the rear short side of the sheet a mark, the larger and preferably longer front sheet side is intact. The bending process can be carried out without additional protective film. This can be advantageous in the manufacture of cabinets, compartments or doors.

In the Fig. 4 is a further and possibly independent execution of the bending tool 4, in particular of the bending die 6 shown, again for like parts, the same reference numerals or component designations as in the preceding Fig. 1 to 3 be used. In order to avoid unnecessary repetition, the detailed description in the previous ones will be used Fig. 1 to 3 referred or referred.

In contrast to the pivotally designed mounting of the workpiece support member 32, in this embodiment, the workpiece support member 32 is formed such that the bending portion 29 facing end portion 38 of the first and displaceably formed workpiece support member 32 automatically opposite to the sheet to be deformed or the workpiece to be formed. 2 acting bending force (F _B ) is formed recoverable. This means that the workpiece support member 32 resets itself automatically starting from its mostly horizontal starting position after the successful bending process and the deformation of the end portion 38 again automatically. This can be done by the material inherent properties. For example, the first workpiece support member 32 may also be formed by a leaf spring.

In order to achieve a mutual support and storage of the workpiece support member 32 on the base body 26, the end facing away from the bending portion 29 of the leaf spring may be fixedly connected to the main body 26. This ensures that in the starting position, in turn, a horizontal or parallel alignment of the workpiece abutment surface 43 with respect to the workpiece support plane 35 takes place. During the execution of the bending process takes place a constant support of the sheet to be deformed to the deformed workpiece 2 on the self-elastically deformable workpiece support member 32. By the applied support force (F) is built in the end portion 38 of the leaf spring one of the bending force generated by the bending punch 5 counteracting supporting force (F), so as to achieve an unambiguous and, above all, shapely deformation of the sheet toward the workpiece 2.

In all the previously described embodiments of the bending tool 4, in particular of the bending die 6, the procedure during the forming process is such that the sheet to be formed is reshaped in a free-form bending operation towards the finished workpiece 2. The bending tool 4 with its bending punch 5 and bending die 6 clamp together the tool plane 30, wherein the sheet to be deformed is introduced between the distancing in the starting position bending tool 4 and positioned there. Subsequently Bend is performed by a relative displacement of at least a portion of the bending tool 4, the bending operation of the sheet in the bending region 29. Due to the two-sided arrangement of the sheet with respect to the tool plane 30, first and second legs 46, 47 are formed in the sheet metal. Due to the previously described alignment of the workpiece abutment surface 44 in the area of the further and stationary workpiece support part 33, an asymmetrical deformation of the two legs 46, 47 with respect to their angular orientation to the tool plane 30 occurs.

As described above, the workpiece abutment surface 44 of the further workpiece support member 33 is relatively steeply aligned with respect to the workpiece support plane 35, wherein the complementary angle is between 40 ° and 85 ° with respect to the previously indicated angular range of the angle 45. This further angle is in Fig. 3 entered with the reference numeral 48.

During the execution of the bending operation, that leg 46 which is formed on the side of the tool plane 30 facing away from the feed side 31 of the sheet is deformed at a greater angular velocity towards the tool plane 30 than the second leg 47 of the sheet, which Supply side 31 is facing. Depending on the angle to be deformed, which is enclosed between the two legs 46, 47, the leg 47 is also deformed in the direction of the tool plane 30 in the region of the feed side 31. However, this is due to the lower required relocation with an angular velocity of the leg 47 to lower angular velocity.

Characterized in that that leg 46, which is arranged on the side of the tool plane 30 facing away from the feed side 31, has a longitudinal extension with respect to the tool plane 30 in the direction perpendicular thereto, which is shorter than the longitudinal extension of the leg 47 in the region of the feed side 31, an unwanted deformation of the leg 47 is avoided even in a region outside the bending region 29 even with thin sheets. As a result, it is possible that the leg 47, which is usually longer, in the region of the feed side 31 with increasing distance from the tool plane 30 in the event of unsupported support and angular velocity in the direction of the tool plane 30, in addition to the desired bending region 29, causes further undesired deformation experiences. This is prevented by the small displacement and the additional support of the leg 47 in the region of the pivotally formed workpiece support member 32.

The embodiments show possible embodiments of the bending tool 4, in particular of the bending die 6, it being noted at this point that the invention is not limited to the specifically illustrated embodiments thereof, but rather various combinations of the individual embodiments are possible with each other and this variation possibility due to Teaching for technical action by objective invention in the skill of those working in this technical field is the expert. So are all conceivable embodiments, which are possible by combinations of individual details of the illustrated and described embodiment variant, includes the scope of protection.

For the sake of order, it should finally be pointed out that for a better understanding of the construction of the bending tool 4, in particular of the bending die 6, this or its components have been shown partly unevenly and / or enlarged and / or reduced in size.

The task underlying the independent inventive solutions can be taken from the description.

Above all, the individual in the Fig. 1 ; 2 . 3 ; 4 shown embodiments form the subject of independent solutions according to the invention. The relevant objects and solutions according to the invention can be found in the detailed descriptions of these figures.

REFERENCE NUMBERS

1

manufacturing plant

2

workpiece

3

bending press

4

bending tool

5

punch

6

bending die

7

machine frame

8th

baseplate

9

side cheek

10

side cheek

11

cross-dressing

12

Front face

13

press beams

14

Front face

15

linear guide

16

press beams

17

face

18

face

19

tool holder

20

tool holder

21

drive arrangement

22

drive means

23

energy grid

24

control device

25

actuating means

26

body

27

headboard

28

end

29

bending area

30

tool plane

31

feeding

32

Workpiece support member

33

Workpiece support member

34

swivel plate

35

Workpiece holding plane

36

swivel axis

37

Retaining plate

38

end

39

40

pressure element

41

end

42

tension element

43

Workpiece support surface

44

Workpiece support surface

45

angle

46

leg

47

leg

48

angle

Claims (10)

Bending tool (4), in particular bending die (6) for a sheet metal bending press, in particular press brake for the free-form bending of workpieces to be produced from sheet metal (2), with a base body (26), wherein an end portion (28) of the base body (26) has a bending area (29), wherein seen in the cross section of the base body (26) through the bending region (29) extends a tool plane (30) and in that the bending region (29) forming end portion (28) of the base body (26) on one side of the tool level (30) a relative to the base body (26) displaceable first workpiece support member (32) and on the other side of the tool plane (30) with respect to the base body (26) fixed further workpiece support member (33) is arranged or formed, characterized in that a bending area (29) facing end portion (38) of the first and displaceably formed workpiece support member (32) is acted upon by a supporting force (F), which acting on the workpiece to be formed (2) bending force (F _B ) counteracts or that the bending region (29) facing end portion (38) of the first and displaceably formed workpiece support member (32) automatically against the force acting on the workpiece to be formed (2) bending force (F _B ) is formed recoverable. Bending tool (4) according to claim 1, characterized in that the displaceably formed first workpiece support part (32) by a pivot plate (34) is formed and the pivot plate (34) about a parallel to a workpiece support plane (35) and parallel to the tool plane (30). aligned pivot axis (36) is pivotally mounted. Bending tool (4) according to claim 1 or 2, characterized in that the first workpiece support member (32) in a portion between the bending region (29) facing end portion (38) and the pivot axis (36) is supported on a pressure element (40) and the pressure element (40) generates the supporting force (F) acting on the workpiece support part (32). Bending tool (4) according to claim 3, characterized in that the pressure element (40) is selected from the group of components of gas spring, pressure-medium-actuated cylinder, elastic pressure body, such as compression spring, elastomeric spring. Bending tool (4) according to one of the preceding claims, characterized in that the first workpiece support member (32) in a portion between the pivot axis (36) and a bending region (29) averted further end portion (41) is connected to a tension element (42) wherein the tension member (42) generates the supporting force (F) acting on the workpiece support member (32). Bending tool (10) according to claim 1, characterized in that the first workpiece support member (32) is formed by a leaf spring and the bending of the area (29) facing away from the end of the leaf spring is fixedly connected to the base body (26). Bending tool (4) according to one of the preceding claims, characterized in that the first workpiece support part (32) is arranged on that side of the tool plane (30) which forms a feed side (31) for the sheet to be bent. Bending tool (4) according to one of the preceding claims, characterized in that the fixed further workpiece support member (33) has a preferably planar formed workpiece abutment surface (44) which is aligned such that this with the tool plane (30) includes an angle (45) , which lies in an angle range between 5 ° and 50 °. Method for free-form bending of workpieces to be produced from sheet metal (2) with a sheet bending press, in particular a press brake, with a bending tool (4), comprising a bending punch (5) and a bending die (6), which together span a tool plane (30), in which the sheet metal is introduced and positioned between the bending tool (4) which is distanced from one another in a starting position, the bending process of the sheet then being carried out in a bending region (29) by a relative displacement of at least one part of the bending tool (4) and thereby on both sides of the tool plane ( 30) first and second legs (46, 47) are formed in the sheet metal, characterized in that the first leg (46), which is formed on a side of the tool plane (30) facing away from a feed side (31) of the sheet, is deformed at a greater angular velocity toward the tool plane (30) than the second leg (47) of the sheet which is adjacent to the feed side (31 ) and this second leg (47) is also deformed towards the tool plane (30). Method according to claim 9, characterized in that the first limb (46) is bent so far towards the tool plane (30) that it encloses with the tool plane (30) an angle (45) which lies in an angle range between 5 ° and 50 °.

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