BENDING MACHINE FOR BENDING FLAT MATERIAL, AND METHOD FOR BENDING SHUT A STANDING FOLD IN A FLAT MATERIAL USING THE BENDING MACHINE

Abstract

A bending machine for bending flat material, including a first clamping beam, a second clamping beam, and a first bending beam. The bending machine includes a counter-holding device for performing a counter-holding function at the flat material. The counter-holding device may include a counter-holding element. The counter-holding element is movable between a parked position, in which it is arranged at a distance from the flat material and in which the counter-holding function cannot be performed, and a counter-holding position, in which it can be in contact with the flat material to be bent and in which the counter-holding function can be performed such that that the counter-holding element is capable of counter-holding against a bending force which is applied to the flat material by means of the first bending beam when the flat material is bent about a bending axis that is spaced apart from the clamping plane.

Claims

1. A bending machine for bending flat material, comprising a first clamping beam and a second clamping beam for clamping the flat material to be bent in a clamping plane, and a first bending beam for bending the flat material wherein the bending machine comprises a counter-holding device for performing a counter-holding function at the flat material to be bent, said counter-holding device being present in addition to the first clamping beam and the second clamping beam and having a counter-holding element, wherein the counter-holding element is movable between a parked position, in which it is arranged at a distance from the flat material to be bent and the counter-holding function cannot be performed, and a counter-holding position, in which it can be in contact with the flat material (F) to be bent and the counter-holding function can be performed in such a manner that the counter-holding element is capable of counter-holding against a bending force which is applied to the flat material by means of the first bending beam when the flat material is bent about a bending axis that is spaced apart from the clamping plane.

2. The bending machine according to claim 1, wherein the counter-holding device is mounted on a machine frame of the bending machine.

3. The bending machine according to claim 2, wherein the machine frame has a machine upper part and a machine lower part, which are movable relative to one another, and the counter-holding device is mounted on the machine upper part.

4. The bending machine according to claim 1, wherein the counter-holding element has a counter-holding surface and/or a counter-holding line for contact with the flat material to be bent.

5. The bending machine according to claim 3, wherein the counter-holding device has at least one carrier arm to which the counter-holding element is fastened.

6. The bending machine according to claim 3, wherein the counter-holding device has at least one carrier arm to which the counter-holding element is fastened.

7. The bending machine according to claim 5, wherein the carrier arm is movable along a guide device between a first end position and a second end position, wherein the first end position corresponds to the parked position of the counter-holding element and the second end position corresponds to the counter-holding position of the counter-holding element.

8. The bending machine according to claim 6, wherein the carrier arm is movable along a guide device between a first end position and a second end position, wherein the first end position corresponds to the parked position of the counter-holding element and the second end position corresponds to the counter-holding position of the counter-holding element.

9. The bending machine according to claim 7, wherein the counter-holding device comprises a setting device for setting a relative location of at least the second end position of the carrier arm relative to the guide device, so that it is possible at least to set the carrier arm such that, in its second end position, it is located in a stop position which is defined by a stop of the guide device.

10. The bending machine according to claim 9, wherein the setting device is a turnbuckle.

11. The bending machine according to claim 9, wherein the stop is adjustable relative to the machine frame or to the machine upper part, and adjusting means for adjusting the stop are present, so that a spatial location of the counter-holding element in its counter-holding position is adjustable when the carrier arm is in the stop position.

12. The bending machine according to claim 8 wherein the guide device is in the form of a slotted link guide and comprises at least one guide plate which is fastened to the machine frame or to the machine upper part, wherein the at least one guide plate or the carrier arm has two slotted link tracks for defining a slotted link guide path, and wherein there are mounted on the carrier arm or on the at least one guide plate at least two slotted link blocks which are each forcibly guided in one of the two slotted link tracks, so that the carrier arm is movable in a spatially oriented defined orientation along the slotted link guide path between its first end position and its second end position.

13. The bending machine according to claim 8 wherein the guide device is in the form of a track guide having at least one track rail which is fastened to the machine frame or to the machine upper part, wherein the carrier arm is movable in the manner of a carriage along the track rail between its first end position and its second end position.

14. The bending machine according to claim 7 wherein the counter-holding device has at least one drive member for moving the carrier arm.

15. The bending machine according to claim 8, wherein the counter-holding device has at least one drive member for moving the carrier arm.

16. The bending machine according to claim 15, wherein a setting device is so arranged in a force transmission path between the drive member and the carrier arm that it is itself involved in the transmission of force between the drive member and the carrier arm.

17. The bending machine according to claim 14, wherein the bending machine has a plurality of carrier arms which together carry the counter-holding element, wherein the counter-holding device comprises a shaft, at least one first lever which is connected in a rotationally fixed manner to the shaft, and a plurality of second levers which are each connected in a rotationally fixed manner to the shaft and are each associated with one of the plurality of carrier arms, and wherein the first lever is operably connected at a point spaced apart from the shaft to the drive member, and the second levers are each operably connected at a point spaced apart from the shaft to the respective carrier element, so that, by actuation of the drive member, a torque can be transmitted to the first lever, to the shaft and to the plurality of second levers, and an actuating force can be applied to the respective carrier arm.

18. A method for bending shut a standing fold in a flat material using a bending machine which has a first clamping beam and a second clamping beam for clamping the flat material to be bent in a clamping plane, and a first bending beam for bending the flat material, wherein the bending machine comprises a counter-holding device for performing a counter-holding function at the flat material to be bent, said counter-holding device being present in addition to the first clamping beam and the second clamping beam and having a counter-holding element, wherein the counter-holding element is movable between a parked position, in which it is arranged at a distance from the flat material to be bent and the counter-holding function cannot be performed, and a counter-holding position, in which it can be in contact with the flat material to be bent and the counter-holding function can be performed in such a manner that the counter-holding element is capable of counter-holding against a bending force which is applied to the flat material by means of the first bending beam when the flat material is bent about a bending axis that is spaced apart from the clamping plane, wherein the method comprises the following steps: moving the counter-holding element from the parked position into the counter-holding position, in which it is spaced apart from the clamping plane and is able to support a first leg of the standing fold that is not to be bent, bending the standing fold shut about the bending axis by applying the bending force by means of the first bending beam to a second leg of the standing fold that is to be bent, and counter-holding against the bending force during step b) in that the first leg that is not to be bent is contacted by means of a counter-holding surface or a counter-holding line of the counter-holding element and is thereby supported.

19. The bending machine according to claim 1 wherein the counter holding element is a counter holding strip.

20. The bending machine according to claim 12, wherein the slotted link tracks are elongated holes.

Description

c) Exemplary Embodiment

[0044] An exemplary embodiment of the bending machine according to the invention and of the method according to the invention will be described hereinbelow by way of example with reference to the accompanying drawings, in which:

[0045] FIG. 1: shows a perspective view of an exemplary embodiment of the bending machine according to the invention, as seen looking from the direction of the operator side;

[0046] FIG. 2: shows a view of part of the bending machine shown in FIG. 1, looking in the direction from the left rear in FIG. 1;

[0047] FIG. 3: shows a perspective view of part of the exemplary embodiment of the bending machine according to the invention according to FIG. 1, looking in the direction from the left rear in FIG. 1, said view showing the various elements of the counter-holding device;

[0048] FIG. 4: shows an enlarged detail view from FIG. 3;

[0049] FIG. 5: shows a perspective view of a counter-holding device of the bending machine according to the invention having four carrier arms, without other components of the bending machine;

[0050] FIG. 6: shows a perspective view of part of the counter-holding device shown in FIG. 5, which shows the mechanics between the shaft and the counter-holding element, wherein the guide plates for guiding the carrier arm that is shown have been omitted;

[0051] FIG. 7: shows a sectional or side view according to arrow A-A in FIG. 2, wherein the carrier arm is in its first end position and the counter-holding element is in its parked position;

[0052] FIG. 8: shows a sectional or side view according to arrow A-A in FIG. 2, wherein the carrier arm is in its second end position and the counter-holding element is in its counter-holding position;

[0053] FIG. 9: shows an enlarged sectional representation of the two clamping beams, of the first bending beam and of the counter-holding element in preparation for bending shut a standing fold in a flat material;

[0054] FIG. 10: shows a sectional view corresponding to FIG. 9, wherein the first bending beam is in its bending start position;

[0055] FIG. 11: shows a sectional view corresponding to FIGS. 9 and 10, wherein the first bending beam is shown while it is bending the standing fold shut; and

[0056] FIG. 12: shows a sectional view corresponding to FIG. 9 to 11, wherein the first bending beam has bent the standing fold shut completely.

[0057] In the drawings, identical reference numerals identify identical elements or parts or elements or parts that correspond functionally to one another.

[0058] FIG. 1 shows an exemplary embodiment of a bending machine 1 according to the invention for bending metallic or non-metallic flat material, said machine being in the form of a so-called dual bender having a first bending beam 4, which is here arranged at the top, and a second bending beam 22, which is here arranged at the bottom. Alternatively, the bending machine 1 could also be in the form of a single bender having only one of the two bending beams 4 and 22. As is known in the case of machines of this type, the elongate bending beams 4 and 22 extend in the longitudinal direction L of the bending machine 1. As is likewise known in the case of machines of this type, the machine operator stands in front of the bending machine 1 in a transverse direction Q of the bending machine 1 which runs perpendicular to the longitudinal direction L and horizontally.

[0059] In the exemplary embodiment shown, the bending machine 1 has a total of six force introduction portions 23, with the aid of which bending forces for bending the flat material can be applied in known manner to the bending beams 4 and 22. The force introduction portions 23 can transmit the bending forces to the bending beams 4 and 22 by the swivel principle mentioned at the beginning or by the wedge principle mentioned at the beginning. The design of the possible force transmission mechanisms in the force introduction portions 23 is well known to the person skilled in the art from the prior art and will therefore not be explained further here.

[0060] In this connection, reference is explicitly made to EP 2 014 381 B1 (swivel principle) and to DE 10 2018 000 344 B3 or DE 20 2020 002 598 U1 (wedge principle) so as to incorporate the disclosure thereof relating to force transmission mechanisms in force introduction portions of the type in question into the present disclosure as the disclosure for possible designs of the force transmission mechanisms in the force introduction portions 23.

[0061] The bending machine 1 shown with its six force introduction portions 23 is also referred to as a long folding machine.

[0062] It is further known to the person skilled in the art that bending machines of the type in question both in the form of dual benders and in the form of single benders always have two clamping beams for firmly clamping the flat material to be bent in a clamping plane. In FIG. 1, only a small piece of a first clamping beam 2, which is here located above the clamping plane, can be seen in the left-hand region of the figure. A second clamping beam 3 located below the clamping plane is not visible in FIG. 1. It can be seen in FIG. 7 to 12.

[0063] FIG. 2 to 6 in particular show a counter-holding device 5 for performing a counter-holding function at the flat material to be bent (see FIG. 5), or individual parts thereof (see FIG. 2 to 4 and 6).

[0064] FIG. 5 shows a counter-holding device 5 for performing the counter-holding function at the flat material to be bent. In order to prevent details in the drawing from becoming too small, FIG. 5 shows a counter-holding device 5 which is shorter than the one that is used in the bending machine 1 according to FIG. 1. In the exemplary embodiment shown, the counter-holding device comprises a pneumatic cylinder 17, which functions as a drive member. A drive rod 24 of the pneumatic cylinder 17 is articulated with a first lever 20, which in turn is connected in a rotationally fixed manner to a shaft 19. In FIG. 5, a total of four second levers 21 are arranged on the shaft 19, each of which levers is connected in a rotationally fixed manner to the shaft 19.

[0065] Instead of the pneumatic cylinder 17, the drive member can also be in the form of an electric servomotor or in the form of a hydraulic cylinder. As the length of the bending machine 1 in the longitudinal direction L increases, two or more drive members can be arranged spaced apart in the longitudinal direction L, as required.

[0066] In the detail view according to FIG. 6 it is shown by way of example how one of the second levers 21 is seated in a rotationally fixed manner on the shaft 19. At its end remote from the shaft 19, the lever 21 is articulated with a setting device, which in the exemplary embodiment shown is in the form of a turnbuckle 18 known per se. The setting functionality of the turnbuckle 18 will be described hereinbelow. At its end remote from the lever 21, the turnbuckle 18 is articulated with a carrier arm 10, which here is flat in the manner of a plate. A counter-holding element in the form of a counter-holding strip 6 is fastened to the carrier arm 10 visible in FIG. 6. A holding clamp 7 is used for this purpose. In FIG. 5, the counter-holding strip 6 is carried or held by a total of four carrier arms 10.

[0067] Each of the carrier arms 10 is movable by means of a guide device between a first end position and a second end position. In the exemplary embodiment shown, the guide device is formed by a slotted link guide and comprises in each case two guide plates 11, 12, which can best be seen in FIG. 4. The guide plates 11, 12 are arranged to run parallel to one another and form between them an intermediate space in which the respective carrier arm 10 is received at least in part.

[0068] For better visibility of the carrier arm 10, the guide plates 11, 12 are not shown in the drawing of FIG. 6. In the exemplary embodiment shown, each of the two guide plates 11, 12 has two slotted link tracks in the form of two elongated holes 13, 14, for example. As can best be seen in FIG. 6, the carrier arm 10 has on each of its sides two slotted link blocks which here are in the form of two rotatably mounted slotted link rollers 15, 16. The slotted link rollers 15, 16 have a running groove, visible in FIG. 6, into which the contour edges of the elongated holes 13, 14 can engage. The carrier arm 10 which can be seen in FIG. 6 is accordingly equipped with a total of four slotted link rollers 15, 16, of which only three are visible.

[0069] In the exemplary embodiment shown, the guide plates 11, 12 are fixedly connected to a machine upper part 8 (see FIGS. 1, 2 and 3), which extends in the longitudinal direction L over the entire length of the bending machine 1. The machine upper part 8 is movable in known manner relative to the machine lower part 9 marked in FIG. 1, so that the clamping beams 2, 3 can in known manner be moved towards one another for clamping the flat material and away from one another for releasing the flat material.

[0070] The fixed connection of the guide plates 11, 12 to the machine upper part 8 takes place by means of holders, which are fastened on the one hand to the machine upper part 8 and on the other hand to the respective guide plate 11 or 12. In FIGS. 2 and 3, holders 25 can be seen which fixedly connect the guide plate 12 to the machine upper part 8. There are also corresponding holders for fastening the guide plate 11 to the machine upper part 8, but these are not shown in the drawings. The holders 25 are fastened to the guide plates 11, 12 using fastening brackets 26, which can best be seen in FIGS. 3 and 5.

[0071] As is shown in FIG. 2 to 6, the shaft 19 is mounted in a plurality of shaft bearings 27. Some of these shaft bearings 27 are fastened to the guide plates 11, 12. Others of these shaft bearings 27 are fixedly connected to the machine upper part 8 by means of fastening flanges 28.

[0072] As can best be seen in FIGS. 2, 3 and 4, the pneumatic cylinder 17 is supported on a support element 29, which here is in the form of an elongate square profile. The support element 29 is in turn fastened to the machine upper part 8.

[0073] In the exemplary embodiment shown, the entire counter-holding device 5, which can be seen in FIG. 5, is thus movable together with the machine upper part 8. The support element 29, the fastening flange 28 (see FIG. 2 to 4), the shaft bearings 27, the guide plates 11, 12 and the fastening brackets 26 are not movable at all relative to the machine upper part 8. Components of the counter-holding device 5 that are movable relative to the machine upper part 8 are the pneumatic cylinder 17 (slight pivoting movement), the drive rod 24, the first lever 20, the shaft 19 (only in rotation, not in translation), the second levers 21, the turnbuckles 18, the carrier arms 10 with their slotted link rollers 15, 16, and the counter-holding strip 16.

[0074] FIGS. 7 and 8 show sectional and side views looking in the direction of the arrow A-A in FIG. 2. For reasons of clarity of the drawings, parts that are not important for the functionality that is to be described have been omitted from FIGS. 7 and 8.

[0075] FIG. 7 shows one of the carrier arms 10 in a first end position, in which it is located furthest to the right and furthest at the top corresponding to the bent profile of the elongated holes 13, 14 in FIG. 7. In the first end position of the carrier arm 10, the counter-holding strip 6 is in a parked position, in which it is arranged at a distance, in particular horizontally, from a flat material F to be bent and cannot perform a counter-holding function at the flat material F. In its parked position, the counter-holding strip 6 is in particular spaced apart from the front, or in FIG. 7 the left, ends of the clamping beams 2, 3.

[0076] When the counter-holding strip 6 is in the parked position, the clamping beams 2, 3 are thus able to perform unhindered their conventional clamping function, in which they clamp the flat material F between them in a clamping plane E and thus hold it securely for planned bending operations. In order to perform this conventional clamping function, the upper clamping beam 2 in FIG. 7 would be moved downwards in order to firmly clamp the flat material F in the clamping plane E.

[0077] In the first end position of the carrier arm 10, or in the parked position of the counter-holding strip 6, which are shown in FIG. 7, the drive rod 24 of the pneumatic cylinder 17 is located in its maximum retracted position. Accordingly, the lever 20 is located in a rotational position which corresponds to its end position in the clockwise direction.

[0078] In FIG. 8, the carrier arm 10 which can be seen in FIG. 7 is shown in a second end position, in which it is located furthest to the left and furthest at the bottom corresponding to the bent profile of the elongated holes 13, 14 in FIG. 8. As the carrier arm 10 moved from its first end position shown in FIG. 7 into its second end position shown in FIG. 8, the counter-holding strip 6 moved from its parked position shown in FIG. 7 into a counter-holding position shown in FIG. 8. In its counter-holding position, the counter-holding strip 6 can come into contact with or be in contact with the flat material F to be bent and can support it during a bending operation.

[0079] FIG. 8 shows how the counter-holding strip 6 counter-holds from the right against a standing fold of the flat material F that has already been bent shut completely, or has been closed completely. In the counter-holding position according to FIG. 8, the counter-holding strip 6 is thus able to perform its counter-holding function as intended.

[0080] Before the counter-holding strip 6 was moved into the counter-holding position shown in FIG. 8, an electronic controller (not shown) of the bending machine 1 caused the two clamping beams 2, 3 to open in that the clamping beam 2 that here is the upper clamping beam moves upwards away from the lower clamping beam 3 and from the clamping plane E. As can be seen in FIGS. 7 and 8 (and in FIG. 9 to 12), this creates the space which the counter-holding strip 6 needs to move between the clamping beams 2, 3 from its parked position shown in FIG. 7 into its counter-holding position shown in FIG. 8.

[0081] As can be seen in FIG. 8, the drive rod 24 of the pneumatic cylinder 17 has been extended completely in order to move the carrier arm 10 into its second end position. The lever 20 that transmits the drive force of the drive rod 24 to the shaft 19 is accordingly in a rotational position that corresponds to its end position in the anti-clockwise direction. Furthermore, in FIG. 8 the pneumatic cylinder 17 has pivoted anti-clockwise slightly compared to its position in FIG. 7.

[0082] A method for bending shut a standing fold in the flat material F using the bending machine 1 according to the invention is illustrated in FIG. 9 to 12. Only the upper bending beam 4 is shown in FIG. 9 to 12. Because the bending machine 1 is in the form of a dual bender, it also has the lower bending beam 22 which is visible in FIG. 1 and has been omitted from the drawing of FIG. 9 to 12.

[0083] If required, the bending beams 4, 22, in known manner, can have at their ends that come into contact with the flat material F during bending separate bending segments and in addition optionally further supplementary bending segments, which are detachably mounted at those ends. Such bending segments and supplementary bending segments are not present in the exemplary embodiment shown and are therefore not shown in FIG. 9 to 12.

[0084] Similarly, if required, the clamping beams 2, 3, in known manner, can have at their ends that come into contact with the flat material F on clamping in the clamping plane E separate clamping segments, which are detachably mounted at those ends. Such clamping segments are also not present in the exemplary embodiment shown and are therefore not shown in FIG. 9 to 12.

[0085] In FIG. 9, the flat material F is shown in an already pre-bent state, in which it has an open standing fold, that is to say a standing fold that has not yet been bent shut. In order to achieve the state of the flat material F shown in FIG. 9, it has already been bent twice in a manner known per se. In order to produce a leg S.sub.2, a bend through 135 from top to bottom was first made by means of the bending beam 4. Thenafter displacement of the flat material F within the clamping plane Ea further bend through 90 from bottom to top was made by means of the lower bending beam 22 (not shown in FIG. 9) in order to produce a leg S1. In the course of these two bending operations, the open standing fold shown in FIG. 9 having the first leg S.sub.1 and the second leg S.sub.2, which have an opening angle of 45 between them, was formed. During each of the two preceding bending operations, the flat material F was firmly clamped in the clamping plane E between the upper clamping beam 2 and the lower clamping beam 3.

[0086] The operation of bending shut the standing fold consists in bending the leg S.sub.2 anti-clockwise through 45 in the direction towards the leg S.sub.1. During this bending operation, the bending axis B lies in known manner at the upper tip of the standing fold in FIG. 9, that is to say substantially at the line of intersection of the legs S.sub.1 and S.sub.2. As can be seen, this bending axis B does not lie in the clamping plane E but is spaced apart upwards therefrom substantially by the length of the leg S.sub.1.

[0087] Before the operation of bending shut the standing fold in the above-mentioned sense is begun, the pneumatic cylinder 17 is actuated in such a manner that it extends its drive rod 24 and moves the lever 20 into its rotational position shown in FIG. 8. As a result, a torque acting in the anti-clockwise direction in FIGS. 7 and 8 is transmitted to the shaft 19. The shaft 19, which thus rotates, transmits this torque to the plurality of levers 21, so that each of the levers 21 moves or presses the carrier arm 10 associated therewith from its first end position shown in FIG. 7 into its second end position shown in FIG. 8. Accordingly, the counter-holding strip 6 held by the carrier arms 10 moves from its parked position shown in FIG. 7 into its counter-holding position shown in FIG. 8.

[0088] When the respective carrier arm 10 is pressed by means of the respective lever 21, the actuating force required therefor is transmitted to the carrier arm 10 in each case by way of the turnbuckle 18. After this feed movement, the counter-holding strip 6 is in its counter-holding position shown in FIG. 9 to 12.

[0089] In the exemplary embodiment shown, the counter-holding element consists of an elongate counter-holding strip 6 having a rectangular cross section, which can best be seen in FIG. 9 to 12. The counter-holding strip 6 is fixedly connected to the respective carrier arm 10 by way of the holding clamp 7. As can be seen in FIG. 9 to 12, the counter-holding strip 6, for counter-holding, abuts the leg S.sub.1 from the right with the short side of its rectangular cross section. Accordingly, the counter-holding strip 6 abuts the leg S.sub.1 along a large-area contact strip, the width of which here corresponds to the length of the short rectangle side, over the entire length of the standing fold running in the longitudinal direction L of the bending machine 1.

[0090] If required, the short side of the rectangular cross section of the counter-holding strip 6 can also be made longer than is shown in the present exemplary embodiment. A wider, large-area contact strip would then be achieved, which distributes the counter-holding force over an even larger area and would thus contribute even better to the avoidance of undesirable imprints on the right-hand side of the leg S1 in FIG. 9. Because the formation of a large-area contact strip is independent of the overall geometry of the cross section of the counter-holding strip 6, the cross section of the counter-holding strip 6 can of course also have a cross-sectional shape other than a rectangle, for example a square shape, triangular shape, trapezium shape, hexagonal shape or the like.

[0091] In order to bend the standing fold shut, the bending beam 4 is first moved from its position shown in FIG. 9 into the bending start position shown in FIG. 10. In this bending start position, the bending beam 4, as shown in FIG. 10, abuts the leg S.sub.2. In the bending start position of the bending beam 4, a bending force is not yet exerted on the leg S.sub.2.

[0092] The bending beam 4 is then moved further into the intermediate position shown in FIG. 11. While it is being moved from the bending start position shown in FIG. 10 into the intermediate position shown in FIG. 11, the bending beam 4 subjects the leg S.sub.2 to a bending force, which bends it about the bending axis B in the anti-clockwise direction in the direction towards the leg S1.

[0093] Starting from the intermediate position according to FIG. 11, the bending beam 4 is finally moved further until it reaches its bending end position shown in FIG. 12, in which the standing fold is completely bent shut, or closed. The overlapping length portions of the legs S.sub.1 and S.sub.2 then lie substantially against one another, or run substantially parallel to one another. The finished standing fold can thus be seen in FIG. 12. It can also be seen at bottom left in FIGS. 7 and 8.

[0094] During the operation of bending the leg S.sub.2 from its bending start position shown in FIG. 10 into its bending end position shown in FIG. 12, the bending force applied by the bending beam 4 to the leg S.sub.2 attempts to bend the other leg S.sub.1 in the clockwise direction. It is precisely this that is prevented by the counter-holding strip 6, in that it counter-holds against the above-mentioned bending force. Neither the upper clamping beam 2 nor the lower clamping beam 3 are involved in this counter-holding process, in which counter-holding is carried out from the right in FIG. 10 to 12. The clamping beams 2 and 3 can be designed in the case of the bending machine 1 in the same manner as in conventional bending machines, or long folding machines, which have long been known from the prior art. The geometry of the counter-holding strip 6, in particular the geometry of the contact surface or of a contact line between the counter-holding strip 6 and the leg S.sub.1, can be designed solely in accordance with the requirements of the counter-holding function.

[0095] In the exemplary embodiment shown, the carrier arms 10 in their respective second end positions according to FIG. 8 are in a stop position. In this stop position, the slotted link rollers 15, 16 abut the stops 30, 31, which are marked in FIGS. 3 and 7 and are formed by the left-hand ends in FIGS. 7 and 8 of the elongated holes 13, 14.

[0096] The spatial position of the second end position of the respective carrier arm 10 is determined by the maximum stroke of the drive rod 24 of the pneumatic cylinder 17. By rotation of the turnbuckle 18, the distance between the lever 21 and the carrier arm 10 (see FIG. 6) can be so changed or set that the slotted link rollers 15, 16 abut the stops 30, 31 in the second end position of the respective carrier arm 10 and are pressed against the stops 30, 31 with a certain stop force.

[0097] The stop force can thus be set in dependence on the counter-holding forces that are to be applied in an individual case, by rotation of the turnbuckle 18. The counter-holding strip 6 is thus held in a mechanically particularly spatially stable manner in its counter-holding position over its entire length during counter-holding.

[0098] In addition, the setting device, which in the exemplary embodiment shown is in the form of the turnbuckle 18, makes it possible for a second end position of the respective carrier arm 10 to be set in which it does not occupy its stop position but, in accordance with the maximum stroke of the drive rod 24, already stops at a position before the stop position is reached. The slotted link rollers 15, 16 then do not abut the stops 30, 31 and consequently are not in contact therewith. In this manner, it is possible in principle to set a second end position of the carrier arm 10 that is different from the stop position, which results in a counter-holding position of the counter-holding strip 6 that is different from the counter-holding position of the counter-holding strip 6 that is associated with the stop position of the carrier arm 10.

[0099] If, as in the exemplary embodiment shown, the stop position of the respective carrier arm 10 is provided as the second end position thereof, the spatial location of the counter-holding strip 6 in its counter-holding position is specified by the stop position. The relative location of the counter-holding position relative to the stop position cannot be changed by means of the turnbuckle 18.

[0100] In order for it to be possible in this case to adjust the spatial location of the counter-holding strip 6 in its counter-holding position in dependence on the counter-holding requirements, the shaft bearings 27, the shaft 19 and the guide plates 11, 12 can be mounted on the machine frame 8 so as to be adjustable relative thereto. For adjusting the shaft bearings 27, the shaft 19 and the guide plates 11, 12, adjusting means in the form of adjusting screws, for example, can be provided at the ends of the guide plates 11, 12 that are remote from the counter-holding strip 6 and/or at the shaft bearings 27. Alternatively or in addition, it is conceivable in this connection to mount the counter-holding strip 6 on the carrier arms 10 so as to be adjustable relative thereto and to provide in this connection adjusting screws for adjusting the counter-holding strip 6.

LIST OF REFERENCE SIGNS

[0101] 1 Bending machine [0102] 2 First clamping beam [0103] 3 Second clamping beam [0104] 4 First bending beam [0105] 5 Counter-holding device [0106] 6 Counter-holding element, counter-holding strip [0107] 7 Holding clamp for fastening the counter-holding strip 6 to the carrier arm 10 [0108] 8 Machine upper part [0109] 9 Machine lower part [0110] 10 Carrier arm [0111] 11 Guide plate [0112] 12 Guide plate [0113] 13 Slotted link track, elongated hole [0114] 14 Slotted link track, elongated hole [0115] 15 Slotted link block, slotted link roller [0116] 16 Slotted link block, slotted link roller [0117] 17 Drive member, servomotor [0118] 18 Setting device, turnbuckle [0119] 19 Shaft [0120] 20 First lever [0121] 21 Second lever [0122] 22 Second bending beam [0123] 23 Force introduction portions [0124] 24 Drive rod of the drive member 17 [0125] 25 Holder for holding the guide plate 12 [0126] 26 Fastening bracket for fastening the holder 25 [0127] 27 Shaft bearing [0128] 28 Fastening flange for fastening shaft bearings 27 to the machine upper part 8 [0129] 29 Support element for supporting the drive member 17 [0130] 30 Stop of the elongated hole 13 [0131] 31 Stop of the elongated hole 14 [0132] B Bending axis [0133] E Clamping plane [0134] F Flat material [0135] L Longitudinal direction of the bending machine 1 [0136] Q Transverse direction of the bending machine 1 [0137] S.sub.1 First leg of the standing fold [0138] S.sub.2 Second leg of the standing fold