EP2726227B1 - Bending press with a folding apparatus and method for carrying out folding - Google Patents

Description

The invention relates to a bending press with a folding device, in particular a press brake, and a method for performing a folding by means of a bending press, in particular a press brake, as specified in claims 1 and 13.

From the prior art, for example AT 505 656 A4 . DE 43 15 706 A1 . EP 0 096 211 A1 . JP 10-137 852 A and US 4,805,438 A , Benders for bending presses are known, which require special and complex upper and lower tools. These special, sometimes multi-stage tools are often relatively expensive. In many cases, these folding devices require a tool change or a displacement of the lower tool tray before a folding can be performed. This results in an increased set-up time during a manufacturing or machining process. For the activation or movement of the folding tools, additional drives and locking devices are sometimes required. When carrying out a bending operation and a subsequent folding operation, the pure processing time is usually considerably increased, since the pressing beam of the bending press usually has to be lowered twice in succession and at least partially raised again.

The present invention has for its object to provide a bending press with a folding device, in particular a press brake, which allows shorter set-up and processing times and at the same time keeps the tooling costs low. Moreover, it is an object of the invention to provide a method for performing a folding by means of a bending press, in particular a press brake, with which the stated objects are achieved.

The first object of the invention is achieved by a bending press according to the features in claim 1.

For this purpose, the movable pressing beam of the bending press is provided with an upwardly directed, in particular horizontal, bearing surface for the workpiece, and a stamping surface which is parallel to and aligned with the bearing surface is arranged above it. Support surface and embossing surface together form the folding device of the bending press and in an upper end position or end position of the press beam, the two surfaces touch each other or form a gap of less than 0.5 mm. When the press beam is lowered or when it is extended in the direction of its lower end position or end position, the support surface and the embossing surface of the folding device are spaced and a particular pre-processed, ie pre-bent or pre-canted workpiece is positioned between the two surfaces. By raising or retracting the press beam in the direction of its upper end position or end position, the support surface and the embossing surface are now moved toward one another and, in particular, pressed against one another and the workpiece is provided with a folding bender. It is essential that the bending device of the bending press comprising a bending punch and a bending die is formed independently of the folding device comprising the support surface and the embossing surface. The bearing surface of the folding device is formed on the pressing beam of the bending press, so that a part of the press beam is used as a folded seam. Due to the independence of the bending device and the folding device a very flexible and optimized design of the two devices is possible on the respective purpose. Thus, in particular a simple and compact design of the folding device is possible, which is optimally adapted to the desired folding process. A separate, special folding tool is not necessary and a conversion of the bending press between the bending operation and the folding process, in particular a change of the upper and / or lower tools or a displacement of the lower tool tray is not necessary. A bending press with the specified folding device thus has shorter set-up or changeover times and does not require complicated, expensive and / or only suboptimal usable for folding special tools.

A particularly surprising advantage of a bending press with the specified folding device is the reduction of the processing time compared to the known from the prior art bending presses, which are also used for folding and thereby doing an additional press beam movement, in particular a second movement of the press bar down. Such additional pressing beam movement is not necessary with the specified folding device and therefore the processing time is reduced, since with the pressing beam movement upwards, which must also be carried out when carrying out a bending operation alone, the folding operation is performed at the same time.

The folding device thus allows the operation of a bending press for bending and folding of workpieces with reduced set-up, conversion and processing times and also avoids the use of complex and expensive additional or special tools, especially in the implementation of the folding process. This allows a more efficient and cost-effective operation of the bending press.

An advantage of this is an embodiment according to claim 2, characterized in that a displacement of the support surface for the workpiece is achieved down, so that the workpiece by a user of the bending press in a simple manner and in particular from the location at which he is also at Performing a bending process is located on the support surface is positionable. Since the lower edge of the frame upper part is often not accessible to an operator without aids and this lower edge defines the lowest position of the embossing surface in a folding device in which no folding punch is present, such an embodiment would have to use an automated bending press with a bending robot, Because of its greater radius of action, it can also reach the area at the lower edge of the upper frame part or the upper side of the press bar in its upper end position or end position. A fundamental advantage is further that in the folding device of the bending punch of the bending press is not used at the same time as a hemming, as a more flexible, simpler and more compact design of the folding device is possible.

Of advantage are the measures according to claim 3, as a particularly simple, robust and easily accessible or visible support surface is created for the workpiece.

In the alternative embodiment according to claim 4, it is advantageous that a folding device integrated in the pressing beam is provided, in which the bearing surface of the folding device lies substantially in one plane with the in particular two drive cylinders of the pressing beam and thus no lever moment on the pressing beam or during the folding operation The drive cylinder acts. Furthermore, in the embodiment according to claim 4, it is advantageous that no protruding extensions are formed on the pressing beam, which could collide with a workpiece, for example, and that no additional components are required in the production of the pressing beam with integrated folding device. The bottom in the recess arranged bearing surface is easily accessible through the front and / or rear opening in the corresponding side surface of the press beam.

In an embodiment according to claim 4, in which the recess is accessible via the front opening in the front side surface and the rear opening in the rear side surface of the press beam, another great advantage is provided by the free press space behind the folding device or behind the pressing beam given. By this clearance, it is possible to use the folding device, for example, for pressing threaded passages or Einpressmuttern in the workpiece, as a protruding part of the workpiece can protrude through the rear opening in the free press room.

Also advantageous are the measures according to claim 5, since thereby the folding device or the recess with the support surface by the operator of the press brake is easily accessible and a possible symmetrical pressure load for the drive cylinder of the press beam is reached. This applies in particular to the case in which two drive cylinders are arranged symmetrically in each case over one side of the press beam and move it up and down in the vertical direction.

In the measures according to claim 6 is of advantage that the stability of the press bar is not significantly or not too greatly reduced by the recess and sufficient force transmission is ensured by the press bar on the punch even with existing folding device or recess in the press bar.

Another advantage is the measures according to claim 7, as this one hand, in a simple manner, a stop for the workpiece is created in the recess and on the other hand penetration of any kind of foreign bodies on the rear opening in the recess is completely prevented.

Of particular advantage are furthermore the measures according to claim 8, since this gives a symmetrical and very stable cross-section of the press beam. In addition, as a result of these measures, the folding punch, whose stamping surface on the underside and the bearing surface in the recess of the press beam, viewed in cross section, are arranged exactly on a line with the center axes of, in particular, two drive cylinders of the press beam be, which is essentially excluded during folding a lever moment about the longitudinal axis of the press bar. As a result, the mechanical load, in particular the piston of the drive cylinder of the press beam is reduced.

Another advantage is an embodiment according to claim 9, since thereby a sliding along side surfaces of the folding punch and the press bar is reduced to a minimum and thereby mechanical abrasion or abrasion effects are particularly inferred. Likewise, a visible orientation possibility is created by a visible positioning of the folding punch or the lower part of the folding punch on the pressing beam for the operator of the folding device exactly where the workpiece or semi-finished product must be positioned on the support surface so that it is folded by the approaching embossing surface. This is therefore particularly easy to recognize for the operator of the folding device in such a configuration, since even with completely lowered press beams, the support surface for the workpiece and the embossing surface must be spaced vertically only to the extent that the workpiece to be folded between these two surfaces can be positioned ,

Also of advantage are the measures according to claim 10, since on the one hand, the stability of the press bar is sufficiently ensured to carry out the bending operation and the folding process. On the other hand, thereby the support surface for the workpiece by the operator of the folding device is simple and without tools, especially from the location where he is also in the implementation of a bending process, accessible.

In the measures according to claim 11 it is advantageous that a particularly robust or simple and therefore cheaper construction of the folding device or its bearing surface and embossing surface is given.

Another advantage is the measures of claim 12, since a very flexible folding device is created, with the particular several different folding operations without tool change are feasible.

The object of the invention, in particular the second mentioned object of the invention, is solved independently by a method according to claim 13.

The achieved by the measures according to claim 13, technical effects or advantages can be found in the preceding description parts, in particular the Vorteilsnennungen to claim 1.

Also advantageous are the measures according to claim 14, since starting immediately from the rest or neutral position of the press beam without further movement of the press beam either a bending or bending or folding operation by moving the press beam downwards or upwards can be. By setting the rest or neutral position of the press bar closer to the upper than to the lower end position or end position, a faster folding process is possible because when folding or pressing a shorter press gear must be moved.

Finally, the measures according to claim 15 are advantageous, as this speeds up the manufacturing process for a combined bending and folding work piece, since the bending or folding operation and the subsequent folding operation on the pre-bent semi-finished product for producing the bent and folded finished product is carried out in one work process. The workflow includes a movement of the press bar down and a movement of the press bar upwards. An intermediate storage of the semifinished product is thereby avoided, whereby the logistical effort in the production of the bending folding work piece is reduced.

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

Fig. 1

eine Vorderansicht einer Biegepresse mit einer Falzvorrichtung in Form einer Aussparung im Pressbalken;

Fig. 2

eine Schnittdarstellung des Pressbalkens der Biegepresse aus Fig. 1 im Bereich der Falzvorrichtung entlang der Linie II-II;

Fig. 3

eine Vorderansicht einer Biegepresse mit einer Falzvorrichtung mit mehreren Paaren einer Auflagefläche und einer korrespondierenden Prägefläche in unterschiedlichen Ausführungsformen;

Fig. 4

eine Schnittdarstellung des Pressbalkens der Biegepresse aus Fig. 3 im Bereich des ersten Paares einer Auflagefläche und einer korrespondierenden Prägefläche entlang der Linie IV-IV;

Fig. 5

eine Schnittdarstellung des Pressbalkens der Biegepresse aus Fig. 3 im Bereich des zweiten Paares einer Auflagefläche und einer korrespondierenden Prägefläche entlang der Linie V-V;

Fig. 6

eine Vorderansicht einer Biegepresse mit einer Falzvorrichtung gemäß einer weiteren, alternativen Ausführungsform und

Fig. 7

eine Schnittdarstellung des Pressbalkens der Biegepresse aus Fig. 6 im Bereich der weiteren, alternativen Falzvorrichtung entlang der Linie VII-VII.

In each case, in a highly simplified, schematic representation:

Fig. 1

a front view of a bending press with a folding device in the form of a recess in the pressing beam;

Fig. 2

a sectional view of the press beam of the bending press Fig. 1 in the region of the folding device along the line II-II;

Fig. 3

a front view of a bending press with a folding device having a plurality of pairs of a support surface and a corresponding embossing surface in different embodiments;

Fig. 4

a sectional view of the press beam of the bending press Fig. 3 in the region of the first pair of a contact surface and a corresponding embossing surface along the line IV-IV;

Fig. 5

a sectional view of the press beam of the bending press Fig. 3 in the region of the second pair of a contact surface and a corresponding embossing surface along the line VV;

Fig. 6

a front view of a bending press with a folding device according to another alternative embodiment and

Fig. 7

a sectional view of the press beam of the bending press Fig. 6 in the area of the further alternative folding device along the line VII-VII.

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 location information chosen in the description, such as top, bottom, side, etc. related to the immediately described and illustrated figure and these position information in a change in position mutatis mutandis to transfer to the new location.

All statements on ranges of values in objective description are to be understood as including any and all sub-ranges thereof, eg the indication 1 to 10 should be understood to include all sub-ranges, starting from the lower limit 1 and the upper limit 10 ie, all sub-regions begin with a lower limit of 1 or greater and end at an upper limit of 10 or less, eg, 1 to 1.7, or 3.2 to 8.1, or 5.5 to 10.

In the Fig. 1 and 2 is a bending press 1 with a first embodiment of a folding device 2 for producing a Falzbugs 3 on a workpiece 4 shown.

The bending press 1 is basically constructed of a fixed frame shell 5 and an associated fixed frame base 6. The lower frame 6 is designed in the form of a table and rests stable with its underside on a bottom-level riot level, in particular on the floor of a workshop building. At the top of the frame base 6, a bending die 7 is arranged, which has an accessible from above, V-shaped recess or groove. During the execution of a bending operation, a bending punch 8 is countersunk into the V-shaped recess of the bending die 7, and a workpiece 4 placed on the upper side of the bending die 7, between the bending die 7 and the punch 8, is bent or folded. The punch 8 is connected via a coupling means 14 fixed to a pressing bar 9, which pressing bar 9 in turn by a drive means, in particular of two drive cylinders 10, 11 via two drive pistons 12, 13, vertically moved up and down. The drive means moves or guides the pressing bar 9 and thus the bending punch 8 in the vertical direction between an upper end position (top dead center) and a lower end position (bottom dead center), preferably in the lower end position of the bending operation is performed ,

The bending punch 8 may be made in one piece, for example, if very wide workpieces 4 are to be processed, or it may also be designed to be split, such as, inter alia Fig. 1 shown. The smaller pressing surface of such a split punch 8 allows for the same pressing force a higher bending pressure on the workpiece 4. The drive cylinder 10, 11 are fixedly connected to the frame upper part 5. The frame upper part 5 comprises a transverse bar which is arranged parallel to the pressing beam 9 and above it.

It is particularly useful now to use the force when driving the press beam 9, in particular at an upper end position or end position of the press beam 9, for folding or pressing and to equip the correspondingly positioned workpiece 4 with a folding bender 3. For this purpose, an upwardly directed, in particular horizontal support surface 15 for the workpiece 4 is formed on the pressing beam 9. In addition, a parallel to the support surface 15 and aligned against this embossing surface 16 of the folding device 2 is arranged. In an upper end position or end position of the press beam 9, the embossing surface 16 and the support surface 15 touch or form a gap 17 of less than 0.5 mm. When lowering or extending the press beam 9, the embossing surface 16 and the support surface 15 move apart and are thereby spaced such that in particular the pre-bent or pre-identified workpiece 4 between the embossing surface 16 and bearing surface 15 can be positioned. During subsequent drive-up or retraction of the press beam 9, the support surface 15 and the embossing surface 16 move toward each other again and provide the workpiece 4 positioned therebetween with the folding bender 3. It is essential in this bending press 1 that on one side the bending device comprising the bending punch 8 and the bending die 7 and on the other side the folding device 2 comprising the support surface 15 and the embossing surface 16 are formed and arranged separately and substantially independently of each other, whereby both devices can be optimally adapted to the requirements of the respective processing operation.

Preferably, the folding device 2 is equipped with a folding punch 18, on the underside of the embossing surface 16 is formed. The folding punch 18 is fixedly connected to the frame upper part 5 and is above a lower edge 19 of the upper frame part 5 down in the direction of the pressing bar 9 and the support surface 15 of the workpiece 4 from.

According to a particularly advantageous embodiment, an elongate, in particular milled recess 20 is formed in the press beam 9, whose bottom end surface forms the bearing surface 15 for the workpiece 4. The recess 20 is via a front opening 21 in a front side surface 22 and / or via a rear opening 23 - see Fig. 5 - In a rear side surface 24 of the press beam 9 accessible. In the in the Fig. 1 and 2 illustrated embodiment of the folding device 2, the recess 20 is accessible only via the front opening 21, since the back of the recess 20 is closed by a rear end wall 25.

It is also particularly expedient to perform the pressing bar 9 slotted over the recess 20 and to move the folding punch 18 in this slot 26. In the upper end position or end position of the pressing bar 9, the folding punch 18 projects through the slot 26 into the recess 20 and into the bearing surface 15 of the recess 20 and the embossing surface 16 of the folding punch 18 approach each other at least up to the minimum gap 17. As a result, the workpiece 4 positioned on the support surface 15 is folded.

Advantageously, the recess 20 and the support surface 15 of the folding device 2 along a width 27 of the press beam 9 is arranged in its central portion. It is also expedient to extend the recess 20 or the support surface 15 to a maximum of 1/5 of the width 27 of the press beam 9. Likewise, it is expedient to arrange the support surface 15 of the workpiece 4 and thus, for example, the recess 20 of the press beam 9 vertically seen in the middle third of a height 28 of the press beam 9.

It is expedient to set a rest or neutral position of the press beam 9 between the upper end position or end position and the lower end position or end position of the press beam 9, preferably closer to the upper end position or end position. This makes it possible starting from the rest or neutral position, directly by moving the press bar 9 up a folding and run by moving the press bar 9 down a bending or bending operation. Likewise, it is expedient first to perform a bending or bending operation for producing a semifinished product with the bending device of the bending press 1 and then to perform a folding operation on the semifinished product for producing a finished product with the folding device 2.

The Fig. 3 to 5 a bending press 1 is shown with further exemplary embodiments of a folding device 2 for producing a Falzbugs 3 on a workpiece 4.

The folding device 2 in Fig. 3 has two pairs of a bearing surface 15 and a corresponding embossing surface 16. When left pair of the support surface 15 and the embossing surface 16 of the folding punch 18 is executed divided and arranged on or in front of the front side surface 22 of the press beam 9, as best of the sectional view in Fig. 4 can be seen. The folding punch 18 is divided into an upper part 29 and a lower part 30. The upper part 29 of the folding punch 18 is fixedly connected to the frame upper part 5 and has an underside 31. If the pressing bar 9 is in its upper end position or end position, the underside 31 of the upper part 29 of the folding punch 18 presses an upper side 32 of the lower part 30 of the folding punch 18 and thus the lower part 30 of the folding punch 18 downwards in the direction of or towards on a projection 33. The projecting extension 33 is at the front Formed between the embossing surface 16 of the lower part 30 of the seaming die 18 and the support surface 15 of the extension 33 workpiece 4 is thus in the upper end position or End position of the press bar 9 is provided with a Falzbug 3.

The lower part 30 of the folding punch 18 is further supported or mounted on guide bars 34 and spring elements 35 in the vertical direction movable on the pressing bar 9. Does the upper part 29 of the folding die 18 with its bottom 31 is not on the top 32 of the lower part 30 of the seaming die 18, the spring elements 35 press the lower part 30 of the seaming die 18 up against stops 36 and the lower part 30 of the seaming die 18th is in a rest position in which the embossing surface 16 and the support surface 15 are spaced from each other. In particular, when the pressing bar 9 is lowered and is in its lower end position or end position, the lower part 30 of the folding punch 18 is in the rest position.

According to an embodiment, not shown, it is also possible to perform the entire folding punch 18 separated from the frame upper part 5 and to store in the vertical direction movable on the pressing beam 9 and to support. In the upper end position or end position of the press beam 9, the movable folding punch 18 is then pressed from a lower side 37 of the frame upper part 5 against the force of the spring elements 35 from a rest position in the direction of the support surface 15 of the workpiece 4.

According to an alternative embodiment of a support surface 15 and an embossing surface 16, which on the right side of the press beam 9 in Fig. 3 and in a sectional view in Fig. 5 is shown, the folding punch 18 can also be moved in one, to one side of the press beam 9 open groove 38. The groove 38 opens at its lower end into the recess 20, which in this case can be reached from the front side surface 22 of the press beam 9 via a front opening 21 and from the rear side surface 24 of the press beam 9 via a rear opening 23. The support surface 15 on the bottom side of the recess 20 for receiving the workpiece 4 is extended by a projecting extension 39, so that the workpiece 4 can be positioned as easily and safely during folding in the folding device 2.

In the Fig. 6 and 7 an embodiment of a folding device 2 is shown, which has no folding punch 18 on the upper frame part 5 and no recess 20 or no extension 33, 39 on the pressing bar 9. Rather, in this folding device 2 forms a top 40 of the press beam 9, the support surface 15 for the workpiece 4 and a portion of the bottom 37 of the frame top 5, the embossing surface 16 of the folding device. 2

For the sake of order, it should finally be pointed out that in order to better understand the structure of the folding device or the bending press, these or their components have been shown partially unevenly and / or enlarged and / or reduced in size.

The task underlying the independent inventive solutions can be taken from the description. <B> Reference Numbers </ b> 1 bending press 26 slot 2 folding device 27 width 3 Falzbug 28 height 4 workpiece 29 upper part 5 Upper frame 30 Lower part 6 Frame bottom 31 bottom 7 bending die 32 top 8th punch 33 extension 9 pressing bars 34 Guide rail 10 drive cylinder 35 spring element 11 drive cylinder 36 attack 12 drive piston 37 bottom 13 drive piston 38 groove 14 coupling agent 39 extension 15 bearing surface 40 top 16 embossing surface 17 gap 18 Falzstempel 19 lower edge 20 recess 21 Front opening 22 Front side surface 23 Rear opening 24 Rear side surface 25 end wall

Claims (15)

1. A bending press (1) having a folding device (2) for producing a hem (3) on a workpiece (4), wherein the bending press (1) is equipped with a fixed frame upper part (5) and frame lower part (6), a fixed bending die (7), a movable bending punch (8) and a pressing bar (9) arranged over the bending punch (8), connected thereto and leading or delivering the bending punch (8) in a vertical direction, characterized in that an upwardly directed, in particular horizontal bearing surface (15) for the workpiece (4) is formed on the pressing bar (9) and that above this a stamping area (16) of the folding device (2) is arranged parallel to the bearing surface (15) directed against said bearing surface, wherein the stamping area (16) and the bearing surface (15) are in contact in an upper end position or final position of the pressing bar (9) or create a gap (17) of less than 0.5 mm and wherein the stamping area (16) and the bearing surface (15) are spaced apart from one another when the pressing bar (9) is lowered or extended, in such a manner that the workpiece (4), in particular, which is prebent can be positioned between the stamping area (16) and the bearing surface (15).
2. The bending press (1) according to claim 1, characterized in that the stamping area (16) of the folding device (2) is formed on an underside of the folding punch (18) which projects beyond a lower edge (19) of the frame upper part (5) downwardly in the direction of the pressing bar (9) and the bearing surface (15) of the workpiece (4).
3. The bending press (1) according to claim 1 or 2, characterized in that a projecting extension (33) is formed on a front (22) and/or rear side face (24) of the press bar (9) which extends at least in a partial region and, in particular, in a central region along a width (27) of the pressing bar (9) and that the bearing surface (15) of the workpiece (4) is formed on a surface of the extension (33).
4. The bending press (1) according to claim 2, characterized in that an elongate, in particular milled, recess (20) is formed in the pressing bar (9), the end surface whereof on the base side forms the bearing surface (15) for the workpiece (4) and which recess (20) is accessible via a front opening (21) in the front side surface (22) and/or via a rear opening (23) in the rear side surface (24) of the pressing bar (9).
5. The bending press (1) according to claim 4, characterized in that the recess (20) is arranged along a width (27) of the pressing bar (9) in the central section thereof.
6. The bending press (1) according to claim 4 or 5, characterized in that the recess (20) extends over no more than one-fifth of the width (27) of the pressing bar (9).
7. The bending press (1) according to one of claims 4 to 6, characterized in that the rear side of the recess (20) is closed by a rear end wall (25), so that the recess (20) is only then accessible via the front opening (21) in the front side surface (22) of the pressing bar (9).
8. The bending press (1) according to one of claims 4 to 7, characterized in that the pressing bar (9) has a slotted design over the recess (20) and the folding punch (18) is movable in the slot (26) of the pressing bar (9), so that in an upper end position or final position of the pressing bar (9) the folding stamp (18) projects inwards through the slot (26) into the recess (20) and the bearing surface (15) of the recess (20) and the stamping area (16) of the folding punch (18) are proximate to one another at least up to a minimal gap (17).
9. The bending press (1) according to one of claims 2 to 8, characterized in that the folding punch (18) or a lower part (30) of the folding punch (18) are mounted or held movably in a vertical direction on the pressing bar (9) via at least one spring element (35) and the folding punch (18) or the lower part (30) of the folding punch (18) are pressed in the upper end position or final position of the pressing bar (9) from a lower side (37) of the frame upper part (5) or an underside (31) of an upper part (29) of the folding stamp (18) against the force of the spring element (35) from a rest position in the direction of the bearing surface (15) of the workpiece (4), so that the bearing surface (15) and the stamping area (16) of the folding punch (18) are proximate to one another, at least up to the minimum gap (17), and wherein in a non-actuated state, the spring element (35) presses the folding punch (18) or the lower part (30) of the folding punch (18) upwards into the rest position so that the stamping area (16) and the bearing surface (15) are spaced apart relative to one another.
10. The bending press (1) according to one of the preceding claims, characterized in that the bearing surface (15) of the workpiece (4) is arranged in the centre third of a height (28) of the pressing bar (9) when viewed vertically.
11. The bending press (1) according to claim 1 or 3, characterized in that the bearing surface (15) of the workpiece (4) is formed by at least a partial section of an upper side (40) of the pressing bar (9) and that the stamping area (16) of the folding device (2) is formed by at least a partial section of an underside (37) of the frame upper part (5) of the bending press (1).
12. The bending press (1) according to one of the preceding claims, characterized in that several pairs of a bearing surface (15) and a corresponding stamping surface (16) are formed on the bending press (1).
13. A method of making a hem by means of a bending press (1), particularly according to one of the preceding claims, wherein during the course of a downwards movement of a pressing bar (9) or a bending punch (8) of the bending press (1) connected thereto, in particular at a lower end position or final position of the pressing bar (9), a prebending action is performed on a workpiece (4), characterized in that during the course of an upwards movement of the pressing bar (9), in particular at an upper end position or final position of the pressing bar (9), by means of a particularly horizontal bearing surface (15) directed upwards on the pressing bar (9) and a stamping area (16) of the folding device (2) arranged thereabove, parallel to the bearing surface (15) and directed against said surface, a folding action is performed to produce a hem (3) on a workpiece (4).
14. The method according to claim 13, characterized in that a rest or neutral position of the pressing bar (9) lies between the upper end position or final position and the lower end position or final position of the pressing bar (9), preferably closer to the upper end position or final position, so that starting from the rest or neutral position, a folding action can be directly performed by moving the pressing bar (9) upwards and a bending or tilting action can be directly performed by moving the pressing bar (9) downwards.
15. The method according to claim 13 or 14, characterized in that a prebending action is carried out first to produce a semi-finished product and that a folding action is then performed on the semi-finished product, in order to produce a finished product.

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