Swivel bending machine for creating an open hem on a sheet and sheet bending method

Abstract

The present invention relates to a swivel bending machine (100) for creating an open hem on a sheet (103), with a lower cheek (101) for supporting the sheet (103), an upper cheek (105) with a wedge-shaped bending edge (107) for clamping the sheet (103) between upper cheek (105) and lower cheek (101), a rotatable or swivelable bending cheek (109) for bending the sheet portion (115) of the sheet (103) protruding from between upper cheek and lower cheek in a first bending step along the wedge-shaped bending edge (107) into an acute angle, and a movement device (111) for moving the wedge-shaped bending edge (107) out of the sheet portion (115) pre-bent into an acute angle. The swivel bending machine (100) is designed to bend the sheet portion (115), which was pre-bent into an acute angle, further in a second bending step between bending cheek (109) and lower cheek (101) into an open hem (125) with further actuation of the bending cheek (109), while the sheet (103) is fixed against the lower cheek by the wedge-shaped bending edge (107). The invention also relates to a corresponding sheet bending method.

Description

[0001] Folding machine for producing a hollow fold on a sheet and sheet bending process

[0002] The present invention relates to a swivel bending machine for producing a hollow fold on a sheet metal and a related sheet metal bending method.

[0003] In a typical design, folding machines have a lower beam for placing the sheet metal, an upper beam that can be moved vertically between an open and a closed position, and a rotating or pivoting bending beam, whereby a sheet metal that is to be bent through a certain angle is first clamped between the upper and lower beams by closing the upper beam, so that the sheet metal section to be bent protrudes between the upper and lower beams and can then be bent by pivoting the bending beam around a bending edge typically provided on the upper beam.

[0004] If hollow folds are created on a sheet using a swivel bending machine according to conventional methods by vertically "pressing" a section of sheet metal that has already been pre-bent to an acute angle with the upper beam, the problem arises that, if the hollow fold is very long or the sheet metal used is very thick, the wedge-shaped bending edge and upper beam increasingly bend upwards in the center. The hollow folds created in this way are therefore less well formed in the center than in the edge areas and are therefore of very limited or almost impossible to produce.

[0005] Furthermore, sheet metal bending methods and suitable swivel bending machines are already known from the prior art, in which the sheet metal section to be bent is first pre-bent into an acute angle by means of the bending beam along a wedge-shaped bending edge in a first bending step, and in which the wedge-shaped bending edge is then moved out of the pre-bent sheet metal section and the hollow fold is subsequently closed in a second bending step by the pre-bent sheet metal section being further bent by means of the bending beam. This is known, for example, from US 2015 / 0151346 A1, FR 2 717 109 and US 2,336,105, with US 3,6622,584 and CH 392 434 showing further similar bending machines and bending methods.

[0006] In the prior art according to all the publications cited above, the wedge-shaped bending edge is not used in the second bending step ("further bending to close the hollow envelope") and additional means are required to fix the sheet in the second bending step.

[0007] Against this background, it is the object of the present invention to provide an improved folding machine and an improved method for producing hollow folds on sheet metal with the simplest possible design, with which hollow folds of great length and high precision can be produced.

[0008] This object is achieved by the subject matter having the features according to the independent claims. Advantageous embodiments are the subject matter of the dependent claims, the description, and the figures.

[0009] In a first aspect of the invention, a folding machine is thus provided for producing a hollow fold on a sheet metal, which comprises the following components: a lower beam for placing the sheet metal, an upper beam with a wedge-shaped bending edge for clamping the sheet metal between the upper beam and the lower beam, a rotatable or pivotable bending beam for bending the sheet metal section protruding between the upper beam and the lower beam in a first bending step along the wedge-shaped bending edge into an acute angle, and a movement device for moving the wedge-shaped bending edge out of the sheet metal section pre-bent into an acute angle.

[0010] According to the invention, it is further provided that the swivel bending machine is designed to further bend the sheet metal section pre-bent into an acute angle into a hollow fold in a second bending step upon further actuation of the bending beam between the bending beam and the lower beam, while the sheet metal is fixed against the lower beam by the wedge-shaped bending edge.

[0011] By forming the hollow fold using the rotating bending beam and simultaneously fixing the sheet against the lower beam using the wedge-shaped bending edge, a hollow fold can be produced over the entire length of the sheet with particularly high precision.

[0012] It has been shown that the inventive fixation of the sheet metal by means of the bending edge during the second bending step allows the production of highly precise hollow folds. A particular advantage is that the sheet metal can be fixed against the lower beam over its entire length by means of the bending edge (after its removal from the pre-bent area), in the immediate vicinity of the bending process taking place in the second bending step.

[0013] To fix the sheet against the lower beam in the second bending step, the wedge-shaped bending edge can be pressed with its underside flat or with line contact against the upper side of the sheet, depending on the specific design of the movement device that specifies the possible positions of the wedge-shaped bending edge.

[0014] As already mentioned, a swivel bending machine according to the invention comprises a wedge-shaped bending edge serving as a top-beam tool for bending the sheet metal section to an acute angle in the first bending step. Depending on the technical and physical conditions, the angle can be no less than approximately 20°.

[0015] The folding machine further comprises a movement device for moving the wedge-shaped bending edge out of the pre-bent area of ​​the sheet metal, so that the sheet metal section pre-bent into an acute angle can then be bent further immediately without having to move the sheet metal. This means that sheet metal parts can be produced quickly and easily. In a technically advantageous embodiment of the folding machine, the movement device comprises a displacement device for linearly pulling out the wedge-shaped bending edge. This achieves the technical advantage, for example, that the wedge-shaped bending edge can be brought quickly and easily into a position in which the pre-bent sheet metal section can be bent further without hindrance and, at the same time, the sheet metal can be fixed against the lower beam by means of the bending edge.During the linear withdrawal of the wedge-shaped bending edge, an opening movement of the upper beam can also take place and, after completion of the withdrawal movement, a renewed closing movement of the upper beam can take place in order to facilitate the repositioning of the wedge-shaped bending edge for the second bending step and to facilitate a good fixation of the sheet against the lower beam in the second bending step.

[0016] In a further technically advantageous embodiment of the folding machine, the movement device comprises a rotating device for rotating or pivoting out the wedge-shaped bending edge. This also allows for rapid repositioning of the bending edge for the second bending step in combination with a simultaneous opening and subsequent closing movement of the upper beam, so that the sheet metal section pre-bent in the first bending step can be bent further without hindrance and can simultaneously be fixed against the lower beam by means of the bending edge.

[0017] In a further technically advantageous embodiment of the invention, the rotating device comprises a plurality of bending edges. This achieves the technical advantage, for example, that bending edges with different profile shapes can be used on a swivel bending machine according to the invention, with which sheets can be bent at different angles and shapes.

[0018] In a further technically advantageous embodiment of the folding machine, the bending beam comprises a bending bar for bending the sheet metal section. This allows hollow folds to be produced with an even tighter tolerance. In a further technically advantageous embodiment of the folding machine, the bending bar or the bending beam comprises a crown for uniformly creating the hollow fold, allowing hollow folds to be produced over the entire length of the sheet with even greater precision.

[0019] In a further technically advantageous embodiment of the folding machine, the bending bar has a profile that is vertically convex in the longitudinal direction of the machine, which can also contribute to increased precision in the production of hollow folds.

[0020] According to a second aspect, the present invention also relates to a sheet metal bending method for producing a hollow envelope ( 125 ) on a sheet metal ( 103 ) using a swivel bending machine according to the invention, comprising the following steps:

[0021] (A) Placing a sheet with a sheet section, which is to be pre-bent into an acute angle, on a lower beam of the folding machine,

[0022] ( B ) Clamping the sheet between an upper beam with a wedge-shaped bending edge and the lower beam,

[0023] ( C ) Bending a sheet metal section protruding between the upper and lower beams by means of the bending beam in a first bending step along the wedge-shaped bending edge into an acute angle,

[0024] ( D ) Moving the wedge-shaped bending edge out of the sheet metal section pre-bent at an acute angle and

[0025] ( E ) Further bending of the sheet metal section in a second bending step into a hollow fold by further pivoting of the bending beam , while the sheet metal is fixed against the lower beam by means of the wedge - shaped bending edge .

[0026] The method achieves the same technical advantages as the folding machine according to the first aspect, so that, to avoid repetition, reference may be made to the above explanations regarding the folding machine according to the invention. Advantageous embodiments of the folding machine according to the invention already described are, of course, equally applicable to the sheet metal bending method according to the invention.

[0027] In a preferred embodiment of the sheet metal bending method according to the invention, the wedge-shaped bending edge can be moved out of the bent area in the opposite wedge direction by means of the movement device.

[0028] In a further technically advantageous embodiment of the sheet metal bending process, the wedge-shaped bending edge is rotated or pulled out of the bent area, which can be overlaid by a simultaneous opening and subsequent closing movement of the upper beam. This allows the bending edge to be removed from the bent area with minimal design effort and to be suitably repositioned for the second bending step.

[0029] In another technically advantageous embodiment of the sheet metal bending process, deflection of the bending beam and / or the bending bar during pre-bending ("first bending step") or further bending ("second bending step") is compensated for by crowning. This achieves the technical advantage, for example, that the hollow envelope can be produced with even greater precision over its entire length.

[0030] Embodiments of the invention are illustrated in the drawings and are described in more detail below.

[0031] It shows :

[0032] Fig. 1 is a front view of a folding machine,

[0033] Fig. 2 is a cross-sectional view through the bending machine,

[0034] Fig. 3 is a further cross-sectional view through the bending machine with the bending edge moved back, Fig. 4 is a further cross-sectional view through the bending machine with the bending edge moved back and the bending beam folded up,

[0035] Fig. 5 is a further cross-sectional view through the folding machine with a shifting device for the bending edge,

[0036] Fig. 6 is a further cross-sectional view through the folding machine with the shifting device for the bending edge,

[0037] Fig. 7 is a further cross-sectional view through the bending machine with a rotating device with a first and second bending edge,

[0038] Fig. 8 is a further cross-sectional view through the bending machine with the rotating device,

[0039] Fig. 9 is a further cross-sectional view through the folding machine for producing a hollow envelope and

[0040] Fig. 10 is a block diagram of a sheet metal bending process.

[0041] Fig. 1 shows a front view of a folding machine 100 for bending flat metal sheets 103, such as steel sheets. For this purpose, the folding machine 100 comprises a stable and immovable lower beam 101 for placing the metal sheet 103. A mechanically movable and movable upper beam 105 serves to clamp the placed metal sheet 103 to the lower beam 101. The metal sheet 103 is clamped immovably between the stationary lower beam 101 and the vertically movable upper beam 105. For this purpose, the upper beam 105 can be moved up and down in the direction of the arrow.

[0042] A sheet metal section 115 of the clamped sheet 103 protrudes between the lower beam 101 and the upper beam 105, which has an approximately triangular lateral cross-section. On the lower front side, the upper beam 105 has a wedge-shaped bending edge 107 as an upper beam tool. The sheet 103 is bent along this bending edge 107. This is done by a rotatably or pivotably mounted, plate-shaped bending beam 109, which bends the protruding sheet metal section 115 along the wedge-shaped bending edge 107. A bending strip 121 of the bending beam 109 lies flat against the protruding sheet metal section 115. During the rotational movement, the protruding sheet metal section 115 is bent accordingly by the bending strip 121, so that in a first bending step an angled end region with an acute angle can be created on the sheet metal 103, which essentially corresponds to the angle of the bending edge 107.

[0043] Fig. 2 shows a cross-sectional view through the folding machine 100. The sheet metal 103 is clamped between the lower beam 101 and the upper beam 105. The bending beam 109 is pivoted upward during the first bending step, so that the protruding sheet metal section 115 is bent around the wedge-shaped bending edge 107. The bent sheet metal section 115 is located between the bending bar 121 of the bending beam 109 and the upper side of the wedge-shaped bending edge 107.

[0044] The achieved bending angle essentially corresponds to the acute angle of the wedge-shaped bending edge 107. The rotational axis of the bending beam 109 runs in a geometrically defined area along the wedge tip of the bending edge 107. In this way, the sheet metal section 115 of the sheet metal 103 is produced at an acute angle in the first bending step.

[0045] The bending strip 121, which has a rectangular cross-section, forms a stop edge for the sheet metal section 115 and additionally reinforces the bending beam 109. The bending strip 121 is formed, for example, by a strip-shaped metal part that extends along the bending beam 109 and is arranged on its upper side. The sheet metal section 115 rests against the side surface of the bending strip 121 during bending.

[0046] Fig. 3 shows a further cross-sectional view through the folding machine 100. The bending beam 109 is in its original position here. After the previous bending step, the sheet metal 103 is bent in one area at an acute angle in the profile of the wedge-shaped bending edge 107. The folding machine 100 comprises a movement device 111 for moving the wedge-shaped bending edge 107 out of the bent area in the opposite wedge direction. This releases the bent wedge-shaped gap between the bent sheet metal section 115 and the remaining sheet metal 103.

[0047] The wedge-shaped bending edge 107 is moved out of the bent area by a lifting movement of the movable upper beam 105 in conjunction with a rotating movement of the upper beam 105. For this purpose, the folding machine 100 comprises both a rotating device 113 for rotatably supporting the upper beam 105 and a sliding device 123 for vertically moving the upper beam 105. The rotating device 113 is formed by a rotatable bearing along the longitudinal axis of the upper beam 105. The bending edge 107 can thus be moved in an interpolated manner, thus the position of the bending edge 107 can always be brought into an optimal position, in particular for clamping the sheet metal. This can be done in a fully controlled process.

[0048] In general, however, the rotating device 113 can also be implemented in a different way. Furthermore, the bending edge 107 can also be removed from the area of ​​the pre-bent sheet metal section in a different way.

[0049] Fig. 4 shows a further cross-sectional view through the folding machine 100 with the bending edge 107 of the upper beam 105 moved back and the bending beam 109 fully folded up after the second bending step has been performed. The pivotally mounted and moved back bending edge 107 is positioned during the second bending step such that it touches the sheet 103 on its upper side, so that the sheet is fixed against the lower beam during the second bending step.

[0050] The rotatable bending beam 109 is in a vertical and upwardly rotated position, so that it, together with the bending bar 121, has created a hollow fold 125 from the pre-bent sheet metal section 115. In the process, the sheet metal section 115 of the sheet 103, which had previously only been bent at an acute angle, has been completely bent. In this way, a hollow fold 125 can be created from the sheet 103 pre-bent at the bending edge 107, in which the sheet 103 is bent at an angle of approximately or exactly 180°.

[0051] By bending using the bending beam 109 and simultaneously fixing the sheet against the lower beam by means of the wedge-shaped bending edge 107, the hollow envelope 125 can be produced with a high degree of accuracy.

[0052] Fig. 5 shows a further cross-sectional view through the folding machine 100 with a further embodiment of a movement device 111 for the bending edge 107. The upper beam 105 is not only vertically movable, but is also mounted so as to be displaceable in the horizontal direction along grooves 117, which form a displacement device 123 for linearly pulling out the wedge-shaped bending edge 107 as the movement device 111.

[0053] The upper beam 105 can thus be displaced horizontally in the grooves 117. In this way, after the first bending step has been carried out, the bending edge 107 can be quickly pulled out of the bent area and reset horizontally so that the sheet 103 can then be bent further. The wedge-shaped bending edge 107 can either slide along the surface of the sheet 103 with slight pressure or, by a slight vertical opening movement of the upper beam, can first be lifted from the sheet, pulled out of the bent area and, by a subsequent closing movement, brought into contact with the upper side of the sheet 103 to clamp the sheet against the lower beam 101 again.

[0054] In this way, the area between the pre-bent sheet metal section 115 and the remaining sheet metal 103 is exposed without the sheet metal having to be repositioned. In general, however, the displacement device 123 can also be implemented in other ways.

[0055] Fig. 6 shows a further cross-sectional view through the folding machine 100 with the retracted bending edge 107 of the upper beam 105. The rotatable bending beam 109 is in a vertical and upwardly folded position, so that it creates a hollow fold 125 from the previously bent sheet metal section 115 by means of the bending bar 121.

[0056] The bending bar 121 can advantageously comprise a fixed or adjustable crown 127, which compensates for any deflection of the bending bar 121 and the bending beam 109 during the bending process. For this purpose, the bending bar 121 can, for example, be somewhat thicker in the center than at the edge regions. As a result, the bending bar 121 is curved in the center compared to the edge regions in order to produce the hollow envelope 125 uniformly over the entire length. The crown 127 is formed by a spherical profile of the bending bar 121.

[0057] Fig. 7 shows a further cross-sectional view through the folding machine 100 with a rotating device 113 for rotating the wedge-shaped bending edge 107 out of the pre-bent area 115 as the moving device 111. The rotating device 113 mounts the upper beam 105 so that it can rotate along its longitudinal axis.

[0058] The upper beam 105 has a first and a second bending edge 107-1 and 107-2. Depending on the angle of rotation of the upper beam 105, either the first bending edge 107-1 or the second bending edge 107-2 can be used to bend the sheet metal 103. The freely positionable and rotatable upper beam 105 allows a multiple tool system with several bending edges 107-1 and 107-2 to be realized.

[0059] Fig. 8 shows a further cross-sectional view through the folding machine 100 with the rotating device 113. The rotatable bending beam 109 is in a vertical position, so that it also creates a hollow fold 125 from the previously bent sheet metal section 115 by means of a rotating movement of the bending beam 109.

[0060] Fig. 9 shows a further cross-sectional view through the folding machine 100 for producing a hollow fold 125. The rotatable bending beam 109 can be moved beyond the vertical position so that a closed hollow fold 125 with a bending angle of >180° can be produced by the bending bar 121, depending on the sheet thickness, bending radius and leg length. In general, the rotatably mounted bending beam 109 can have a pivoting range of more than 180°, starting from its vertical downward position, in order to produce a parallel hollow fold. This overbending can compensate for different springback rates of the various materials.

[0061] Fig. 10 shows a block diagram of a sheet metal bending method according to the invention, in which the steps (A) to (E) of the claimed sheet metal bending method already explained above are carried out in a linear sequence.

[0062] All features explained and shown in connection with individual embodiments of the invention can be provided in different combinations in the subject matter according to the invention in order to simultaneously realize their advantageous effects.

[0063] All method steps can be implemented by devices suitable for carrying out the respective method step. All functions performed by physical features can, in an analogous manner, characterize a method step of a method.

[0064] The scope of the present invention is given by the claims and is not limited by the features explained in the description or shown in the figures.

Claims

A folding machine (100) for producing a hollow fold on a sheet metal (103) comprising: a lower beam (101) for placing the sheet metal (103), an upper beam (105) with a wedge-shaped bending edge (107) for clamping the sheet metal (103) between the upper beam (105) and the lower beam (101), a rotatable or pivotable bending beam (109) for bending the sheet metal section (115) of the sheet metal (103) projecting between the upper beam and the lower beam in a first bending step along the wedge-shaped bending edge (107) into an acute angle, and a movement device (111) for moving the wedge-shaped bending edge (107) out of the sheet metal section (115) pre-bent into an acute angle, characterized in that the folding machine (100) is designed toto further bend the sheet metal section (115) pre-bent into an acute angle into a hollow envelope (125) in a second bending step upon further actuation of the bending beam (109) between the bending beam (109) and the lower beam (101), while the sheet metal (103) is fixed against the lower beam by the wedge-shaped bending edge (107). The folding machine (100) according to claim 1, wherein the movement device (111) comprises a displacement device (123) for linearly pulling out the wedge-shaped bending edge (107). The folding machine (100) according to claim 1 or 2, wherein the movement device (111) comprises a rotation device (113) for rotating or pivoting out the wedge-shaped bending edge (107). A bending machine (100) according to claim 3, wherein the rotating device (113) comprises a plurality of bending edges (107-1, 107-2). The folding machine (100) according to one of the preceding claims, wherein the bending beam (109) comprises a bending bar (121) for bending the sheet metal section (115). The folding machine (100) according to claim 5, wherein the bending bar (121) or the bending beam (109) comprises a crown (127) for uniformly producing the hollow fold (125). The folding machine (100) according to claim 6, wherein the bending bar (121) has a profile that is perpendicularly convex in the longitudinal direction of the machine. A sheet metal bending method for producing a hollow fold (125) on a sheet metal (103) using a folding machine according to one of claims 1-7, comprising the steps: (A) Placing a sheet (103) with a sheet section (115) which is to be pre-bent into an acute angle, on a lower beam (101) of the folding machine (100), (B) clamping the sheet between an upper beam (105) having a wedge-shaped bending edge (107) and the lower beam (101), (C) Bending a sheet metal section (115) projecting between the upper and lower beams by means of the bending beam (109) in a first bending step along the wedge-shaped bending edge (107) into an acute angle, (D) Moving the wedge-shaped bending edge (107) out of the sheet metal section (115) pre-bent at an acute angle and (E) further bending the sheet metal section (115) in a second bending step into a hollow envelope (125) by further pivoting the bending beam (109), while the sheet metal (103) is fixed against the lower beam (101) by means of the wedge-shaped bending edge (107). Sheet metal bending method according to claim 8, wherein the wedge-shaped bending edge (107) is formed from the pre-bent sheet metal section (115) in in the opposite wedge direction by a movement device (111). The sheet metal bending method according to claim 9, wherein the wedge-shaped bending edge (107) is rotated or pulled out of the bent sheet metal section (115). The sheet metal bending method according to any one of claims 8-10, wherein deflection of the bending beam (109) and / or the bending strip (121) during the first or second bending step is compensated for by a crowning (127).

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