WO1991013704A1

WO1991013704A1 - Sheet-metal bending device

Info

Publication number: WO1991013704A1
Application number: PCT/AT1991/000044
Authority: WO
Inventors: Otto Schubert
Original assignee: Lift Verkaufsgeräte-Gesellschaft M.B.H.
Priority date: 1990-03-15
Filing date: 1991-03-14
Publication date: 1991-09-19
Also published as: KR920700792A; ATE105216T1; RU2015769C1; EP0476092A1; ATA62190A; JPH04506182A; DE59101563D1; EP0476092B1; AT393639B

Abstract

Described is a sheet-metal bending device (1) with a sword-like upper punch (10) which can be moved up and down relative to a frame (2), at right angles to the plane of the sheet, and can optionally be rotated. Facing the upper punch (10) are two jaw-like lower punches (19, 20) which cen be rotated relative to the upper punch (10) about a common axis passing through the zone in which bending of the sheet (18) takes place, the rotary motion being provided by a rotation mechanism (24), and the upper punch (10), when in its working position against the surface of the sheet (18), acting during the bending operation as a stationary counterpunch about which the sheet (18) is bent by the lower punches (19, 20).

Description

Sheet metal bending device

Field of the Invention

The invention relates to a sheet metal bending device with an upper punch which can be moved up and down relative to a frame transversely to the sheet plane and which is opposed by two lower stamps arranged on the frame.

Underlying state of the art

Usually, a sheet is bent along a straight bending edge by moving an upper punch (also called upper tool) against the sheet resting on a lower die or on two lower, stationary punches (lower tools), the upper punch being the sheet with the area of the bending edge to be molded into the die or between the two lower punches, whereby the bending of the sheet is accomplished. The disadvantage here is that generally no precisely defined or sharp bending edges can be formed, and furthermore that a considerable part of the energy applied is lost due to friction on the die or on the stationary lower punches.

Also known is a bending device for already profiled sheets (WO 81/02535) in order to provide these profiled sheets with a corrugation, with an upper, up and down movable die with a stationary lower die and with oblique ones arranged on both sides in the direction their main level works diagonally up and down movable additional stamps. While the upper stamp forms the corrugation in the sheet with the stationary lower stamp opposite it, the two oblique stamps on the side prepare the next corrugation. This known bending machine is not designed and is not suitable for simple bending of a sheet with the sharpest possible bending edge.

Summary of the invention

It is an object of the invention to provide a sheet metal bending device of the type mentioned at the outset, which is used to bend sheet metal while producing sharp bending edges Enables with relatively little energy and with the lowest possible design effort, the sheet to be bent should be treated as gently as possible.

The plate bending device according to the invention of the type mentioned at the outset is characterized in that at least two stamps are mounted in the frame so as to be pivotable about an axis which generally extends in the region of the bending of the plate and are coupled to a pivoting mechanism.

With such a design, the above objective is advantageously met, whereby at least one of the lower punches - in this case together with the upper punch - or both lower punches are pivoted when bending the sheet metal with the sheet metal areas to be bent against one another only a gentle, energy-saving bending work on the sheet is made possible, but moreover, since then the upper punch can be easily formed with a sharp lower edge around which the sheet is bent, also sharp or precisely defined bending edges can be generated. The construction of the bending device can be relatively simple, in particular no solid frame is required as in conventional bending presses. In this context, it is also particularly advantageous if the two lower punches are mounted in the frame so as to be pivotable in opposite directions about an axis running in the region of the bending of the sheet. During the bending work, the movement of the lower punches can take place in equilibrium with the upper punch or with each other, and since the swiveling of the lower punches together with the sheet metal sections can be found with comparatively low forces.

In view of the above-mentioned desired balance of forces and the lowest possible load on the frame, it is particularly advantageous if the lower stamps are coupled in their pivoting movement and can be pivoted symmetrically. This design also has the advantage that, as will be explained in more detail below, a particularly simple drive option with a common drive motor for the two lower punches is easily possible.

In order to achieve the desired precisely defined bending edges, particularly in the case of thin sheets, it is also advantageous if the lower punches can be pivoted about a common axis. The mentioned common axis, about which the lower punches are pivoted, lies in the area of the bending edge to be formed in the sheet. Furthermore, the common axis for the intended purpose of the sharp bending edge is preferably in the plane of the up and down movement of the upper punch.

It has also proven to be advantageous if the upper punch can be locked in its working position brought up to the surface of the sheet to be bent and thus forms a stationary counter-punch during bending, around which the sheet can be bent by means of the counter-rotating lower punch.

For example, in order to hold back a hindrance by the upper punch, against which the multi-bent sheet then abuts, when bending a sheet several times, it is also advantageous if the upper punch with its holder is moved up and down on the support on the frame an axis parallel to or coinciding with the bending edge in the sheet metal is pivotably mounted. With such a design, a lateral pivoting away of the upper punch in the final phase of the respective bending process is made possible when the multi-bent sheet metal abuts against it. The upper punch can be pivoted freely, or it can be connected to a swivel drive which is activated, for example, by a microswitch against which the sheet metal abuts.

It is also advantageous here for a smooth course of the bending process and to achieve the desired sharp bending edges if the horizontal pivot axis of the upper punch in its operating position coincides at least substantially with the common pivot axis of the lower punch. As such, it would be conceivable to equip the upper punch drive with an eccentric drive, as described, for example, in WO 81/02535, but, as was found, in the present bending device, a spindle drive can simply be assigned to the upper punch for up and down movement. With such a spindle drive, the above-mentioned locking in the working position of the upper punch is also possible without problems simply by locking the spindle.

In order to accomplish the pivoting of the lower punches in a way that is as simple as possible in terms of design, it is advantageous if the lower punches are assigned a rack and pinion gear as a pivoting mechanism. The rack and pinion gears are preferably arranged symmetrically and in particular coupled to a common drive motor.

An advantageous embodiment is further characterized in that several racks are articulated on each lower punch distributed over the width of the device, which in turn mesh with gearwheels seated on a shaft, as a result of which the lower punch can be driven simultaneously in several places across the width of the device .

To simplify the drive mechanism, it is also advantageous here if two intermeshing gearwheels sit on the two shafts assigned to the two lower punches, and so one shaft driven by the drive motor drives the other shaft rotating in opposite directions.

For a gentle treatment of the sheet during bending, it is then also advantageous if the lower punches have pressure bodies which are freely pivotable on their upper sides and come into contact with the sheet.

It is furthermore advantageous if the pressure bodies are flat on their upper side and are each mounted in a partially cylindrical bed provided in the corresponding lower punch. On the other hand, when bending smaller sheets in view of the desired sharp, precisely defined bending edges, it can also be advantageous if the lower punches are designed in a cutting-like manner on their upper side, with a convex curve.

It is also advantageous if the upper one, e.g. sword-shaped stamp a cutting-like lower bending edge, e.g. with convex curvature.

In order to achieve a completely synchronized pivoting of the lower stamps around a precisely defined, imaginary pivot axis, it has also proven to be advantageous if the lower stamps are coupled with at least one pair of angle levers for their movement during pivoting, which in turn are connected to one another centrally via a joint are. The angle levers can be provided on one or both end faces of the bending device, or several angle lever pairs can be provided over the width of the device, which is particularly preferred for larger constructions. The joints, via which the angle levers of a pair are tied together, move in particular in the vertical center plane of the bending device, in which the common pivot axis mentioned also lies.

This center plane is, in particular, also the plane along which the upper punch can possibly be moved up and down.

A simple and robust construction can then be achieved in the latter embodiment in that the angle levers are in each case articulated on the one hand with one of the lower punches and on the other hand are displaceably guided with a sliding block or the like in a sliding groove of the other of the lower punches.

In order to particularly protect the sheet metal to be bent on its surface and accordingly to keep relative movements between the bending punches and the sheet metal as far as possible in the plane of the sheet metal surface, it has also proven to be advantageous proved if the two lower punches are connected in an articulated manner with shoes which are guided in arcuate guideways with the center in the area of the sheet metal bend and are held in frictional engagement on the sheet metal to be bent by the downwardly movable upper die. Through the articulated mounting of the lower punches, their contact surfaces on the sheet metal can be retained when the sheet is bent, as a result of which a particularly high surface quality can be achieved.

An embodiment which is kinematically equivalent to the above embodiments, but which is preferred in certain cases with regard to the design of the stationary part of the bending device (for example because of the stationary fixation of one sheet metal section during bending), is further characterized in that one lower punch is stationary and the other lower Stamp and the upper stamp are pivotally mounted, wherein the pivotable lower stamp can be driven at twice the angular speed compared to the upper stamp.

In all cases, the lower punches - like the upper punches - can be cheek-shaped.

Brief description of the drawing

The invention is explained in more detail below on the basis of particularly preferred exemplary embodiments illustrated in the drawing, to which, however, it is not intended to be limited. Show it:

Figure 1 is a schematic, perspective view of a sheet metal bending device according to the invention in the rest position.

2 shows a corresponding schematic, diagrammatic view of this sheet metal bending device, the opposite side being visible;

3 shows a diagrammatic representation corresponding to FIG. 1 of this sheet metal bending device in a work phase in which the sheet metal bending is started;

4 shows a corresponding illustration of this sheet bending device, in which the sheet to be bent is already largely bent; 5 shows a further illustration of this sheet metal bending device, but now at the end of the bending process;

6 shows a very schematic, partially sectioned end view of the essential working parts of the sheet metal bending device in the rest position corresponding to FIG. 1;

7 shows a corresponding schematic end view of these working parts of the sheet metal bending device, but now in accordance with the illustration in FIG. 2 at the beginning of the bending process;

FIG. 8 shows a corresponding front view of these working parts as shown in FIG. 4, with the sheet almost bent;

9 is a corresponding front view of the working parts of the sheet metal bending device at the end of the bending process, in a work phase representation according to FIG.

5;

10 and 11 each show very schematic end views of bending tools when bending different sheet thicknesses, the phase at the beginning of the bending process and that at the end of the bending process being illustrated;

FIG. 12 shows a schematic front view corresponding to FIG. 9 of an embodiment of the bending device with modified lower bending dies;

13 shows a schematic partial view of a further modified lower bending punch;

Fig. 14 is a schematic cross section through the upper part of a lower, e.g. 6 left bending punch, along the line XIV-XIV in Fig. 15, to illustrate bearing recesses and sliding or. Guide grooves in the punch;

Figure 15 is a partial view of the inside of this lower punch, seen essentially in the direction of arrow XV in Fig. 14 .; 16 shows an axonometric representation of a double angle lever arrangement serving for the articulated connection, mounting and movement control for the lower bending punches;

FIG. 17 is a sectional view similar to FIG. 14, but now with a double angle lever arrangement, along the line XVII-XVII in FIG. 18;

Fig. 18 is a view, partly in section, along the line XVIII in Fig. 17;

19 to 21 are sectional views similar to FIGS. 14 and 17, but now with both lower bending punches and the double angle lever arrangement, to illustrate different phases during the pivoting of the lower bending punches;

22 shows a schematic, diagrammatic view of the arrangement of the punches of a further modified bending device;

23, 24 and 25 in schematic end views similar to FIGS. 10 and 11 different phases in sheet metal bending with a bending device according to FIG. 22, the initial position being shown in FIG. 23, an intermediate position in FIG. 24 and the end position in FIG. 25 are; and

26 is a schematic end view, generally corresponding approximately to the illustration in FIG. 7, of yet another bending device, the initial position of the bending tools being shown with full lines and an intermediate position with dashed lines. Detailed description of the preferred embodiments

1 to 5 and 6 to 9, the present, generally designated 1 sheet bending device or press in the currently particularly preferred embodiment has a lower frame 2, on which 3, 4 vertical guides 5 are provided in the front main supports, in which columnar supports 6, 7 are guided vertically up and down. These carriers 6, 7 carry an upper holder 8 with a crosshead 9 on which an upper, cheek-shaped or sword-shaped punch 10 (also an upper tool, an upper bending tool or an upper bending punch) )) is fastened in an exchangeable manner, the holder 8 for the upper punch 10 being mounted on the supports 6, 7 in conventional pivot joints 11, 12, which are conventional per se and are only illustrated schematically, for example freely pivotable. The purpose of this pivot bearing will be explained in more detail below with reference to FIGS. 5 and 9.

The pivot axis defined by the pivot joints 11, 12 of the holder 8 on the supports 6, 7 preferably runs along the lower bending edge 13 of the upper bending punch 10, which is designed like a blade.

For moving the upper punch 10 up and down, conventional spindle drives, for example, are connected to the supports 6, 7, as is illustrated only very schematically at 14 in FIG. 1. These spindle drives 14 contain, for example, spindles 16 driven by a drive motor 15, optionally via a gear and a clutch (not shown), which cooperate with a spindle nut 17 provided on the underside of the carriers 6, 7, in order to support the carriers when the spindles 16 rotate 6 or 7 to move up and down in their guides 5. These spindle drives 14 and further drive devices to be explained in more detail are accommodated on or in the frame 2 in a conventional manner.

To bend a sheet 18, two lower, in particular plate or cheek-shaped bending punches 19, 20 (also called lower tools, lower bending tools or simply lower punches) are further provided on the frame 2. These two lower bending dies 19, 20 are pivotally mounted on the frame 2 in a manner not illustrated in FIGS. 1 to 9, for example with the aid of double lever arrangements hinged on the end face or cam guides on the main supports 3, 4. An example of such an arrangement for guiding the movement of the two lower bending dies 19, 20 when pivoting will be explained below with reference to FIGS. 14 to 21. Another example is shown in FIG. 26. Based on these Movement guidance, the two lower bending dies 19, 20 are at least essentially pivotable about a common pivot axis 21 (see, for example, FIGS. 7 and 8), which lies in the region of the bending edge 22 to be produced in the sheet 18 to be bent, and in particular also in the plane 23 of FIG Up and down movement of the upper punch 10 lies. The common pivot axis 21 preferably coincides with the axis defined by the pivot joints 10, 11 for the pivoting of the upper punch 10 together with its holder 8 relative to the supports 6, 7 when the upper punch 10 is in its working position according to FIG. 3 to 5 or 7 to 9, in which it serves as a stationary counter tool for bending. In this context, it should also be pointed out that in the schematic representations according to FIGS. 6 to 9 as well as that according to FIG. 12, the up and down displaceable carriers 6, 7 have been omitted and only the holder 8 with the upper stamp 10 and the Swivel joints 10, 11 are indicated schematically.

The plane in which the upper punch 10 can be moved up and down is indicated at 23 in FIGS. 6 to 8.

A drive mechanism for pivoting the lower bending dies 19, 20 around the common pivot axis 21 is a pivot mechanism which, in the present exemplary embodiment, distributed over the width of the bending device 1, contains a plurality of rack and pinion gears schematically indicated at 24 in FIGS. 1 to 5. A rack 25 is articulated in each case in the lower region of the respective lower bending die 19 or 20, as indicated schematically at 26 in FIG. 6. These toothed racks 25 mesh with shafts 29 and 30 of the same size that sit on shafts parallel to one another and to the bending dies 19, 20 (which are indicated in FIGS. 6 to 9 by their geometric axes 27 and 28, respectively). The one shaft, for example 27, is driven by a drive motor, preferably the single, common drive motor 15, which also drives the spindle drives 14 for the upper punch 10, as shown schematically in FIG. 6 6, a gear mechanism 'symbolically indicated in FIG. 6 by a gear 31 may be interposed, in a manner similar to that which can also be provided in the case of the spindle drive 14 (not shown).

The two shafts 27, 28 extend over the entire width of the bending device 1, and they are rotatably mounted on the front side and optionally also at intermediate points, between the individual rack drives 24, in corresponding bearings (not shown) in the frame 2. For each rack and pinion gear 24 there is a rack 25 and a gear 29 or 30 mounted on the corresponding shaft 27 or 28 in a rotationally fixed manner. When the shafts 27, 28 are driven in rotation, the toothed racks 25 are therefore shifted lengthways, pivoting the lower bending punches 19, 20 connected to them in a symmetrical movement in the manner of a spreading apart, cf. in particular the representations in Fig. 7 (rest position) and 8 (swung-apart working position). In order to enable the necessary slight pivoting movement of the toothed racks 25 around the shafts 27 and 28, the toothed racks 25 can be accommodated and guided in tubular housings 32, as is schematically illustrated in FIG. 6, these housings 32 having flange sections 33 of the respective shaft 27 and 28 are freely rotatable. The gears 29, 30 pass through slot openings parallel to the longitudinal axis of the rack 25 in the tubular housings 32 in order to be able to mesh with the racks 25 stored therein.

The mode of operation of the sheet metal bending device 1 described will now be explained with reference to the schematic representations of FIGS. 6 to 9 and also with reference to FIGS. 1 to 5 and also to FIGS. 10 and 11.

The starting or rest position of the sheet metal bending device 1 is illustrated in FIGS. 1, 2 and 6. The upper punch 10 assumes its upper rest position, which is lifted from the sheet 18, and in this position a position to be bent can be used Sheet 18 is manually or mechanically fed to the bending device 1 and brought into position on it. If a sheet metal bending cycle is now started, the upper punch 10 together with its holder 8 is first moved downwards in the guides 5 with the aid of the supports 6, 7 until the upper punch 10 with its edge 13 (which is in particular in alignment with the axis 11, 12) touches the sheet 18 to be bent, which was previously brought onto the lower bending dies 19, 20. This phase, in which the sheet 18 is practically clamped between the three bending dies 10, 19 and 20, but has not yet been bent, is illustrated in FIGS. 3 and 7 and further with solid lines in FIGS. 10 and 11.

The drive to the drive shafts 27, 28 of the rack and pinion gear 24 for the lower bending dies 19, 20 is now closed, that is to say switched on, for example via a clutch (not illustrated in any more detail). Accordingly, the toothed racks 25 are driven in pairs symmetrically obliquely upwards, pivoting the lower punches 19, 20 in opposite directions about the pivot axis 21 common to them, that is to say as shown in FIGS. 7 and 8, the left bending punch 19 becomes clockwise and the right bending punch 20 pivoted counterclockwise. With the help of the swiveling lower tools 19, 20, the sheet 18 is bent symmetrically by contact with the lower edge 13 of the upper punch 10, the bending edge 22 being produced. During this bending process, the upper punch 10 together with its holder 8, for example with the aid of the spindle drive 14 (FIG. 1), is advantageously locked or locked in position so that it forms a stationary counter-punch during this bending process. The sheet 18 is bent, for example, by approximately 90 ° along the bending edge 22, cf. the representation in Figures 4 and 8; As is further illustrated in FIGS. 10 and 11, an acute bending angle can also be brought about in the sheet 18 during this bending process, cf. there the position of the lower bending dies 19, 20 shown in dashed lines. 5 and 9 can then in the present sheet metal bending device 1, provided that the sheet 18 has previously been subjected to a bending process, the upper punch 10 together with its holder 8 about the axis defined by the joints 11, 12 (FIG. 1), the as mentioned in the working position essentially coincides with the bending axis or the pivot axis 21 of the lower punches 19, 20, are pivoted to the side so as to make room for the edge 34 of the sheet 18 which has already been bent.

The bending process is thus ended and the drives are reversed in order to pivot the lower bending dies 19, 20 back into the vertical starting position and to move the upper bending die 10 upwards and to straighten them again. The bent sheet 18 can now be advanced one step further or removed from the device 1.

As can be seen from FIGS. 6 to 9 and in particular from FIGS. 10 and 11, the lower, pivotable bending punches can be provided on their upper side in the rest position with rod-like pressure bodies 35, 36 which are approximately semicircular in cross section and which are arranged in a semi-cylindrical Bed 37 and 38 (Fig. 10 and 11) on the upper sides of the lower punch 19, 20 are freely pivoted. With this design, with the pivotable pressure bodies 35, 36, which have a flat surface 39 facing the sheet 18 to be bent, an adaptation to the respective sheet 18, in particular with different sheet thicknesses, is possible in a simple manner.

However, the lower bending punches 19, 20 can instead also be provided with a cutting-like upper side, with a convex rounding, as illustrated at 40 in FIG. 12. Otherwise, this embodiment corresponds to the device described above, and in particular the representation in FIG. 12 corresponds to the representation in FIG. 9, ie the final state after a bending process, with the upper punch 10 pivoted to the side, is illustrated, so that a new one Explanation of how given above with reference to FIGS. 1 to 5 or 6 to 9, can be omitted.

In Fig. 13 is a schematic partial view of another embodiment of the lower punch, e.g. of the punch 19, illustrated. Here, too, a pressure body 35 with a flat upper side 39 is pivotably mounted on the upper side of this bending die 19. Here, for example, schematically illustrated front pivot pins 41 and a channel-shaped bearing recess 42 are provided for mounting the prismatic pressure body 35, which is approximately triangular in cross section.

An example of an arrangement for mounting, articulated connection and movement control of the lower bending punches 19, 20 will now be described with reference to FIGS. 14 to 21. 14 and 17, the upper part of the lower bending die 19, as shown in FIG. 6, but without the pressure body 35 (FIG. 6), is illustrated in a cross-sectional illustration. 15 and 18 show this upper part of the lower left bending punch 19 in a partial view from the inside to illustrate the shape or profile of the bearing and guide recesses for angle levers to be described. For a general explanation of this embodiment, it should also be mentioned that FIGS. 14 and 15 only show the upper part of the lower bending die 19, whereas in FIGS. 17 and 18 the upper part of this lower bending die 19 is shown together with a pair of angle levers. This pair of angle levers is illustrated by itself in a schematic axonometric view in FIG. 16.

As can be seen from FIGS. 14, 15, 17 and 18, a blind hole-like bearing recess 43 and a continuous slot-shaped opening 44 with straight sliding grooves 45 are provided in the respective lower bending punch, for example in the bending punch 19, wherein in view (see FIG 15) results in a cross shape of this opening 44 with the sliding grooves 45. At least one pair of double angled ones is used for the articulated connection of the two lower bending dies 19, 20 (see FIGS. 19 to 21) Angle levers 46, 47, s. also FIG. 16, these angle levers 46, 47 being pivotally connected to one another in an angular range at 48. The reference numeral 48 in FIG. 16 indicates a pin for the pivot connection of the two angle levers 46, 47, but it can also be a continuous axis that extends over the entire width of the bending device according to FIGS. 1 to 5, wherein such a design will be provided if several such pairs of angle levers are provided distributed over the width of the bending device 1, similar to that described for the rack and pinion gear 24.

Each lower punch, e.g. the bending die 19 is articulated to one of the angle levers 46, 47 of such a pair of articulated angle levers, in the region of its bearing recess 43 in which one end of an arm 49 of the one angle lever, e.g. of the angle lever 46 (FIGS. 14, 17 and 18), is pivotably articulated by means of a pivot pin (or in turn a continuous pivot axis) 50. Furthermore, this lower bending punch, e.g. 19, the opposite end of the other angle lever, ie here the angle lever 47, is displaceable in the sliding grooves 45 of the through opening or opening 44. For this purpose, a pair of sliding blocks 51 can be pivotably attached to the end of the angle lever 47, and these sliding blocks 51 are guided in the sliding grooves 45 in a linearly displaceable manner, cf. from FIG. 16 in particular also the representation in FIGS. 17 and 18. It should be pointed out that in FIG. 18 the second sliding block 51 is covered by the other angle lever 46 and therefore cannot be seen.

Of course, the arrangement with respect to the other lower punch 20 is completely analog, i.e. on the other punch 20, the angle lever 47 is articulated, whereas the angle lever 46 is displaceably guided, cf. the representations in FIGS. 19 to 21.

19 to 21, the sequence of movements when pivoting the lower bending dies 19, 20 can then be seen, if these bending dies 19, 20 are pivoted, for example with the aid of the toothed gear 24, which is explained with reference to FIGS. 6 to 9 and not shown in FIGS. 14 to 21, as a pivoting drive or pivoting mechanism. The double lever arrangement (s) with the pair of angle levers 46, 47 secures or secures an exactly opposite, synchronous pivoting movement of the lower bending dies 19, 20, while determining the exact position of the imaginary pivot axis 21, see. 20 and 21. In detail, the starting or rest position is shown in FIG. 19, in which the lower bending dies 19, 20 are arranged horizontally with their upper sides. In the position according to FIG. 20, the lower bending dies 19, 20 have already been pivoted over part of their swivel stroke, and according to the illustration in FIG. 21 they have finally reached their end swivel position, for example. 19 to 21 it can be seen that the hinge axis 48 of the angle lever pairs 46, 47 moves essentially vertically according to the center plane (plane 23 according to FIG. 6). Otherwise, the sliding blocks 51 slide in their sliding or control grooves 45 during this pivoting movement, whereas the angle levers 46, 47 are pivoted with their opposite ends relative to the respective bending dies 19, 20.

As for the pivoting of the angle levers 46, 47 in the lower bending dies 19, 20 (hinge axis 50), it is also conceivable to use bearing blocks (not shown) in the bearing recesses 43 from the inside or front side (which can be seen in FIG. 15) ) to be used, the ends of the angle levers 46, 47 being pivoted in these bearing blocks. The dimensions of these bearing blocks, which are not illustrated in more detail in the drawing, can correspond exactly to the bearing recesses 43, and can also be secured in these bearing recesses 43 with the aid of screws or bolts.

22 to 25, a further sheet metal bending device 1 is illustrated very schematically with its essential working parts, with regard to the relative movement of its Stamp or tools 10, 19 and 20 completely corresponds to the previously described exemplary embodiments, but during the bending process it is not the upper stamp 10 that is held stationary, but the one, as shown in FIGS. 22 to 25, the lower stamp 20 on the right, whereas the other lower punch 19 is pivoted when bending the sheet metal 18 (see FIGS. 23 to 25) in accordance with the previous exemplary embodiments, and in order to bring about the relative pivoting movements between the stamps, the upper punch 10 - with half the angular velocity in comparison to the lower left punch 19 - is pivoted, see also the intermediate position of the three punches shown in FIG. 24 and the end position shown in FIG. 25. If one were to observe the movement sequence from the upper punch 10 (rest position) in this embodiment according to FIGS. 22 to 25, a completely identical swivel movement sequence would result as explained above with reference to FIGS. 1 to 11. 22 to 25, however, the individual movement phases are shown observed from the stationary frame (which is not illustrated in more detail in FIGS. 22 to 25). Such kinematics, as in the bending device according to FIGS. 22 to 25, may be desirable if only a slight movement, if any, is to take place on the sheet 18 to be bent on one side of the bending edge.

22 to 25, the two lower punches 19, 20 are hingedly connected to one another with interlocking eyelet members 52 to form the hinge joint 53, a hinge axis 54 extending through the entire joint arrangement. To the side of the hinge joint 53, the two lower punches 19, 20 have a rounded cheek shape where they come into contact with the sheet 18 to be bent. The two lower tools or stamps 19 can also be lighter Interchangeability, be made up of individual segments 55, which are firmly connected to a tool carrier or punch lower part 56, for example with the aid of bolts 57. As a swivel drive for the lower left punch 19, circular-shaped guide rails 58 can be provided with a toothing, not shown, which extend through guide slots 59 in the base part 56 of the other lower punch 20 and with drive gear wheels 60, which in principle correspond to the gear wheels 29 and 30, respectively 6 to 9 correspond, comb. The drive for these gear wheels 59 can take place in the manner already mentioned with reference to FIGS. 6 to 9 via a drive motor (not shown in more detail in FIG. 22) and a transmission.

In Fig. 22 it is also schematically illustrated with broken lines how, when the gear 60 is rotated counterclockwise (see arrow), the left stamp 19 outwards, i.e. is pivoted away from the right stamp 20. For the sake of simplicity, it has not been illustrated that simultaneously with this pivoting movement of a lower stamp 19, the upper stamp 10 also pivots - as mentioned at half the angular velocity in relation to the lower stamp 19.

The drive of the upper punch 10 can take place in a manner basically analogous to that for the lower punch 19, the required transmission ratio of 2: 1 having to be ensured via a gear. Such a drive arrangement is conventional per se, so that it does not need to be explained further at this point.

It should also be mentioned that the mounting of the upper punch 10 in the frame (not illustrated in more detail) in the bending device according to FIG. 22 can in principle be provided in a manner similar to that explained above with reference to FIGS. 1 to 5, i.e. in particular with supports 6, 7 and an upper bracket 8 pivotably mounted thereon.

23 to 25 also the pivot axis 21 for the relative pivoting between the lower bending dies 19, 20 is illustrated, which here with the geometric axis of the Joint axis 54 (FIG. 22) of the hinge joint 53 coincides. The upper punch 10 is also pivoted about this pivot axis 21 during bending, see the illustration in FIGS. 24 and 25.

Of course, the center of the arcuate rails 58 lies on this pivot axis 21 (i.e. the geometric axis of the hinge axis 54).

In the exemplary embodiment according to FIG. 26, the two lower punches 19, 20 are in turn pivoted symmetrically relative to the upper punch 10, which is only symbolized here by a circle illustrating the curvature of the bending edge, with circular guideways with correspondingly circular tooth segments 61 (for the Bending punch 19) or 62 (for the bending punch 20) are provided. These arcuate toothed segments or toothed rails 61,

62 each mesh with a gear 63 (for the toothed rail 61) or 64 (for the toothed rail 62). The gear

63 is driven by a common drive gear 65, which can be coupled to a motor (corresponding to the motor 15 in FIG. 6), and the gears 63, 64 mesh directly with one another for their counter-rotating movement, similar to the gears 29, 30 according to FIG. 6.

Shoes 66 and 67 are firmly connected to the toothed rails 61 and 62, these shoes 66, 67 being guided as sliding shoes in the slideways which are not shown in more detail and which are equipped with the toothed rails 61, 62. With these shoes 66, 67, the tool holders 68, 69 for the lower tools 19, 20 are connected via joints 70 and 71, respectively, so as to enable slight compensating movements of the lower tools or punches 19, 20 relative to the sheet metal surface during bending.

The upper punch 10 is driven vertically downward when the sheet 18 is bent, for example with the aid of a drive similar to the spindle drive 14 according to FIG. 1, this vertical downward drive with the pivoting movement of the lower tools 19, 20, for example via a numerical control a computer (not shown) - is coupled to depending on To achieve sheet thickness that when bending the sheet 18, when the two lower punches 19, 20 swing apart and at the same time the upper punch 10 moves downward, cf. the dashed intermediate position shown in FIG. 26 when bending to achieve a frictional engagement of the lower punches 19, 20 on the sheet 18, so that there is no relative movement between these punches and the sheet 18 along its surface. This ensures a particularly gentle treatment of the sheet 18 during bending, and surface defects that otherwise occur frequently are avoided.

If the invention was explained in more detail above on the basis of particularly preferred exemplary embodiments, numerous modifications and modifications are possible without leaving the scope of the invention. It is also conceivable, especially when bending thicker sheets, to pivot the lower bending dies 19, 20 about parallel axes that are spaced apart from one another. Furthermore, the drive of the bending punches 19, 20 or 10, 19 can also be accomplished with the help of working cylinders instead of with the aid of the rack and pinion gears described; The upper punch 10 can also be moved up and down, for example, with the aid of an eccentric drive or a working cylinder, it being possible for the upper punch 10 to be locked in the lower working position according to FIG. 3 or 7 by simply parking the eccentric drive in this position. For example, an electric motor can be used as the drive motor 15. In addition, it goes without saying that circular-toothed racks, as explained with reference to FIGS. 22 or 26, can also be used in the embodiment according to FIGS. 1 to 11 (and conversely straight-line racks, for example, in the embodiment according to FIGS. 22 or 26). A subdivision into individual stamp segments 55, as explained with reference to FIG. 22, can of course also be provided in all other exemplary embodiments.

Claims

Claims:

1. sheet bending device (1) with a relative to a frame (2) transversely to the sheet plane up and down movable upper punch (10), the two on the frame (2) arranged lower punch (19, 20), characterized in that at least two punches (19, 20; 10, 19) around an axis generally running in the area (22) of the bend of the sheet (18)

(21) are pivotally mounted in the frame (2) and coupled with a pivot mechanism (24).

2. Bending device according to claim 1, characterized in that the two lower punches (19, 20) by one in the area

(22) the bend of the sheet (18) extending axis (21) in the opposite direction is pivotally mounted in the frame (2).

3. Bending device according to claim 2, characterized in that the lower punches (19, 20) are coupled in their pivoting movement and can be pivoted symmetrically.

4. Bending device according to claim 2 or 3, characterized in that the lower punch (19, 20) about a common axis (21) are pivotable.

5. Bending device according to claim 4, characterized in that the common axis (21) lies in the plane (23) of the up and down movement of the upper punch (10).

6. Bending device according to one of claims 2 to 5, characterized in that the upper punch (10) can be locked in its working position brought up to the surface of the sheet (18) to be bent and thus forms a stationary counter-punch during bending, around which the sheet (18) is bendable by means of the counter-rotating lower punch (19, 20).

7. Bending device according to one of claims 1 to 6, characterized in that the upper punch (10) with its holder (8) on a on the frame (2) up and down carrier (6, 7) to a generally in the area Bending edge (22) in the sheet (18) extending axis (11, 12) is pivotally mounted.

8. Bending device according to claim 7 and according to claim 4 or 5, characterized in that the horizontal pivot axis (11, 12) of the upper punch (10) in its operating position at least substantially with the common pivot axis (21) of the lower punch (19, 20) coincides.

9. Bending device according to one of claims 1 to 8, characterized in that a spindle drive (14) is assigned to the upper punch (10) for up and down movement.

10. Bending device according to one of claims 2 to 9, characterized in that the lower punches (19, 20) are assigned as a swivel mechanism rack and pinion gear (24).

11. Bending device according to claim 10, characterized in that the rack and pinion gear (24) are arranged symmetrically.

12. Bending device according to claim 10 or 11, characterized in that the rack and pinion gear (24) are coupled to a common drive motor (15).

13. Bending device according to one of claims 10 to 12, characterized in that on each lower punch (19, 20) over the width of the device (1) distributed a plurality of racks (25) are articulated, which in turn with a shaft (27, 28) combing seated gears (29, 30), whereby the lower punches (19, 20) can be driven simultaneously in several places over the width of the device (1).

14. Bending device according to claim 12 and 13, characterized in that on the two, the two lower punches (19, 20) associated shafts (27, 28) two intermeshing gears (29, 30) and so the one, from the drive motor (15) driven shaft (27) drives the other shaft (28) rotating in opposite directions.

15. Bending device according to one of claims 1 to 14, characterized in that the lower punches (19, 20) on their upper sides freely pivotably mounted on the sheet metal (18) come to rest pressure body (35, 36).

16. Bending device according to claim 15, characterized in that the pressure body (35, 36) on it Top side (39) are flat and are each mounted in a partially cylindrical bed (37, 38) provided in the corresponding lower punch (19, 20).

17. Bending device according to one of claims 1 to 15, characterized in that the lower punches (19, 20) on their upper side (40) are cut-like, with a convex curve.

18. Bending device according to one of claims 1 to 17, characterized in that the upper punch (10) has a cutting-like lower bending edge (13) with a convex curve.

19. Bending device according to claim 18, characterized in that the upper punch (10) is sword-shaped.

20. Bending device according to one of claims 2 to 19, characterized in that the lower punches (19, 20) are coupled for their movement during pivoting with at least one pair of angle levers (46, 47), which in turn are centered via a joint (48) are interconnected.

21. Bending device according to claim 20, characterized in that the angle levers (46, 47) are in each case articulated on the one hand with one of the lower punches (19, 20) and on the other hand with a sliding block or the like (51) in a sliding groove (45) the other of the two lower stamps (19, 20) are guided displaceably.

22. Bending device according to one of claims 2 to 5, characterized in that the two lower punches (19, 20) with shoes (66, 67) which are guided in circular arcuate guide tracks (61, 62) with the center in the region of the sheet metal bend , are connected in an articulated manner and are held in frictional engagement on the sheet metal (18) to be bent during sheet metal bending by the downwardly movable upper punch (10).

23. Bending device according to claim 1, characterized in that the one lower punch (20) is stationary and the other lower punch (19) and the upper punch (10) are pivotally mounted, wherein the pivotable lower punch (19) can be driven at twice the angular speed compared to the upper punch (10).

24. Bending device according to one of claims 1 to 23, characterized in that the lower punches (19, 20) are cheek-shaped.