EP0215263B1 - Press brake - Google Patents

Abstract

A bending press includes a work support table comprised of a pair of support elements, at least one of which is mounted on the frame for movement generally vertically relative to the work support plane. Workpiece positioning elements are located on opposite sides of the work station defined by the upper and lower dies and are movable horizontally of the work support plane defined by the work support table. A drive motor effects horizontal movement of at least one of the workpiece positioning elements relative to the other positioning elements so as to move the workpiece on the work support table and effect its precise positioning in desired positions relative to the work station. The machine includes a computer control for operating the various drive motors and may include a rotatable work support table for effecting rotation of the workpiece to reorient it relative to the work station. Moreover, the press may include magazines which store a multiplicity of dies and die changing apparatus to exchange the dies in the die holding devices in response to instructions from a computer control.

Description

The invention relates to a bending press with an upper tool and a lower tool interacting therewith, as well as an adjustable first stop and a second stop opposite it and adjustable in the same coordinate direction, the direction of adjustment of the stops being approximately perpendicular to the infeed direction of the controlled movable tool and each stop by means of a drive motor is adjustable, which can be switched on and off by means of a program control, and with a support device for the workpiece. Such a bending press has become known from DE-A-3 407 445. It is operated in conjunction with a handling robot, which brings the parts to be bent into the bending area of the press and removes them after the bending process. When inserting these parts are pressed against lateral and rear attachment points. As soon as the part to be bent is aligned, the bending process is program-controlled.

With the help of this combination of bending press and handling robot, only simple workpieces that can be gripped by the handling robot can be manufactured in a controlled manner. This combination cannot be used for the production of more complicated parts with, for example, opposing bends. On the other hand, increasingly complex parts are required in technology, and there is a requirement to be able to manufacture the latter fully automatically.

The object of the invention is therefore to develop a bending press of the type described in such a way that, while maintaining program-controlled, machine-made, pre-pressing operations, more complicated parts can be manufactured quickly, easily and precisely.

To achieve this object, it is proposed according to the invention that the bending press is designed according to the preamble of claim 1 in accordance with the characterizing part of this claim.

The workpiece, preferably a sheet metal, can also be placed on the support device here with the aid of a manipulator, but of course also by hand. If the first stop is already aligned with the tool, the workpiece is moved against the first using the second stop. The second stop takes on the function of a displacement device. If the first stop is not permanently installed, but is preferably also adjustable, you can first bring this or the second stop into the correct position with respect to the tool and then push the workpiece with the other stop against the one that was initially positioned.

For the sake of simplicity, we will only speak of a "sheet" below and also assume that the upper tool is a wedge-shaped bending punch and the lower tool is a cross-section corresponding to a bending die, without this being to be understood as restrictive.

With this press, you do not need to insert the sheet exactly, which is why a loading device of the simplest type or loading by hand is possible. On the other hand, you have to position the first fixed stop very precisely in relation to the bending tool. However, this is easily possible due to the automatic program. Of course, the two stops are arranged and movable so that the sheet can be assigned to the bending tool in any desired manner.

The support device for the sheet metal is, for example, a two-part support table, a grate, a latticework or a similar device with a flat support surface for the sheet metal. One support sub-device is to a certain extent in front of the bending tool and the other behind it. Because of their lateral spacing, there is a passage opening between the two for the movable tool part. The shaping part of the lower tool, for example the groove of the bending die, is assigned to the support surface at least of the one support sub-device in the manner required for the respective bending process. The upper ends of the two groove flanks can lie, for example, in the plane defined by the support surface of this support sub-device.

As mentioned, the use of two support sub-devices means that the space between the latter can be used for the bending tool and, if appropriate, for the passage of the movable bending tool part. The support sub-devices can each be individually moved or raised and lowered by means of a controllable motor, the motors being at least switchable on and off by means of the program control. If necessary, you can also regulate the speed of the motors via the program control.

If you bend a flat sheet metal with the help of a wedge-shaped bending punch and a bending die and the flanks of the bending die extend inclined to the bearing surface for the sheet metal, in particular enclose an angle of 45 °, the two angle legs of the angled sheet metal run in the direction of the flanks of the bending die, ie they also close with the contact surface of the support device or at least one support sub-device one or respectively an angle of z. B. of 45 °. In other words, when bending, the two sheet metal parts on either side of the bending point stand out from the support surfaces. After pulling back the upper tool, the bob remains gene sheet in this position, unless special precautions are taken.

Because exchanging the upper tool for the lower tool and vice versa by hand is undoubtedly time-consuming, the bending press not only has removable or exchangeable tool parts, but also a motor-driven tool changing device for the tool parts. Each tool changing device can be from known Bauert. With their help, the upper tool is removed from the upper tool holder and the lower tool from the lower tool holder simultaneously or separately.

In order to fundamentally keep the sheet metal plane free for moving the sheet metal, two separate tool changing devices are provided, the one for the upper tool being above the sheet metal plane and the one for the lower tool below the sheet metal plane. These are essentially and preferably hydraulic or pneumatic working cylinders with a corresponding gripping device for the tool in question, for example gripping pliers each with gripping fingers which can be pivoted relative to one another. A prerequisite for the automatic change with these devices is an automatic locking and unlocking device which is common in other machine tools with a reciprocating working movement, the locking and unlocking e.g. B. is accomplished by controllable wedges, which implement a horizontal movement in a transverse locking movement or locking movement. After removing the upper and lower tools from their tool holders, one removes these two tools from their changing devices and exchanges them for one another or exchanges them with the other tools assigned to one another in the same way or in an interchanged manner.

Each drive motor of each tool changing device can be switched on and off via the program control. In the case of a hydraulic or pneumatic working cylinder, the control switches the pump motor on and off, for example, or opens and closes a blocking element for the pump medium.

The position of the sheet after bending can be suitable for further processing and also for removal, in particular the automatic pushing out with the aid of one of the stops. For this reason, a further embodiment of the invention provides that deliverable hold-down sub-devices are present and that these are preferably program-controlled. With the help of one of these hold-down devices, the sheet can be tipped to the desired side. A program-controlled movement makes sense if, due to the special shape of the bent sheet or the special center of gravity, a mechanical tilting back is always or at least mostly necessary.

A further development of the invention provides that the upper and lower tool holder are at least essentially designed and dimensioned the same. You can then swap the upper tool with the lower tool, more precisely, insert the upper tool into the tool holder of the lower tool and the lower tool into the tool holder of the upper tool. This enables the sheet to be bent in a different bending direction than before. For example, you can bend up one edge of a sheet and bend down another in the opposite direction. A Z-shaped structure is then created. The latter can be part of a housing or the like. The sheet does not have to be turned or turned over, although it is angled in the opposite direction. It is only necessary to exchange the upper and lower tool after the first bending process and to move the sheet metal into the correct position for the second bending process. It is easy to see that this design enables the automated production of complicated sheet metal parts, in particular in connection with the lowerable sub-devices. By lowering one or, if necessary, both support sub-assemblies, you create the necessary space for bending with reversed upper and lower tools. The workpiece can be brought back into a desired position by raising it.

Another embodiment of the invention is that the support sub-devices can be moved up and down parallel to themselves, but inclined to their support surface or the like. For the workpiece. One can speak of an inclined lowering or raising of each support sub-device. However, this takes place in such a way that the support sub-device moves with its lowering movement away from the plane defined by the bending punch. In particular, only one support sub-device is intended to be lowered. This presupposes that the workpiece is suitably prevented from tipping over, which would occur if the center of gravity of the sheet is assigned to the support subassembly to be lowered. For example, the sheet metal could then be held with the help of the bending tool, to be precise, clamped between the upper and lower tool without a bending process first taking place.

Another variant of the invention is characterized in that each hold-down device consists of at least one, but preferably a plurality of pins, bolts or the like elements arranged at a lateral distance. If a hold-down subassembly consists of a bolt group or the like, it is possible, especially in the case of program control and the production of bends in complicated sheet metal structures, if necessary also individual pins or reset and reset pin groups. However, the prerequisite is that each pin has its own drive and each of these drives can be controlled separately.

A preferred embodiment of the invention is characterized in that the direction of changing or replacing the tool changing devices runs transversely to the infeed direction of the deliverable tool and parallel to the bending line. It is taken into account here that the bending tool is not rotationally symmetrical, but is generally elongated, i.e. H. consists of a sword-like bending punch and a correspondingly long and shaped bending die. Such a bending tool requires a special assignment of your tool changing device.

A further development of the invention is characterized by a device for rotating the workpiece, in particular within the workpiece plane. This allows workpieces with the shape of a box base to be manufactured, i.e. H. all four edges of a rectangular sheet can be bent with a single straight-line bending tool. First you bend the two opposite longitudinal edges one after the other and after a 90 ° rotation of the workpiece in two further bending processes the remaining sheet metal edges that run transversely to this. This is another important cut for the fully automatic production of such structures that are required, for example, for switch boxes and the like.

At this point, however, it is expressly pointed out that not only rectangular and not only sheets with straight edges can be processed with such a press, but also sheets with quite special contour lines. This is possible above all when using stop sections.

The two, however independent parts of each stop can have different lengths, even different designs. If they can be delivered separately, the two stop sections of a stop can be used to move a sheet cleanly parallel to one another even if the longitudinal edge assigned to these stop sections runs in a step-like manner. Corresponding to the ledge, one of the stop sections runs ahead of the other during the displacement movement. The same also applies when placing on fixed stop sections.

A further embodiment of the invention provides that the upper and lower tools form part of a workpiece turning device, these tools being rotatably mounted in their tool holders or the latter being rotatably mounted in a holder for the tool holder and each tool or tool holder with is equipped with a rotary drive. The axis of rotation for the workpiece runs parallel to the feed direction of the movable tool. The rotary drive can be designed in a known manner by, for example, concentrically attaching a pinion or the like to a tool shank or to a shank of a tool holder. The machine element, which by means of a suitable other machine element, for example a rack or a gearwheel, which or a corresponding controllable motor is connected to a rotary drive. It is obvious that the tool is also rotated, preferably via a correspondingly expanded program control. Of course, the workpiece must be secured against displacement transversely to the axis of rotation during the rotary movement. However, this is generally not possible with the aid of stops that can only be moved linearly. One solution to this problem is that the workpiece is clamped between the upper and lower tools while it is being rotated without causing any deformation. The tool then also simultaneously forms a holding device for the workpiece during the turning.

Another variant of the invention is characterized by a tool magazine for receiving a plurality of upper and lower tools, the tool changing device being selectively assignable to the tool magazine or the tool holder. With the help of the tool changing device, an upper and a lower tool are removed from the preferably two-part tool magazine. The upper tool is then transferred to the upper tool holder and the lower tool in the lower tool holder and locked. After use, you take both of their tool holders and bring them back to the tool magazine. The next required tool is then taken from this. The latter can optionally be of the same design as the one used previously, with the difference that the tool changing device now exchanges a tool in the upper tool holder which corresponds to that which was previously in the lower tool holder and vice versa. Such a tool change enables the bending of a sheet metal edge and the subsequent bending down of a second, for example parallel, sheet metal edge in the manner described above. The tool changing device can optionally assign its gripping device or the like to the tool magazine or the tool holder of the press. As a result, the tool magazine must be adjusted when changing from one tool to another. There is the possibility of making this tool magazine rotatable in the manner of a carousel, or of using a magazine that can be pushed back and forth linearly.

All of the described movements of the machine and its auxiliary devices are preferably by means of an overall program controllable.

Another embodiment of the invention is characterized in that the tool magazine can be moved laterally next to the tool holder transversely to the bending line.

A further preferred embodiment of the invention is characterized by a third and fourth, respectively adjustable stop, the third stop being located between the first and the second stop, but being laterally offset, and the fourth being opposite the third stop, and in one to the direction of movement of the first and second stops perpendicular to the coordinate direction is movable, each stop also consists of two separately adjustable and resettable stop sections. With regard to the adjustment, all stops are primarily motor-driven and in particular program-controlled motor-driven adjustment. Assuming the same starting position of all stop sections, the two stop sections of each stop are in extension from each other or respectively on a common straight line, but they are spaced apart from one another. If the first and second stops are referred to as "cross stops" and the third and fourth stops as "longitudinal stops", the arrangements can preferably be made such that a cross stop half is assigned to a longitudinal stop half. If strip-shaped stops are involved, a cross-stop half and a longitudinal stop half each form a "stop corner". However, the two elements of each stop corner must be able to be moved past one another without hindrance. Furthermore, it is very advantageous that each stop or each stop section is detachably held in a stop holder. If necessary, it can be removed and, if necessary, also replaced by a stop or a stop section of another type. The latter affects both the shape and the size.

The third adjustable stop, as already explained, is located between the first and second stop, but is laterally offset from it. If you work with only three stops, a square plate must first be created at the third stop. It is then moved, for example with the aid of the second stop, along the third stop towards the first. Here, the first and the third stop must be correctly aligned with the bending tool before the second stop is delivered.

The automatic placement of the workpiece at the third stop is comparatively easy to carry out with the fourth stop because it is opposite the third stop. With four stops, you can assign a stop to each of the four edges of a square, in particular rectangular sheet. Two of these four stops are or are initially precisely aligned with the bending tool. With the help of the other two, the sheet is pushed against the positioned stops. At the end of this step, it is in the correct position in relation to the bending tool.

With four deliverable stops, for example, the infeed direction of the first and second stop is in the direction of a Y coordinate, while the infeed direction of the third and fourth stop is in the direction of an X coordinate. Each of these four stops can be either a stop or a shifting device, one stop of each coordinate always being aligned first and then the sheet being moved with the other stop of each coordinate to rest against the two fixed or fixed stops. Of course, the four stops must be designed and arranged so that none comes into the range of movement of the tool that can be advanced, in particular the upper tool. This primarily concerns the two stops, which are assigned to the sheet metal edges that run perpendicular to the longitudinal direction of the wedge-shaped bending die.

It follows from the foregoing that it is very advantageous if the adjustment direction of the four stops is approximately perpendicular to the feed direction of the movable tool. This means that in the mentioned X-Y coordinate system the deliverable tool is moved in the direction of a Z axis.

The drive motors for the stops can be both an electric motor and a hydraulic or pneumatic motor. In the former case, the rotary movement of the motor must be converted into a suitable translational movement, which can be easily accomplished, for example, using a pinion and a rack or spindle. In the second case, the motor is already performing a linear adjustment movement. The movable stop can be coupled directly or indirectly using an intermediate element to the piston of a hydraulic or pneumatic working cylinder. Otherwise, electric or electromagnetic drives with a linear adjustment movement are known and can be used.

In connection with the program control, it is advisable to provide a drive motor for each stop. The program control then brings two of the four stops into the position required for bending the sheet at the intended location. After their alignment, the program-controlled delivery of the other two, for example the second and fourth stop, takes place. Of course, the four stops are also ge with the help of the program control before inserting the sheet at a sufficiently large mutual distance brings - if they are not already - so that the sheet can be inserted into the "field" defined by the four stops without hindrance from the stops. The deliverable tool part is located above this field and underneath the tool part, which is stationary at least during the pressing process.

So if the dimensions of the sheet are within the maximum distances of this bending press, you can use the program control to bend a workpiece fully automatically, precisely and quickly in the desired manner. The program also enables the press to be loaded and the bent sheet to be brought out quickly, safely and in a precisely recurring manner. The application can be done e.g. B. with the help of at least one movable stop, or at least with the help of the latter. For this it may be necessary under certain circumstances that this stop can be moved beyond the vertical plane defined by the bending die, ie from a room on this side to a room on this plane. In order not to have to accept any restrictions in this regard, it is expedient if all four stops can be moved in this way over approximately the entire contact area.

Moving beyond the support surface of the support device is possible if the stops are not stored on the support device, but preferably in locally separate guides that extend far enough beyond the support surface of the support device or at least moving the stops beyond the limits allow the contact surface.

The program control for the stop adjustment is part of a program control for the tool movement. This enables a fully automatic and correctly timed program sequence, starting with the alignment of the sheet, the subsequent bending and, if necessary, the subsequent removal of the bent part.

• Fig. 1 Die Seitenansicht einer Biegepresse in schematischer Darstellung,
• Fig. 2 einen Querschnitt nach Fig. 1,
• Fig. 3 eine geschnittene Seitenansicht einer anderen Ausführungsform,
• Fig. 4 die teilweise geschnittene Vorderansicht einer anderen Ausführungsform,
• Fig. 5 eine teilweise geschnittene Draufsicht nach Fig. 4,
• Fig. 6 die Seitenansicht einer anderen Ausführungsform,
• Fign. 7a bis 7h eine schematische Seitenansicht in verschiedenen Arbeitslagen.

The invention is explained below with reference to the drawing. The drawing shows exemplary embodiments of the invention. They represent:

• 1 is a side view of a bending press in a schematic representation,
• 2 shows a cross section according to FIG. 1,
• 3 is a sectional side view of another embodiment,
• 4 shows the partially sectioned front view of another embodiment,
• 5 is a partially sectioned plan view of FIG. 4,
• 6 is a side view of another embodiment,
• Fig. 7a to 7h a schematic side view in different working positions.

The frame 1 of the bending press consists of a column and a cantilever, at the free end of which a press cylinder 28 is arranged. The support surface 18 for the workpiece 6 is supported on the support device 5, which is divided into two support sub-devices 16 in order to allow the upper tool 2 fastened in the tool holder 21 to pass through. Each of the sub-devices 16 is provided with a height adjustment motor 17, so that different heights can be set depending on the requirements. The lower tool 3 is likewise arranged in a tool holder 21 between the two support part devices 16.

A rear stop 4 is initially provided for the workpiece 6 and is adjustable in order to obtain a basic setting. Opposite this is a second deliverable stop 7, which at the same time takes over the function of a displacement device. Laterally, a third stop 8 and a fourth stop 9 opposite this are provided, which are adjustable perpendicular to the direction of movement 11 of the two other stops 4, 7. Drive motors 13, which are connected to a control device 14, serve to move the stops 4, 7-9. As can be seen in FIG. 2, each of the four adjustable stops consists of two stop halves, which in turn are combined into corner stops, as a result of which a very precise alignment of the workpiece 6 can be achieved. If a workpiece 6 is not exactly rectangular, then compensating, appropriately shaped inserts are used for the corners. The stops are fastened in stop receptacles 15, which in turn can be moved on guide rods 29.

It is now only necessary to place the workpiece 6 on the support surface 18. Then the rear stop 4 is brought into the desired basic position in one coordinate direction 11 and the stops 8 and 9 are aligned in the coordinate direction 10, so that the workpiece 6 is guided laterally against the rear stop 4 into the machining position by means of the second stop 7 becomes. The bending process can then be carried out by infeed of the upper tool 2 in the direction of arrow 12.

3 additionally shows a hold-down device, each hold-down device 16 being assigned a hold-down device 19 with holding pins 20. This division is necessary in order to enable adaptation to different height settings of the support sub-devices 16 and to push back the bent workpieces and to prevent the workpiece from tipping over when the support surfaces are of different heights.

When machining a Z-shaped work piece 6, this would have to be applied in the opposite sense to the angle. As FIGS. 4 and 5 show, another way is selected according to the present invention, in which the workpiece 6 remains in its position, but the upper and lower tools 2, 3, as shown in FIGS. 4 and 5, are changed. For this purpose, a tool changing device 22 is provided, which consists of two changing and changing devices 23 for the upper tool 2 and the lower tool 3. The tools are each gripped by the grippers 31 and inserted into empty chambers of the tool magazine 25. A separate magazine 25 is provided for each of the upper and lower tools, the magazines being arranged on guide rails 30 so as to be displaceable in the direction of arrow 26. The new tool is then removed from a full chamber and inserted into the holder.

For some types of processing, the workpiece must be turned in its plane. For this purpose, a rotatable support 32 is provided in FIG. 6, onto which the workpiece 6 is pressed. For this purpose, a pressure pin 34 provided with a turntable at its free end is provided. The rotary drive takes place via a special motor 33. It is of course also possible to arrange the two tools 2 and 3 rotatably and to clamp the workpiece between them for rotation.

The variety of processing options results from the sequence of the representations according to FIG. 7. Here, the production of a Z-shaped sheet is shown. In Fig. 7a, all parts are in a starting position and the workpiece 6 has been placed on the support surface 18. Then the rear stop 4 is then moved into the desired position. 7b shows that the second stop 7 has placed the workpiece 6 on the rear stop 4. In the subsequent bending process according to FIG. 7c, workpiece 6 bends up on both sides. After the workpiece has been released by the upper tool 2, it tilts back automatically, this movement being able to be supported by the pin 20 of the hold-down device 19 shown in broken lines. Then, as Fig. 7e shows, the tools are changed so that a bend in the opposite direction is possible. In addition, if necessary, the workpiece 6 is then displaced by the stops into the position according to FIG. 7f. The support part device 16 on the right in the plane of the drawing must be lowered so that the free end of the workpiece 6 can deflect downwards during bending, as shown in FIG. 7g. The height of the two partial support surfaces 16 is then adjusted relative to one another in such a way that the workpiece 6 is aligned according to FIG. 7h and the stops can push out the workpiece. While it was previously necessary to place and remove the workpiece several times and to turn and turn it, a Z-shaped workpiece can now be manufactured by hand without any intervention.

Claims (12)

1. A bending press with an upper tool (2) and co-operating therewith a bottom tool (3) and with an adjustable first abutment (4) and opposite this and adapted to be advanced in the same direction of co-operating a second abutment (7), the direction (10) of displacement of the abutments (4, 7) extending substantially at right-angles to the direction of feed (12) of the tool (2) which is adapted for controlled movement, each abutment being adjustable by means of a driving motor (13) which can be switched on and off by means of a programme control unit (14), and with means (16 to 18) for supporting the workpiece (6) characterised in that the means (18) for supporting the workpiece (2) comprise two support indexing devices (16) one of which is on this side while the other is on the other side of the bending tool, and of which each can be raised and lowered individually transversely to the direction of movement of the adjustable abutments (4, 7) by means of respective controllable motors (17), the motors (17) being capable of being at least switched on and off by means of the programme control unit and in that furthermore the upper tool (2) and bottom tool (3) are removably held in a respective upper or lower tool support (21), the upper and lower tools each being interchangeable by means of a motor-driven tool changing device (22), each driving motor switched on and off by the programme control unit of the bending press (1).

2. A bending press according to Claim 1, characterised in that at a distance above each support indexing device (16) there is an advanceable depressor indexing device (19), each depressor indexing device (19) being adapted to be fed towards and moved away from the associated support indexing device (16) under control, preferably programmed control.

3. A bending press according to Claim 1 or 2, characterised in that the top and bottom tool supports (21) are at least substantially of the same shape and dimensions.

4. A bending press according to at least one of Claims 1 to 3, characterised in that the support indexing devices (16) are adapted to be moved upwards and downwards parallel with each other but at an angle to their supporting surface (18) or the like for the workpiece (6).

5. A bending press according to at least one of Claims 1 to 4, characterised in that the each depressor indexing device (19) consists of at least one but preferably a plurality of laterally spaced apart pins (20), bolts or like elements.

6. A bending press according to at least one of the preceding Claims, characterised in that the direction of fitment or removal of the tool changing devices extends transversely to the direction of feed (12) of the advanceable tool (2) and parallel with the bending line.

7. A bending press according to at least one of the preceding Claims, characterised by a device (33, 34) for rotating the workpiece (6), particularly within the workpiece plane.

8. A bending press according to at least one of the preceding Claims, characterised in that the top tool (2) and bottom tool (3) form a part of a workpiece turning device, these tools being mounted to rotate in their tool holders (21) or the latter being mounted to rotate in a respective tool holder support, each tool or each tool holder being equipped with a rotary drive.

9. A bending press according to at least one of the preceding Claims, characterised by a tool magazine (25) to hold a plurality of top tools (2) and bottom tools (3), the tool changing device (22) being capable of being associated optionally with the tool magazine (25) or the tool holder (21).

10. A bending press according to Claim 9, characterised in that the tool magazine (25) is adapted for movement tansversely to the bending line laterally alongside the tool holder (2).

11. A bending press according to at least one of the preceding Claims, characterised by a third and fourth respectively adjustable abutment (8) or (9), the third abutment being disposed between the first (4) and the second abutment (7), while being offset laterally thereto while the fourth is opposite the third abutment and are adapted for movement in a co-ordinates direction (10) extending at a right-angle to the direction of movement (11) of the first and second abutments (4, 5) and in that each abutment (4, 7, 8, 9) consists of two partial abutments adapted to be advanced and withdrawn separately.

12. A bending press according to Claim 11, characterised in that each abutment (4, 7, 8, 9) or each partial abutment is removably supported in an abutment holder (15).

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