EP1495816B1 - Bending tool with adjustable workpiece contrasting segments as well as bending machine comprising such a bending tool - Google Patents

Abstract

A press tool for a metal bending/folding machine has the press tool and the die with a segmented construction with overlapping edge profiles. This enables both sides of the bending line to be set with infinite adjustment and without having to change the bending tools. The overlapping profiles are arranged each side of the bending line to produce an even bending/folding effect.

Description

The invention relates to a bending tool for bending workpieces, in particular sheets, with at least one bending tool part, by means of which a workpiece bend can be created on the workpiece under its action by a workpiece abutment of the bending tool part along a tool-side loading line, wherein at least one bending tool part has workpiece abutment segments, which in Direction of .Beaufschlagungslinie are adjustable relative to each other in different functional positions.

In practice, there is often the need to change bending tools or individual bending tool parts in their width. If, for example, by means of a conventional bending tool with bending punch and bending die a tab be folded, which was previously cut free on a sheet with unilateral connection with the residual sheet and is to avoid deformation of the remainder sheet, the width of the punch and the width of the bending die may Abkantlänge on the tab at best to exceed the width of the kerf between the tab and the residual sheet. Different Abkantlängen require correspondingly different widths of punch and bending die. Also conceivable are processing cases in which only the width of one of the two bending tool parts is to be changed.

Segmented bending punches and bending dies whose individual segments are available in different widths are commonly used to provide variable bending tool widths. By appropriate combination of segments, the bending tool width can be adapted to the requirements of the respective processing task. The segments of both the punch and the bending die are lined up without gaps. If the required bending tool width changes, bending tool segments are to be removed without replacement, added or replaced by segments of different widths.

A generic bending tool is known from EP 0 577 068 A1. In the case of the prior art, a bending tool part in the form of a blank holder cooperating with a pivotable bending beam is subdivided into hold-down segments, which are arranged side by side in the direction of the loading line resulting from the workpiece machining. By means of an adjusting device, the distances between adjacent hold-down segments can be varied. In this way, the overall width of the blank holder can be varied. The minimum width of the hold-down results when the hold-down segments are arranged close together. An enlargement of the hold-down segments is accompanied by the formation of gaps in the tool-side Beaufschlagungslinie.

To provide a bending tool by means of which high-quality machining can be carried out regardless of a variable tool part width and to provide a bending machine with such a bending tool, the present invention has set itself the goal.

This object is achieved according to the invention by the bending tool according to claim 1 and the bending machine according to claim 10.

In the case of the invention, it is possible to vary the width of the bending tool or of the respective bending tool part by changing those positions which are mutually different along the tool-side Beaufschlagungslinie adjacent workpiece abutment segments to each other. To increase the width of the relevant workpiece abutment segments, for example, starting from a close juxtaposition apart. In many cases, an exchange or the removal or addition of workpiece abutment segments for tuning the width of the bending tool or bending tool part to changing machining tasks can be dispensed with. Due to the mutual overlap of workpiece abutment segments in the direction of the loading line and due to the mutual separation of such workpiece abutment segments along said line is avoided that at a setting movement to change the width of the bending tool or the respective bending tool part between the relatively displaced workpiece abutment segments at the loading line a gap results. The part of the loading line formed by the one workpiece abutment segment is immediately followed by the part of the loading line assigned to the adjacent workpiece abutment segment. Regardless of the division of the workpiece abutment in workpiece abutment segments which can be adjusted relative to each other, a high machining quality can consequently be achieved. Implemented with advantages is the inventive concept of bending tools of different types. As one of several candidate tool types mentioned are bending tools, swivel and rotary bending tools. At Biegestempeln conventional Gesenkbiegewerkzeuge the Beaufschlagungslinie runs in or near the punch forming edge. At Biegematrizen such bending tools, the Beaufschlagungslinien extend approximately in dependence on the cross-sectional shape of the die groove on the flanks or at the longitudinal edges thereof.

Particular embodiments of the bending tool according to claim 1 and thus also special embodiments of the bending machine according to the invention will become apparent from the dependent claims 2 to 9.

In a preferred embodiment of the invention, the relevant abutment segments are continuously adjustable to each other (claim 2)

In the interests of mechanization of the arrangement, in the case of the invention type of construction according to claim 3, an adjusting device is provided for mutual adjustment of the workpiece abutment segments.

The evidence of claims 4 and 5 in the invention, individually or in combination with each other provided measures are used to automate the mutual adjustment of the workpiece abutment segments. In particular, it is possible to adjust the workpiece abutment segments and thus to integrate the width adjustment of the bending tool or of the respective bending tool part into automated processes on a bending machine.

A defined adjustment movement and thus an exact and appropriate positioning of the workpiece abutment segments is ensured in the case of the invention types according to claims 6 and 7. Due to the mutual guidance of the workpiece abutment segments to be adjusted relative to one another described in claim 7, these can form an inherently stable overall arrangement, regardless of their relative mobility.

A preferred type of bending tool according to the invention comprises a bending tool part in the form of a blank holder and / or a bending tool part in the form of a bending cheek (claim 8).

It is particularly advantageous if the holding-down device has a plurality of workpiece abutment segments which are adjustable relative to one another in the direction of the loading line relative to one another and which overlap each other along the loading line in the direction of the loading line, of which at least one workpiece abutment segment located outside in the direction of the loading line forms a corner segment is, that in turn has a projecting in the direction of the loading line lateral projection (claim 9).

Such bending tools are also used for the production of complex shaped bent parts. Claiming corner segments of the blank holder extend with its front side along the bending line of the bend to be created and engage with their lateral projection, for example, in the interior of already created upstands, which in turn with a workpiece leg in the direction of the bending line of the bend to be created to the hold down protrude. Before the actual workpiece machining, the hold-down is first to move past the previously created upstand to the workpiece and then introduce with the corner segment in the interior of the upstand. Due to the inventive design of the hold-down can first be provided by tight abutment of the abutment segments with a relatively small width and placed in this state on the workpiece or transferred to a workpiece-near position. Subsequently, the width of the hold-down can be increased by appropriate mutual adjustment of adjacent abutment segments until the corner segment has reached its rear grip position. In the resulting state, the hold-down can effectively act on the workpiece over the entire length of the bend to be created while forming a gap-free Beaufschlagungslinie.

Fig. 1

einen Biegestempel mit relativ zueinander einstellbaren Stempelsegmenten in einem ersten Betriebszustand sowie eine Biegematrize mit relativ zueinander einstellbaren Matrizensegmenten,

Fig. 2

den Biegestempel nach Fig. 1 in einem zweiten Betriebszustand sowie eine zweite Biegematrize mit relativ zueinander einstellbaren Matrizensegmenten,

Fign. 3, 4

die Stempelsegmente des Biegestempels nach den Fign. 1 und 2,

Fig. 5

den Biegestempel nach Fig. 2 in der perspektivischen Draufsicht auf die Umformkante,

Fig. 6

zwei Matrizensegmente der Biegematrize nach Fig. 2,

Fig. 7

einen Niederhalter eines Schwenkbiegewerkzeugs mit relativ zueinander einstellbaren Niederhaltersegmenten in einem ersten Betriebszustand an einem Werkstück,

Fig. 8

den Niederhalter nach Fig. 7 in einem zweiten Betriebszustand und

Fig. 9

zwei Niederhaltersegmente des Niederhalters nach den Fign. 7 und 8.

The invention will be explained in more detail with reference to schematic representations of exemplary embodiments. Show it:

Fig. 1

a punch with relatively adjustable punch segments in a first operating state and a bending die with relatively adjustable die segments,

Fig. 2

1 in a second operating state and a second bending die with relatively adjustable die segments,

FIGS. 3, 4

the punch segments of the punch according to FIGS. 1 and 2,

Fig. 5

2 in the perspective plan view of the forming edge,

Fig. 6

two die segments of the bending die of FIG. 2,

Fig. 7

a holding-down device of a swivel bending tool with holding-down segments which can be adjusted relative to one another in a first operating state on a workpiece,

Fig. 8

the hold-down of FIG. 7 in a second operating state and

Fig. 9

two hold-down segments of the hold-down according to FIGS. 7 and 8.

According to FIG. 1, a bending punch 1 and a bending die 2 form a bending tool 3, which serves as a die bending tool for deforming a sheet 4 along a bending line 5. The bending punch 1 consists of two workpiece abutment segments in the form of punch segments 6, 7. The bending die 2 comprises as workpiece abutment segments a total of four die segments 8. The punch segments 6, 7 and the die segments 8 are each adjustable in the direction of the bending line 5 relative to each other in different functional positions. An adjusting device 9 for the die segments 8 comprises a knurled screw 10 serving as a set screw, which is seated on a threaded bolt 11. The threaded bolt 11 passes through the die segments 8.

At the axial end, not visible in FIG. 1, the threaded bolt 11 is supported in the axial direction on the outer left-hand die segment 8 in FIG. Between the die segments 8 sitting on the threaded bolt 11 coil springs, which are under bias. If the knurled screw 10 is rotated counterclockwise starting from the ratios according to FIG. 1, the preloaded coil springs move the die segments 8 apart. As a result, the width of the bending die 2 formed by the die segments 8 increases. In such a widened state, FIG. 2 shows a bending die 2 a composed of workpiece abutment segments in the form of die segments 8 a. As an alternative to the illustrated manual adjusting device 9 mechanical adjusting devices are conceivable, which may also have a numerical control under certain circumstances.

In a corresponding manner, the width of the punch 1 is variable. The provided for this purpose actuator is shown in FIGS. 1 and 2 for the sake of simplicity not shown. In Fig. 1, the punch segments 6, 7 are in the direction of the bending line 5 close together. In this operating state, the punch 1 has its minimum width. In Fig. 2, the punch segments 6, 7 in the direction of the bending line 5 auseinandergerück. The width of the punch 1 has thus increased compared to the ratios of FIG.

Evidenced the Fign. 3 and 4, the punch segments 6, 7 guided relative to each other in the direction of their adjustment movement to each other. As guide means serve a cross-sectionally T-shaped guide rail 12 on the punch segment 7 and a complementarily shaped undercut guide groove 13 on the punch segment 6. Due to the selected type of leadership form the punch segments 6, 7, regardless of their relative mobility is a stable unit.

As is apparent from Fig. 5, the punch segments 6, 7 are separated from each other in a Umformkante. In a good approximation, the forming edge defines a loading line 14, that is to say the area with which the bending punch 1 acts on the sheet 4 during the processing to form the bending line 5. During workpiece machining, the loading line 14 and the bending line 5 run parallel to one another. Over their entire mutual adjustment overlap the punch segments 6, 7 with each other. As a result of the separation of the punch segments 6, 7 in the Umformkante or the Beaufschlagungslinie 14 and due to the mutual overlap of the punch segments 6, 7 results in spaced apart punch segments 6, 7 in the direction of the Beaufschlagungslinie 14 and the bending line 5 without licking the loading Sheet 4.

Correspondingly, the conditions on the bending dies 2, 2 a represent themselves. For the bending die 2 a, this can be seen from FIG. 6.

Loading lines 15, 16 extend on flanks 17, 18 of a die groove 19. The die segments 8a overlap one another in the direction of the loading lines 15, 16. The separation of the die segments 8a takes place along the loading lines 15, 16. Even when the die segments 8a are moved apart, there are no gaps whatsoever in the admission lines 15, 16.

During the processing of the sheet 4, for example, depending on the radius of the tip of the punch 1 or the thickness of the sheet 4 to be machined, the loading lines 14, 15, 16 may wander in their transverse direction.

FIG. 6 shows the passages provided on the die segments 8a for the threaded bolt of the adjusting device for mutual adjustment of the die segments 8a.
End extensions of the passages for the threaded bolts serve to receive the biased coil springs disposed between the die segments 8a.

FIGS. 7 to 9 relate to a bending tool designed as a swivel bending tool 20. The swivel bending tool 20 comprises in addition to a conventional bending cheek a hold-down 21 with workpiece abutment segments in the form of hold-down segments 22, 23. The hold-down segments 22 are designed as corner segments and as such each provided with a lateral projection 24.

The swivel bending tool 20 is used for machining a workpiece 25. Along the bending line 5 indicated by dashed lines in FIG. 7, a workpiece flap 27 already provided with an upstand is to be bent on a base plate 26 of the workpiece 25. At its other edges, the workpiece 25 is already provided with corresponding bends. The bends extending perpendicularly to the bending line 5 have, in addition to a vertical, also a horizontal limb extending toward the hold-down device 21.

To create the desired bending of the hold-down 21 is first placed in the state shown in FIG. 7 on the bottom plate 26 of the workpiece 25. The hold-down segments 22, 23 lie close together; the hold-down 21 has its minimum width and can therefore pass through the horizontal legs of the already existing lateral bends in its movement on the bottom plate 26. In the in Fig. 7 shown operating state of the hold-down 21 is depressurized on the bottom plate 26 of the workpiece 25.

Based on these conditions, the corner segments 22 of the blank holder 21 are displaced by means of an adjusting device, not shown, with respect to the inner hold-down segments 23 to the outside. The lateral projections 24 of the corner segments 22 thereby enter into the space between the horizontal limbs of the lateral bends and the bottom plate 26 of the workpiece 25. The resulting conditions are shown in FIG. 8. An application of the bottom plate 26 is now possible even below the horizontal legs of the lateral bends.

After pushing apart the hold-down segments 22, 23 of the now widened hold-down 21 is pressed onto the bottom plate 26 of the workpiece 25. The result is a two-dimensional pressurization of the bottom plate 26 by the hold-down 21st

By pivoting the bending cheek, not shown, then the workpiece tab 27 is bent. In order to form the bending line 5, the hold-down device 21 acts under a loading line 28 with the bending cheek, while the surface plate 26 is still subjected to a two-dimensional action. Also at the bending cheek this results in a loading line.

Since the inner hold-down segments 23 overlap with the immediately adjacent corner segment 22 in the direction of the Beaufschlagungslinie 28 and each inner hold-down segment 23 is separated from the associated corner segment 22 along the Beaufschlagungslinie 28 results in opposite the inner hold-down segments 23 outwardly bent corner segments 22 nevertheless a continuous loading of the bottom plate 26 of the work piece 25 along the loading line 28 or the bending line 5.

As is apparent from Fig. 9, the mutually associated hold-down segments 22, 23 guided by means of a trapezoidal in cross-section guide bar 29 on the inner hold-down segment 23 and provided with a corresponding cross-sectional shape guide groove 30 on the outer corner segment 22 in the direction of their adjustment movement to each other.

After bending the workpiece tab 27, the pressurization of the bottom plate 26 is canceled by the hold-21. By pushing together the hold-down segments 22, 23 of the hold-down 21 is then set back in its state shown in FIG. With the then resulting width of the blank holder 21, the finished bent part can be removed from the swivel bending tool 20.

Claims (10)

1. Bending tool for bending workpieces (4, 25), in particular metal sheets, having at least one bending tool part, by means of which workpiece bending can be brought about at the workpiece (4, 25) by the workpiece being acted upon by a workpiece abutment of the bending tool part along a tool-side operating line (14, 15, 16, 28), at least one bending tool part having workpiece abutment segments (6, 7; 8; 8a; 22, 23) which can be adjusted relative to each other in the direction of the operating line (14, 15, 16, 28) into various operative positions, characterised in that workpiece abutment segments (6, 7; 8; 8a; 22, 23) which can be adjusted relative to each other into various operative positions in the direction of the operating line (14, 15, 16, 28) and which have mutual separation along the operating line (14, 15, 16, 28) overlap each other in the direction of the operating line (14, 15, 16, 28).
2. Bending tool according to claim 1, characterised in that the relevant workpiece abutment segments (6, 7; 8; 8a; 22, 23) can be adjusted steplessly relative to each other in the direction of the operating line (14, 15, 16, 28).
3. Bending tool according to any one of the preceding claims, characterised in that workpiece abutment segments (6, 7; 8; 8a; 22, 23) can be adjusted relative to each other in the direction of the operating line (14, 15, 16, 28) by means of an adjustment device (9) .
4. Bending tool according to claim 3, characterised in that the adjustment device is numerically controlled for the mutual adjustment of the workpiece abutment segments (6, 7; 8; 8a; 22, 23) in the direction of the operating line (14, 15, 16, 28).
5. Bending tool according to claim 4, characterised in that the numerical control of the adjustment device for the mutual adjustment of the workpiece abutment segments (6, 7; 8; 8a; 22, 23) in the direction of the operating line (14, 15, 16, 28) can be integrated in a numerical control unit of a bending machine.
6. Bending tool according to any one of the preceding claims, characterised in that workpiece abutment segments (6, 7; 8; 8a; 22, 23) which can be adjusted relative to each other in the direction of the operating line (14, 15, 16, 28) are guided so as to be movable relative to each other in the direction of the adjustment movement.
7. Bending tool according to any one of the preceding claims, characterised in that workpiece abutment segments (6, 7; 8; 8a; 22, 23) which can be adjusted relative to each other in the direction of the operating line (14, 15, 16, 28) are guided against each other so as to be movable relative to each other in the direction of the adjustment movement.
8. Bending tool according to any one of the preceding claims, having a bending tool part in the form of a retaining member (21) and/or having a bending tool part in the form of a bending wall, the workpiece (25) being able to be acted upon by means of the retaining member (21) and/or by means of the bending wall along an operating line (28), and the retaining member (21) and/or the bending wall having a workpiece abutment having workpiece abutment segments (22, 23) which can be adjusted relative to each other in the direction of the operating line (28) into various operative positions, characterised in that the workpiece abutment segments (22, 23) of the retaining member (21) and/or the bending wall overlap each other in the direction of the operating line (28) with mutual separation along the operating line (28).
9. Bending tool according to claim 8, the retaining member (21) having workpiece abutment segments (22, 23) which can be adjusted relative to each other in the direction of the operating line (28) into various operative positions and which overlap each other in the direction of the operating line (28) with mutual separation along the operating line (28), characterised in that at least one workpiece abutment segment (22), that is located outwardly in the direction of the operating line (28), is in the form of a corner segment having a lateral projection (24) which projects in the direction of the operating line (28).
10. Bending machine for bending workpieces (4, 25), in particular for bending metal sheets, characterised by a bending tool (3, 20) according to any one of the preceding claims.

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