EP1570927B1 - Feeding device for a press brake with a lighting device and method for feeding metal sheets - Google Patents

Abstract

A sheet metal holder presents pre-cut flat sheets of metal to a bending press (1). The holder has a manipulator (11) to grip and lift the sheet metal components (3) by e.g. suction or magnetic pads (15) operated by an electronic control system. The assembly further incorporates an opto-electroic measuring system (16) to determine the position of the sheet metal components, and a transparent panel (19) within a surrounding rigid frame (17). Also claimed is a commensurate operating process.

Description

The invention relates to a sheet receiving system for the parts receiving and loading a sheet metal bending machine, in particular a press brake, comprising at least one manipulator for gripping and moving sheet metal parts with a gripper head equipped with gripping means, an electronic control device for controlling the movement of the manipulator and a measuring system for determining the position of the sheet metal parts according to the preamble of claim 1 and a method for receiving sheet metal parts from a sheet stack and positioning the sheet metal parts in a sheet metal bending machine, in particular a press brake, by means of a sheet receiving system comprising at least one manipulator for gripping and moving the sheet metal parts with a gripper head equipped with gripping means, a Electronic control device for controlling the movement of the manipulator and a measuring system for determining the position of the sheet metal parts, according to the preamble of claim 5.

Conventional sheet receiving system for sheet metal bending machines, in particular for press brakes, usually comprise a manipulator which is positioned in a specific position in front of the sheet metal working machine and feeds the sheet metal parts from a supply device of the press. The achievement of an exact gripping position of the sheet metal parts, which is a prerequisite for an accurate placement in the press, can be done on the one hand by the exact alignment of the sheet metal parts in the supply device, on the other hand by detecting the alignment of the edges of the sheet metal parts by means of a special usually mechanical detector device. However, these methods require elaborate devices and are on the one hand very time-consuming and on the other hand relatively imprecise. Another approach is the implementation of a sheet metal part identification with sensors arranged on the manipulator, whereby an exact alignment of the sheet metal parts in the supply device can be omitted.

From the document DE 100 27 814 A1 is a generic sheet receiving system, suitable for the parts receiving and loading a sheet metal bending machine, comprising a manipulator for gripping and moving sheet metal parts and an electronic control device for controlling the movements of the manipulator, known. A box-shaped gripper head connected to a vacuum source has a receiving plate provided with gripping means and further comprises an optoelectronic measuring device, in particular an image acquisition means and a lighting device.

The DE 196 39 590 A1 describes a bending center, which includes, inter alia, a loading device with a feed table and a manipulator assembly. To improve the loading times, the loading device has a sensor which determines the bearings of the recorded sheet metal part relative to a defined insertion position in a bending cell. In an advantageous embodiment, the sensor is formed by a light barrier arranged on a fork. The disadvantage here is that a clear distinction or determination of the sheets can be done very time consuming and also not in any case, especially in similar sheet metal shapes, safe.

The object of the invention is to provide a sheet metal receiving system or a method for sheet metal receiving, which allows a fast and reliable identification of the sheet metal parts.

This object of the invention is achieved independently by a sheet receiving system according to claim 1 and by a method for receiving sheet metal parts according to claim 5. The advantage here is that even with complex sheet metal forms or isolated holes and recesses fast and reliable sheet metal detection is possible, whereby the cycle times shortened and the Committee can be reduced. Another advantage is reflected in reflective or galvanized surfaces of the sheet metal part, as a conventional lighting, in particular a flash lighting, this strong reflections that makes secure sheet metal detection impossible, or complex countermeasures, such as multiple shots, special recordings with polarized light, etc. required. By means of the illumination according to the invention by means of the transmitted-light table, these reflections are avoided and at the same time a high contrast of the recorded image is produced, in order thereby to carry out a position determination of the sheet-metal part with high accuracy.

According to the embodiment, it is provided that the transmitted-light platform forms a support surface for the sheet metal parts, whereby the sheet metal parts come in a well-defined height and location for filing and no additional storage facilities are necessary and thereby optimal quality of optoelectronic measurement and optimal contrast can be achieved , As well as the fact that partial areas of the support surface are formed of a transparent material creates the advantage that a mechanically more stable transmitted light platform can be provided because, for example, areas which are not transparent, can be formed from more stable materials, such as metals.

It is also possible for the transmitted-light platform to have a lighting device which extends over at least 30% of the area of the partial areas and is arranged on a side facing away from the support surface, whereby a high contrast for the optoelectronic measurement can be achieved in an advantageous manner on the other hand a uniform illumination of the sub-area is given and thereby a high quality of the images is achieved.

It is also advantageous if the transmitted-light platform has means for determining the position, since this makes it possible to determine the exact position of the platform in order to calibrate the system and thereby achieve a secure and accurate storage of the sheet-metal parts.

If the transmitted-light platform has one to a maximum of three spaced-apart subregions, there is the advantage that very similar sheet metal parts can still be distinguished from one another reliably, and nevertheless a high stability of the transmitted-light platform is provided.

According to a development of the method, according to which a height determination and a coarse determination of the position of the receiving position of the sheet metal part takes place before the first recording of the sheet metal part, with the measuring system, the advantage is achieved that consuming Provision facilities for receiving the sheet metal parts can be omitted by the manipulator, since no specific number of sheets or sheet metal layers must be available.

According to a variant, according to which prior to the first recording of the sheet metal part, with the measuring system, a height determination of the receiving position of the sheet metal part, the advantage of a lower cycle time is achieved because a position correction can be done by the rapier head when re-recording after filing on the transmitted light platform and no additional position measurement is necessary.

It is also possible that the determined outline data are compared with stored in a storage device data, in particular CAD data of the sheet metal part, are compared by the computer and positive identification of the sheet metal part is released for further processing, whereby a safe and rapid control or identification of the sheet metal parts can be done In addition, existing data from the CAD data can be used.

The fact that a negative message identification issued by the computer and the sheet metal part is sorted out, the advantage is achieved that only the intended for the bending sheet metal parts are inserted into the sheet bending machine, whereby damage to the system can be avoided or waste and time can be saved can.

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

Fig. 1

eine erste Ausführungsvariante eines erfindungsgemäßen Blechaufnahmesystems in schematischer Darstellung;

Fig. 2

das erfindungsgemäße Blechaufnahmesystem in Draufsicht.

Each shows in a schematically simplified representation:

Fig. 1

a first embodiment of a sheet receiving system according to the invention in a schematic representation;

Fig. 2

the sheet receiving system according to the invention in plan view.

By way of introduction, it should be noted that in the differently described embodiments, identical parts are provided with the same reference numerals or the same component designations, wherein the disclosures contained in the entire description can be applied mutatis mutandis to the same parts with the same reference numerals or identical component names.

1 shows a schematic representation of a press brake 1 with the sheet metal receiving system 2 according to the invention.

In the press brake 1 of the sheet receiving system 2 according to the invention sheet metal parts 3 are formed, for example, to profiles or housing parts, etc. In this case, the sheet-metal part 3 is deformed between an upper tool 4 and a lower tool 5 in a bending plane 6 running vertically with respect to a contact surface.

The upper tool 4 and the lower tool 5 are connected to an adjustable pressing beam 7 and a fixed press table 8. To reshape comes a sheet metal part 3 in the amount of a working level 9 on the lower tool 5 on a stop 10 to the plant.

A manipulator 11 comprises a plurality of pivotally connected articulated arms 12, wherein the articulated arms 12 may be arranged at an end region on a movable chassis (not shown in Fig. 1). In a further end region of the manipulator 11, an at least rotatably mounted gripper head 13 is arranged, wherein a rotation axis 14 lies in the plane of the working plane 9.

Furthermore, 13 gripping means 15 are arranged on the gripper head, which can be formed for example by a vacuum gripping device. This can for example be equipped with suction cups and formed by a device equipped with the required supply channels.

Of course, the gripping means 15 can also be used in other embodiments, such as e.g. Magnetic gripper or mechanical gripper, etc.

It should be noted at this point that the number of articulated arms 12 of the manipulator 11 should not be limited to the embodiment shown in FIG. 1, but their number or the arrangement of the axes of rotation 14 can be adapted to the respective requirements. In particular, it is of course possible that the axis of rotation 14 of the gripper head 13 extends in a direction parallel to the arranged articulated arm 12 direction thereby to allow additional degrees of freedom of movement.

Furthermore, an optoelectronic measuring device 16 can be arranged on the gripper head 13. The optoelectronic measuring device 16 is preferably fastened on a side of the gripper head 13 arranged opposite to the gripping means 15. However, it is also possible that the optoelectronic measuring device 16 is arranged on the same side of the gripper head 13 as the gripping means 15 or that the gripping means 15 and the optoelectronic measuring device 16 are arranged on the gripper head 13 in a common device.

The optoelectronic measuring device 16 can, in particular, record information about the sheet metal parts 3 to be processed, such as, for example, the type of sheet metal part 3, outline, position, etc. The optoelectronic measuring device 16 is preferably formed by an image acquisition means, for example by an electronic camera. In a preferred embodiment, this camera can be formed by a camera operating on the basis of a CCD element. Also possible are line scan cameras which have only individual recording lines and the required recording area is optionally scanned in the form of a translatory movement.

It is of course also possible that the image acquisition means is formed by a plurality of cameras, in particular CCD cameras. The image acquisition means may preferably have a coarse recognition camera and a fine recognition camera.

The required for the positioning of the image acquisition means position or the required distance to the sheet metal parts 3, for example, by means of coarse detection camera and a laser arranged on the image sensing means, which on the uppermost sheet metal part 3, a characteristic mark, for example a cross, projected, for example, determined by a triangulation method known from the prior art.

But there are also other known from the prior art methods and methods for distance determination, such as ultrasonic measurements or other transit time measurements or measurements by means of conventional displacement sensors, possible.

However, it is also possible according to the invention for the sheet metal parts 3 to be gripped by the manipulator 11 without further position determination, only by means of a height determination or distance determination in a previously only roughly predetermined pickup position, and their position determined only in the subsequent fine recognition process.

It is also possible to grasp the sheet metal parts 3 without any position or height determination. The receiving position must then be determined beforehand by entering or detecting the position of the sheet stack and is corrected according to the recorded sheets to the respective sheet thicknesses.

The coarse identification and / or fine recognition of the sheet metal parts 3 can be done according to CAD data from the planning or construction, which are stored in a computer of the electronic control device. From these data, patterns are generated which are searched for in the recorded image and, if they match, the respective sheet metal part 3 is released.

The coarse detection and the fine detection can also be realized by a single optoelectronic measuring device 16, in particular a camera.

The optoelectronic measuring device 16 is part of a measuring system, which further comprises a transmitted-light platform 17.

In order to take the sheet metal parts 3 positionally accurate, special demands are placed on the image processing. Essential components are the optoelectronic measuring device 16 and the illumination in the form of the transmitted light platform 17 according to the invention.

The transmitted light platform 17 can be arranged arbitrarily in an environmental region of the sheet metal bending machine or the press brake 1. For this purpose, it is possible that the transmitted light platform 17 has means for determining position. These can be formed, for example, by reference marks arranged on the transmitted-light platform 17 or other clear markings, for which purpose it is once necessary for the calibration to first determine the position of the transmitted light platform 17 by means of the optoelectronic measuring device 16.

After coarse detection of the position of the sheet metal part 3 on a sheet metal part stack and a completed height measurement recorded by the rapier head 13 sheet metal part 3 is first stored on the transmitted light platform 17. Subsequently, an image of the sheet metal part 3 is detected by the optoelectronic measuring device 16 of the measuring system and made available to a computer for determining the outline data. This position determination or fine detection of the sheet metal parts 3 now allows an application of the gripper head 13 and the gripping means 15 in a corrected position on the sheet metal part 3 to accurately position the sheet metal part 3 in the sheet metal bending machine, in particular the press brake 1 according to the requirements.

The transmitted light platform 17 can form a support surface 18 for the sheet metal parts 3.

According to the invention, it is possible for partial regions 19 of the support surface 18 to be formed from a transparent material. These subregions 19 may be formed, for example, from glass or highly transparent plastic and their size and arrangement on the support surface 18 of the transmitted light platform 17 are individually adapted to the requirements. It can also be inventively formed up to three spaced-apart portions 19, whereby a distinction of very similar sheet metal parts 3 can still be done safely and yet a high stability of the transmitted light platform 17 is given.

It is also possible that the transmitted-light platform 17 has a lighting device 20 arranged on the side facing away from the support surface 18 for the sheet-metal parts 3. The illuminance is chosen so that a sufficient contrast for recording an image with the optoelectronic measuring device 16 is achieved, but no overexposure and thus a poor quality of recording occurs.

In order to achieve a further increase in the recording quality, an electronic adaptation of the exposure times and / or a change in the number of recordings can furthermore be provided.

It is also possible that the illumination device 20 of the transmitted-light platform 17 has lighting means which extend over at least 30% of the area of the partial regions 19. This improves the quality of the images through a flat illumination and a constant contrast ratio.

The transparent material of the partial area 19 of the support surface 18 may preferably also be such that a diffuse scattering of the light beams emitted by the illumination device 20 takes place, thereby likewise improving the image acquisition by a contrast ratio that remains constant over the entire area of the partial area 19 ,

According to one embodiment of the invention, it is also possible for the transmitted-light platform 17 to be arranged on a front side of the press brake 1, in particular the press table 8, facing the manipulator 11. In this case, the transmitted-light platform 17 can preferably be arranged in a vertical position (not shown in FIG. 1). It is advantageous if the optoelectronic measuring device 16 is associated with the transmitted light platform 17 and is positioned in a suitable position and a suitable distance from the transmitted light platform 17. The optoelectronic measuring device 16 can be made adjustable in its position in order to make necessary position corrections easy. On the gripper head 13 may be an additional optoelectronic measuring device 16 for determining an on-taking position of the sheet metal parts 3 may be arranged.

2 shows a schematic plan view of the sheet metal receiving system 2 according to the invention.

Shown is a press brake 1 with the sheet receiving system 2 according to the invention in a plan view. For the sake of clarity, the manipulator 11 from FIG. 1 is not shown, but only the optoelectronic measuring device 16, which is shown on the gripper head 13 of the manipulator 11 according to FIG. 1.

The transmitted-light platform 17 forms a bearing surface 18 for the sheet-metal parts 3. Furthermore, a partial region 19 of the transparent plates, which may be formed from a transparent material, for example glass or transparent plastic, is formed.

In a side facing away from the sheet metal part 3 of the portion 19 and the support surface 18, a lighting device 20 is arranged, which is preferably formed over at least 30 ° of the surface of the portion 19.

According to the invention, it is also possible that a plurality of transparent subregions 19 are arranged on the transmitted light platform 17 and, for example, to illuminate characteristic areas in the case of larger or strongly similar sheet metal parts 3.

It is advantageous if markings which represent a reference position of the position of the transmitted light platform 17 in space are arranged on the transmitted light platform 17.

The sheet metal part 3 can be placed on the transmitted light platform 17 and it can be a rotation of the gripper head 13 about the axis of rotation 14 to determine by means of the optoelectronic measuring device 16, the deviation of the position of the sheet metal part 3 on the support surface 18 of a desired desired position. The sheet metal part 3 is now gripped by the gripper head 13 by means of the gripping means 15 in a corrected position and fed to the press brake 1 in the correct position for the bending operation. In an embodiment variant in which the optoelectronic measuring device 16 is arranged on the same side of the gripper head 13 as the gripping means 15 or that the gripping means 15 and the optoelectronic measuring device 16 are arranged in a common device on the gripper head 13, a storage of the sheet metal part 3 and a rotation of the gripper head 13 omitted.

It is also possible that the transmitted-light platform 17 is not arranged separately from the press brake, as shown in FIG. 2, but is arranged at a suitable position on the press brake 1, as has already been explained in more detail in FIG.

Due to the backlighting of the sheet-metal parts 3 by the illumination device 20, reflections and scattered light influences are largely eliminated and can thus provide an optimum contrast ratio for capturing the image and for computer-aided further processing the resulting outline data can be achieved.

In particular, in mirrored or galvanized or chrome-plated surfaces increased recording quality is achieved by the sheet receiving system 2 according to the invention and thus on the one hand, the cycle time and the other the metrological effort would otherwise be necessary to achieve impeccable recordings, such as an angular orientation of a direct lighting or example a formation of sum images of multiple frames for reflection reduction, are lowered, whereby the cycle time and the processing cost is reduced.

Furthermore, it is possible that the optoelectronic measuring device 16 according to the invention, which is preferably formed by an electronic camera, is equipped with corresponding lenses for adjusting the focal length. When arranging a coarse identification camera and an additional fine recognition camera, of course, different lenses can be used.

On the gripper head 13 can be used for the distance determination, an additional diode laser for the projection of a mark used for distance determination on the sheet metal parts 3.

A positioning of the sheet metal parts 3 in the press brake 1 is carried out by detecting a characteristic area of the sheet metal part 3, according to the specifications of a production program for the production of a workpiece, which can be taken over by a computer directly from the design area, especially the CAD data.

The electronic control device for controlling the movement of the manipulator 11 may be integrated in the computer and at the same time take over the task of the Brechteilerkennung.

If the optoelectronic measuring device 16 or the transmitted light platform 17 are arranged directly on the sheet metal bending machine, no new gripping of the sheet metal part 3 takes place after the position detection, but a correction of the position of the gripper head 13 or sheet metal part 3 is performed directly and the sheet metal part 3 of the press brake 1 in the for the Bending process fed correct position.

For the sake of order, it should finally be pointed out that, for a better understanding of the structure of the sheet-receiving system 2, this or its components have been shown partially unevenly and / or enlarged and / or reduced in size.

The problem underlying the independent inventive solutions can be taken from the description.

REFERENCE NUMBERS

1

press brake

2

Sheet recording system

3

sheet metal part

4

upper tool

5

lower tool

6

bending plane

7

press beams

8th

press table

9

working level

10

attack

11

manipulator

12

articulated arm

13

gripper head

14

axis of rotation

15

gripping means

16

measuring device

17

Lighting platform

18

bearing surface

19

subregion

20

lighting device

Claims (9)

1. Feeding device (2) for feeding parts and supplying a press brake, in particular a bending press (1), comprising at least one manipulator (11) for gripping and moving metal sheets (3), having a gripper head (13) equipped with gripping means (15) and an electronic control system for controlling the movement of the manipulator (11), and with a measuring system for determining the position of the metal sheets (3) provided in the form of an optoelectronic measuring device (16), in particular an image detection means, and a lighting platform (17), characterised in that the lighting platform (17) constitutes a support surface (18) for the metal sheets (3) and part-regions (19) of the support surface (18) are made from a transparent material.
2. Feeding device (2) as claimed in claim 1, characterised in that the lighting platform (17) has a lighting device (20) extending across at least 30% of the surface of the part-regions (19) on a side remote from the support surface (18) for the metal sheets (3).
3. Feeding device (2) as claimed in claim 1 or 2, characterised in that the lighting platform (17) has means for determining a position.
4. Feeding device (2) as claimed in claim 1 or 2, characterised in that the lighting platform (17) has up to a maximum of three mutually spaced-apart part-regions (19).
5. Method of feeding metal sheets (3) from a sheet stack and positioning the metal sheets (3) in a press brake, in particular a bending press (1), by means of a feeding device (2) comprising at least one manipulator (11) for gripping and moving the metal sheets (3), with a gripper head (13) equipped with gripping means (15), an electronic control system for controlling the movement of the manipulator (11), as well as a measuring system for determining the position of the metal sheets (3), characterised in that a metal sheet (3) is held by means of the gripping means (15) of the manipulator and fed to a lighting platform (17) constituting a support surface (18) for the metal sheets (3), and a lighting device (20) illuminates at least part-regions (19) of the lighting platform (17) from the side remote from the gripping means (15) of the manipulator (11), and an optoelectronic measuring device (16) of the measuring system detects an image of the metal sheet (3), in particular a part-region of the metal sheet (3), and contour data is computed from the image data by means of a computer and a new gripping position or a correction of the position of the gripper head (13) is computed therefrom, and the gripper head (13) feeds the metal sheet (3) to the press brake in the new gripping position and corrects its position.
6. Method as claimed in claim 5, characterised in that, prior to feeding the metal sheet (3) for the first time, a height is determined and a rough assessment of the position of the feeding position of the metal sheet (3) is determined by the measuring system.
7. Method as claimed in claim 5, characterised in that, prior to feeding the metal sheet (3) for the first time, a height of the feeding position of the metal sheet (3) is determined by the measuring system.
8. Method as claimed in claim 5, characterised in that the computer compares the detected contour data with data stored in a memory device, in particular CAD data pertaining to the metal sheet (3), and in the event of a positive identification, the metal sheet (3) is released for further processing.
9. Method as claimed in claim 5, characterised in that, if the computer emits a negative identification, an error message is output and the metal sheet (3) is removed from the system.

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