BENDING ANGLE MEASURING METHOD

Abstract

The invention relates to a bending angle measuring method for a bending machine (1), in particular a bending press or brake press, and the bending machine (1) has a bending tool arrangement (2) with at least one upper (3) and lower tool (4). A sheet to be formed (5) is placed in the bending tool arrangement (2). A light pattern (13) is emitted onto a section by means of a lighting device (11) of a bending angle measuring device (7), the section being a single part and surrounding a sub-region on a lateral surface of the lower tool (4) and of the sheet (5) placed in the bending tool arrangement. The light pattern (13) on the lower tool (4) and on the sheet (5) is detected by an image detecting device (10) of the bending angle measuring device (7), and a bending angle is ascertained from detected light pattern (13) by an analysis module. Furthermore, a transition portion (9) between the lower tool (4) and the sheet (5) is ascertained and, based thereon, a sub-detection region (19) in the detection range (8) of the image detecting device (10) is ascertained. The sub-detection region (19) is detected by the image detecting device (10) and the currently produced bending angle is ascertained while carrying out the bending process.

Claims

1-10. (canceled)

11. Bending angle measuring method for a bending machine (1), in particular a bending press or brake press, and the bending machine (1) has a bending tool arrangement (2), which bending tool arrangement comprises at least an upper (3) and lower tool (4), and a sheet to be formed (5) is placed in the bending tool arrangement (2); a light pattern (13) is emitted onto a section by means of a lighting device (11) of a bending angle measuring device (7), said section being a single part and covering a sub-region on a lateral surface of the lower tool (4) and the positioned sheet (5); the light pattern (13) on the lower tool (4) and on the sheet (5) is detected by an image detecting device (10) of the bending angle measuring device (7); a bending angle is ascertained from the detected light pattern (13) by an analysis module; a transition portion (9) between the lower tool (4) and the sheet (5) is ascertained in the detected image by the analysis module; wherein based on the transition portion (9), a sub-detection region (19) in the detection range (8) of the image detecting device (10) is ascertained; the sub-detection region (19) is detected by the image detecting device (10) provided in the form of a high-resolution camera with a resolution of at least 500 ppi in the sub-detection region (19); and the currently produced bending angle is ascertained while carrying out the bending process.

12. Bending angle measuring method according to claim 11, wherein the transition portion (9) is determined from the detected light pattern (13).

13. Bending angle measuring method according to claim 12, wherein a light line (16) is emitted by the lighting device (11).

14. Bending angle measuring method according to claim 12, wherein the transition portion (9) is determined by finding a discontinuity of the geometry in the detected light pattern (13).

15. Bending angle measuring method according to claim 11, wherein the transition portion (9) is determined on the basis of a code of the lower tool (4) that is stored or determined.

16. Bending angle measuring method according to claim 15, wherein a tool code applied to the lower tool (4) is read by the image detecting device (10).

17. Bending angle measuring method according to claim 11, wherein the sub-detection region (19) is detected in high resolution.

18. Bending angle measuring method according to claim 11, wherein the sub-detection region (19) is formed such that the transition portion (9) lies in the peripheral region of the sub-detection region (19).

19. Bending angle measuring method according to claim 11, wherein the bending angle measuring device (7) is pushed along the lower tool (4).

20. Bending machine (1) having a bending angle measuring device (7), which bending angle measuring device (7) is configured to implement a method according to claim 11, and the image detecting device (10) detects the light pattern (13) emitted by the. lighting device (11) onto the lower tool (4) and onto the sheet to be formed (5), wherein the image detecting device (10) is a high-resolution camera with a resolution of at least 500 ppi in the sub-detection region (19).

Description

[0023] These are highly simplified, schematic diagrams of the following:

[0024] FIG. 1 a bending machine with a lower tool of a first width, with a view to illustrating the proposed method;

[0025] FIG. 2 a bending machine with a lower tool of a second width, with a view to illustrating the proposed method;

[0026] FIG. 3 a perspective diagram of a bending machine, with a view to illustrating the proposed method;

[0027] FIG. 4a) and b) determining the sub-detection regions from the total detection range for lower tools of differing widths.

[0028] FIG. 1 illustrates part of a bending machine 1 with a bending tool arrangement 2, which bending tool arrangement 2 has at least one upper 3 and lower tool 4. The other components of the bending machine 1, in particular the machine frame and the drive means for moving the bending tool arrangement 2 and thus implementing the bending process, are not illustrated because they are of no relevance to the description of the proposed method.

[0029] To prepare for the bending process, a sheet 5 to be formed is placed in the bending tool arrangement 2. In the case illustrated, a lower tool 4 having the smallest possible width 6 is disposed in the bending machine 1, which represents a first extreme situation in terms of orienting the bending angle measuring device 7. The other extreme based on the widest possible lower tool is illustrated and described in FIG. 2.

[0030] In this configuration of the bending tool arrangement 2, it is necessary to ensure that the detection range 8 and in any case the transition portion 9 between the lower tool 4 and sheet 5 lies in the detection range 8 of the image detecting device 10. In accordance with the proposed method, the transition portion 9 between the lower tool 4 and sheet 5 is determined and a sub-detection region in the detection range 8 of the image detecting device 10 is determined on the basis of this transition portion 9.

[0031] FIGS. 1 and 2 illustrate a simplified form of the lower tool, in particular the transition portion 9. The transition portion 9 is not disposed entirely at the outer edge of the lower tool 4 but rather is slightly offset from the die recess of the tool, as may be seen from FIG. 3. Since the sheet lies along this edge of the die recess during the bending operation, it is important for the bending angle measuring device 7 to be able to detect this transition portion 9 efficiently and in high resolution.

[0032] FIG. 2 illustrates the situation in which a lower tool 4 having the largest possible width 6 is being used in the bending tool arrangement 2. Again in this case, the detection range 8 of the image detecting device 10 of the bending angle measuring device 7 is large enough to detect both the lower tool 4 and the sheet 5 disposed in the bending tool arrangement 2, in particular the transition portion 9 between the lower tool 4 and sheet 5.

[0033] FIG. 3 is a perspective diagram of the lower tool 4 disposed in the bending machine 1. The lower tool 4 has a V-shaped die recess 12 into which the sheet 5 is pressed by the upper tool. By transmitting this force to the sheet 5, the latter is reshaped so that the sheet 5 is formed to the predefined shape of the recess 12, in particular the opening width of the die recess. In accordance with the proposed method, a light pattern 13 is emitted by a lighting device 11 of the bending angle measuring device 7 onto a section on the bottom face 14 of the sheet 5 and also onto a section on the side wall 15 of the lower tool 4. Based on a preferred embodiment, the light pattern 13 is a light line 16, which light line 16 is clearly visible as a line on the side wall 15 of the lower tool 4 and on the bottom face 14 of the sheet 5.

[0034] In accordance with the proposed method, the detection range 8 of the image detecting device 10 is large enough to detect all possible different widths 6 of the lower tool 4 and the light pattern 13 projected onto the lower tool 4 and sheet 5. It is therefore possible to use every lower tool 4 and/or every bending tool arrangement 2 that can be used for this bending machine 1 without having to calibrate the bending angle measuring device 7 to the lower tool 4 currently being used. In particular, therefore, it is not necessary to pivot the bending angle measuring device 7 relative to the lower tool 4 about a longitudinal direction 17 of the lower tool 4. The transition portion 9 relevant to determining the bending angle therefore always lies within the detection range 8.

[0035] Based on another embodiment, the bending angle measuring device 7 can be pushed in the longitudinal direction 17 of the lower tool 4. With this additional feature, it is possible to determine the current bending angle at several positions along the sheet 5. This is of particular advantage if a very long sheet is being bent and there is a risk of an uneven bend being formed along the sheet. The pushing movement is achieved due to the fact that the bending angle measuring device 7 can be moved along a guide device 18, for example, and the movement is preferably effected by a drive means.

[0036] FIGS. 4a and 4b illustrate how the sub-detection region is formed from the detection range of the image detecting device.

[0037] FIG. 4a represents the situation from FIG. 1 and FIG. 4b represents the situation from FIG. 2. FIG. 4 illustrates the total detection range 8 of the image detecting device, which is captured by the image detecting device, for example a CCD camera. A light pattern, preferably a light line, is emitted by the lighting device onto the lower tool and sheet. As may be seen from FIG. 3, there is an offsets between the lighting device 11 and the image detecting device 10 so that the detection range of the image detecting device 10 detects the light line 16 projected onto the sheet 5 at an angle relative to the direction in which the light pattern 13 is projected. Due to this offset and the angled image detection, the transition portion 9 that is of interest for the proposed method can be seen as a kink in the detected light pattern 13. 16. This situation is illustrated in FIGS. 4a and 4b. In the images, the horizontal part of the light line 16 corresponds to the projection of the light line onto the bottom face 14 of the sheet and the rising part of the light line 16 corresponds to the projection of the light pattern onto the side wall 15 of the lower tool 4.

[0038] When using a lower tool 4 with a smaller width 6, this transition portion 9 lies at a different point in the detection range 8 than is the case with a wide lower tool.

[0039] In accordance with the proposed method, a sub-detection region 19 in the detection range 8 of the image detecting device 10 is created on the basis of the transition portion 9. In order to determine the bending angle correctly and reliably during the bending process, it is important that the region of the sheet that lies as close as possible to the bending edge in the lower tool 4 is clearly detected. In the detected section, this corresponds to the region of the light line 16 directly adjoining the transition portion 9, which in the diagram is the horizontal portion of the light line 16 to the right of the transition portion 9. Since only this region to the right of the transition portion 9 is of interest and the remaining area of the detection range 8 contains no information relevant to determining the bending angle being set, this sub-detection region 19 is formed in such a way that the transition portion 9 and a relevant portion of the light pattern 13 or light line 16 lies in the sub-detection region 19. Based on the claimed method, this sub-detection region 19 is detected by the image detecting device in high resolution. The advantage of reducing the detected image to the sub-detection region 19 is, firstly, that the detection and reading speed of the image detecting device 10 is significantly higher than would be the case if detecting or reading the entire detection range 8. Furthermore, due to the smaller sub-detection region 19, the quantity of data to be processed by the analysis module is also reduced, thereby enabling a high processing speed to be obtained. This in turn enables the current bending angle to be determined on a very accurate and timely basis, thereby increasing the throughput rate of the bending machine.

[0040] By a high resolution in this context is meant that the region of the light pattern 13 or light line 16 is detected at least from the transition portion 9 with a resolution of at least 500 ppi. This resolution enables the course of the bending line in the region of the bending edge of the lower tool to be determined very accurately and very rapidly and from this the resultant bending angle being set and if necessary a rebounding movement that can be expected. Furthermore, since the image detecting device no longer has to be pivoted to obtain its relative orientation with respect to the lower tool or sheet so that it can be used for lower tools of differing widths, the accuracy that can be achieved and reproduced when determining the bending angle can be significantly increased.

[0041] The proposed method therefore results in an increase in processing speed and hence an increase in the throughput rate of sheets to be formed. At the same time, a long-term stability is achieved with the process of determining the bending angle due to the fact that a high accuracy can be achieved on a reproducible basis when determining the bending angle using a bending angle measuring device of a simple design.

[0042] Finally, it should be pointed out that the same parts described in the different embodiments are denoted by the same reference numbers and the same component names and the disclosures made throughout the description can be transposed in terms of meaning to same parts bearing the same reference numbers or same component names. Furthermore, the positions chosen for the purposes of the description, such as top, bottom, side, etc., relate to the drawing specifically being described and can be transposed in terms of meaning to a new position when another position is being described.

[0043] FIG. 3 illustrates another and optionally independent embodiment of the bending angle measuring method, the same reference numbers and component names being used to denote parts that are the same as those described with reference to the preceding drawings. To avoid unnecessary repetition, reference may be made to the more detailed description of the drawings given above.

[0044] The embodiments illustrated as examples represent possible variants of the bending angle measuring method, and it should be pointed out at this stage that the invention is not specifically limited to the variants specifically illustrated, and instead the individual variants may be used in different combinations with one another and these possible variations lie within the reach of the person skilled in this technical field given the disclosed technical teaching.

[0045] Furthermore, individual features or combinations of features from the different embodiments illustrated and described may be construed as independent inventive solutions or solutions proposed by the invention in their own right.

[0046] The objective underlying the independent inventive solutions may be found in the description.

[0047] All the figures relating to ranges of values in the description should be construed as meaning that they include any and all part-ranges, in which case, for example, the range of 1 to 10 should be understood as including all part-ranges starting from the lower limit of 1 to the upper limit of 10, all part-ranges starting with a lower limit of 1 or more and ending with an upper limit of 10 or less, e.g. 1 to 1.7, or 3.2 to 8.1 or 5.5 to 10.

[0048] Above all, the individual embodiments of the subject matter illustrated in FIGS. 1-4 constitute independent solutions proposed by the invention in their own right. The objectives and associated solutions proposed by the invention may be found in the detailed descriptions of these drawings.

[0049] For the sake of good order, finally, it should be pointed out that, in order to provide a clearer understanding of the set-up of the bending angle measuring method, it and the parts involved are illustrated to a certain extent out of scale and/or on an enlarged scale and/or on a reduced scale.

LIST OF REFERENCE NUMBERS

[0050] 1 Bending machine

[0051] 2 Bending tool arrangement

[0052] 3 Upper tool

[0053] 4 Lower tool

[0054] 5 Sheet

[0055] 6 Width

[0056] 7 Bending angle measuring device

[0057] 8 Detection range

[0058] 9 Transition portion

[0059] 10 Image detecting device

[0060] 11 Lighting device

[0061] 12 Die recess

[0062] 13 Light pattern

[0063] 14 Bottom face

[0064] 15 Side wall

[0065] 16 Light line

[0066] 17 Longitudinal direction

[0067] 18 Guide device

[0068] 19 Sub-detection region