A TOOL FOR A BENDING PRESS AND AN APPARATUS FOR MONITORING THE STRESS EXERTED BY SAID TOOL

Abstract

Disclosed is a tool for a press brake, of the type adapted to produce a bend line in a sheet material, where the tool includes a body connectable to a movable or fixed part of a press brake, characterized by including at least one optical fibre a section of which is fixed stably to a surface of the body, and wherein in the section the optical fibre includes at least one Bragg grating.

Claims

1. A tool for a press brake, of the type adapted to produce a bend line in a sheet material, where said tool comprises a body connectable to a movable or fixed part of a press brake, further comprising at least one optical fibre a section of which is fixed stably to a surface of the body, and wherein in the aforesaid section said optical fibre includes at least one Bragg grating.

2. The tool according to claim 1, wherein the ends of the optical fibre are provided with connection elements that allow several optical fibres to be connected in series or the optical fibre to be connected to a monitoring system.

3. The tool according to claim 2, wherein the optical fibre comprises two free end portions that carry said connection elements.

4. The tool according to claim 1, comprising two or more optical fibres or one optical fibre provided with two or more Bragg gratings aligned with and spaced from one another.

5. The tool according to claim 1, wherein said optical fibre is arranged along a direction parallel to the bend line.

6. The tool according to claim 1, wherein a slot is produced on the surface of the body, in which at least one section of the optical fibre is housed, the size of the slot being such that the optical fibre is below said surface.

7. The tool according to claim 1, wherein the body comprises a coupling portion, adapted to allow the body to be fixed, directly or indirectly, to the press, which extends from an abutment face substantially transverse to the direction of movement of the cross beam and wherein said optical fibre is applied to said abutment face.

8. (canceled)

9. The tool according to claim 1, comprising a blocking device of a working tool.

10. The tool according to claim 1, comprising a working tool of punch or die type.

11. The tool according to claim 9, wherein said optical fibre is applied to a rear surface of the body of the blocking device.

12. The tool according to claim 11, wherein the body comprises a fixed abutment element that coacts with a clamp, adapted to block the working tool, said optical fibre being applied to the rear surface of said fixed abutment element.

13. A device for monitoring distribution of the stress exerted by one or more tools of a press brake on a metal sheet to be bent, said device comprising at least one tool according to claim 1 and a monitoring system, connected to at least one optical fibre of said at least one tool, configured to: send a broadband light signal through said optical fibre; receive one or more signals reflected by one or more Bragg gratings included in said optical fibre; analyse said one or more reflected signals to determine a state of strain of the body of the tool.

14. A press brake equipped with one or more tools according to claim 1.

15. The tool according to claim 2, comprising two or more optical fibres or one optical fibre provided with two or more Bragg gratings aligned with and spaced from one another.

16. The tool according to claim 3, comprising two or more optical fibres or one optical fibre provided with two or more Bragg gratings aligned with and spaced from one another.

17. The tool according to claim 2, wherein said optical fibre is arranged along a direction parallel to the bend line.

18. The tool according to claim 3, wherein said optical fibre is arranged along a direction parallel to the bend line.

19. The tool according to claim 4, wherein said optical fibre is arranged along a direction parallel to the bend line.

20. The tool according to claim 2, wherein a slot is produced on the surface of the body, in which at least one section of the optical fibre is housed, the size of the slot being such that the optical fibre is below said surface.

21. The tool according to claim 3, wherein a slot is produced on the surface of the body, in which at least one section of the optical fibre is housed, the size of the slot being such that the optical fibre is below said surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Further features and advantages of the present invention will be more apparent from the description of a preferred, but not exclusive, example of embodiment of a die for a press brake, as illustrated in the accompanying figures, wherein:

[0075] FIG. 1 is a front view of a tool mounted on a press brake, according to an embodiment of the present invention where said tool is an “intermediate” or “clamping tool”.

[0076] FIG. 2 is a sectional side view of the tool of FIG. 1;

[0077] FIG. 3 is a schematic front view of a press brake equipped with a device according to the present invention comprising several tools of FIG. 1;

[0078] FIG. 4 is a front view of a tool mounted on a press brake, according to another embodiment of the present invention where said tool is an “intermediate” or “clamping tool”.

[0079] FIG. 5 is a sectional side view of the tool of FIG. 4;

[0080] FIG. 6 is a front view of a tool for a press brake according to another embodiment of the present invention where said tool is a punch.

[0081] FIG. 7 is a sectional side view of the tool of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0082] With reference to the accompanying FIGS. 1 and 2, the number 10 indicates as a whole a tool 10 for a press brake configured as blocking device or “intermediate”, adapted to allow a working tool 110 of punch type to be fixed to the press brake.

[0083] The intermediate 10 comprises a body 11 with a coupling portion 12 in the upper part, generally in the form of shank that extends from an abutment face 13. Said abutment face is generally adapted to abut against a respective surface of the cross beam or “ram” T of the press brake.

[0084] The intermediate 10 further comprises clamping means, typically of shoe type or the like, adapted to clamp a corresponding coupling portion of the punch 110.

[0085] In the example illustrated, said means comprise a shoe 14, or the like, which coacts with a fixed abutment element 16 of the body 11. A seat 17 is produced between said shoe 14 and said fixed abutment element 16, which can house the coupling portion 112 of the punch 110 to be blocked. Typically, said shoe 14 is subject to the action of operating or clamping means (not illustrated) that allow it to move reciprocally toward and away from the fixed abutment element 16 in order to clamp said coupling portion 112 of the punch 110.

[0086] Nonetheless, these clamping means can be various type and, being well known to those skilled in the art, will not be described in greater detail.

[0087] The width of the body 11, i.e. in the direction X of the bend line, can vary both as a function of the form/type of tool to be blocked and as a function of the type of press brake on which the intermediate must be mounted. In many cases the body 11 has a width of around 150-300 mm but, in some cases, it can have the same width as the cross beam of the press brake.

[0088] An optical fibre 20 comprising one or more Bragg gratings 21, two in the example in the figures, is applied stably to the body 11 of the intermediate 10, and more precisely to the abutment face 13. The optical fibre is constrained to the body 11 by means of gluing or equivalent systems, so that it is completely integral therewith.

[0089] According to a preferred variant of the invention illustrated in FIGS. 1, 2 and 3, the optical fibre 20 is housed in a slot 15 produced on the abutment face 13 so as to be completely below the surface. Said slot 15 preferably extends for the whole of the length of the body 11. According to the invention, the optical fibre 20 has a section 20a fixed to the body 11 of the intermediate tool 10 and two free end portions 20b, which extend from said body 11 and which are equipped with connectors 22 that allow the optical fibre to be connected to others or to a monitoring device, as better described below.

[0090] Said free end portions 20b are typically covered with a protective sheath, or buffer, while in the section 20a the optical fibre is in direct contact with the surface of the body of the tool.

[0091] According to a preferred variant, the protective sheath of the optical fibre 20 extends for a short section also inside the slot 15, generally from both ends. This allows the strains and curvatures of the optical fibre to be limited in the point of detachment/exit from the body of the tool.

[0092] An example of optical fibre provided with Bragg gratings suitable for use in the present application is the model SGC-01 manufactured by FBGS Technologies GmbH. Preferably, for an intermediate having a length ranging from 100 mm to 300 mm it is possible to use an optical fibre of this type provided with Bragg gratings in a number from 1 to 4. At least two Bragg gratings are preferable, both to have a comparison of at least two measurements in the same body, so as to be able to detect anomalies of the measurement system, and to evaluate possible unbalance of the intermediate, for example when using a tool of limited width blocked by only one intermediate.

[0093] FIG. 3 schematically represents a part of a press brake P on which a device 50 according to the present invention is installed.

[0094] The press brake comprises an upper cross beam T, or ram, on which one or more intermediate tools 10 according to the invention are mounted. In turn, said intermediate tools 10 clamp punch tools 110. The various optical fibres 20 mounted on each intermediate tool 10 are connected to one another in series by means of the respective connectors 22.

[0095] One of the optical fibres 20 placed at the end of the series is connected to a monitoring system 40 comprising an interrogator device, optionally connected to and controllable by an information system, such as a computer, or a mobile electronic device, such as a tablet or smartphone.

[0096] Operation of the interrogator device is known to those skilled in the art and therefore will not be described in detail.

[0097] FIGS. 4 and 5 illustrate another embodiment of the invention in which the optical fibre 20 is fixed to a surface placed on the rear side of the body 11 of the tool. More in detail, the optical fibre 20 is fixed to the rear surface 16a of the fixed abutment element 16 of the clamping means. Also in this case, the optical fibre is preferably housed in a slot 15 produced on said surface 16a.

[0098] The features of the optical fibre and its fixing are the same described for the previous variant.

[0099] According to a further variant, not illustrated, the tool can comprise at least a first optical fibre fixed to the abutment face 13 and at least a second optical fibre fixed to the rear surface 16a of the fixed abutment element 16.

[0100] FIGS. 5 and 6 illustrate another embodiment of the invention in which the tool that carries the optical fibre 20 is a working tool of punch type. Therefore, according to this variant, the optical fibre 20 is mounted directly on the body 111 of the punch.

[0101] Also in this case, the body 111 has a shank 112, which extends from an upper abutment face 113, which allows blocking of the punch 110 in the press brake. The arrangement of the optical fibre 20 on the body 111 of the punch is substantially symmetrical to the arrangement provided on the body 11 of the intermediate 10. In fact, said optical fibre 20 is preferably applied at the abutment face 113. Also in this case, the optical fibre 20 is preferably housed in a slot 115 produced on said abutment face 113. The advantages linked to this arrangement of the optical fibre 20 are the same as those already described for the previous variants.

[0102] According to the invention, it is possible to equip a press brake with a device 50 that includes one or more tools 10 of intermediate type or tools 110 of punch type, or both, which are equipped with optical fibres 20 that carry the Bragg gratings.

[0103] When both the intermediates 10 and the punches 110 carry the optical fibres 20, it is possible for all the aforesaid optical fibres 20 to be connected to one another in series and all connected to a single monitoring device, or for the two assemblies of tools, intermediates and punches, to be monitored independently.

[0104] The invention has been described purely for non-limiting illustrative purposes, according to some preferred embodiments. The person skilled in the art may find numerous other embodiments and variants, all falling within the scope of protection of the appended claims.