DEVICE FOR HOLD A SHEET OF SHEET METAL DURING ITS BENDING BY A DOUBLE-APROOM BENDING MACHINE

Abstract

The invention relates to a device (2) for holding a sheet metal part (3) in a double-bedded press brake (1), the device (2) comprising at least one retaining jaw (10) for an edge (9) of the sheet metal part (3), said jaw (10) being mounted in a support (13), characterized in that at least the jaw (10) is movable within the support (13) in a vertical plane and along a circular arc trajectory (F12). The invention also relates to a press brake (1) thus equipped. Figure to be published with the abbreviation: Fig. 2

Description

Title of the invention: DEVICE FOR HOLD A SHEET OF SHEET METAL DURING ITS BENDING BY A DOUBLE-APROOM FOLDER

[0001] The invention relates to a device for holding a sheet metal during its bending by a double-apron bending machine.

[0002] A double-apron press brake allows for bending a sheet of metal in two opposite directions. It is thus possible to create ribs on a sheet of metal by alternately bending it in one direction and then the other, using two aprons moving in opposite directions. Such a press brake allows for the creation of ribs of various dimensions with an adjustable alternation. Such press brakes are known, for example, from EP-A-434 541 and EP-A-3 403 738. The principle of this type of press brake is to move the sheet of metal laterally after the bend has been made in order to perform the next bend. The portion of the sheet of metal already bent is therefore outside the press brake. With a sheet of metal wider than 1 m, a lateral movement of the sheet of metal induces an uncontrolled and random vertical movement of the sheet.Such a movement causes the sheet metal to shift in the bending machine and affects the safety of the bending machine's users, as the sheet metal risks injuring a person through these uncontrolled movements.

[0003] The invention aims to provide a solution to secure the use of the sheet metal during its bending and to preserve the positioning of the sheet metal in the bending machine during the bending process.

[0004] For this purpose, the invention relates to a device for holding a sheet metal in a double-apron bending machine, the device comprising at least one jaw for holding an edge of the sheet metal, said jaw being mounted in a support, characterized in that at least the jaw is movable in the support, in a vertical plane and along a circular arc trajectory.

[0005] Thanks to the invention, the jaw moves by following the alternating up-and-down movements of the sheet metal as it is bent by either of the aprons. The jaw's support not only prevents any flapping of the sheet metal by immobilizing and guiding it during bending, but also protects any user of the bending machine from the risk of injury from the sheet metal, as the latter is constantly held in place.

[0006] According to advantageous, but not mandatory, aspects of the invention, such a device may comprise one or more of the following features:

[0007] The radius of the arc trajectory is centered on a point of bending of the sheet metal by the aprons of the bending machine.

[0008] The support comprises an arc-shaped rail equipped with a carriage that moves along the rail and on which the jaw is mounted.

[0009] The device comprises at least two supports, each equipped with at least one jaw.

[0010] Each support is mounted on a carriage and is mobile in translation along a direction parallel to the length of the sheet metal when the latter is in place in the bending machine.

[0011] Each support is mobile in translation along a direction parallel to the width of the sheet metal when the latter is in place in the bending machine, the distance between the device and the bending machine being thus adjustable.

[0012] The movement of each jaw and each support is simultaneous and subject to the bending movements of the sheet metal.

[0013] At least one rail of a support is equipped with a rack on which moves the carriage on which the jaw is fixed.

[0014] The invention also relates to a folding machine equipped with at least one holding device conforming to any one of the preceding characteristics.

[0015] The invention will be better understood and other advantages thereof will become more apparent upon reading the following description, given solely by way of non-limiting example and with reference to the accompanying drawings in which:

[0016] [Fig-1] is a lateral perspective view of a conforming retaining device to an embodiment of the invention and installed on a double-apron folding machine,

[0017] [Fig.2] is a simplified diagram illustrating the device in a so-called holding position neutral, when the sheet metal is not being bent.

[0018] [Fig.3] is a diagram at the same scale and similar to [Fig.2] illustrating the device in a first position called active, the sheet metal is bent in one direction and,

[0019] [Fig.4] is a diagram similar to the previous diagrams, at the same scale, in a second position called active, the sheet metal being bent in a direction opposite to that illustrated in [Fig.3].

[0020] Figure 1 illustrates a double-bedded press brake 1 equipped with a sheet metal holding device 2 according to an embodiment of the invention. A sheet metal 3 is held between an upper bed 4 and a lower bed 5. Here, the beds 4 and 5 are identical. Alternatively, they are different. The beds alternately move from bottom to top as indicated by the double arrow Fl in Figure 2. During this movement, the free edge of one of the moving beds 4 or 5 presses against and bends the sheet metal 3 either upwards or downwards depending on which bed 4 or 5 is in action. The area where the beds 4 and 5 bear on the sheet metal 3 is designated and named as the bending point 6. It is understood that this is in fact a bending line extending along the entire length of the free edge of the bed 4 or 5. Hereafter, the term "bending point" will be used. Depending on the geometric configuration of the folding point 6, and therefore of the edges of the aprons 4, 5, we creates a U-shaped, V-shaped, rounded groove, or other rib. Here, the bending is carried out along the length of the sheet metal, which, in this example, is at least 1 m wide. In Figures 1 and 2, the sheet metal 3 is approximately horizontal and parallel to a plane P marked by the ground on which the bending machine 1 rests.

[0021] A portion 7 of the sheet metal 3 is located inside the press brake 1, between the aprons 4 and 5 and upstream of the bending point 6, relative to the lateral translational feed direction, illustrated by arrow F3, of the sheet metal 3 in the press brake 1. This portion 7 is flat and not ribbed. In other words, no bending has yet been performed on this portion 7 of the sheet metal 3. The portion 8 of the sheet metal located downstream of the bending point 6, according to the translational feed direction F3 of the sheet metal 3, is ribbed with at least one, and here several, ribs which, in this case, are not identical but contiguous. Alternatively, the shape and / or number of ribs and / or the interrib areas are different from those illustrated, a press brake 1 with a double apron allowing for the production of various types of ribbed sheets. In other words, the folder 1 produces a part 8 that has been folded at least once. Part 8 extends beyond the folding point 6, therefore outwards, beyond the folder 1..

[0022] A free edge 9 of the part 8 is held by at least one jaw 10. Such a jaw, known per se, has a variable configuration and / or dimensions depending on the configuration of the edge 9 to be held and the holding principle used. By way of non-limiting example, it may be a pinch or clamping mechanism, automatic or manual, a magnetic connection, a connection based on complementary shapes, or other means. In all cases, the jaw 10 defines a specific holding recess for the edge 9 of the sheet metal 3. The jaw 10 is configured to hold the edge 9 without modifying or damaging it. To achieve this, the jaw 10 does not clamp tightly on the edge 9, and cushioning elements, such as foam, line the inside of the jaw 10.

[0023] In all cases, the jaw 10 is mounted on a carriage 11 attached to a rail 12 configured as an arc. The rail 12 defines a path of movement, in both directions, for the jaw 10. The movement of the carriage 11 along the rail 12 is, for example, achieved by a rack and pinion system. Alternatively, it may be a double rail, a tread, a segmented belt, or some other element on which the jaw 10 moves.

[0024] In all cases, the element on which the jaw 10 moves is configured as an arc of a circle whose opening is oriented towards the bending point 6. Whatever the dimension of the rail 12, the radius R of curvature of the latter must be centered on the bending point 6. It is understood that the jaw 10 moves simultaneously with the movement of the carriage 11 along the rail 12, in one direction or the other, in a semi-circular movement F12 similar to the movement of the sheet Fl and of a similar amplitude.

[0025] The rail 12 and the jaw 10 are mounted on a support 13. The support 13 is movable in translation along at least two directions. The double arrow D represents a first direction of lateral movement of the support 13. Thus, the latter can move closer to or further from the bending machine 1, and therefore from the bending point 6, in a direction parallel to the width of the sheet metal 3 when the latter is in place in the bending machine 1. The centering of the radius R of curvature of the rail 12 is thus adjusted according to the width of the sheet metal 3.

[0026] The double arrow Dl in [Fig. 1] illustrates a longitudinal translational movement of the support 13 along a direction parallel to a longitudinal axis of the press brake 1, i.e., along the length of the sheet metal 3. This movement is achieved, for example, by a carriage 14 on which the support 13 is fixed and which moves on wheels, rollers, rails, or other means. It is thus possible to position the jaw 10 at a desired location on the edge 9 of the part 8.

[0027] As shown in [Fig. 1], depending on the dimensions of the sheet metal 3, several devices 2 will be used, here identical and illustrated as two in number. Alternatively, the number may be greater than two. In all cases, the operation of all the devices is identical and simultaneous. Subsequently, the operation of the device will be described with reference to Figures 2 to 4 for a single device 2 in order to simplify reading.

[0028] In [Fig. 2], it can be seen that a principal plane P3 of the sheet metal 3 is parallel to the plane P, the sheet metal 3, and in particular part 8, being held in this position due to its attachment between the jaw 10 and the bending point 6. Such a position is said to be neutral. This is the position of the sheet metal 3 and the device 2 when no bending is in progress, therefore a position of the sheet metal before or after a bend.

[0029] Figure 3 represents a first, so-called active position of the device 2. Here, the lower apron 5 is in operation and the sheet metal 3 is bent upwards. Thus, part 8 is positioned angularly above part 7, at an angle A relative to the plane P3 of the sheet metal 3. The carriage 11 and the jaw 10, which holds the edge 9 of part 8, have also been moved upwards at angle A. The movement is not free, but generated by a motor, electric, pneumatic, or other, simultaneously and in a similar manner to the movement of the apron 5. The holding of part 8 of the sheet metal 3 is ensured during bending; no free movement of this part 8 is possible. Thus, not only is user safety ensured, but the positioning of the sheet metal 3 in the bending machine 1 is maintained, which ensures the production of ribs conforming to the specifications.

[0030] Figure 4 represents a second, so-called active, position in which the upper apron 4 is in action, the sheet metal 3 being bent downwards at an angle B. As in the previous position, no free movement of this part 8 is possible, the support being ensured by the jaw 10. The angles A and B are not necessarily identical, they depend directly on the movements of the aprons 4, 5, therefore on the bending values ​​of the ribs as defined.

[0031] It is readily understood that the positions illustrated in Figures 3 and 4 are not the only existing positions; all intermediate positions are possible, and the transition from one active position to another is continuous and smooth. In other words, the device 1 continuously follows and accompanies the movement of part 8 of the sheet metal 3, holding it to prevent any movement. The device 1 allows for the reproduction of manual holding of the sheet metal 3.

[0032] In an embodiment not illustrated, the device comprises several supports 13, for example four, six, eight or more aligned in order to simultaneously hold two, three, four or more independent sheets during their simultaneous bending by the bending machine 1. Such a configuration allows, with a long bending machine 1, to bend simultaneously and in an identical or different manner several sheets 3, depending on the configuration of the aprons 4, 5.

[0033] The invention makes it possible, in an automatic and adjustable manner, to improve the safety of the bending operation of a sheet 3 and to guarantee the characteristics of the ribs of the sheet 3. The invention can easily be mounted on an existing bending machine, provided that space is available near the bending machine 1.

Claims

Demands

1. A retaining device (2) for a sheet metal (3) in a double-apron bending machine (1), the device (2) comprising at least one retaining jaw (10) for an edge (9) of the sheet metal (3), said jaw (10) being mounted in a support (13), characterized in that at least the jaw (10) is movable in the support (13), in a vertical plane and along a circular arc trajectory (F12).

2. Device according to claim 1, characterized in that the radius (R) of the arc trajectory (F 12) is centered on a bending point (6) of the sheet metal (3) by the aprons (4, 5) of the bending machine (1).

3. Device according to claim 1, characterized in that the support (13) comprises a circular arc rail (12) equipped with a carriage (11) movable along the rail (12) and on which the jaw (10) is mounted.

4. Device according to claim 1, characterized in that the device comprises at least two supports (13) each equipped with at least one jaw (10).

5. Device according to claim 4, characterized in that each support (13) is mounted on a carriage (14) and movable in translation along a direction (Dl) parallel to the length of the sheet (3) when the latter is in place in the bending machine (1).

6. Device according to claim 4, characterized in that each support (13) is movable in translation along a direction parallel to the width of the sheet (3) when the latter is in place in the bending machine (1), the distance (D) between the device (2) and the bending machine (1) being thus adjustable.

7. Device according to claim 4, characterized in that the movement of each jaw (10) and each support (13) is simultaneous and subject to the bending movements of the sheet metal (3).

8. Device according to claim 1, characterized in that at least one rail (12) of a support is equipped with a rack on which the carriage (11) on which the jaw (10) is fixed moves.

9. Bending machine (1) equipped with at least one retaining device (2) for a sheet (3) conforming to any one of the preceding claims.

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