阅读说明：本技术 用于金属板片的折弯机 (Bending machine for metal sheets ) 是由 S·法布里斯 G·费里纳 于 2018-05-11 设计创作，主要内容包括：用于金属板片的折弯机(1)包括：冲头装置(2),其包括上部横梁(3),该上部横梁(3)适于支承沿纵向折弯方向(A)对准且可相互定位的多个上部折弯工具(40,41,42),以形成上部折弯工具的一定组合；冲模装置(4),其包括下部横梁(5),该下部横梁(5)适于支承沿着所述折弯方向(A)对准并相互定位的多个下部折弯工具(30-35),以形成下部折弯工具的相应组合；至少一个后挡规单元(6),其可在所述折弯机(1)的操作区域(W)内移动,并且被布置成相对于所述冲模装置(4)抵接并定位工件,所述至少一个后挡规单元(6)包括钩挂元件(7),该钩挂元件(7)布置成与至少一个下部折弯工具(30-35)接合,以便使至少一个下部折弯工具(30-35)沿所述折弯方向(A)在所述下部横梁(5)上移动；所述多个下部折弯工具(30-35)包括至少一组侧部下部折弯工具(30),所述至少一组侧部下部折弯工具(30)在相应的非操作配置(R1)中定位在所述下部横梁(5)的所述端部部分(5a,5c)处,下部横梁(5)的所述端部部分(5a,5c)在所述操作区域(W)之外并且不能由所述后挡规单元(6)到达；所述侧部下部折弯工具(30)可逆地彼此连接以便形成在数量上可选择的一组(G)侧部下部折弯工具(30),所述组(G)的至少一个所述侧部下部折弯工具(30)在所述操作区域(W)内部定位在所述非操作配置(R),以便它可以与所述后挡规单元(6)的所述钩挂元件(7)接合,并可以由所述钩挂元件(7)沿着所述折弯方向(A)与所述组(G)一起移动。(Bending machine (1) for metal sheets comprising: a punch device (2) comprising an upper cross-beam (3), the upper cross-beam (3) being adapted to support a plurality of upper bending tools (40, 41, 42) aligned along a longitudinal bending direction (a) and mutually positionable so as to form a certain combination of upper bending tools; a die device (4) comprising a lower cross-member (5), the lower cross-member (5) being adapted to support a plurality of lower bending tools (30-35) aligned along said bending direction (a) and mutually positioned to form respective combinations of lower bending tools; -at least one rear gauge unit (6) movable within an operating area (W) of the bending machine (1) and arranged to abut and position a workpiece with respect to the die device (4), the at least one rear gauge unit (6) comprising a hooking element (7), the hooking element (7) being arranged to engage with at least one lower bending tool (30-35) so as to move the at least one lower bending tool (30-35) on the lower crosspiece (5) along the bending direction (a); said plurality of lower bending tools (30-35) comprises at least one set of side lower bending tools (30), said at least one set of side lower bending tools (30) being positioned at said end portions (5a, 5c) of said lower crosspiece (5) in a respective non-operating configuration (R1), said end portions (5a, 5c) of the lower crosspiece (5) being outside said operating region (W) and not reachable by said back gauge unit (6); said lateral lower bending tools (30) being reversibly connected to each other so as to form a group (G) of lateral lower bending tools (30) selectable in number, at least one of said lateral lower bending tools (30) of said group (G) being positioned inside said operating region (W) in said inoperative configuration (R) so that it can engage with said hooking element (7) of said back gauge unit (6) and can be moved by said hooking element (7) together with said group (G) along said bending direction (A).)

1. Bending machine (1) for metal sheets, said bending machine (1) comprising:

-a punch device (2) comprising an upper cross-beam (3), the upper cross-beam (3) being adapted to support a plurality of upper bending tools (40; 41, 42) aligned along a longitudinal bending direction (A) and mutually positionable, so as to form a certain combination of upper bending tools;

-a die device (4) comprising a lower cross-member (5), the lower cross-member (5) being adapted to support a plurality of lower bending tools (30-35) aligned along said bending direction (a) and mutually positioned to form respective combinations of lower bending tools;

-at least one back stop unit (6) movable within an operating region (W) of the bending machine (1) and arranged to abut and position a workpiece with respect to the die device (4), said at least one back stop unit (6) comprising a hooking element (7), which hooking element (7) is arranged to engage with at least one lower bending tool (30-35) in order to move at least one lower bending tool (30-35) on the lower crosspiece (5) along the bending direction (a);

said bending machine (1) being characterized in that said plurality of lower bending tools (30-35) comprises at least one set of lateral lower bending tools (30), said at least one set of lateral lower bending tools (30) being positioned at an end portion (5a, 5b) of said lower crossbar (5) in a respective inoperative configuration (R1), the end portion (5a, 5b) of the lower crossbar (5) being outside said operating region (W) and inaccessible by said back gauge unit (6), said lateral lower bending tools (30) being reversibly connected to each other so as to form a group (G) of lateral lower bending tools (30) selectable in number, at least one of said lateral lower bending tools (30) of said group (G) being positioned inside said operating region (W) in said inoperative configuration (R), so that it can engage with the hooking element (7) of the back gauge unit (6) and can be moved by the hooking element (7) together with the group (G) along the bending direction (a).

2. Machine (1) according to claim 1, wherein each lateral lower bending tool (30) comprises connection means (15, 16) to engage or disengage respective connection means (15, 16) of adjacent lateral lower bending tools (30) to connect or disconnect said adjacent lateral lower bending tools (30) from each other and form a group (G) of said lateral lower bending tools (30).

3. Machine (1) according to claim 2, characterized by comprising actuating means (10), said actuating means (10) selectively acting on said connecting means (15, 16) of said lower side bending tools (30) to cause mutual engagement or disengagement of the connecting means (15, 16) and allow the connection or disconnection of the respective lower side bending tools (30).

4. Machine (1) according to claim 3, wherein said connecting means comprise a first connecting element (15) and a second connecting element (16) fixed on opposite sides of the respective lateral lower bending tool (30), said first connecting element (15) being movable between a hooking position (L) and a release position (S) by said actuating means (10) to engage or disengage, respectively, the second connecting element (16) of the adjacent lateral lower bending tool (30).

5. Machine (1) according to claim 4, wherein said first connecting elements (15) comprise connecting pins (17), said connecting pins (17) being slidably mounted on respective lateral lower bending tools (30) and being movable so as to protrude from a rear surface (30a) of said lateral lower bending tools (30) in said hooking position (L), said second connecting elements (16) being fixed to said rear surface (30a), projecting transversely and provided with connecting pins (17) suitable to receive the first connecting elements (15) of adjacent lateral lower bending tools (30).

6. Machine (1) according to claim 4 or 5, wherein said actuating means (10) comprise a plurality of actuating cylinders (11) positioned adjacent to said lower crosspiece (5), each actuating cylinder (11) being arranged to move a first connecting element (15) of a respective lateral lower bending tool (30) so as to move said first connecting element (15) between said hooking position (L) and said release position (S).

7. Machine (1) according to claim 6, wherein said actuating cylinders (11) are regularly spaced from each other along said bending direction (A) and equal in number to said lateral lower bending tools (30).

8. Machine (1) according to any one of the preceding claims, wherein said lower bending tools (30-35) comprise respective hooking cavities (38), in particular made on the rear surface of said lower bending tools (30-35), arranged to receive and engage said hooking elements (7) of said at least one rear gauge unit (6).

9. Machine (1) according to any one of the preceding claims, characterized in that said at least one back gauge unit (6) comprises an abutment element (8), said abutment element (8) being adjacent to said hooking element (7) and being movable between an operating position (E) in which said abutment element (8) is arranged so that an end (8a) thereof abuts a workpiece, and a non-operating position (F) in which said abutment element (8) allows said hooking element (7) to engage with a lower bending tool (30-35).

10. Machine (1) according to any one of the preceding claims, wherein said at least one backstop unit (6) is movable within said operating region (W) along three orthogonal movement axes (X, Y, Z), one of which being parallel to said bending direction (A).

11. Machine (1) according to any one of the preceding claims, comprising drive means (21, 22) to move said upper bending tool (40) on said upper crosspiece (3) along said bending direction (A).

12. Machine (1) according to any one of the preceding claims, wherein said upper bending tools (41, 42) comprise respective hooking cavities (48), said hooking cavities (48) being arranged to receive and engage said hooking elements (7) of said at least one backstop unit (6), said hooking elements (7) being arranged to move said upper bending tools (41, 42) along said upper crosspiece (3) of the punch device (2).

13. Machine (1) according to claim 12, wherein said plurality of upper bending tools (41, 42) comprises at least one respective group of lateral upper bending tools (42), at least one respective group of lateral upper bending tools (42) being positionable, in a respective inoperative configuration (R2), at an end portion (3a, 3c) of said upper crosspiece (3), which end portion (3a, 3c) of the upper crosspiece (3) is outside said work area (W) and is not reachable by said back gauge unit (6), said lateral upper bending tools (42) being connectable to each other so as to form a respective group of lateral upper bending tools (42) selectable in number, at least one of said lateral upper bending tools (42) positioned in said respective inoperative configuration (R2) being inside said work area (W), so that it can be engaged by the hooking element (7) of the back gauge unit (6) and moved by the hooking element (7) along the bending direction (a) together with the lateral upper bending tool (42) of the respective group.

14. Machine (1) according to claim 13, wherein each lateral upper bending tool (42) comprises respective connecting means (15, 16) to engage or disengage respective connecting means (15, 16) of adjacent lateral upper bending tools (42) to connect or disconnect said adjacent lateral upper bending tools (42) from each other and form said group of lateral upper bending tools (42).

15. Machine (1) according to claim 14, characterized by comprising further actuating means (20), said further actuating means (20) selectively acting on said connecting means of said upper lateral bending tools (42) to mutually engage or disengage them and allow the respective upper lateral bending tools (42) to be connected or disconnected.

Technical Field

The present invention relates to a bending machine arranged to bend and deform a metal strip, a metal sheet, a section bar in order to obtain semi-finished products and/or finished products. In particular, the present invention relates to a bending machine provided with modular and combinable punches and dies constituted by respective series of bending tools fixed in a sliding and adjustable manner to upper and lower tool holder crossbeams (cross) of the bending machine.

Background

There are known bending machines, also called press brakes, comprising a mechanically or hydraulically operated press capable of moving an upper tool, called punch, against a lower tool, called die, on which a workpiece is positioned. The punch exerts a force on the workpiece that is capable of deforming and bending the workpiece according to the determined angle on the upper and lower tool configurations.

One type of bending machine comprises a punch constituted by a bending blade or cutter able to deform a metal workpiece along a predetermined bending line, the metal workpiece being suitably positioned on an opposite die provided with a longitudinal seat or groove intended to interact with the punch in order to bend the workpiece.

In order to hold the workpiece in the correct position on the die during bending, a suitable back stop arrangement or back stop is typically provided. The back stop comprises respective abutment elements intended to be abutted by the workpiece transversely and/or longitudinally with respect to the bending line, so as to define exactly the position of said workpiece with respect to the bending tool. The back stop gauge can also be moved, manually or using suitable actuating means, along three orthogonal directions to position workpieces having different shapes and/or dimensions with respect to the tool and according to the bends to be performed.

The bending punch or blade is typically made up of a set of upper bending tools or sections mounted on an upper tool holder beam to form a modular and sectional punch. In practice, the number, size (width) and position of the upper tools are selected according to the length of the bend to be performed and/or the dimensions of the workpiece, while the type of tools is selected according to the type of bend (angle, shape).

Similarly, the die may be comprised of a generally fixed set of lower bending tools or sections mounted on a lower tool holder cross-beam to form a modular and sectional die. The number, size (width) and position of the lower tools correspond to the number, size and position of the upper tools in order to perform bending of a defined length.

In order to perform a length of bend on a workpiece, an adjacent tool having a dimension (width) must be selected from a group of tools mounted on upper and lower cross members to allow the desired length to be accurately achieved. Because the tool dimensions are standardized and discretely variable (typically varying in steps of 10 mm) depending on the predefined size (width), it is not always possible to perform the required bending using the set of tools currently mounted on the beam. In order to carry out subsequent and different work cycles, it is generally necessary to replace, at least partially, the bending tools mounted on the crossbar.

In the case where several operations or processes have to be carried out to obtain the desired product from the initial piece (usually a panel made from a flat sheet of metal), the initial piece must be transferred in sequence, for example to several bending machines arranged in a line.

If the workpiece has a small size, all the processes can be performed on a single bending machine, moving said workpiece through a subsequent station or work area of the bending machine, in which the bending tools mounted on the same tool holder beam perform the necessary bending. In this case, it is necessary to appropriately select bending tools and arrange the bending tools along the cross beam in accordance with the desired combination at respective different stations in order to perform subsequent bending.

Also in this case, the bending tools mounted on the cross beam must often be at least partially replaced in order to obtain the various tool combinations required for the work cycle.

There are known automatic bending tool replacement and installation systems in bending machines for installing/removing and positioning the bending tools required for various processes on/from the beam. The aforementioned system comprises a pick-up and transfer device provided for mounting the tools picked up from a tool holder magazine, which is usually located inside the bending machine, behind or above the upper beam, in the desired position on the beam. The aforementioned pick-up device also removes the tools to be replaced from the crossbar and inserts them into the magazine.

The pick and transfer device includes an external manipulator, such as a robot or an articulated mechanism, which inserts and picks up the desired tools by rotational and/or translational movement in order to achieve a combination of tools of the desired length on the beam.

There are also known bending machines in which a back stop gauge device is used to replace the upper and lower bending tools.

For example, document EP 0530375 describes a bending machine in which the back stop device shows a vertically movable part for replacing the tools mounted on the punch and/or die of the bending machine with the tools behind the punch housed in a magazine located inside the bending machine.

Document WO 2012/151601 describes a bending machine in which the device for backing gauge workpieces is also used to change and replace the tools mounted on the dies with tools housed in a back box on a particular beam.

A disadvantage of known bending tool machines lies in the fact that, in order to perform bends of different lengths, they generally require replacement of the tools in order to produce a tool combination of the required length. In order to perform the operations of mounting and/or dismounting the tools (which must be picked up from the magazine and/or put back into the magazine), a considerable time interval is required at which the machine must be stopped, thus interrupting production and consequently reducing the productivity of the machine itself.

Furthermore, the replacement and/or positioning of the tool can only be performed at the beginning of the workpiece machining cycle and not during the cycle. In fact, in this case, the cycle will last too long, reducing the productivity of the machine.

Another drawback of the known bending machines consists in that not only are the bending tools replaced, but they are also moved along the crossbar in order to combine appropriately in number and combination the bending tools to form bending blades of the required length and arranged along the crossbar, thus increasing the cost and complexity of the pick-up and delivery system.

Document EP 1658908 shows a bending machine in which the back stop gauge is also used to move a tool mounted on the die of the machine. In particular, each back stop supports a respective arm that rotates in a horizontal position in which its extendable portion can extend to engage and move the tools individually or in groups along the beam of the die.

A drawback of this solution lies in the fact that the back stop devices are movable inside the bending machine, in particular in the working area delimited by the side uprights of the machine support structure, they cannot reach the bending tools located at the ends of the crosspiece outside the operating area; in practice, the cross beam typically has a greater longitudinal extension or length than the bender support structure. Thus, a dedicated pusher is required to move the tool from the end of the die beam along the die beam into the operating area of the back stop.

Disclosure of Invention

One purpose of the present invention is to improve the known bending machines, which are arranged to bend and deform metal strips, metal sheets, metal profiles, and which are in particular provided with modular and combinable punches and dies constituted by a set of bending tools fixed in a sliding manner to a tool holder cross-beam.

Another object is to obtain a bending machine which allows to realize the combination of tools in a quick and precise manner, thus minimizing the downtime, in particular allowing to configure and arrange the lower bending tools of the dies.

Another object is to provide a bending machine with a device for automatic configuration and positioning of the lower bending tools, which has a simple and economical structure and has an efficient and reliable operation.

These objects and others are achieved by a bending machine according to claim 1.

Drawings

The invention may be better understood and put into practice with reference to the accompanying drawings, which illustrate embodiments by way of non-limiting example, and in which:

figure 1 is a schematic front view of the bending machine of the present invention;

figure 2 is a partial rear view of the bending machine shown in figure 1, showing a set of lower lateral tools and a rear gauge unit in an operating configuration;

figure 3 is another partial rear view of the bending machine shown in figure 1, showing a set of lateral lower bending tools, a rear lay unit and an upper bending tool drive.

Figures 4 and 5 are enlarged perspective views of a set of lower side tools equipped with connecting means and associated with actuating means in two different operating configurations;

figure 6 is an enlarged and partial view of the bending machine shown in figure 1, showing a set of lateral lower bending tools moved by the back gauge unit;

figure 7 is an enlarged perspective view of a lower side tool provided with a connection device;

figure 8 is another enlarged perspective view of the lower side tool, shown in broken lines, to better highlight the connection means;

figures 9 and 10 are partial and enlarged perspective views of the backstop unit, with the abutment element in the operative position and in the inoperative position, respectively;

figure 11 is a schematic front view of a variant of the bending machine of the invention.

Detailed Description

With reference to figures 1 to 10, a bending machine 1 for metal sheets according to the present invention is shown, which comprises a punch device 2, which punch device 2 comprises an upper cross-beam 3 suitable for supporting a plurality of upper bending tools 40, or more simply upper tools 40, the upper bending tools 40, or more simply upper tools 40, being called bending blades or segments, aligned along a longitudinal bending direction a, mounted adjacent and mutually positionable so as to form a certain combination of upper tools.

The aforementioned bending tools 40 form a modular and combinable punch that is slidable and adjustable along the upper crosspiece 3 of bending machine 1.

Bending machine 1 also comprises a die device 4, which die device 4 comprises a lower beam 5, which lower beam 5 is adapted to support a plurality of lower bending tools 30-35 or more simply lower tools 30-35, which lower bending tools 30-35 or more simply lower tools 30-35 are aligned along bending direction a, adjacent and mutually positionable so as to form respective combinations of lower tools.

Lower bending tools 30-35 thus form a modular and combinable punch that is slidable and adjustable along lower beam 5 of bending machine 1.

The combination of the upper tool and the lower tool is arranged to bend the workpiece according to a respectively defined bending line. The bending direction a is parallel to a bending line performed on the workpiece.

Bending machine 1 comprises a frame 9, which frame 9 is intended to support the upper beam 3 of punch means 2 and the lower beam 5 of die means 4. In particular, the upper crosspiece 3 comprises a substantially vertical plate parallel to the bending direction a, this upper crosspiece 3 being moved in a direction transverse and substantially perpendicular to the bending direction a by mechanical and/or hydraulic actuators, of known type and not shown.

Alternatively, the upper cross beam 3 may move according to an arcuate motion trajectory, for example pivoting to the frame 3 according to a horizontal axis parallel to the bending direction a.

In the embodiment shown in the figures, the upper cross-member 3 overlaps and is aligned with the lower cross-member 5 and can be moved downwards from the top to act on and thus bend the workpiece.

In order to increase the productivity and the operating flexibility of bending machine 1, the length of upper crosspiece 3 and lower crosspiece 5 is greater than the width of machine frame 3, in other words the end portions of crosspieces 3, 5 project laterally from the dimension defined by frame 9 described above.

The bending machine 1 comprises at least one movable back gauge unit 6, which at least one movable back gauge unit 6 is arranged to abut and position the workpiece with respect to the die set 4, in particular by means of respective abutment elements 8.

The back lay unit 6 further comprises a hooking element 7, which hooking element 7 is arranged to selectively engage one of the lower tools 30-35 in order to move the lower tool 30-35 and/or the lower tool adjacent to the hooking element in the bending direction a on the lower cross beam 5.

In the embodiment shown, bending machine 1 comprises two backstop units 6 movable within operating area W in a compartment 50 constituted by lateral walls 9a and by a rear wall of frame 9.

Each backstop unit 6 is movable within the operating zone W along three orthogonal movement axes X, Y, Z, one of which, for example, the third axis Z is parallel to the bending direction a. The back lay unit 6 is moved along three orthogonal axes X, Y, Z by a conveyor device of known type and not shown.

Thus, due to the structure of the frame 9, the movement of the back lay unit 6 along the third axis Z is delimited by the side walls 9a inside the compartment 50. In other words, the rear lay unit 6 can only move within the operating area W and in particular along the middle zone 5b of the lower crosspiece 5 and inside said operating area W at the middle zone 5b facing the compartment 50.

The plurality of lower tools 30-35 arranged on the lower crossbar 5 comprises at least one set of lateral lower bending tools 30 which can be positioned even in a respective non-operating configuration R1 outside the operating area W at one of the end portions 5a, 5c of the lower crossbar 5 projecting laterally from the frame 9 of the machine 1 and in any case not accessible by the rear lay unit 6.

When the side lower tools 30 are not used in the operation of bending the workpiece, they are positioned in a respective inoperative configuration R1 on one of the end portions 5a, 5c of the lower cross-beam 5.

The lateral lower tools 30 can be reversibly connected to each other so as to form a group or a group G of lateral lower tools 30, the number of which can be selected such that, even in the non-operating configuration R1, at least one, the innermost one, remains positioned inside the operating region W and can therefore be reached and engaged by the hooking element 7 of one of the two back gauge units 6, in particular of the most adjacent back gauge unit 6. Thus, the side lower tool 30 can be moved in the bending direction a together with the group G by the back gauge unit 6.

In the embodiment shown, with reference to the view of fig. 1, the side lower tool 30 can be positioned in the right end position 5a in the non-operative configuration R1. More precisely, lower tools having different dimensions can be mounted on the lower cross beam 5 to realize a plurality of different tool combinations having different lengths to cooperate with the upper tool 40 combination to make corresponding bends on the workpiece.

In the example shown in the figure, in addition to the side lower tools 30 all having the same dimensions, a first central lower tool 31, a second central lower tool 32, a third central lower tool 33, a fourth central lower tool 34, a fifth central lower tool 35 having different and increasing dimensions (widths) are also mounted on the lower cross beam 5 to form a modular die.

It is also possible to provide a set of lower side tools on the lower cross beam 5, which have different dimensions and are conveniently placed and positioned one with respect to the other to form different sets of lower side tools having different bending lengths.

On the other hand, on the upper beam 3, a plurality of upper tools 40 identical to each other are mounted to form a modular punch. However, it is also possible to mount upper tools of different sizes and suitable placement and distribution on the upper cross beam 3 in order to achieve a plurality of different tool combinations with corresponding bending lengths.

Each side lower tool 30 comprises a connecting means 15, 16 to engage or disengage with a corresponding connecting means 15, 16 of an adjacent side lower tool 30 in order to connect or disconnect adjacent side lower tools 30 to each other and form a group G of side lower tools 30 (fig. 6).

Bending machine 1 has actuating means 10, which actuating means 10 selectively act on connecting means 15, 16 of lower side tools 30 to mutually engage or disengage connecting means 15, 16 and thus allow connection or disconnection of respective lower side tools 30. The actuating device 10 is fixed at its end portion 5a (right) to the lower cross beam 5, on which end portion 5a the side lower tools 40 are movable.

With particular reference to fig. 7 and 8, the connection means of each side lower tool 30 comprise a first connection element 15 and a second connection element 16 fixed on opposite sides of the respective side lower tool 30. The first connecting element 15 can be moved by the actuating device 10 between the hooking position L and the release position S, respectively, to engage or disengage the second connecting element 16 of the adjacent lateral under-bending tool 30.

More particularly, the first connection element 15 comprises a connection pin 17, which connection pin 17 is slidably mounted on the respective side lower tool 30 and is movable, in particular movable transversely to the bending direction a, so as to protrude from the rear surface 30a of the side lower tool 30 into the hooking position L. The second connection element 16 is fixed on the rear surface 30a, projecting laterally from the opposite side with respect to the first connection element 15, and the second connection element 16 is provided with a seat 16a suitable for housing the connection pin 17 of the first connection element 15 of the adjacent lower side tool 30.

The actuating means 10 comprises a plurality of actuating cylinders 11 located near the lower cross member 5 at the right end portion 5a of the lower cross member 5. Each actuating cylinder 11 is arranged to actuate and move the first connecting element 15 of the corresponding lower lateral tool 30 so as to move said first connecting element 15 between the hooking position L and the release position S.

The actuating cylinders 11 are regularly spaced from each other in the bending direction a and equal in number to the lateral lower tools 30. Actuating cylinder 11 is controlled by the control unit of bending machine 1.

The actuating device 10 further comprises a support element 12, for example an elongated and moulded element, which is arranged to support the actuating cylinder 11 and is fixed to the right end portion 5a of the lower cross beam 5.

In addition to the connecting pin 17, the first connecting element 15 comprises an actuating pin 18, which is slidably mounted and connected to the connecting pin 17 so as to slide integrally with the connecting pin 17 transversely to the bending direction a. The actuating pins 18 project from the lower surface 30a of the lateral lower tool 30 so as to be abutted by the rods 11a of the respective actuating cylinders 11. This actuating cylinder 11, when actuated by the control unit of bending machine 1, is able to move actuating pin 18 and therefore connecting pin 17 connected thereto between a hooking position L and a release position S.

In the embodiment, an elastic means, not shown, is inserted into the side lower tool 30 to keep the connecting pin 17 protruding from the lower surface 30a in the hooking position L. The elastic means can act directly on the connecting pin 17 or on the actuating pin 18. In this way, when the actuating cylinder 11 is not actuated (in other words, the rod 11a does not act on the actuating pin 18), the connecting pin 17 engages with the second connecting element 16 of the adjacent lower lateral tools 30, the adjacent lower lateral tools 30 being mutually connected to each other.

The lower tools 30-35 comprise respective hooking cavities 38, for example made on the rear surface of the aforesaid lower tools, arranged to receive and engage with the hooking elements 7 of one of the rear gauge units 6.

Each back lay unit 6 is provided with an abutment element 8 adjacent to the hooking element 7 and movable between an operative position E, in which the abutment element 8 is arranged in such a way that the work piece is in contact with one of the shaped ends 8a of the abutment element, and a non-operative position F, in which said abutment element 8 allows the hooking element 7 to engage the established lower tool 30-35. More precisely and in the embodiment shown, the hooking element 7 is fixed and connected to an end 14a of the main body 14 of the back lay unit 6, while the abutment element 8 is rotatably fixed on said end 14a of the main body 14 so as to rotate about a rotation axis K parallel to the first axis X and to the bending direction a. In this way, the abutment elements 8 are moved by the respective rotary motors 13 (for example pneumatic or electric) between an operating position E, in which said abutment elements 8 are arranged substantially horizontally, superimposed on the hooking elements 7, so as to abut the workpiece, and a non-operating position F, in which said abutment elements 8 are rotated upwards by about 90 ° in an almost vertical position, so as to allow the hooking elements 7 to interact with the lower tools 30-35.

As shown in the figures, each lower tool 30-35 comprises, at its upper portion, a longitudinal seat or cavity 37 substantially "V" shaped. In the combination of lower tools 30-35, adjacent and aligned longitudinal seats 37 form a longitudinal groove 39 with a transverse "V" shaped section, parallel to bending direction a and having a length defined by a preselected combination of lower tools 30-35. The longitudinal grooves 39 of the die set 4 cooperate with upper tools 40, the upper tools 40 also being grouped in suitable length combinations to form bending blades of the punch device 2 for bending on the workpiece.

The shape and dimensions of the longitudinal seat 37, and in particular of its transverse "V" section, are determined and selected according to the type of work to be performed on the workpiece and to the shape and dimensions of the workpiece.

In order to vary the shape and section of the longitudinal seat 37 and therefore of the longitudinal groove 39, the lower bending tools 30-35 must be replaced.

In a variant of bending machine 1, not shown in the figures, each lower tool may be of the adjustable type and comprise a body, the lower part of each lower tool being constituted by two opposite and substantially symmetrical parts forming a longitudinal "V" shaped seat. The two opposite parts can be moved further or closer with respect to each other to allow the shape and the transverse dimensions of the aforementioned V-shaped longitudinal seat to be modified. By suitably adjusting the distance of the two opposite parts of each lower tool constituting the desired combination of tools, it is thus possible to vary the shape and the transverse dimensions of the longitudinal groove which cooperates with the upper tool 40 of the punch device 2 to achieve different types of bending.

This variant of bending machine 1 of the invention allows to realize a combination of tools with different bending lengths and different sizes of longitudinal grooves. Bending machine 1 comprises locking means, not shown, of a known type, associated with lower crosspiece 5 and arranged to lock lower tools 30-35 to lower crosspiece 5 at least during the bending phase of the workpiece to prevent accidental movement of the lower tools in bending direction a.

With particular reference to figure 3, in the embodiment shown, bending machine 1 of the invention comprises drive means 21, 22 associated with punch means 2 and arranged to move upper bending tool 40 on upper crosspiece 3 along bending direction a. The position of the driving means is controlled by the control unit of bending machine 1 and comprises, for example, a first carriage 21 and a second carriage 22, both of which are movable along upper beam 3 along bending direction a. Each carriage 21, 22 is provided with a respective withdrawal device 23, which withdrawal device 23 is able to hook or engage a defined upper tool 40 and move this upper tool 40 together with the upper tool or tools 40 adjacent thereto in the bending direction a.

The operation of bending machine 1 of the invention envisages the required stages of tool configuration in order to arrange the combination of upper and lower tools required to make the desired length of bend on the workpiece on crossbars 3, 5 of punch means 2 and die means 4.

For this purpose, the locking means that fasten the lower bending tools 30-35 to the guiding longitudinal grooves formed in the lower cross beam 5 are disabled, so as to allow the lower tools 30-35 to slide freely along the lower cross beam 5. At least one rear lay unit 6 with the abutment element 8 rotating in the inoperative position F is moved to engage with the lower tools 30-35 defined, so as to insert the hooking elements 7 into the respective hooking cavities 38. In this way, the back lay unit 6 can move the lower tool 30 and/or a plurality of lower tools 30 adjacent thereto on the lower cross beam 3 along the bending direction a. More precisely, by moving the lower tool 30 engaged by the hooking element 7 of the back stop gauge unit 6 to the right (with reference to the view of fig. 1), all the adjacent lower tools located to the right of the aforesaid lower tool 30 can also be moved. Similarly, by moving the lower tool 30 engaged by the hooking element 7 to the left, all the adjacent lower tools located to the left of the aforesaid lower tool 30 can also be moved together therewith.

The backstop unit 6 is able to engage and move all the lower tools 30-35 located in the central portion 5b of the lower cross beam 5 facing the compartment 50, which central portion 5b is in the operating area W. In particular, the back lay unit 6 is able to engage and move all the central lower tools 31-35, the central lower tools 31-35 even having different dimensions and being able to move along the central portion 5b of the lower crosspiece 5.

Due to the connecting means 15, 16 provided with the side lower tools 30, the back lay unit 6 is also able to move one or more side lower tools 30 of the set of side lower tools 30, even if the one or more side lower tools 30 are positioned in one of the end portions 5a, 5c of the lower cross member 5 which cannot be directly reached by the back lay unit 6.

For this purpose, the back lay unit 6 engages a first lateral lower tool 30 of the set with the hooking element 7 and hooks the hooking element 7, the first lateral lower tool 30 being adjacent to the central portion 5b of the lower crosspiece 5 and within the operating zone W. The aforementioned first lateral lower tool 30 is connected to the adjacent lateral lower tool 30 (to the right with reference to the view of fig. 1) by means of connecting means 15, 16. In the non-operating configuration, in which actuating device 10 is not driven by the control unit of bending machine 1, connecting pin 17 of first connecting element 15 is actually engaged with second connecting element 16 in hooking position L. In this arrangement, by moving the first side lower tool 30, the entire set of side lower tools 30 is moved from the back lay unit 6 along the lower cross beam 5.

However, by actuating a certain actuating cylinder 11, it is possible to disengage the connecting means 15, 16 of the respective lower side tool 30, in order to separate the respective lower side tool 30 from the adjacent lower side tool 30.

As shown in fig. 6, the operation of the actuating cylinder 11 (for example, with reference to the second actuating cylinder 11 seen from the right in fig. 1) allows the actuating pin 18, and therefore the connecting pin 17 connected to it, to move from the hooking position L to the release position S, in which said connecting pin 17 is disengaged from the second connecting element 16 by the adjacent lateral lower tool 30, i.e. by the tool located on the left with reference to fig. 1 (the third lateral lower tool 30 from the right). In this way, the side lower tools 30 whose driving pins 18 are engaged by the respective actuating cylinders 11, and all the adjacent side lower tools 30 which may be on the right thereof, cannot be moved by the back stop unit 6 and remain stopped on the end portion 5a of the lower cross beam 5. Thus, the group G of lower side tools 30 movable on the lower cross beam 5 by the back lay unit 6 is constituted by the lower side tools 30 engaged by the hooking elements 7 of the back lay unit and the lower side tools 30 connected to the hooking elements of the back lay unit and located to the left of them (whose driving pins 18 are occupied by the respective actuating cylinders 11).

By suitably selecting the actuating cylinders 11 of the actuating devices 10 according to the work requirements, it is thus possible to select the number of lateral lower tools 30 forming the group G moved by the back stop unit 6 along the lower crosspiece 5, to realize one or more tool combinations with or without the central lower tools 31-35.

Due to the back stop unit 6 and the side lower tools 30 provided with the respective connecting means 15, 16, it is possible to form on the lower crossbar 5 of the die arrangement 4a desired combination of lower tools 30-35, which is suitable and complementary to the selected respective combination of upper tools 40 moved by the driving tools 21, 22 on the upper crossbar 3 of the punch arrangement 2.

The same back lay unit 6 moves the unused side lower tools 30 and/or the central lower tools 31-35 on the parts (e.g. end parts) of the lower crossbeam 5 that are not used during the bending process.

Two or more combinations of lower tools 30-35 can be arranged on the lower cross beam 5 to sequentially perform respective subsequent bending operations on the same workpiece to obtain a final product cooperating with two or more respective combinations of upper tools 40 arranged on the upper cross beam 3.

By using the back stop gauge unit 6, the bending machine 1 of the present invention allows to select and place the lower bending tools 30-35 mounted on the lower crosspiece 5 according to the production needs, as required. Thus, unlike known bending machines, no special hooking and driving means, comprising an external manipulator such as a robot or articulated hooking mechanism, are required to produce a tool combination of the required length on the lower crosspiece 5.

The structure of bending machine 1 according to the present invention can therefore be simplified and made more economical. Furthermore, the backstop unit, movable along the three axes X, Y, Z, allows the lower bending tools 30-35 required for the required machining to be arranged more quickly and accurately, thus minimizing machine downtime, in other words, speeding up the work piece machining cycle time.

It should be noted that by means of the lower bending tools 30-35 mounted on the lower cross member 5, it is possible to produce, together with the upper bending tool 40 mounted on the upper cross member 3, bends with variable lengths without the need for tool replacements. In fact, by suitably separating and grouping the lower and upper tools, having different sizes and dimensions and suitably placed on the crossbeams 3, 5, it is possible to produce all the tool combinations necessary to perform different bending lengths, only having to separate the selected tools (always adjacent to each other) from the remaining ones, without having to mount/dismount the above-mentioned tools from the crossbeams 3, 5.

Bending machine 1 of the present invention therefore offers a high operating flexibility and allows to optimize the work piece processing cycle.

In a variant of bending machine 1 of the invention, not shown in the figures, the plurality of lower tools 30 comprises two sets of lateral lower tools 30, which can slide on lower crosspiece 5 and can be arranged at two end portions 5a, 5b of lower crosspiece 5 in respective non-operating configurations. The lateral lower tools 30 of each group can be connected to each other to form a respective group G of lateral lower tools 30, the number of lateral lower tools 30 being selectable and being movable by the respective back lay unit 6 in the bending direction a to form a desired combination of lower bending tools even in cooperation with one or more central lower tools 31-35.

At both end portions 5a, 5b of the lower cross-beam 5 respective actuating means 10 are provided to selectively act on the connecting means 15, 16 of the side lower tools 30 of the two sets of side lower tools to mutually engage or disengage the connecting means 15, 16 and allow the respective side lower tools 30 to be connected or disconnected.

The operation of this version of bending machine 1 of the invention is substantially the same as that of the version described above and shown in the figures. In this case, the combination of lower tools 30-35 for bending the workpiece may also consist of the side lower tools 30 of the two sets of side lower tools arranged on the two opposite end portions 5a, 5b of the lower cross beam 5 in addition to the central lower tools 31-35. Each back gauge unit 6 is provided for picking up and moving a respective group G of lower side tools 30, the respective group G of lower side tools 30 being formed by hooking a certain number of lower side tools to each other.

With reference to figure 11, a further variant of the bending machine 1 of the invention is shown, in which the back gauge unit 6 is also arranged to engage and move the upper bending tools 41, 42 along the upper crosspiece 3 of the punch means 2, the back gauge unit 6 replacing the drive means 21, 22. For this purpose, the upper tools 41, 42 comprise respective hooking cavities 48, these hooking cavities 48 being arranged to receive and engage with the hooking element 7 of one of the back gauge units 6 so as to be moved along the upper crosspiece 3 by the hooking element 7. In this form of bending machine, it is also envisaged that the plurality of upper bending tools 41, 42 should comprise a set of central upper tools 41 and at least one corresponding set of lateral upper tools 42, which can be positioned, in a corresponding inoperative configuration R2, at an end portion 3a of the upper crosspiece 3, which end portion 3a projects from the frame 9 and is located outside the operative area W and therefore not reachable by the backstop gauge unit 6. When the side upper bending tool 42 is not used at the time of bending the workpiece, the side upper bending tool 42 is positioned at the end portion 3a of the upper beam 3 in the corresponding non-operating configuration R2 (for example, the end portion on the right with reference to the view of fig. 11).

The lateral upper bending tools 42 are reversibly connected to each other so as to form a respective set of lateral upper bending tools 42, the number of which is selectable, at least one, innermost one of which remains within the operating region W even in the non-operating configuration R2 and is thus accessible and usable by the hooking element 7 of one, in particular the nearest one, of the two back gauge units 6. In this way, the lateral upper tools 42 can be moved on the upper cross member 3 along the bending direction a by the back stop gauge unit 6 together with the respective sets.

Also in this case, each lateral upper tool 42 comprises respective connection means 15, 16 to engage or disengage the respective connection means 15, 16 of the adjacent lateral upper tools 42, so as to connect or disconnect the aforesaid adjacent lateral upper tools 42 to each other and form a set of lateral upper tools 42.

The connecting means 15, 16 are identical to the connecting means 15, 16 of the lower side tool 30 described above and shown in the drawings.

Similarly, further actuating means 20 are associated with the upper crosspiece 3 to selectively act on the connecting means 15, 16 of the side upper tools 42 to mutually engage or disengage the connecting means 15, 16, allowing the respective side upper tools 42 to be connected or disconnected.

The further actuating means 20 associated with the upper cross member 3 are identical to the actuating means 10, the actuating means 10 being associated with the lower cross member 5 and acting on the side lower tools 30.

In the embodiment shown, the central upper tool 41 and the lateral upper tools 42 have the same dimensions. However, central and/or lateral upper tools may be provided on the upper cross beam 3 of the punch device 2, said tools having different dimensions and being suitably mutually placed and positioned to form different combinations of upper tools having different bending lengths.

The operation of this variant of bending machine 1 of the invention is substantially identical to that of the bending machine in the embodiment described above and shown in the figures, since the procedure for selecting a set of upper lateral tools 42 among a set of upper lateral tools and moving the set of upper lateral tools 42 on the upper crosspiece 3 of the punch means 2 is identical to that described for the lower lateral tools 30 of the die means 4.

In this version of bending machine 1 according to the invention, therefore, rear gauge unit 6 can be advantageously used to select and move lower tools 30-35 placed on lower crosspiece 5 and upper tools 41, 42 placed on upper crosspiece 3. The structure of bending machine 1 is simplified and more economical, since it is no longer necessary for dedicated drive means (carriages 21, 22 with respective connecting means 23) to be mounted on upper crosspiece 3 to select and move upper bending tools 41, 42.

It should be noted that in this version of machine 1, also since the lateral upper tools 42 are selectively and reversibly connected to each other by respective connecting means 15, 16 so as to form a set of a desired number of tools, all the upper tools 41, 42 mounted on the upper crosspiece 3 can be selected and moved by the back stop gauge unit 6.