BENDING PRESS

Abstract

 A press brake is described for bending a workpiece, comprising: a frame; a lower bending table which is fixed to the frame and adapted to receive one or more dies; an upper bending table which is adapted to receive one or more bending punches and movable relative to the frame towards the lower table to press the workpiece between a die and a punch; a horizontal guide mounted on the frame; and a movable picker which is coupled to the guide to move horizontally from a tool storage unit to one of said tables and configured to pick up a tool from the tool storage unit and mount it on that table.
To move more stably a tool, the picker comprises two protruding members each configured to be able to hook and transport a tool or the same tool.

Description

[0001] The present invention relates to a press brake and a method of operation thereof.

[0002] Press brakes are known, such as in EP4487977. To set up a line of tools on a pressing table, a pair of carriages that work together is used. A manipulator prepares a train of tools for the pair of carriages, after which one carriage inserts the leading tool and the other carriage the trailing tool via a respective protruding pin with which it can hook the tool. Once the tools are packed and properly aligned, the two carriages translate horizontally to transport the train of tools along a horizontal guide to the designated bending table. See, for example, http://www.youtube.com/watch?v=Mc5oQPhvzFs.

[0003] This system has several problems.

[0004] Setting up the tools before moving them onto the pressing table reduce the setup speed. Furthermore, the system only allows the use of single-size tools, while larger tools, needed for bending very wide sheets, are assembled by placing several tools of the same size side by side.

[0005] Furthermore, and most importantly, this system severely limits the freedom to set up tools on the pressing table and in the tool storage unit. Consider, for example, the case where the tool furthest from the storage unit needs to be removed from the pressing table: all the other tools in the row must then be removed to create a clear path for retrieving that last tool. This clearly translates into long cycle times and/or inconvenient constraints in arranging tools on the pressing table during bending.

[0006] The main object of the invention is to eliminate or mitigate the aforementioned drawbacks by making a different press brake.

[0007] Another object is to increase the set-up speed of the press brake while maintaining the flexibility of the press brake with tools of different sizes.

[0008] Another specific object is to reduce the setup cycle time and/or increase the freedom of arrangement of the tools on the pressing table during bending.

[0009] A press brake is then proposed for bending a work-piece, comprising:

• a frame;
• a lower bending table which is fixed to the frame and adapted to receive one or more dies;
• an upper bending table which is

  ∘ adapted to receive one or more bending punches and

  ∘ translatable relative to the frame towards the lower table to press the work-piece between a die and a punch;

• a horizontal guide mounted on the frame;
• a movable picker which is
  • coupled to the guide to move horizontally from a tool storage unit toward one of said tables and
  • configured to pick up a tool from the tool storage unit and mount it on that table;

wherein the picker comprises two protruding members each configured to be able to hook and transport a tool.

[0010] The two protruding members are configured to be able to hook and transport simultaneously the same tool or two distinct tools, one for each protruding member.

[0011] An advantage of the two protruding members is that they can support very heavy tools, e.g. up to 30 kg, and/or very long tools, e.g. up to 50 cm wide.

[0012] Advantageously, the two protruding members are configured to always move the tools in a balanced manner, providing two support points that ensure precise tool verticality. This facilitates the movements from the storage unit to the table and, above all, facilitates the operation of inserting the tool shank into the table, an operation that becomes more imprecise the more the tool is tilted from the vertical.

[0013] Advantageously, the two protruding members are configured to simultaneously unlock two safety pins that block the tool suspended from the table. For example, the two protruding members allow the extraction/removal of two identical or different tools that require pick-up with a single pin (for example, a 20 mm tool and a 100 mm tool).

[0014] Another advantage is the ability to extract the tools vertically from the tables, which allows the bending stations to be reconfigured without having to necessarily unload the tools (with the well-known dragging version it is necessary to remove all the tools located between the storage unit and the tool to be dragged).

[0015] In one embodiment one or each protruding member

has a maximum dimension along a first axis (horizontal in use), and

is provided with a movable pressing member capable of moving along a second axis (vertical in use) orthogonal to the first axis to protrude from the lower external surface of the protruding member.

[0016] In one embodiment one or each protruding member is an oblong pin.

[0017] In one embodiment the picker comprises a drive for selectively moving the pressing member so that it protrudes or not from the lower outer surface of the protruding member.

[0018] To stabilize tools of different shapes and/or mounted on the protruding member with two opposite orientations, in one embodiment the protruding member comprises two pressing members which are

structured as said pressing member, and

arranged aligned and spaced along the first axis.

In particular, the protruding member comprises

an internal cavity that develops along the first axis, and

a stem or shaft that is slidably mounted inside the cavity and coupled with said or each pressing member so as to convert a translation of the stem into a translation of said or each pressing member along the second axis.

[0019] In one embodiment, the shaft or stem is so shaped as to allow one or each pressing member to be pushed and translated vertically within said holes toward the outside of the protruding member. Specifically, as a simple yet effective solution, the stem or shaft comprises an inclined plane adapted to engage one or each pressing member so as to convert said translation into a translation of the pressing member along the second axis.

[0020] In one embodiment, one or each pressing member is housed in a translatable manner within a cavity provided in the protruding member, the cavity preferably having a vertical longitudinal axis.

[0021] To transport tools of large dimensions, in one embodiment the picker is a carriage slidable on the horizontal guide and comprises a head provided with two protruding members as said protruding member.

[0022] In one embodiment, one or each protruding member is horizontally retractable and configured to engage a corresponding through cavity formed in a tool (punch or die).

[0023] In one embodiment the head of the picker is movable along a vertical axis and/or such head is movable along a horizontal axis orthogonal to the longitudinal axis of the horizontal guide (i.e. orthogonal to a plane containing at least one of said tables).

[0024] In one embodiment the two protruding members are equal to each other and/or have the same length, and/or are coplanar with respect to a horizontal plane.

[0025] In one embodiment the two protruding members are separated horizontally by a fixed distance.

[0026] In one embodiment the two protruding members are separated horizontally by a variable distance, the head of the picker comprising actuators for horizontally moving one or each of the protruding members relative to the other protruding member while keeping it parallel to itself.

[0027] In one embodiment, one or each pressing member has a mushroom shape. Specifically, one or each pressing member comprises a stem, radially outermost with respect to the internal cavity of the protruding member, and a head, radially innermost with respect to the internal cavity of the protruding member. The stem is preferably cylindrical with a rounded and convex base, preferably in the shape of a spherical cap or hemisphere; the head preferably has a convex shape, more preferably in the shape of a spherical cap or hemisphere.

[0028] The holes preferably have a cross-section substantially complementary to the diameter of the stem while the lower part of the head of the pressing member is mounted to rest on an internal step of the internal cavity of the protruding member.

[0029] In one embodiment, the shaft or stem comprises an alternating series of first segments, complementary to the cross-section of the internal cavity of the protruding member, and of second segments of smaller cross-section.

[0030] In one embodiment, each second segment comprises a first portion, preferably cylindrical in shape, and a second truncated-cone portion that joins smoothly the first portion to an adjacent first segment. The first portion may also be absent.

[0031] In one embodiment, the second segments are axially arranged at the pressing members, and such that the inclined outer surface of a second portion can slide on a pressing member (or the head of the pressing member) to push such pressing member outward of the protruding member and cause such pressing member (or its shank) to protrude from the bottom of the protruding member.

[0032] In one embodiment, two second segments are axially arranged at the two pressing members, and so that the inclined outer surface of each second portion can slide on the respective pressing member (or on the head of the pressing member) to simultaneously push the two pressing members outward from the protruding member and cause the two pressing members (or their respective stems) to protrude from the bottom of the protruding member.

[0033] In one embodiment the press comprises a processing unit programmed or programmable for

moving the picker along the horizontal guide to pick a punch from the tool storage unit and mount it on the upper table and /or

moving the picker along the horizontal guide to pick up a die from the tool storage unit and mount it on the lower table.

[0034] The two protruding members are configured to be able to hook and transport the same tool or two separate tools at the same time, one for each protruding member.

[0035] Another aspect of the invention relates to a method for moving a tool in a press brake made according to one of the above-mentioned variants, with the steps of

moving the picker so as to insert two through cavities obtained in a tool with the two protruding members of the picker, and

moving the picker to mount the tool on a table or in a tool storage unit.

[0036] Another aspect of the invention relates to a method for moving a tool in a press brake made according to one of the above-mentioned variants, with the steps of

moving the picker so as to insert, by means of each of the two protruding members of the picker, a through cavity made in a tool, and

moving the picker to mount the two tools thus hooked on a table or in a tool storage unit.

[0037] As a variant each method has the step of

inserting the protruding member into a through cavity of the tool, and

moving a pressing member vertically from the inside of the protruding member to the outside so that the pressing member abuts a lower surface of the cavity to block the tool on the protruding member.

[0038] Each of the variants defined above may be implemented alone or in combination with one or each of the others.

[0039] The advantages of the invention will be further clarified by preferred embodiments described below with reference to the accompanying drawings, wherein:

• Figure 1 shows a three-dimensional view of a press brake according to the invention;
• Figures 2 and 3 show a three-dimensional view of a component of the press brake in fig. 1;
• Figure 4 shows a vertical cross-sectional view of the component of Fig. 2;
• Figures 5 and 6 show details of vertical cross-sectional views of the component of fig. 2 compared to two different tools.

[0040] Equal numbers in the figures indicate equal or substantially equal parts. To avoid crowding the drawings, identical members are sometimes left unnumbered.

[0041] Let's define a set of Cartesian directions or axes XYZ, where X and Y are horizontal directions or axes that are orthogonal to each other and Z is the vertical direction or axis that is orthogonal to the XY plane. For brevity, expressions such as "along X" mean along an axis that is coincident with or parallel to the X axis.

[0042] A press brake 10 comprises:

a C-shaped frame 12 having a lower portion 14 and an upper portion 16 corresponding to the ends of the C,

a fixed support 18 for receiving a bending die which is integral with the lower portion 14, and

a table 22, for receiving a bending punch, which is mounted vertically translatable on the upper portion 16 to be translated vertically along Z with respect to and towards the fixed support 18 in order to effect a bending of a work-piece placed between the punch and the die.

[0043] The table 22 is movable by a drive 28, e.g. two pneumatic cylinders, mounted on the frame 12 and connected to opposite ends of the table 22 respectively.

[0044] To set-up the table 22 and the fixed support 18 with the necessary tools, the press brake 10 comprises a shuttle carriage 40 which is movable on a horizontal guide 38 along X to pick up tools 42 from a storage unit 44 and carry them to the table 22 or the fixed support 18, or vice versa.

[0045] The shuttle carriage 40 comprises (see fig. 2 and 3) a head 56 equipped with two horizontal pins 50, 52, preferably identical, which extend along Y from the head 56 towards the guide 38. The pins 50, 52 are parallel, of substantially the same length, protrude forward from the head 56 by substantially the same length, and are coplanar with respect to an XY plane. That is, the level along Z of the pin 50 with respect to the guide 38 is the same as the level of the pin 52.

[0046] The pins 50, 52 are used to attach one or more tools 42 to the shuttle carriage 40.

[0047] In operation, the shuttle carriage 40 is moved to thread corresponding through-slots in a tool 42 (fig. 3 and 4) with the pins 50, 52 in order to transport the tool 42 to and from the table 22 or the fixed support 18.

[0048] To facilitate the hooking and transport of the tool 42, in one embodiment the head 56 is also movable along Z and Y relative to the rest of the shuttle carriage 40 (thanks to actuators mounted on the shuttle carriage 40). In one embodiment the pins 50, 52 are movable along Y relative to the rest of the shuttle carriage 40 or relative to the head 56 (thanks to actuators mounted on the shuttle carriage 40).

[0049] The pins 50, 52 are separated along X by a distance D, see fig. 3.

[0050] In one embodiment, of simpler construction, the distance D is fixed.

[0051] In one embodiment, the distance D is variable. For this purpose, the head 56 comprises actuators for moving one or each of the pins 50, 52 along X while keeping it parallel to itself. A variable distance D allows the shuttle carriage 40 to be adapted to multiple tools.

[0052] When there is only one pressing member acting on an unbalanced tool or one with an eccentric centre of gravity, e.g. for a gooseneck tool (see gig. 5 ÷ 6 or WO2021090197), the tool can often become tilted, which compromises the insertion of the tool into the respective receiving groove in the table 22, in the fixed support 18 or in the storage unit 44.

[0053] This problem is solved by an embodiment for one or each pin 50, 52, illustrated in fig. 4 et seq.

[0054] The pin 50, which is referred to here as an example, has a hollow tubular oblong body 70 which extends along Y and is provided with a coaxial internal cavity 72. Inside the cavity 72 is movably housed a shaft 74 which, when actuated by an actuator 102 located in the head 56, can translate along Y and cooperate with pressing members 80.

[0055] The pressing members 80 are housed in holes 82 obtained on a lower surface 86 of the body 70 and are aligned along Y. The holes 82 have an axis along Z and the pressing members 80 are mounted to be able to slide along Z within the holes 82.

[0056] In one embodiment, the pressing members 80 have a mushroom shape, in particular they comprise a stem 88, radially more external than the cavity 72, and a head 90, radially more internal than the cavity 72. The stem 88 is preferably cylindrical with a rounded and convex base 92, preferably in the shape of a spherical cap or hemisphere. The head 90 preferably has a convex shape, more preferably of a spherical cap or hemisphere.

[0057] The holes 82 preferably have a cross-section substantially complementary to the diameter of the stem 88 while the lower part of the head 90 can rest on an internal step of the cavity 72.

[0058] The shaft 74 has a shape that allows the pressing members 80 to be pushed and made to translate along Z inside the holes 82 towards the outside of the body 70. In one embodiment, the shaft 74 comprises an alternating series of segments 76, complementary to the cross-section of the cavity 72, and segments 78 of smaller cross-section. Each segment 78 comprises a portion 94, preferably of cylindrical shape, and a truncated conical portion 96 that smoothly joins the portion 94 to the adjacent segment 76. The segments 78 are axially arranged in correspondence with the pressing members 80, and in such a way that the inclined external surface of the portion 96 can slide on the head 90 to push the stem 88 towards the outside of the body 70 and to protrude the stem 88 from the bottom of the body 70.

Operation:

[0059] Once the pins 50, 52 have been inserted into the through slot 110 of the tool 42, the body 70 can expand thanks to the protrusion of the pressing members 80. Thus the tool 42 remains blocked and integral with the pin 50, 52. For this purpose the drive 102 is activated to pull the shaft 74 towards the head 56, so that each portion 96 slides on the head 90 and pushes the shank 88 against an internal wall of the tool 42.

[0060] The interaction between the portion 96 and the head 90 allows the pressing member 80 to be pushed with great force, resulting in a tenacious clamping of the tool 42 on the pin 50, 52.

[0061] The advantage of having two pressing members 80 is that the tool 42 can also be rotated by 180° around Z.

[0062] Figures 5 and 6 respectively illustrate two identical gooseneck tools 42a, 42b which are mounted upside down by 180° around Z. It can be noted that in both cases at least one pressing member 80 is able to push against the internal lower surface of the slot 110 of the tool 42a, 42b.

[0063] Since the pressing members 80 come out from below the body 70, their thrust supports the tool 42 and above all straightens it, generating a momentum contrary to the weight of the tool 42 and centering the slot 110 on the upper part of the pin 50. The pressing member 80 pushes the tool 42 inside the support plane of the tool 42 and manages to generate said momentum.

[0064] Furthermore, the slot 110 has a radiused shape so that the forced abutment between the upper part of the pin 50 and the radiused vault of the slot 110 centers the tool along X on the pin 50. In fact, the tool 42 is forced to move onto the vertical diameter of the slot 110 thanks to the rounded shape of the cross-section of the body 70 (which preferably is substantially complementary to the perimeter of the slot 110).

[0065] By combining this effect with the fact of having two pins 50, 52, one finally gets that the tool 42 is hooked onto the shuttle carriage 40 compensating for handling tolerances or errors that would tilt the tool 42 with respect to the horizon.

[0066] Furthermore, this way it is possible to compensate for the machining tolerances of the slot 110.

[0067] Note that the particular construction of the pin 50 is not linked to the characteristic presence of two pins 50, 52 on the shuttle carriage 40, and may be exploited individually, or vice versa.

Claims

1. Press brake for bending a workpiece, comprising:

• a frame;

• a lower bending table which is fixed to the frame and adapted to receive one or more dies;

• an upper bending table which is

adapted to receive one or more bending punches and

movable relative to the frame towards the lower table to press the workpiece between a die and a punch;

• a horizontal guide mounted on the frame;

• a movable picker which is

coupled to the guide to move horizontally from a tool storage unit to one of said tables and

configured to pick up a tool from the tool storage unit and mount it on that table;

wherein the picker comprises two protruding members each configured to be able to hook and transport a tool or the same tool.

2. Press according to claim 1, wherein one or each protruding member

has a maximum dimension along a first, horizontal in use, axis and

is provided with a movable pressing member capable of moving along a second axis, orthogonal to the first axis and vertical in use, to protrude from the lower external surface of the protruding member.

3. Press brake according to claim 2, wherein the picker comprises a drive for selectively moving the pressing member so that it protrudes or not from the lower external surface of the protruding member.

4. Press brake according to any preceding claim, comprising two pressing members that are

structured as said pressing member, and

arranged aligned and spaced along the first axis.

5. Press according to any preceding claim, wherein one or each protruding member comprises

an internal cavity extending along the first axis, and

a stem or shaft which is slidably mounted inside the cavity and coupled with one or each pressing member so as to convert a translation of the stem or shaft into a translation of one or each pressure member along the second axis.

6. Press according to claim 5, wherein the shaft or stem has a shape such as to allow one or each pressure member to be pushed and made to translate vertically inside a hole towards the outside of the pressing member.

7. Press according to any preceding claim, wherein said or each pressing member is housed in a translatable manner within a cavity provided in the protruding member, the cavity preferably having a vertical longitudinal axis.

8. Press according to any preceding claim, wherein the two protruding members are coplanar with respect to a horizontal plane.

9. Method for moving a tool in a press brake made according to one of the preceeding claims, with the steps of

moving the picker so as to insert two pass-through cavities formed in a tool with the two protruding members of the picker, and

moving the picker to mount the tool on a table or in a tool storage unit.

10. Method according to claim 9, with the steps of

inserting the two protruding members into two through cavities of the tool, and

vertically moving a pressing member from the inside of each protruding member towards the outside so that each pressing member abuts on a lower surface of the cavity to lock the tool on the protruding members.

Drawing