Abstract
The present invention relates to a press brake and a method for operating a press brake. The press brake according to the present invention includes a press brake frame; a lever that is moveably attached to the frame and that is moveable between a press position and a release position; a motor that is operatively attached to the frame and the lever, which the motor is configured to move the lever between the press position and the release position; and a pressing element including a top pressing part and a bottom pressing part. The bottom pressing part is operatively connected to the frame. The top pressing part is operatively connected to the lever. The top pressing part and the bottom pressing part are configured to mate when the lever is in the press position.
Claims
1. A press brake, comprising: a lever that is moveably attached to the frame and that is moveable between a press position and a release position; a motor that is operatively attached to the frame and the lever, wherein the motor is configured to move the lever between the press position and the release position; and a pressing element comprising a top pressing part and a bottom pressing part, wherein one of the bottom pressing part and the top pressing part is operatively connected to the frame, wherein the other of the top pressing part and the bottom pressing part is operatively connected to the lever, and wherein the top pressing part and the bottom pressing part are configured to mate when the lever is in the press position.
2. The press brake according to claim 1, wherein the lever is pivotably connected to the frame, and/or wherein the motor comprises an electric motor, and/or wherein the press brake further comprises a pulley assembly that is operatively connected to and positioned between the motor and the lever.
3. The press brake according to claim 2, wherein the pulley assembly comprises 2-20 pulleys, preferably 2-12 pulleys, and most preferably 8-10 pulleys.
4. The press brake according to claim 2, wherein the pulley assembly comprises a plurality of frame pulleys that is fixed to the frame and a plurality of lever pulleys that is operatively connected to the lever, wherein a connecting element is alternately placed around a frame pulley and a lever pulley, and wherein the connecting element is connected to the motor at a first end of the connecting element and fixed to the frame at a second end of the connecting element.
5. The press brake according to claim 4, wherein the press brake further comprises a pulley carrier element that is operatively connected to the plurality of lever pulleys and the lever, wherein the lever pulleys are positioned on the pulley carrier element.
6. The press brake according to claim 1, wherein the motor comprises a high-speed motor operatively connected to a shaft, wherein the shaft is operatively connected to the lever for moving the lever, wherein the motor further comprises a low-speed motor that is operatively connected to the shaft via a one-way bearing, wherein preferably an disconnectable coupling is provided for coupling the low-speed motor to the shaft, wherein preferably the disconnectable coupling is a magnetic coupling.
7. The press brake according to claim 1, wherein at least one side of the frame that is perpendicular to a longitudinal axis of the press brake has an access opening for accessing a plate to be pressed in and/or replacing of tools of the press brake.
8. The press brake according to claim 1, comprising two levers that are positioned substantially at opposite longitudinal sides of the frame.
9. The press brake according to claim 7, further comprising one or more levers that, when viewed along the longitudinal axis, are positioned substantially in between the longitudinal sides of the frame.
10. The press brake according to claim 1, wherein the lever comprises an angle, wherein the angle is preferably in the range of 70° - 135°, more preferably in the range of 80° - 135°, and most preferably is about 90°.
11. The press brake according to claim 1, further comprising a return element configured to return the lever from the press position to the rest position, wherein the return element preferably is a spring element, further preferably comprising a load that at or near a first end is pivotably connected to the frame and that at or near a second end thereof is operatively connected to the lever, wherein the weight of the load at least partially counteracts the weight of the top pressing part, and wherein the load in the press position acts on the spring element.
12. The press brake according to claim 11, wherein the return element comprises a first end and a second end, wherein the first end is hingeably connected to the frame and a second end is connected to two support hinge elements, wherein a first support hinge element is hingably connected to the lever and a second support hinge element is connected to the frame, wherein preferably the return element and the two support hinge elements are positioned in a Y-configuration.
13. The press brake according to claim 1, further comprising: a front motor attached to the frame, preferably near a front side thereof; and a second pulley assembly that is operatively connected to the front motor and wherein the second pulley assembly comprises: a plurality of front frame pulleys attached to the frame; a plurality of pressing pulleys that are provided at least partially inside the top pressing part, wherein the pressing pulleys, at least in the release position, are positioned substantially above the front frame pulleys; and a front connecting element alternately placed around a front frame pulley and a pressing pulley, and wherein the front connecting element is connected to the front motor at a first end of the front connecting element and fixed to the frame at a second end of the front connecting element.
14. The press brake according to claim 13, wherein the plurality of pressing pulleys and front frame pulleys are provided at an angle relative to a plane perpendicular to a longitudinal axis of the press brake.
15. A method for operating a press brake, comprising: providing a press brake according to claim 1; moving the lever from the release position to the press position; and pressing a plate with the pressing element, further preferably comprising: returning the lever to the release position, preferably using the returning element.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0107] Further advantages, features and details of the invention are elucidated on the basis of preferred embodiments thereof, wherein reference is made to the accompanying drawings, in which:
[0108] FIG. 1 shows an example of a press brake according to the invention;
[0109] FIGS. 2A-B show a side view of an example of a press brake according to the invention;
[0110] FIG. 3 shows a side of an alternative example of a press brake according to the invention;
[0111] FIG. 4 shows an example of removing the pressing element from a press brake according to the invention;
[0112] FIG. 5 shows an alternative example of a press brake according to the invention.
[0113] FIGS. 6A-B show a schematic front view of an alternative embodiment according to the invention;
[0114] FIG. 7 shows a schematic top view of an alternative embodiment according to the invention;
[0115] FIGS. 8A-B show respectively a schematic front and side view of an alternative embodiment according to the invention; and
[0116] FIGS. 9A-B show an alternative example of a press brake according to the invention.
DESCRIPTION OF THE INVENTION
[0117] Press brake 2 (FIG. 1) comprises press brake frame 4. Press brake frame 4 has a longitudinal axis 6, which stretches out between longitudinal sides 8. Longitudinal sides 8 are substantially perpendicular to longitudinal axis 6. Press brake frame 4 further has front 10 where pressing element 12 is positioned. Pressing element 12 comprises top pressing part 14 and bottom pressing part 16. Top pressing part 14 and bottom pressing part 16 are both plate shaped in the illustrated embodiment and are positioned in the same or similar direction as longitudinal axis 6 of press brake frame 4. Bottom pressing part 16 is fixed to the frame and top pressing part 14 is operatively connected to lever 18. Lever 18 is positioned such that the plane in which it transfers forces is substantially parallel to the plane of longitudinal sides 8. Lever 18 is pivotably connected to press brake frame 4 via pivot connection 26, in this example embodied as a hinge. Near pivot connection 26 lever 18 has a substantially perpendicular angle, such that a compact press brake 2 is obtained. Longitudinal axis 6 stretches out along the contact line between top pressing part 14 and bottom pressing part 16 when lever 18 is in press position 46.
[0118] Height L of press brake 2 in this example is 2.5 meters. Longitudinal sides 8 further comprise access openings 20, such that a plate to be bent can be slid out of press brake 2 in a sideways direction. Further attached to press brake frame 4 near longitudinal side 8 is electric motor 22. Electric motor 22 is operatively connected to lever 18 via pulley assembly 24. Pulley assembly 24 is also positioned such that it transfers forces in a substantially parallel plane of longitudinal sides 8. Alternatively, electric motor 22 is positioned in a plane substantially perpendicular to the plane of longitudinal sides 8.
[0119] Attached to press brake frame 4 (FIG. 2A) on longitudinal side 8 is electric motor 22 and pulley assembly 24. Pulley assembly 24 comprises in this example frame pulleys 30 attached to press brake frame 4, lever pulleys 32 attached to pulley carrier element 34 and connecting element 27, in this example a belt. Frame pulleys 30 and lever pulleys 32 are both placed in a line. Pulley carrier element 34 is operatively connected to first end 38 of lever 18. Lever 18 in this example further comprises support bar 19 to provide extra stability to lever 18. Connecting element 27 has been connected to electric motor 22 at motor end 28 of connecting element 27. At frame end 36 connecting element 27 has been attached to press brake frame 4. Connecting element 27 is alternately placed around frame pulleys 30 and lever pulleys 32, thereby providing an operative connection between electric motor 22 and lever 18 via pulley assembly 24 and pulley carrier element 34. At second end 40 lever 18 is connected via press connection 42 to top pressing part 14. Press connection 42 is operatively connected to second end 40 of lever 18 with first hinge connection 45 and operatively connected to top pressing part 14 with second hinge connection 43. Further shown is bottom pressing part 16. Lever 18 is in release position 44.
[0120] In release position 44 (FIG. 2A) lever pulleys 32 are positioned substantially away from frame pulleys 30. In release position 44 top pressing part 14 is therefore positioned at distance D from bottom pressing part 16. This provides the ability to position for example a steel plate on bottom pressing part 16.
[0121] Lever 18 is positioned in press position 46 (FIG. 2B). In press position 46 of lever 18 top pressing part 14 is substantially pressed against bottom pressing part 16. In press position 46 electric motor 22 has pulled in connecting element 27 such that lever pulleys 32 have been brought towards frame pulleys 30. By pulling lever pulleys 32 towards frame pulleys 30 first end 38 of lever 18 is pulled towards frame pulleys 30, as first end 38 is operatively connected to lever pulleys 32 via pulley carrier element 34. Through pivot connection 26 and press connection 42 the movement of first end 38 of lever 18 is transferred to a substantially linear downwards movement of top pressing part 14. When for example a steel plate is placed on bottom pressing part 16, the top pressing part 14 will bend the steel plate such that it obtains a desired angle. Further provided in press brake frame 4 is guide 15 for guiding top pressing part 14 in a substantial linear downwards movement to bottom pressing part 16.
[0122] Press brake 102 (FIG. 3) comprises electric motor 122 attached to press brake frame 104 and operatively connected via connecting element 127 to lever 118 at first end 138 of lever 118. Lever 118 is pivotably connected to press brake frame 104 and at second end 140 of lever 118 operatively connected with top pressing part 114 via press connection 142. Press brake 102 further comprises return element 148, in this example an actuator, that is connected to second end 140 of lever 118. By providing return element 148 lever 118 will automatically return to release position 144 when it is has been brought in press position 46. Return element 148 could also be embodied as a spring element.
[0123] Press brake 202 (FIG. 4) comprises press brake frame 204 and pressing element 212. Pressing element 212 comprises top pressing part 214 and bottom pressing part 216. Top pressing part 214 and bottom pressing part 216 can be easily removed sideways through access opening 220. This provides the ability to easily replace one or more parts from pressing element 212.
[0124] Press brake 302 (FIG. 5) also comprises press brake frame 304 and top pressing part 314 and bottom pressing part 316. In this alternative embodiment according to the invention motor 322 is placed substantially closer to the ground on press brake frame 304. Furthermore, frame pulleys 330 are attached to the frame and are connected via connecting element 327 to lever pulleys 332 which are attached to first end 338 of lever 318. Lever 318 pivots around pivot connection 326. Second end 340 of lever 318 is via first hinge connection 345 to press connection 342. Because press connection 342 is connected via second hinge connection 343 to top pressing part 314, by use of motor 322 first end 338 of lever 318 can be brought closer to frame pulleys 330, thereby moving top pressing part 314 down to bottom pressing element 316. Furthermore shown in FIG. 5A is load or weight 350 that is pivotely connected to press brake frame 304 by load pivot connection 352. At load end 354 load 350 is connected with load connecting element 356, via first load pulley 358 and second load pulley 360 to second end 340 of lever 318. This achieves that by a movement of lever 318 from release position 344 (shown here) to press position 46, load end 354 is moved upwards in direction D towards return element 348, which in this embodiment is spring 348. As such, load 350, which in this example is counterweight 350, forms a counterweight for the top pressing part. By moving load end 354 upwards, return element 348 is compressed, thereby providing the counterforce to move press brake 302 back from press position 346 to release position 344. The advantage of using load 350 is that it counters the weight of top pressing part 314, which achieves that the size of return element 348 can be reduced. Therefore, a more compact design of press brake 302 is obtained. Additionally or alternatively, press brake 302 is able to move faster from press position 346 to release position 344.
[0125] In an embodiment according to the invention lever 18 is in release position 44. Electric motor 22 pulls in connecting element 27 which is alternately placed around frame pulleys 30 and lever pulleys 32. Because connecting element 27 is connected to press brake frame 4 at frame end 36, the pulling in of connecting element 27 by electric motor 22 causes lever pulleys 32 to move towards frame pulleys 30, because frame pulleys 30 are fixed on press brake frame 4. The movement of the lever pulleys causes first end 38 of lever 18 to move towards frame pulleys 30, because first end 38 is operatively connected to lever pulleys 32 via pulley carrier element 34. This moves lever 18 from release position 44 to press position 46. Through pivot connection 26 lever 18 transfers the movement of first end 38 to second end 40 of lever 18. Second end 18 transfers the movement via press connection 46 to top pressing part 14, causing top pressing part 14 to make a substantially linear downwards movement towards bottom pressing part 16, hereby bending a plate to be bend and that is placed on bottom pressing part 16. When lever 18 is in press position 46, return element 148 provides a force on second end 40 of lever 18 such that lever 18 returns to its release position 44. The plate can be removed from press brake and a new plate can be provided in the opening between the pressing parts. Then a new pressing cycle of going from release position 44 to press position 46 could be started.
[0126] Front press brake 402 (FIG. 6A) comprises front press brake frame 404. On front press brake frame 404 front frame pulleys 472 are attached. In holes 474 provided in an upper part of top pressing part 414 pressing pulleys 470 are attached. In this embodiment pressing pulleys 470 and front frame pulleys 472 are perpendicular to the longitudinal axis 406 of front press brake 402. These pressing pulleys 470 are substantially provided inside top pressing part 414 and thus are at least partially positioned therein. Alternately placed around pressing pulleys 470 and front frame pulleys 472 is front connecting element 476, which can for example be a band, a chain, a belt or a string. A first end 480 front connecting element 476 is connected to front motor 478, wherein front motor 478 is attached to front press brake frame 404. At second end 482 front connecting element 476 is connected to frame 404. Front press brake 404 in FIG. 6A is shown in its release position 444. When front motor 478 is activated and shortens front connecting element 476, front press brake 402 is brought in its press position 446 (FIG. 6B). By shortening front connecting element 476 pressing pulleys 470 attached on top pressing part 414 is brought towards front frame pulleys 472, thereby bringing top pressing part 414 towards bottom pressing part 416.
[0127] FIG. 7 is a top schematic top view of front press brake 402. Herein shown is top pressing part 414, wherein holes 474 are provided such that pressing pulleys 470 can be attached substantially inside top pressing part 414. Between and below pressing pulleys 470 front frame pulleys 472 are attached on front press brake frame 404 and front connecting element 476 is alternately placed around a pressing pulley 470 and a front frame pulley 472. Pressing pulleys 470 and front frame pulleys 472 are provided at an angle α relative to plane P being perpendicular to longitudinal axis 406 of front press brake 402, such that a compact design of the pulley assembly is achieved. It is noted that front frame pulleys 472 are therewith also at an angle with longitudinal axis 406, which angle is related to angle α in that the angle with longitudinal axis 406 is 90° - α.
[0128] It is explicitly noted that a design shown in FIGS. 6A-B and FIG. 7 can be used as a stand alone drive of a press brake. Furthermore, this design can also be applied on a press brake according to the FIGS. 1 - 5. However, the application of the design of FIGS. 6A-B and FIG. 7 is not limited thereto, as it could also be used as an extra drive for any of the prior art press brakes. For example, it could be applied to a press brake making use of a hydraulic drive or with a spindle configuration.
[0129] In FIGS. 8A-B an alternative front press brake 402 is shown. Herein are front frame pulleys 472 provided in holes 484, which have substantially a vertical size of the path length which top pressing part 414 makes when moving from the release position to the press position. Having front frame pulleys 472 provided in holes 484 assures that front frame pulleys 472 are positioned substantially in the same vertical plane as pressing pulleys 470. This has the advantage that an effective and compact front press brake 402 is obtained, as the force exerted on front connecting element 476 is substantially in the same direction as the direction of front connecting element 476. Attached to support frame 486 (FIG. 8B) are front frame pulleys 472, wherein support frame 486 is provided in holes 484.
[0130] In FIGS. 9A-9B another example of press break 502 according to the invention is shown. Press brake 502 also comprises press brake frame 504 wherein top pressing part 514 and bottom pressing part 516 are provided. In the illustrated embodiment motor 522 is placed substantially closer to the ground on press brake frame 504 similar to the embodiment of FIG. 5. Furthermore, frame pulleys 530 are attached to the frame and are connected via connecting element 527 to lever pulleys 532 which are attached to first end 538 of lever 518. Lever 518 pivots around pivot connection 526. Second end 540 of lever 518 is via first hinge connection 545 connected to press connection 542. Because press connection 542 is connected via second hinge connection 543 to top pressing part 514, by use of motor 522 first end 538 of lever 518 can be brought closer to frame pulleys 530, thereby moving top pressing part 514 down to bottom pressing element 516.
[0131] Furthermore shown in FIG. 9A is return element 548, in this example embodied as a spring element. Return element 548 has a first end 588 that is hingeably connected to frame 504. Second end 590 of return element 548 is hingably connected to two support hinge elements 592 and 594. Support hinge element 592 is hingably connected to lever 518 through connection 593, while support hinge element 594 is hingably connected to press brake frame 504 through connection 595. Return element 548 and support hinge elements 592 and 594 are positioned in (an inverse) Y-shaped configuration, wherein support hinge elements 592 and 594 are the arms of the Y-shape. As second end 590 of return element 548 is positioned above connections 593 and 595, return element 548 will contract when lever 518 is brought from the release position to the press position. In the (unlikely) situation that connecting element 527 breaks, configuration lever 518 will automatically return to its release position, thereby further increasing the safety of press break 502. Preferably, return element 548 is positioned such that the force applied on connecting element 527 is substantially constant.
[0132] Motor 522 comprises high-speed motor 535 and low speed motor 537. High-speed motor 535 is in this example provided on the outer side 523 of press break frame 504. High-speed motor 535 is operatively connected to shaft 525 (schematically shown in FIG. 9b) on which connecting element 527 is attached (not shown). On the inner side 529 of press break frame 504 low-speed motor 537 is attached. High-speed motor 535 and low-speed motor 537 are connected with each other through a magnetic coupling 531 and one-way bearing 533 as well as shaft 525. When lever 518 is in its release position, high-speed motor 535 first realizes a fast downward movement of top pressing part 514. High-speed motor 535 and low-speed motor 537 are in this stage coupled through magnetic coupling 531. After high-speed motor 535 slows down, low-speed motor 537 takes over the drive of the downward movement of top pressing part 514. Due to the one-way bearing provided between shaft 525 and low-speed motor 537, the overtake from high-speed motor 535 to low-speed motor 537 is flawless, which means the transition occurs stop or sudden change in speed. Low-speed motor 537 then drives top pressing part 514 with enough force to bend metal sheets that are provided through opening 520. For moving top pressing part 514 upwards and thus moving lever 518 to its release position, magnetic coupling 531 is uncoupled such that high-speed motor 535 moves top pressing part 514 upwards with a high speed. Due to this configuration of the drive a fast and sufficiently powerful press brake is obtained.
[0133] The present invention is by no means limited to the above described preferred embodiments thereof. The rights sought are defined by the following claims within the scope of which many modifications can be envisaged.
