Abstract
The invention relates to a clamping system for a press brake, the clamping system comprising an elongate beam comprising a receiving space for receiving a part of a bending tool, a clamping element, the clamping element being movable between a first position, in which it may engage on the bending tool for clamping it in the receiving space, and a second position for releasing the bending tool, and an actuating member for displacing the clamping element, the actuating member being movable between an active position, in which it urges the clamping element towards the first position, and an inactive position in which it allows the clamping element to move to the second position. The clamping system is characterized by a first biasing member acting on the actuating member for biasing the actuating member towards its inactive position. The invention also relates to a press brake comprising such a clamping system.
Claims
1-20. (canceled)
21. A clamping system for a press brake, the clamping system comprising: an elongate beam comprising a receiving space for receiving a part of a bending tool; a clamping element, the clamping element being movable between a first position in which it may engage on the bending tool for clamping it in the receiving space, and a second position for releasing the bending tool; an actuating member for displacing the clamping element, the actuating member being movable between an active position in which it urges the clamping element towards the first position, and an inactive position in which it allows the clamping element to move to the second position, and a first biasing member acting on the actuating member for biasing the actuating member towards its inactive position.
22. The clamping system according claim 21, the clamping system having a pressing direction, wherein the first biasing member is arranged substantially parallel to the pressing direction.
23. The clamping system according to claim 21, wherein the actuating member is movable in a direction substantially parallel to the pressing direction between its active and inactive position.
24. The clamping system according to claim 21, wherein the first biasing member extends at least partly in a first cavity in the actuating member, or extends at least partly around the actuating member.
25. The clamping system according to claim 21, wherein the first biasing member is arranged on a side of the actuating member proximate the clamping element.
26. The clamping system according to claim 21, further comprising a first stop for limiting movement of the actuating member beyond its active position.
27. The clamping system according to claim 21, wherein the clamping element is movable in a direction substantially perpendicular to the pressing direction and to a longitudinal direction of the elongate beam between its first and second position.
28. The clamping system according to claim 21, further comprising a second biasing member acting on the clamping element for biasing the clamping element towards the second position.
29. The clamping system according to claim 21, wherein the second biasing member is arranged substantially perpendicular to the pressing direction and to a longitudinal direction of the elongate beam.
30. The clamping system according to claim 27, wherein the second biasing member extends at least partly in a second cavity in the elongate beam.
31. The clamping system according to claim 28, wherein the clamping element comprises a protrusion for engaging the second biasing member.
32. The clamping system according to claim 21, further comprising a second stop for limiting movement of the clamping element beyond its second position.
33. The clamping system according to claim 32, wherein the second stop engages the protrusion in the second position.
34. The clamping system according to claim 21, wherein the clamping element comprises a recess for receiving at least part of the first biasing member.
35. The clamping system according to claim 21, wherein the first or the second biasing member comprises a compression spring.
36. The clamping system according to claim 21, wherein at least one of the clamping element and the actuating member is provided with an engagement surface for engaging the other of the clamping element and the actuating member, and wherein at least a part of the engagement surface is inclined with respect to a direction of movement of the respective element.
37. The clamping system according to claim 21, wherein the actuating member comprises a piston of a hydraulic or pneumatic actuation system.
38. The clamping system according to claim 21, wherein the actuating member extends at least partly in a third cavity in the elongate beam.
39. The clamping system according to claim 21, wherein the third cavity is integrally formed in the elongate beam.
40. A press brake comprising at least one said clamping system according to claim 21.
Description
[0070] The invention will be further elucidated with reference to the attached drawings, in which:
[0071] FIGS. 1A and 1B show schematically a cross-sectional side view and a front view respectively of a press brake with an exchangeable clamping system;
[0072] FIGS. 2A and 2B show schematically a cross-sectional side view and a front view respectively of a press brake with an integrated clamping system;
[0073] FIGS. 3A-3C show schematically a clamping system and a tool in perspective and transversal cross-sectional views;
[0074] FIGS. 4A and 4B show schematically a perspective view and a longitudinal cross-sectional view of an elongate beam of the clamping system of FIGS. 3A-3C;
[0075] FIG. 5 shows schematically a variation on the clamping system of FIGS. 3A-5;
[0076] FIG. 6 shows schematically a variation on the clamping system of FIGS. 3A-5;
[0077] FIGS. 7A-7C show schematically another clamping system and a tool in perspective and side views;
[0078] FIG. 8 shows schematically a variation on the clamping system of FIGS. 7A-7C;
[0079] FIG. 9 shows schematically a transversal cross-sectional view of yet another clamping system;
[0080] FIGS. 10A and 10B show schematically a perspective view of an elongate beam of the clamping system of FIG. 9 and of a longitudinal cross-sectional thereof;
[0081] FIGS. 11A-11D show schematically steps in a method of interconnecting cavities in an elongate beam; and
[0082] FIG. 12 shows schematically a variation on the clamping system of FIG. 5.
[0083] FIGS. 3B, 3C, 5, 6, 7B, 7C, 8, 9 and 12 show views from the same side as that of FIGS. 1A and 2A.
[0084] In the figures, like elements are referred to with like reference numerals. Corresponding elements of different embodiments are referred to with reference numerals increased by a multiple of one hundred (100).
[0085] FIGS. 1A and 1B show a press brake 1 placed on a ground surface G. The press brake 1 includes a top beam 2 and a bottom beam 3. The top beam 2 is provided with a top clamping system 4. The clamping system releasably holds a top tool 5. The bottom beam 3 is provided with a bottom clamping system 6, which releasably holds a bottom tool 7. The top beam 2 and the bottom beam 3 are moveable towards and away from each other by means of hydraulic systems 8. Accordingly, the top and bottom tools 5, 7 are also moveable towards and away from each other. To bend sheet metal, the sheet is inserted between the tools 5, 7 which are then moved towards each other. The top tool 5 then forces the sheet metal into the bottom tool 7 in order to deform the sheet metal by bending. After bending, the tools 5, 7 are moved away from each other by moving the top beam 2 via the hydraulic systems 8. The clamping systems 4, 6 are releasably attached to the top and bottom beam 2, 3 respectively via a suitable locking system. Accordingly, the clamping systems 4, 6 can be exchanged for clamping systems suitable for other tools, or the clamping systems 4, 6 can be taken out for servicing them.
[0086] FIGS. 2A and 2B show a similar press brake 101, which will be described here only in as far as it differs from the press brake 1 in of FIGS. 1A and 1B. The clamping systems 104, 106 of the press brake in FIGS. 2A and 2B are integrated with the top and bottom beams 102, 103 respectively. As such, the clamping systems 104, 106 are not exchangeable. The tools 105, 107 held by the clamping systems 104, 106 are exchangeable.
[0087] FIGS. 3A-3C show a clamping system 204, that could for instance be used in a press brake shown in FIGS. 1A-2B. The clamping system 204 has as a main body an elongate beam 209. A receiving space 210 in the elongate beam 209 accommodates a part of tool 205. The clamping system further comprises an actuating member 211 and a clamping element 212. The actuating member 211 is moveable upwards, to an inactive position, and downwards, to an active position. The clamping element 212 is moveable between a first position, in which it extends into the receiving space 210 for engaging on the tool 205, and a second position, in which it is retracted away from the receiving space 210 to release the tool. The clamping element 212 has an engaging tip 213 which cooperates with an engaging recess 214 in the tool 205 in order to clamp the tool 205 securely in the receiving space 210. In the active position, the actuating member 211 engages the clamping element 212 and urges it towards the receiving space 210. FIG. 3B shows the actuating member 211 in the active position, so that the tool 205 is clamped in the receiving space 210 by the clamping element 212. The actuating member 211 has for the purpose of engaging the clamping element 212 an inclined engaging surface 215 which engages on a similarly cooperating inclined engaging surface 216 of the clamping element 212. Accordingly, when the actuating member 211 moves to its active position, i.e. downwards in the figures, the engaging surface 215 of the actuating member 211 engages the engaging surface 216 of the clamping element 212 and, due to its inclination, urges the clamping element 212 to its first position, i.e. leftwards in the figures. FIG. 3C shows the actuating member 211 in its inactive position, with the clamping element 212 retracted away from the receiving space 210 to its second position, thereby releasing the tool 205.
[0088] The actuating member 211 is movably arranged in a pressure chamber 217. The pressure chamber 217 is made directly into the elongate beam 209, which also has the receiving space 210. The pressure chamber 217 is thus integrally formed in the elongate beam 209. The actuating member 211 is provided with sealing means 218 which seal the actuating member 211 to the wall of the pressure chamber 217, i.e. to the inside of the elongate beam 209. As such, the actuating member 211 works as a piston moveable in the pressure chamber 217, which accordingly works as a cylinder. Accordingly, the actuating member 211 can be pushed towards its active position by introducing a fluid in the pressure chamber 217. The pressure chamber 217 of this clamping system 204 is adapted for receiving a hydraulic liquid as pressure fluid, in order to move the actuating member 211.
[0089] The clamping system 204 is provided with a first biasing member in the form of a first compression spring 219. The first compression spring acts on the actuating member 211. The first compression spring 219 is arranged vertically, which corresponds to the pressing direction P defined by the clamping system 204, and the depth direction of the receiving space 210. The first compression spring 219 biases the actuating member 211 upwards, i.e. towards its inactive position. Accordingly, when pressure of the hydraulic liquid in the pressure chamber 217 is stopped, the first compression spring 219 pushes the actuating member 211 upwards further into the pressure chamber 217 thereby forcing the hydraulic fluid to flow out of the pressure chamber 217. The first compression spring 219 supports on a support 220 provided by a cover 221. The cover 221 covers clamping element 212, the actuating member 211 and the pressure chamber 217. The cover 221 also forms a first stop 222 for the actuating member 211 to hit, in order to limit movement of the actuating member 211 beyond the active position. The actuating member 211 has a movement limiter 223 for engaging the first stop 222. The first compression spring 219 extends partly in a first cavity 224 in the actuating member 211. A second biasing member is provided in the form of a second compression spring 225. The second compression spring 225 is arranged horizontally, i.e. perpendicular to the pressing direction P and a longitudinal direction of the elongate beam 204. The second compression spring 225 acts on the clamping element 212 via a protrusion 226 thereof. the first compression spring 225 extends partly in a second cavity 227 in the elongate beam. The cover 221 also provides a second stop 228 for engaging the protrusion 226 of the clamping element 212, to limit the movement of the clamping element 212 beyond its second position.
[0090] FIGS. 4A and 4B show the elongate beam 209 of the clamping system 204 described above in more detail. Repeating elements in FIGS. 4A and 4B have not been provided with reference numerals in each instance. As can be seen, multiple pressure chambers 217 are lined up in the elongate beam 209 in its longitudinal direction L. The pressure chambers 217 are connect to each other, i.e. interconnected, via interconnections consisting of channels 229 extending between side walls 230 of adjacent pressure chambers 217. The pressure chambers 217 have an opening 231 on one end, and are closed on the other end 232. The channels 229 are provided close to said other end 232. One pressure chamber 217 is connected to the external of the elongate beam 209 via a channel 233. It is visible from FIGS. 4A and 4B, that the pressure chambers 217 are arranged in the elongate beam 209 integrally, in the same piece of material comprising the receiving space 210. The pressure chambers 217 are interconnected internally, since the interconnection is made via channels 229 that do not reach the outside of the elongate beam 209.
[0091] FIG. 5 shows a clamping system 304 that differs only from the above described clamping system 204 in that its elongate beam 309 is comprised of two separate components 309-1 and 309-2. The main body 309-1 of the elongate beam can be manufactured separate from the auxiliary body 309-2, and attached to it later. The pressure chamber 317 is formed in the auxiliary body 309-2.
[0092] FIG. 6 shows a clamping system 404 that differs only from the clamping system 204 described in relation to FIGS. 3A-4B in that the pressure chamber 417 is formed within a cylinder 434 which is placed in a cavity 435 in formed integrally the elongate beam 409. It is of course possible to provide the cavity 435 in an auxiliary body as described with respect to FIG. 5, thereby combining the differing features of FIGS. 5 and 6.
[0093] FIGS. 7A-7C show a clamping system 504 that differs only from the clamping system 204 described in relation to FIGS. 3A-4B in the features described below. Firstly, the elongate beam 509-1, 509-2 consists of two separate components 509-1 and 509-2. The main body 509-1 of the elongate beam can be manufactured separate from the auxiliary body 509-2, and attached to it later. The pressure chamber 217 is formed by a pneumatic hose 536 which has a deformable wall. The hose 536 runs in the longitudinal direction L of the elongate beam 509-1, 509-2 through a cavity 535 therein. The hose 536 expands when fluid is pressurized in the pressure chamber 517, and contracts when pressure is released. As the hose 536 expands (see FIG. 7B), it pushes the actuating member 511 to its active position. The first compression spring 519 aids in pushing fluid out of the pressure chamber 517 when pressure therein in lowered, by pushing the actuating member 511 upwards (see FIG. 7C). Moreover, the protrusion 526 of the clamping element 512 is placed on a top side of the clamping element 512 for engaging the second compression spring 525. This leaves free an end surface 537 of the clamping element 512 for engaging the second stop 528. Further, the clamping element 512 is provided with a recess 538 for accommodating the first compression spring 519 when the clamping element 512 is in the second position, i.e. moved towards the right in the figures. No first stop or movement limiter of the actuating member is provided, as was the case in the embodiment of FIGS. 3A-4B. Finally, a protrusion 599 is provided that forms a hook inside the receiving space 510. The protrusion 599 is used to hang the tool 505. For insertion or removal, the tool 505 needs to be moved around the protrusion 599. As such, the receiving space 510 has a relatively large width D as compared to the tool 505 which has a smaller width d. Accordingly, the clamping element 512 has a relatively large stroke for clamping the tool 505.
[0094] FIG. 8 shows a clamping system 604 that differs from the clamping system 504 of FIGS. 7A-7C in that the elongate beam 709 is made of one piece of material. Accordingly, the cavity 635 is formed integrally in that one piece of the elongate beam 609.
[0095] FIG. 9 shows a bottom clamping system 706, that has the features of the clamping system 204 described in relation to FIGS. 2A-3B, apart from a different position of the protrusion 725 of the clamping element 712. The protrusion 726 leaves free an end surface 737 to cooperate with the second stop 728.
[0096] Obviously, the bottom clamping system 706 could be altered by applying any of the features described above, such as the separate elongate beam and/or the separate cylinder in the cavity and/or the hose as a pressure chamber.
[0097] FIGS. 10A and 10B show the elongate beam 709 in more detail. Its features are similar to those described in relation to FIGS. 3A and 3B.
[0098] FIGS. 11A-11D show how cavities 817 in an elongate beam 809 can be interconnected internally. First, an elongate beam 809 is provided (see FIG. 11A) with cavities 817 therein. The cavities are not yet interconnected. Then (see FIG. 11B) a milling tool is inserted through the opening 831 of one cavity 817. The milling tool has a narrow stem 850 and a larger head 851. The milling tool is inserted in an insertion direction I. Then (see FIG. 11C) the milling tool is moved in a machining direction M towards another cavity 817, thereby eroding material of the elongate beam 809 and creating a channel 829 between the two cavities. As shown in FIG. 11D, the cavities 817 are thereafter interconnected.
[0099] FIG. 12 shows yet another clamping system 904, that differs from the clamping system 304 described in relation to FIG. 5 in that the first compression spring 919 is provided around the actuating member 911 instead of in a cavity therein. No first stop has been shown in FIG. 12. The first compression spring of other clamping systems shown in this application could also be provided around their respective actuating members.
[0100] Although the invention has been described hereabove with reference to a number of specific examples and embodiments, the invention is not limited thereto. Instead, the invention also covers the subject matter defined by the claims, which now follow.
