Clamping system for a press brake having a first biasing means acting on an actuating member and press brake equipped with the clamping system

Abstract

The present invention relates to a clamping system for a press brake, the clamping system comprising: The present invention relates to a press brake including an elongated beam having a receiving space for receiving a portion of a bending tool, a clamping element movable between a first position (where the clamping element can engage the bending tool to clamp 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 actuating position that biases the clamping element toward the first position and an inactive position that 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 to bias the actuating member toward its inactive position. The present invention also relates to a press brake including such a clamping system.

Description

[Technical Field]

[0001] The present invention relates to a clamping system for a press brake, comprising an elongated beam including a receiving space for receiving a portion of a bending tool, a clamping element, and an actuating member for displacing the clamping element, the clamping element being movable between a first position (a position in which it can engage the bending tool to clamp it in the receiving space) and a second position for releasing the bending tool, the actuating member being movable between an actuating position in which it biases the clamping element towards the first position and a non-actuating position in which it can move the clamping element to the second position.

[0002] A press brake is a machine used to bend or fold sheet material, such as sheet metal. To this end, a press brake includes a bottom beam and a top beam that are movable relative to one another. Both the top and bottom beams hold tools, between which a workpiece is presented for bending. Typically, the bending tools of a press brake are interchangeable to produce different types of bends or folds and to allow for tool maintenance. Therefore, press brakes are equipped with a clamping system that can releasably clamp the tools. The clamping system can be provided on the top beam, the bottom beam, or both of the press brakes.

[0003] There are two types of press brakes. The first type has a clamping system that is an integral part of either the top or bottom beam. The other of the top or bottom beam may or may not have an additional clamping system. The integrated clamping system cannot be removed from the top or bottom beam and therefore cannot be replaced with another clamping system, but the tooling that the clamping system can hold is replaceable. The second type has an interchangeable clamping system that is connected and fixed to either the top or bottom beam. The other of the top or bottom beam may or may not have an additional clamping system. The interchangeable clamping system allows for tooling to be replaced, but can also be removed from the top or bottom beam, for example, for maintenance or to replace with another clamping system. This is a technique used to make one press brake suitable for different tooling types that may require different clamping systems and / or to service the clamping system.

[0004] Further clamping systems exist that can be clamped by other clamping systems as if they were tools, for example, by a system for a first type of tool, but can itself clamp a second type of tool, so that such a clamping system acts as an adapter between clamping systems and tools that would otherwise be incompatible.

[0005] The present invention relates to clamping systems integrated with bottom or top beam press brakes, interchangeable clamping systems, and clamping systems that act as adapters.

[0006] A press brake and its clamping system are known, for example, from the applicant's earlier application WO 2010 / 056110 A1, which describes a clamping device for clamping a tool. The clamping device comprises an actuating member and an engaging member. The actuating member is, for example, hydraulically or pneumatically driven.

[0007] Although the clamping device disclosed in WO 2010 / 056110 A1 worked well and still works today, there is a need for further improvements to the clamping device, particularly with respect to the time required for tool changes, since reducing the time required for tool changes allows for more efficient use of the press brake. Summary of the Invention

[0008] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a clamping system that can operate more efficiently.

[0009] According to the invention, this object is achieved by a clamping system for a press brake according to the preamble, characterized in that a first biasing member acts on the actuating member to bias the actuating member towards its inoperative position.

[0010] Applicant discovered that a relatively large portion of the time required to change tools is consumed by displacing the clamping element toward its second position to release the tool. To move the clamping element toward its second position, for example, if the actuating member is pneumatically or hydraulically driven, it is necessary to stop the pneumatic or hydraulic pressure on the actuating member and allow the pneumatic or hydraulic fluid to flow back, returning the actuating member to its inoperative position. However, it may take 10 seconds or more for the pneumatic or hydraulic fluid to retract sufficiently to release the tool. To facilitate the retraction of the pneumatic or hydraulic fluid, a first biasing member acting on the actuating member is provided. The biasing member biases the actuating member toward its inoperative position, thereby forcing the pneumatic or hydraulic fluid out when the pneumatic or hydraulic pressure is sufficiently released. As a result, the time required to return the actuating member to its inoperative position, thus allowing the tool to be released, can be reduced to, for example, about 1-2 seconds.

[0011] Of course, the first biasing member may be used to perform a similar function when drive means other than pneumatic or hydraulic drive means are used.

[0012] For example, it should be noted that a first biasing member acting on the actuating member, rather than the clamping element, can provide a relatively large space for the first biasing member. In particular, the first biasing member acting on the actuating member can be relatively long and / or relatively wide. Thus, the first biasing member can be relatively large, allowing for a relatively high spring constant in the case of a compression spring, for example, so that the compression spring can provide a relatively large biasing force, which helps to reduce the time required to move the actuating member. The length of the spring can also, or alternatively, allow for a relatively wide range of movement of the actuating member while being biased by the spring.

[0013] The relatively wide range of motion of the actuating member is particularly important when a relatively large stroke of the clamping element is required. Some clamping systems include a protrusion acting as a hanger or hook inside a receiving space, on which a tool can be supported and / or suspended. The receiving space is relatively wide compared to the tool, since the tool requires sufficient space inside the receiving space to manipulate the tool around the protrusion in order to insert or remove it. Such clamping systems require a relatively large stroke of the clamping element, since the clamping element must at least partially traverse the relatively wide receiving space.

[0014] It should be noted that the force exerted by the first biasing member must be overcome to move the actuating member into its actuated position. Thus, the overall force required to clamp the tool is increased by the first biasing member. This can be achieved by selecting an appropriately powerful drive means, such as a hydraulic or pneumatic drive means, to drive the actuating member.

[0015] A first biasing member acting on an actuating member can be understood here as the first biasing member acting initially on the actuating member. Of course, the actuating member can then act, for example, on a clamping element or, for example, on a drive means. It should be understood that, while the clamping element acts on the actuating member, for example, a biasing means acting initially on a clamping element is not understood here as acting on the actuating member. Thus, the first biasing member may act directly on the actuating member.

[0016] The first biasing means may act on any element that moves in the same direction and at the same speed as the actuating member, for example any element that is fixedly connected to the actuating member.

[0017] In one embodiment of the clamping system, the clamping system has a pressing direction and the first biasing member is arranged substantially parallel to the pressing direction. The first biasing member may itself be arranged vertically.

[0018] By arranging the biasing member substantially parallel to the pressing direction, the press brake can be constructed relatively compactly. In particular, the first biasing member can be arranged at least partially along the receiving space. Additionally or alternatively, this embodiment allows the use of a relatively long first biasing member in a relatively small, particularly relatively narrow, elongated beam.

[0019] Providing a compact structure helps reduce the risk of the workpiece colliding with the press brake. For example, if the workpiece is to be bent multiple times, e.g., at different locations, the workpiece may be folded back toward the elongated beam. The elongated beam can then limit the size of the workpiece and / or the amount of bend that can be made in the workpiece before the elongated beam cuts off the workpiece during bending. Therefore, configuring the press brake compactly is important to allow space for as many workpieces as possible, so that the press brake can be used to bend complex shapes and / or relatively large workpieces with many folds.

[0020] The above-mentioned effect can also be achieved in the press brake described in the preamble of claim 1, wherein the press brake defines a pressing direction and the first biasing member is disposed substantially parallel to the pressing direction. Therefore, when the first biasing member is disposed substantially parallel to the pressing direction, it is not necessarily required that the first biasing member act on the operating member.

[0021] The pressing direction is the direction in which the tool clamped by the clamping system moves relative to the other tool to bend the workpiece. The pressing direction may correspond to the depth direction of the receiving space. The pressing direction may be vertical.

[0022] In another embodiment of the clamping system, the actuating member is movable in a direction substantially parallel to the pressing direction between its actuated and inactuated positions.

[0023] If the actuating member is movable substantially parallel to the pressing direction, the drive means for driving the actuating member may be located, for example, towards the top or bottom of the actuating member rather than at the side. Such a clamping system can therefore be constructed relatively compactly. It should be noted that if the elongated beam is a top beam, the drive means may be located towards the top of the actuating member, whereas if the elongated beam is a bottom beam, the drive means may be located towards the bottom of the actuating member.

[0024] In yet another embodiment of the clamping system, the first biasing member extends at least partially into a first cavity in the actuation member or extends at least partially around the actuation member.

[0025] Thus, the first biasing member is disposed partially within or around the actuating member. Thus, the first biasing member can be relatively long without requiring a relatively large storage space extending beyond the first biasing member. A relatively long first biasing member is particularly useful for providing a biasing force over a relatively long path of travel.

[0026] It should be noted that a first biasing member that extends at least partially around the actuating member should be interpreted as surrounding the actuating member over at least a portion of the length of the first biasing member. Thus, the first biasing member at least partially surrounds a portion of the actuating member. A first biasing member that is merely disposed proximate to the actuating member is not to be understood as constituting a first biasing member that extends around the actuating member.

[0027] Throughout this application, the terms "first," "second," "third," etc., indicating numbers are used only to distinguish one from another. Thus, a cavity in an actuating member referred to as a "first cavity" does not imply the presence of more cavities in the actuating member. Furthermore, a second cavity is not necessarily a cavity in the actuating member.

[0028] In yet another embodiment of the clamping system, the first biasing member is disposed on a side of the actuating member adjacent the clamping element.

[0029] Locating the first biasing member proximate to the clamping element allows the first biasing member to urge the biasing member back to its inactivated position, which in turn leaves the distal end of the actuating member free for the drive means to engage the actuating member.

[0030] In yet another embodiment of the clamping system, the clamping system includes a first stop for limiting movement of the actuating member beyond its actuated position.

[0031] Limiting the travel of the actuating member can prevent damage to the first biasing member, for example, by over-compressing it, and thus the first stop can be separate from the engagement surface against which the first biasing member rests.

[0032] In yet another embodiment of the clamping system, the clamping element is movable between its first and second positions in a direction substantially perpendicular to the pushing direction and the longitudinal direction of the elongate beam. The clamping element may also be movable horizontally.

[0033] This allows the clamping element to be retracted from the receiving space to release the tool towards the side of the elongate beam.

[0034] In yet another embodiment of the clamping system, the clamping system includes a second biasing member acting on the clamping element to bias the clamping element towards the second position.

[0035] Biasing the clamping element to the second position ensures that the clamping element moves to the second position when the actuating member is moved to its inactivated position, which assists in releasing the tool. Additionally, the second biasing member may assist the first biasing member in pushing back the actuating member by providing a force through the clamping element that directs the biasing member toward its inactivated position. Thus, the second biasing member helps achieve the advantages described with respect to the first biasing member.

[0036] When the first and second biasing means are used together, a relatively large overall biasing force may be generated, particularly in a limited space, and therefore the clamping system of this embodiment can be configured relatively compactly.

[0037] It should be noted that the first and / or second biasing members may comprise resiliently deformable members that deform in response to movement of the actuating member or clamping member, respectively, and provide resilient forces in opposite directions to bias the actuating member or clamping member, respectively. Other suitable biasing means, such as gas-operated springs, may alternatively be used.

[0038] In yet another embodiment of the clamping system, the second biasing member is disposed substantially perpendicular to the pressing direction and the longitudinal direction of the elongate beam. The second biasing member may be disposed horizontally.

[0039] Positioning the second biasing member in this direction helps to enable a compact configuration.

[0040] In yet another embodiment of the clamping system, the second biasing member extends at least partially into a second cavity in the elongate beam.

[0041] In this embodiment, the second biasing member may be relatively long, but the elongated beam may be relatively compact. Therefore, the second biasing member may have a relatively wide range of motion. Furthermore, if the second biasing member comprises a compression spring, disposing the spring at least partially within the second cavity allows for the selection of an appropriate spring constant.

[0042] It should be noted that the cavity in the elongate beam is referred to as the second cavity only to distinguish it from the cavity in the first biasing means, which is referred to as the first cavity. There need not be additional cavities in the elongate beam, and the first and second cavities need not have anything in common other than the fact that they are both cavities.

[0043] In yet another embodiment of the clamping system, the clamping element includes a protrusion for engaging the second biasing member.

[0044] By providing a protrusion for engagement with the second biasing member, it is possible to position the second biasing member adjacent to the clamping element, which allows the clamping system to be constructed in a particularly compact manner.

[0045] The second biasing member may extend substantially parallel to the clamping element.

[0046] In yet another embodiment of the clamping system, the clamping system further comprises a second stop for limiting movement of the clamping element beyond the second position.

[0047] Limiting movement of the clamping element beyond the second position helps to prevent damage to the second biasing means, for example, by preventing over-traction or over-compression of the second biasing means. Additionally or alternatively, the second stop can help to increase the reliability of the clamping system by preventing jams that may occur when the clamping element moves beyond the second position.

[0048] In yet another embodiment of the clamping system, a second stop engages the protrusion at the second position.

[0049] By using a protrusion to engage the second stop, it is possible to position the second stop laterally relative to the clamping element, for example, to position the actuating member in a space corresponding to the longitudinal extension of the clamping element.

[0050] In yet another embodiment of the clamping system, the clamping element includes a recess for receiving at least a portion of the first biasing member.

[0051] The recess forms a notch into which the first biasing member can be at least partially received. As a result, the first biasing member and the clamping element can be positioned relatively close to each other. In particular, in the second position of the clamping element, the surface of the clamping element for engaging a tool can be relatively close to the first biasing member. This reduces the space occupied by the clamping element and the first biasing member together, allowing for a relatively compact structure of the elongated beam.

[0052] When the first biasing member is received in the recess, the clamping element can extend at least partially around the first biasing member, i.e., the clamping element can partially surround the first biasing member. The clamping element extending at least partially around the first biasing member can allow the actuating member to engage a portion (e.g., a protrusion) of the clamping element that defines the recess and protrudes toward or beyond the first biasing member in the clamping element's second position. The protrusion helps to provide a relatively large area with which the actuating member can engage, while the recess allows for a compact design of the protrusion and first biasing element.

[0053] The recess may further act as a guide for the first biasing member.

[0054] In yet another embodiment of the clamping system, the first or second biasing member comprises a compression spring. Accordingly, the recess may correspond to the cylindrical shape of the biasing member.

[0055] Applicant has found that the use of a compression spring allows for reliable performance of the clamping system. Furthermore, the compression spring can provide sufficient biasing force without requiring external actuation.

[0056] It should be noted that when a compression spring is used, the first and second cavities provide the additional advantage of allowing a larger compression spring to be used, thereby allowing a wider selection of compression springs. When a compression spring is used, the first and second stops can help prevent damage or wear to the compression spring.

[0057] In yet another embodiment of the clamping system, at least one of the clamping element and the actuating member comprises an engagement surface for engaging the other of the clamping element and the actuating member, at least a portion of the engagement surface being inclined relative to the direction of movement of the respective element.

[0058] Such inclined engagement surfaces provide transmission between the clamping element and the actuating member, allowing the clamping element and the actuating member to be positioned at an angle relative to each other, thereby allowing a relatively compact construction of the clamping system.

[0059] The angle at which the engagement surface is inclined can be selected to select an appropriate transmission ratio between the movement of the actuating member and the clamping element. This angle may vary smoothly or abruptly across the engagement surface to provide different transmission ratios at different positions on the engagement surface. In particular, the engagement surface may be curved or may consist of two sections with different inclination angles.

[0060] In yet another embodiment of the clamping system, the actuating member comprises a piston of a hydraulic or pneumatic actuation system.

[0061] The first biasing member can therefore act directly on said piston, which allows a very direct force transmission from the first biasing member to the respective hydraulic or pneumatic fluid.

[0062] In yet another embodiment of the clamping system, the actuation member extends at least partially into a third cavity in the elongate beam.

[0063] By providing a cavity in the elongated beam for the actuating member, the clamping system can be constructed compactly.

[0064] The cavity in the elongate beam is referred to as the third cavity only to distinguish it from the first and second cavities. Thus, the use of the term "third" does not imply or exclude the presence of more than one cavity in the elongate beam. The first cavity and / or the second cavity and / or the third cavity need not have anything in common other than being cavities in their respective parts.

[0065] In yet another embodiment of the clamping system, the third cavity is integrally formed within the elongate beam.

[0066] Integral formation of the cavity within the elongated beam prevents the need for a separate part for the cavity that must be secured and sealed to the elongated beam. Because such a seal could present a risk of leakage or failure, the integrally formed third cavity reduces the likelihood of leakage or failure. Furthermore, separate parts introduce additional error when positioning the press brake parts relative to one another, particularly when positioning the cavity relative to the clamping elements.

[0067] Additionally or alternatively, integrally forming the cavity within the elongate beam may make the clamping system more cost-effective to produce.

[0068] The invention also relates to a press brake comprising at least one clamping system as described above, which may have any of the above-described features, alone or in any suitable combination.

[0069] The clamping system can be located in the top beam of the press brake, in the bottom beam of the press brake, or both. The clamping system can be a separate, replaceable clamping system, often referred to in the art as a clamping beam, or it can be an integral part of the press brake. [Brief explanation of the drawings]

[0070] The invention will now be further described with reference to the accompanying drawings. [Figure 1A] FIG. 1A shows a schematic cross-sectional side view of a press brake with an interchangeable clamping system. [Figure 1B] FIG. 1B shows a schematic front view of a press brake with an interchangeable clamping system. [Figure 2A] FIG. 2A shows a schematic cross-sectional side view of a press brake with an integrated clamping system. [Figure 2B]FIG. 2B shows a schematic front view of a press brake with an integrated clamping system. [Figure 3A] FIG. 3A shows a schematic perspective cross-sectional view of the clamping system and tool. [Figure 3B] FIG. 3B shows a schematic cross-sectional view of the clamping system and tool. [Figure 3C] FIG. 3C shows a schematic cross-sectional view of the clamping system and tool. [Figure 4A] FIG. 4A shows a schematic perspective view of an elongated beam of the clamping system of FIGS. 3A-3C. [Figure 4B] FIG. 4B shows a schematic longitudinal cross-sectional view of an elongated beam of the clamping system of FIGS. 3A-3C. [Figure 5] FIG. 5 shows a schematic diagram of a variation of the clamping system of FIGS. 3A-5. [Figure 6] FIG. 6 shows a schematic diagram of a variation of the clamping system of FIGS. 3A-5. [Figure 7A] FIG. 7A shows a schematic perspective view of another clamping system and tool. [Figure 7B] FIG. 7B shows a schematic side view of another clamping system and tool. [Figure 7C] FIG. 7C shows a schematic side view of another clamping system and tool. [Figure 8] FIG. 8 shows a schematic diagram of a variation of the clamping system of FIGS. 7A-7C. [Figure 9] FIG. 9 shows a schematic cross-sectional view of yet another clamping system. [Figure 10A] FIG. 10A shows a schematic perspective view of an elongated beam of the clamping system of FIG. [Figure 10B] FIG. 10B shows a schematic longitudinal section of an elongated beam of the clamping system of FIG. [Figure 11A] FIG. 11A shows general steps in a method for interconnecting cavities in an elongated beam. [Figure 11B] FIG. 11B shows schematic steps in a method for interconnecting cavities in an elongated beam. [Figure 11C] FIG. 11C shows schematic steps in a method for interconnecting cavities in an elongated beam. [Figure 11D] FIG. 11D shows schematic steps in a method for interconnecting cavities in an elongated beam. [Figure 12] FIG. 12 shows a schematic diagram of a modification of the clamping system of FIG. Detailed Description

[0071] 3B, 3C, 5, 6, 7B, 7C, 8, 9 and 12 show views from the same side as FIGS. 1A and 2A.

[0072] In the figures, like elements are numbered likewise, and corresponding elements in different embodiments are referenced by reference numbers incremented by multiples of one hundred (100).

[0073] 1A and 1B show press brake 1 installed on ground surface G. Press brake 1 includes top beam 2 and bottom beam 3. Top beam 2 is provided with top clamping system 4, which removably holds top tool 5. Bottom beam 3 is provided with bottom clamping system 6, which removably holds bottom tool 7. Top beam 2 and bottom beam 3 are movable toward and away from each other via hydraulic system 8. Accordingly, top tool 5 and bottom tool 7 are also movable toward and away from each other. To bend sheet metal, the sheet is inserted between tools 5 and 7, which are then moved toward each other. Top tool 5 then pushes the sheet metal into bottom tool 7 to bend and deform the sheet metal. After bending, tools 5 and 7 are moved away from each other by moving top beam 2 via hydraulic system 8. The clamping systems 4, 6 are removably attached to the top beam 2 and bottom beam 3, respectively, via a suitable locking system, so that the clamping systems 4, 6 can be replaced with clamping systems suitable for other tools, or the clamping systems 4, 6 can be removed for inspection.

[0074] 2A and 2B show a similar press brake 101, and only the differences from the press brake 1 of FIGS. 1A and 1B will be described here. The clamping systems 104, 106 of the press brake of FIGS. 2A and 2B are integrated with the top beam 102 and bottom beam 103, respectively. Therefore, the clamping systems 104, 106 are not interchangeable. The tools 105, 107 held by the clamping systems 104, 106 are interchangeable.

[0075] 3A-3C show a clamping system 204 that can be used, for example, in the press brake shown in FIGS. 1A-2B. The clamping system 204 has an elongated beam 209 as a main body. A receiving space 210 within the elongated beam 209 accommodates a portion of the tool 205. The clamping system further includes an actuating member 211 and a clamping element 212. The actuating member 211 is movable upward to an inoperative position and downward to an operative position. The clamping element 212 is movable between a first position in which it extends into the receiving space 210 to engage the tool 205 and a second position in which it retracts from the receiving space 210 to release the tool. The clamping element 212 has an engagement tip 213 that cooperates with an engagement recess 214 within the tool 205 to securely clamp the tool 205 within the receiving space 210. In the actuating position, the actuating member 211 engages with the clamping element 212 and urges it toward the receiving space 210. FIG. 3B shows the actuating member 211 in the actuating position such that the tool 205 is clamped within the receiving space 210 by the clamping element 212. The actuating member 211 has an inclined engagement surface 215 for engaging the clamping element 212, which in turn engages with an inclined engagement surface 216 of the cooperating clamping element 212. Thus, when the actuating member 211 moves to its actuating position, i.e., downward in the figure, the engagement surface 215 of the actuating member 211 engages with the engagement surface 216 of the clamping element 212, and due to its inclination, presses the clamping element 212 toward its first position (i.e., to the left in the figure). FIG. 3C shows the actuating member 211 in the inactive position, with the clamping element 212 retracted from the receiving space 210 to a second position, thereby releasing the tool 205.

[0076] The actuating member 211 is movably disposed within a pressure chamber 217. The pressure chamber 217 is formed directly within the elongated beam 209 and also has a receiving space 210. Thus, the pressure chamber 217 is integrally formed within the elongated beam 209. The actuating member 211 is provided with sealing means 218 that seals the actuating member 211 to the wall of the pressure chamber 217, i.e., the inside of the elongated beam 209. In this way, the actuating member 211 functions as a piston that is movable within the pressure chamber 217, and the piston therefore functions as a cylinder. The actuating member 211 can therefore be pushed towards its actuated position by introducing a fluid into the pressure chamber 217. The pressure chamber 217 of this clamping system 204 is configured to receive hydraulic liquid as a pressure fluid for moving the actuating member 211.

[0077] The clamping system 204 comprises a first biasing member in the form of a first compression spring 219. The first compression spring 219 acts on the actuating member 211. The first compression spring 219 is arranged vertically, corresponding to the pressing direction P defined by the clamping mechanism 204 and the depth direction of the receiving space 210. The first compression spring 219 biases the actuating member 211 upward, i.e., towards its inactive position. Thus, when the pressure of the hydraulic fluid in the pressure chamber 217 is stopped, the first compression spring 219 pushes the actuating member 211 further into the pressure chamber 217, forcing the hydraulic fluid out of the pressure chamber 217. The first compression spring 219 rests on a support 220 provided by a cover 221. The cover 221 covers the clamping element 212, the actuating member 211 and the pressure chamber 217. The cover 221 also forms a first stop 222 against which the actuating member 211 abuts to limit movement of the actuating member 211 beyond the actuated position. The actuating member 211 has a travel limiter 223 for engaging the first stop 222. The first compression spring 219 extends partially into a first cavity 224 within 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 disposed horizontally, i.e., perpendicular to the pushing direction P and the longitudinal direction of the elongated beam 204. The second compression spring 225 acts on the clamping element 104 via a protrusion 226 on the clamping element 212, and the first compression spring 225 extends partially into a second cavity 227 within the elongated beam. The cover 221 also provides a second stop 228 that engages the protrusion 226 of the clamping element 212 to limit movement of the clamping element 212 beyond the second position.

[0078] 4A and 4B show the elongated beam 209 of the clamping system 204 described in more detail above. In each example, repeated elements in FIGS. 4A and 4B are not given reference numerals. As can be seen, a plurality of pressure chambers 217 are aligned within the elongated beam 209 in the longitudinal direction L. The pressure chambers 217 are connected to each other, i.e., interconnected, via interconnecting portions formed by channels 229 extending between side walls 230 of adjacent pressure chambers 217. The pressure chambers 217 have an opening 231 at one end and are closed at the other end 232. The channel 229 is located adjacent to the other end 232. One pressure chamber 217 is connected to the exterior of the elongated beam 209 via a channel 233. As can be seen from FIGS. 4A and 4B, the pressure chambers 217 are integrally arranged within the elongated beam 209 and are arranged within the same piece of material that forms the receiving space 210. The pressure chambers 217 are interconnected via channels 229 that do not reach the outside of the elongated beam 209 and are therefore internally interconnected.

[0079] 5 shows a clamping system 304 that differs from the clamping system 204 described above only in that its elongated beam 309 is composed of two separate components 309-1 and 309-2. The elongated beam's main body 309-1 may be manufactured separately from and subsequently attached to the secondary body 309-2. A pressure chamber 317 is formed within the secondary body 309-2.

[0080] Figure 6 shows a clamping system 404 which differs from the clamping system 204 described in relation to Figures 3A-4B only in that the pressure chamber 417 is formed in a cylinder 434 which is located in a cavity 435 which is integrally formed with the elongated beam 409. Of course, it is possible to provide the cavity 435 in the auxiliary body, as described in relation to Figure 5, thereby making it possible to combine the different features of Figures 5 and 6.

[0081] 7A-7C illustrate a clamping system 504 that differs from the clamping system 204 described in connection with FIGS. 3A-4B only in the following features. First, the elongated beams 509-1, 509-2 consist of two separate components 509-1 and 509-2. The elongated beam's main body 509-1 may be manufactured separately from the secondary body 509-2 and attached later. The pressure chamber 217 is formed by an air hose 536 having a deformable wall. The hose 536 extends through a cavity 535 in the longitudinal direction L of the elongated beams 509-1, 509-2. The hose 536 expands when fluid is pressurized in the pressure chamber 517 and contracts when the pressure is released. When the hose 536 expands (see FIG. 7B), it pushes the actuating member 511 to its actuated position. The first compression spring 519 pushes the actuating member 511 upward, thereby helping to expel fluid from the pressure chamber 517 when the pressure is reduced (see FIG. 7C). A protrusion 526 of the clamping element 512 is positioned on the upper side of the clamping element 512 to engage with the second compression spring 525. This frees the end face 537 of the clamping element 512 for engagement with the second stop 528. The clamping element 512 also has a recess 538 for accommodating the first compression spring 519 when the clamping element 512 is in the second position, i.e., when moved to the right in the figure. As in the embodiment of FIGS. 3A-4B, no first stop or travel limiter for the actuating member is provided. Finally, a protrusion 599 is provided inside the receiving space 510, forming a hook. The protrusion 599 is used to hang the tool 505. For insertion or removal, the tool 505 must be moved around the protrusion 599. Thus, the receiving space 510 has a relatively large width D compared to the tool 505, which has a smaller width d. The clamping element 512 therefore has a relatively large stroke for clamping the tool 505.

[0082] Figure 8 shows a clamping system 604 that differs from clamping system 504 of Figures 7A-7C in that elongated beam 709 is made from a single piece of material. Thus, cavity 635 is integrally formed within the single piece of elongated beam 609.

[0083] 9 shows a bottom clamping system 706 that has the features of the clamping system 204 described in connection with FIGS. 2A-3B, apart from the different position of the projection 725 of the clamping element 712. The projection 726 cooperates with a second stop 728, leaving an end face 737 free.

[0084] Obviously, the bottom clamping system 706 can be modified by applying any of the above mentioned features such as a separate elongated beam within the cavity and / or a separate cylinder and / or hose as a pressure chamber.

[0085] Figures 10A and 10B show elongated beam 709 in more detail, the features of which are similar to those described in connection with Figures 3A and 3B.

[0086] 11A-11D illustrate how cavities 817 within elongated beams 809 can be internally interconnected. First, elongated beams 809 are provided (see FIG. 11A) with cavities 817 therein. The cavities are not yet interconnected. Next (see FIG. 11B), a milling tool is inserted through opening 831 of one cavity 817. The milling tool has a thin stem 850 and a larger head 851. The milling tool is inserted in insertion direction I (see FIG. 11C). The milling tool is moved toward another cavity 817 in machining direction M, thereby eroding the material of elongated beam 809 and creating a channel 829 between the two cavities. As shown in FIG. 11D, the cavities 817 are then interconnected.

[0087] Figure 12 shows another clamping system 904 that differs from the clamping system 304 described in connection with Figure 5 in that the first compression spring 919 is provided around the actuating member 104 rather than within a cavity in the actuating member 911. The first stop is not shown in Figure 12. The first compression springs of the other clamping systems shown in this application may also be provided around their respective actuating members.

[0088] While the present invention has been described above with reference to numerous specific examples and embodiments, the invention is not limited thereto. Instead, the present invention also encompasses subject matter defined by the claims, which follow.

Claims

1. In clamping systems for press brakes, an elongated beam including a receiving space for receiving a portion of a bending tool; a clamping element movable between a first position (wherein the clamping element can engage the bending tool to clamp it into the receiving space) and a second position for releasing the bending tool; an actuation member for displacing the clamping element, the actuation member being movable between an actuation position that biases the clamping element toward a first position and an inactuation position that allows the clamping element to move to a second position; Equipped with a first biasing member acting on the actuating member to bias the actuating member toward the inactivated position; The clamping system has a pressing direction, and the first biasing member is disposed substantially parallel to the pressing direction.

2. The clamping system of claim 1 , wherein the actuating member is movable in a direction substantially parallel to the pressing direction between its actuated and inactuated positions.

3. The clamping system of any one of claims 1 to 2, wherein the first biasing member extends at least partially into a first cavity in the actuation member or extends at least partially around the actuation member.

4. The clamping system according to any one of claims 1 to 3, wherein the first biasing member is arranged on a side of the actuating member adjacent to the clamping element.

5. The clamping system of any one of claims 1 to 4, further comprising a first stop for limiting movement of the actuating member beyond its actuated position.

6. 6. The clamping system of claim 1, wherein the clamping element is movable in a direction substantially perpendicular to the pushing direction and the longitudinal direction of the elongate beam between the first position and the second position.

7. The clamping system of any one of claims 1 to 6, further comprising a second biasing member acting on the clamping element to bias the clamping element towards the second position.

8. The clamping system of claim 7 , wherein the second biasing member is disposed substantially perpendicular to the pushing direction and the longitudinal direction of the elongated beam.

9. The clamping system of any one of claims 7 to 8, wherein the second biasing member extends at least partially into a second cavity in the elongate beam.

10. The clamping system according to any one of claims 7 to 9, wherein the clamping element comprises a protrusion for engaging the second biasing member.

11. The clamping system of any preceding claim, further comprising a second stop that limits movement of the clamping element beyond its second position.

12. A clamping system as described in claim 11, wherein the clamping element has a protrusion for engaging with a second biasing member and further has a second stop that limits movement of the clamping element beyond its second position, the second stop engaging the protrusion at the second position.

13. The clamping system of any one of claims 1 to 12, wherein the clamping element comprises a recess for receiving at least a portion of the first biasing member.

14. The clamping system of any preceding claim, wherein the first biasing member comprises a compression spring.

15. 15. The clamping system according to claim 1, wherein at least one of the clamping element and the actuating member comprises an engagement surface for engaging the other of the clamping element and the actuating member, at least a portion of the engagement surface being inclined relative to the direction of movement of each element.

16. A clamping system according to any one of the preceding claims, wherein the actuating member comprises a piston of a hydraulic or pneumatic actuation system.

17. The clamping system of any preceding claim, wherein the actuation member extends at least partially into a third cavity in the elongate beam.

18. The clamping system of claim 17 , wherein the third cavity is integrally formed within the elongated beam.

19. A press brake comprising a clamping system according to any one of claims 1 to 18.

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