EP2812135B1 - Press table or press beam having adjustable beam element - Google Patents

Description

The invention relates to a press table or press beam for a press brake according to the preamble of claim 1.

When folding workpieces, especially with long bending edges, there is often the problem that the bending angle reached after the bending process along the bending edge is not constant, since at the bending tool carrying the press beam or press table by the forming forces a deflection takes place, which also at very massive construction can not be completely prevented. The immersion depth of a punch is thereby lower in the center of the workpiece than at the ends of the bending edge and, accordingly, the forming angle.

To avoid these workpiece errors, it is known to bend the tool abutment surface on an active press table or press beam by suitable devices to a degree convex outward in a bending operation, which corresponds to the deflection of the non-actively deformable press beam or press table. The support surfaces carrying the bending tools thereby extend approximately parallel to one another and the immersion depth of a bending punch is constant along the bending edge, as a result of which a uniform forming angle is also achieved.

A press brake, in which the convex curvature of the press table or press beam, which is also referred to as a crown, can be effected by a biasing device is off AT 351896 B known. The press table or press beam consists of two half-cheeks, which are biased against each other by means of a biasing device, whereby the tool contact surface can be convexly curved outward. Wedge arrangements or hydraulic cylinders are disclosed as possible embodiments of the pretensioning device.

The disadvantage of this embodiment is that the biasing forces causing the curvature are introduced at predetermined positions as point loads by such biasing devices, and thereby results in a course of curvature that coincides with the deflection of the press bar corresponds only slightly, since this is highly dependent on the positioning of the workpiece and the length of the bending edge.

The object of the invention is to provide a press brake, in which a curvature can be adjusted on the press table or press beam, which allows for many applications, a high bending accuracy with uniform forming angles and still has a simple structure.

The object of the invention is achieved by a generic press table or a pressing bar with the characterizing features of claim 1.

Characterized in that the actuator arranged between the mutually facing pressure surfaces and adjoining these and can be filled with hydraulic fluid hose assembly which extends substantially in the longitudinal direction of the beam member, the curvature of the beam member is caused by a direct load and not by point loads. Since the forming forces resulting from the workpiece during the bending process also represent a constant load and a corresponding bending line results for the deflection of the deformed, non-actively adjustable press bar or press table, the curvature caused by the hose arrangement on the actively adjustable press table or pressing bar is a better approximation to FIG Deflection, as when using point loads for biasing the beam element on the active press table or pressing beam. Furthermore, the hose assembly is a simple component for generating the bias and are in most press brakes hydraulic units for the pressing beam drive available, which can also be used to supply the hose assembly with pressurized fluid.

A high rigidity with a slim design of a press table or press beam is achieved when the beam element and the support beam element are plate-shaped, overlap each other at least in sections and extend substantially parallel to the working plane or press plane. High flexural rigidity of the beam member prevents local deformations or deflections of the beam member from occurring for workpieces having shorter bending edges that act approximately like point loads, which could otherwise occur due to the point-type compliant hose assembly.

It is advantageous if the beam element or the support beam element at least partially forms a U-shaped cross section with a base and adjoining legs and the beam element engages around the support beam element or the support beam element at least partially on both sides with the legs. The enclosed between the pressure surfaces hose assembly is thereby arranged in the interior of the press table or press bar and well protected against mechanical damage. Furthermore, this gives good mutual guidance and lateral support of the beam element and the support beam element.

In order to bias also very rigid beam elements, it is advantageous if the hose assembly has an effective length between the pressure surfaces, which corresponds approximately to the distance between two connection points on the beam element. As a result, the entire bending length is subjected to a constant load, thereby achieving a high biasing force.

Alternatively, the connection points or the bolts can be arranged in the working direction in the direction of the height of the beam member in the spaced-apart from the support surface half, resulting in a more homogeneous bending curve of the beam element.

If a pivot bearing is formed at the connection points between the beam element and the support beam element, this results in a bending line of the beam element which is essentially caused only by the uniform load of the hose arrangement and thus disturbing internal tension in the press table or pressing beam is avoided since minor mutual angle changes are not hindered ,

Similarly advantageous effects can also be achieved if a sliding bearing is formed at the connecting points, as this does not hinder changes in length between the connecting points resulting from the deformation of the beam element and the supporting beam element.

Increased mobility between the beam element and the support beam element can also be achieved by moving from the connection points on the beam element in each case at least one bending bar element extends to an attachment point on the support bar element.

When the legs of the U-shaped beam element, viewed from the support surface, are held at a fixed distance from one another with at least one transverse connector, the stability of the press table or the press beam is increased and deformations or warping transverse to the pressing direction are prevented.

The hose assembly may comprise at least two parallel extending hose sections, which are connected in parallel hydraulically, whereby the force is distributed in the pressure surface of the beam element on a plurality of contact lines or contact surfaces. The introduction of force is thereby more uniform and load peaks are reduced at the hose arrangement as well as at the beam element or the support beam element.

The handling and assembly of the hose assembly is facilitated when adjacent parallel hose sections are connected together to form a hose package. The connection can be made by welding or gluing along generatrices of the tube sections.

The hose assembly may comprise two or more superimposed in the pressing direction hose packages, whereby the deformation height can be increased if a hose package to produce the required maximum crowning is not sufficient. The hose packages can be separated by a stiff intermediate layer

The pressure surfaces on the beam member and / or support beam member may have concave recesses for partially receiving the hose assembly, thereby reducing load peaks on the hose assembly and avoid undefined deformations of the hose assembly.

For bending operations in which a crowning of the press table or press bar is not required, it can be provided that, in the case of a pressure-less hose arrangement, the bar element contacts the support bar element in the area of the pressure surfaces. The bending stiffness and strength of the beam element is thereby supplemented by those of the support beam element. So that the hose assembly has a higher flexibility and thus also deformability, the hose assembly may comprise a hose portion with a reinforcing member made of a synthetic fiber braid.

The pressure fluid supply unit connected to the hose arrangement can comprise at least one essentially leakage-free valve, in particular a seat valve or cartridge valve, for simple regulation of the filling volume and thus of the pressure and the crowning height. An existing bias voltage can be easily maintained because no pressure drop occurs after closing the valve.

In order to easily integrate the operation of the valve in an existing control device of the press brake and to make a fast and sensitive adjustment of the filling volume and the crown height, it is advantageous if the valve comprises an electromagnetic actuator.

In particular, the control of the valve can be effected by means of a pulse-width modulator.

For a better understanding of the invention, this will be explained in more detail with reference to the following figures.

Fig. 1

eine Ansicht einer Abkantpresse mit beim Pressvorgang auftretenden Verformungen;

Fig. 2

eine Ansicht einer Abkantpresse gemäß Fig. 1, bei der die Verformung des Pressbalkens durch eine aktive Verformung des Presstisches ausgeglichen wird;

Fig. 3

einen Teilschnitt durch einen erfindungsgemäßen Presstisch gemäß Linie III - III in Fig. 2;

Fig. 4

einen Schnitt durch eine mögliche Ausführungsform eines Presstisches gemäß Linie IV - IV in Fig. 3;

Fig. 5

eine weitere mögliche Ausführungsform der Verbindung zwischen Balkenelement und Zusatzbalkenelement;

Fig. 6

eine weitere mögliche Ausführungsform der Verbindung zwischen Balkenelement und Zusatzbalkenelement;

Fig. 7

eine weitere mögliche Ausführungsform der Verbindung zwischen Balkenelement und Zusatzbalkenelement;

Fig. 8

eine weitere mögliche Ausführungsform der Verbindung eines Balkenelements und eines Zusatzbalkenelements.

Each shows in a highly schematically simplified representation:

Fig. 1

a view of a press brake occurring during the pressing process deformations;

Fig. 2

a view of a press brake according to Fig. 1 in which the deformation of the press beam is compensated by an active deformation of the press table;

Fig. 3

a partial section through a press table according to the invention along line III - III in Fig. 2 ;

Fig. 4

a section through a possible embodiment of a press table according to line IV - IV in Fig. 3 ;

Fig. 5

a further possible embodiment of the connection between the beam element and additional beam element;

Fig. 6

a further possible embodiment of the connection between the beam element and additional beam element;

Fig. 7

a further possible embodiment of the connection between the beam element and additional beam element;

Fig. 8

a further possible embodiment of the compound of a beam element and an additional beam element.

By way of introduction, it should be noted that in the differently described embodiments, the same parts are provided with the same reference numerals or the same component names, wherein the disclosures contained in the entire description can be mutatis mutandis to the same parts with the same reference numerals or component names. Also, the location information chosen in the description, such as top, bottom, side, etc. related to the immediately described and illustrated figure and are to be transferred to the new situation mutatis mutandis when a change in position. Furthermore, individual features or combinations of features from the different exemplary embodiments shown and described can also represent independent, inventive or inventive solutions.

Fig. 1 shows the front view of a press brake 1, with which on a workpiece 2 rectilinear bending transformations can be performed. For this purpose, the press brake 1 comprises two pressing bars which are adjustable relative to one another and act on the workpiece 2 with bending tools in the form of a bending punch and a bending die. The in Fig. 1 shown, lower fixed pressing beam is referred to in sequence as a press table 3, which serves together with the bending die as a support for the workpiece 2 and cooperates with the adjustable pressing beam 4 and the bending punch arranged thereon. The press bar 4 is here is mounted adjustably by means of a guide assembly 5 on the fixed machine frame of the press brake 1 and is driven by drive means 6, for example in the form of hydraulic cylinders.

As Fig. 1 shows, in general, in a bending operation on the pressing bar 4 set a dashed line indicated elastic deflection 7, since the lines of action of the forces of the drive means 6 and the force exerted by the workpiece 2 on the pressing bar 4 force do not coincide. Likewise, a deflection 7 is possible on the press table 3, since the lines of action of the forces exerted by the workpiece 2 on the press table 3 and the forces exerted by the footprint 8 on the press table 3 forces do not coincide.

Such a deflection 7 of the press bar 4 or the press table 3 causes a workpiece 2 is pressed in the middle of the edge to be bent by the punch less deeply in the bending die, as at the ends of the bending edge, which is why on the curved workpiece 2 along the Bending edge can give different bending angles and such a workpiece may need to be reworked or unusable. The respective bending 7 causing forces 9 are in Fig. 1 on the press table 3 or on the press bar 4 simplified represented by arrows.

To avoid the adverse effects on a workpiece 2 due to deflection 7 of the press table 3 and the press bar 4, it is known from the prior art to provide on the press table 3 in this regard active countermeasures. As in Fig. 2 shown, a uniform penetration depth of the punch into a workpiece 2 can be achieved by compensating for a deflection 7 on the pressing beam 4, caused by the driving forces 10 of the drive means 6 and the forming force 11 from the workpiece 2, simultaneously on the press table 3 a crown 12 active is brought about, which approximately corresponds to the deflection 7 on the pressing beam 4.

The concave underside 13 of the press beam 4 due to the deflection 7 cooperates by this measure with the convex, cambered top 14 of the press table 3 and thereby results along the bending edge a uniform penetration depth of the punch into the workpiece 2 and thereby also a along the bending edge largely constant bending angle.

In the following, possible embodiments of a press table 3 according to the invention are shown, wherein the described structural features and measures can be analogously transferred to an adjustable pressing bar 4 and thus not only in a press table 3 but also in a press bar 4, the support surface for a bending die 15th or a punch 16 can be actively adjusted from a flat initial position into a convex, outwardly curved shape.

Fig. 3 shows a section along line III - III in Fig. 2 by a press table 3 a press brake 1. This comprises a beam member 17 which has on its upper side 14 extending in the direction of the width of the press brake 1, elongated support surface 18. In the exemplary embodiment shown, a bending tool 19, here in the form of a bending die 15, is attached to the support surface 18 by means of a clamping device 20. The beam element 17 is U-shaped, wherein the support surface 18 is formed by the base of the U and the legs 21 of the U-shaped beam element 17 extending from the base parallel to the working plane 22 of the press brake 1 down.

The support surface 18 forming the base 23 of the U-shaped beam member 17 by itself would have a very low bending stiffness, the connection with the parallel to the working plane 22 legs 21, the beam member 17 has a total but a relatively high bending stiffness, as in press brakes. 1 generally required. The connection between the base 23 and the legs 21 may in particular comprise a positive connection parallel to the working plane 22, whereby a stable power transmission between the base 23 and the legs 21 is given. Also possible is a one-piece, e.g. welded connection between base 23 and legs 21.

The beam element 17 is connected to a support beam element 24 of approximately equal length, which also has a plate-shaped basic structure and extends approximately parallel to the working plane 22. In the illustrated embodiment, the support beam member 24 is disposed inside the U-shaped beam member 17 and it is trapped between the two legs 21. At the beam element 17 while connecting points 25 are formed, where it is connected by means of connecting elements 26, for example in the form of bolts 27 with the support beam member 24. The bar element 17 and the support bar element 24 thus overlap in the region of the legs 21.

The bolts 27 are perpendicular to the working plane 22 of the press brake 1 and enforce both the legs 21 of the beam member 17 and the support beam member 24. Such a design of a press table 3 and a press beam 4 with overlapping portions of the beam member 17 and support beam member 24 can also as Sandwich arrangement can be designated.

The beam element 17 has a pressure surface 28, which faces the support beam element 24 and in the illustrated embodiment is located on the inside of the base 23. Furthermore, the support beam element 24 has a pressure surface 29, which faces the pressure surface 28 on the beam element 17. In order on the support surface 18 of the beam member 17 is a in Fig. 2 shown active crowning 12 is disposed between the pressure surface 28 on the beam member 17 and the pressure surface 29 on the support member 24, an actuator 30 which extends approximately in the pressing direction 31, which is directed at a press table 3 upwardly extending adjusting force 32 on the Can exercise underside of the beam member 17.

The actuator 30 is formed by a hose assembly 33 which extends in the longitudinal direction of the beam member 17 and can be filled with hydraulic fluid 34. In the illustrated embodiment, the hose assembly 33 comprises three mutually parallel hose sections 35 which are supported by filling with hydraulic fluid 34 both on the pressure surface 28 of the beam member 17 and on the pressure surface 29 on the support beam element and thereby exert the adjusting force 32 on the beam member 17.

In the Fig. 3 illustrated three mutually parallel hose sections 35 of the hose assembly 33 are embedded in concave recesses 36 in the pressure surfaces 28 and 29, but it is also possible that the pressure surfaces 28 and 29 are flat and the hose assembly 33, for example, a single, flattened hose larger Cross-section includes.

The press table 3 can be designed so that the beam element 17 is supported laterally of the hose assembly 33 with the support surface 28 on the support surface 29 of the support beam member 24 in unfilled or pressureless hose assembly 33, whereby during operation of the press brake 1 without activating the crowning device, the flexural rigidity the beam element 17 is additionally supported by the bending stiffness of the support beam element 24.

The hose assembly 33 comprises flexible hose sections whose strength is dimensioned so that the maximum occurring pressures can be borne by the hydraulic fluid 34 without bursting. An advantageous embodiment is that hoses are used with a reinforcement made of a synthetic fiber braid, since they have a higher elasticity than hoses with a metal braid and thereby larger adjustment in the production of the crown 12 are possible.

The hose assembly 33 preferably has an effective length between the pressure surfaces 28 and 29, which corresponds approximately to the distance between two connection points 25 on the beam element 17. The entire free bending length of the beam member 17 can be acted upon by a caused by the hose assembly 33 uniform load and thereby a crown 12 are generated, which is approximately parallel to the deflection 7 of the press bar 4.

Parallel extending tube sections 35 may, as in Fig. 3 shown to be connected to a hose package 37, such as by the individual tube sections 35 are glued to each other on generatrices or welded. To produce a uniform adjusting force 32, the individual tube sections 35 are hydraulically connected in parallel.

As Fig. 3 1, the hose assembly 33 may be positioned closer to the support surface 18 than the connection points 25 on the beam member 17. The crowning curve is less affected by the spacing of the connection points 25 than if the connection points 25 were located closer to the support surface 18.

Fig. 4 shows a section through a press table 3 according to line IV - IV in Fig. 3 , Wherein corresponding components are identified by the same reference numerals and this is dispensed with a new description of the same or equivalent components.

Fig. 4 shows the support beam member 24 which is supported on the footprint 8 and the beam member 17, the base 23 forms the support surface 18 for the bending tool and the legs 21, the support beam member 24 overlap on both sides. As Fig. 4 shows, the connection points 25 are arranged on the beam member 17 symmetrical to the median plane 37 of the press table 3, in particular, however, the connection points 25 are preferably on the extended lines of action of the drive means 6, which results in a bending length 38 between the connection points 25 on the beam element 17, which preferably coincides with the corresponding bending length between the drive means 10 on the adjustable pressing beam 4. Furthermore, beam element 17 and support beam element 24 have substantially the same length 39, which corresponds to the working width of the press brake 1.

In the embodiment according to Fig. 4 are the two legs 21, which may also be referred to as aprons, in addition to the base 23 by means of cross connectors 40, which prevent warping of the legs 21 transverse to the working plane 22. The cross connectors 40 are arranged in this embodiment at the lower end of the legs 21 and extend in a recess 41 on the underside of the support bar member 24. The hose assembly 33 can that of the basis of the Fig. 3 described hose assembly 33 and this can by filling with hydraulic fluid 34 exert a constant load on the pressure surface 28 on the underside of the base 23, whereby the support surface 18 is arched between the connection points 25, and thereby a in Fig. 2 shown crowning 12 is achieved.

The extent of the bulge can be determined by the controlled supply of hydraulic fluid 34 and concomitant controlled increase in pressure in the hose assembly 33. For example, in a bending operation it is possible to calculate the deflection 7 of the pressing beam on the basis of workpiece parameters or to detect it by means of a suitable measuring arrangement during the bending operation and, based thereon, to set the crowning 12 to the same extent by controlled supply of hydraulic fluid 34. In advance calculation of the expected deflection 7 of the press bar 4, the crown 12 of the press table 3 can also be adjusted before carrying out the bending process. When measuring the deflection 7 during the bending process, the crown 12 is also adjusted during the bending process suitable. In addition, it is possible that the crowning 12, ie the curvature of the support surface 18 is measured during the bending process, whereby a regulation of the crown 12 can be done by these adjusted the measured or calculated deflection 7 of the press bar 4 adjusted.

The supply of the hose assembly 33 with hydraulic fluid 34 is effected by means of a pressure fluid supply unit 42, which comprises at least one substantially leak-free valve 43, whereby the fluid pressure can be kept constant during a bending operation in a simple manner when the valve is closed. The valve 43 is designed, for example, as a seat valve or cartridge valve. The operation of the valve 43 is preferably carried out by means of an electromagnetic actuator unit, whereby the supply of the hose assembly 33 can be integrated with hydraulic fluid 34 in a simple manner in the control device of the press brake 1. The control of the valve 43 can be effected in particular by means of a pulse-width modulator 44, which can be integrated in the pressure fluid supply unit 42 or can be formed by the control device of the press brake 1.

The tube assembly 33 may also be designed in several layers, for example, in the two in Fig. 3 shown hose packages are arranged one above the other, and between a suitable, rigid intermediate plate is arranged. As an alternative to a hose package with several parallel hose sections 35, it is also possible to use a single hose of larger cross-section, which is in the pressureless starting position between the pressure surfaces 28 and 29 in an oval, flattened shape and increases in height by filling with hydraulic fluid 34.

As Fig. 4 However, it is also possible that, as shown in dashed lines, the connection points 25 with respect to the height 45 of the beam element in FIG the spaced from the support surface 18, the lower half are arranged.

In Fig. 5 an alternative embodiment of the connection between the beam element 17 and support beam element 24 is shown. The supporting beam element 24 contacts the supporting surface 8 with the adjustable feet 46 and encloses the beam element 17 with a U-shaped cross section of the supporting beam element 24, as already described in US Pat Fig. 3 and 4 is shown.

As connecting elements 26 between beam element 17 and support beam element 24 are not used in this embodiment, as in the bolts Fig. 3 and 4 but the cross connector 40, which connect the legs 21 of the beam member 17 at the bottom together and upon activation of the hose assembly 33 by supplying hydraulic fluid, the recess 41 on the underside of the support beam member 24 contacted. The cross connector 40 can bear directly on the underside of the support beam element 24, it is advantageous, however, if, as in Fig. 5 shown, between the support beam member 24 and the cross connector 40, a pressure segment 47 is arranged, which rests with its flat bottom 48 on the flat top of the cross connector 40 and is inserted with a circular arc-shaped top 49 in a circular arc-shaped bearing recess 50 in the support beam element. A sliding bearing 51 is thereby formed between the underside 48 of the pressure segment 47 and the upper side of the transverse connector 40, which facilitates the relative movements occurring between the beam element 17 and the support beam element 24 upon activation of the deformation. Due to the bulging of the support surface 18 between the connection points 25, the support surface 18 is slightly extended, while the underside of the beam member 17 undergoes a slight shortening. Conversely, the support beam element undergoes an extension due to the uniform load exerted by the hose arrangement 33 on the underside, ie in the region of the recess 41, and a slight shortening in the area of the pressure surface 29, whereby the sliding bearing 51 facilitates these length changes and internal stresses in the press table 3 be reduced. In addition, the upper side 49 of the pressure segment 47 and the bearing recess 50 in the support bar element 24 forms a pivot bearing 52, which also permits slight changes in angle due to the deformations or bending lines of the bar element 17 and the support bar element 24 that are opposite from the tube arrangement 33.

In the Fig. 6 a further and possibly independent embodiment is shown, in turn, the same reference numerals or component names for the same parts as in the preceding Fig. 1 to 5 be used. In order to avoid unnecessary repetition, the detailed description in the previous ones will be used Fig. 1 to 5 referred or referred.

Here, too, a sliding bearing 51 and a pivot bearing 52 is formed by use of a pressure segment 47 between the beam element 17 and support beam element 24, which allows the bending deformation of the beam element 17 and support beam element 24 caused by the hose arrangement 33 and by deformation forces during the bending process, without high internal stresses in the Press table 24 arise. In this embodiment, the bottom is of the pressure segment 47 circular arc-shaped running and the top 49 as a flat surface.

In the Fig. 7 a further and possibly independent embodiment is shown, in turn, the same reference numerals or component names for the same parts as in the preceding Fig. 1 to 6 be used. In order to avoid unnecessary repetition, the detailed description in the previous ones will be used Fig. 1 to 6 referred or referred.

In this embodiment, the pressure segment 47 has both on the bottom 48 and on the top 49 a circular arc shape and thereby has a lenticular cross-section. The underside 48 is inserted at the cross connector 40 in a corresponding recess and the curved top 49 inserted in a slider 53 which is slidably mounted on the top with a flat sliding surface 54 in a guide recess 55 on the underside of the support beam member 24. Also in this embodiment, a sliding bearing 51 and a pivot bearing 52 is realized at the connection point 25 thereby.

Fig. 8 shows another possible embodiment of the connection between the beam member 17 and the support beam member 24, wherein also here the connection point 25 is positioned on the lower cross connector 40 of the U-shaped beam member 17. As a connecting element 26 is used in this embodiment, a bending bar element 56 which is fixedly secured with its lower end to the cross connector 40 and the upper end of which is fixedly connected to an attachment point 57 on the support bar element 24. The bending bar element 56 may be formed as a separate component which is fixed at its two ends at the connection point 25 and at the attachment point 57, but it is also possible for the bending bar element 56 to be formed by the support bar element 24 itself, by inserting into the plate-shaped base body of the support bar element 24 vertical slots 58 are introduced and thereby between the parallel slots 58, the bending bar element 56 is formed. The direction of the slots 58 may also be different from the vertical.

Due to the length of the bending bar element 56, despite the fixed connection to the connection point 25 on the transverse connector 40 and at the attachment point 57, increased mobility is created between the beam member 17 and the support beam member 24, which aids in the active generation of the crown 12. The relative mobility can be further increased by, for example, adding additional slots 58 in the Fig. 8 are shown dashed, are provided.

The embodiments show possible embodiments of a press table according to the invention or press bar, it being noted at this point that the invention is not limited to the specifically illustrated embodiments thereof, but also various combinations of the individual embodiments are possible with each other and this variation possibility due to the teaching technical action by objective invention in the skill of working in this technical field expert. So are all conceivable embodiments, which are possible by combinations of individual details of the illustrated and described embodiment variant, includes the scope of protection.

All statements on ranges of values in the description of the present invention should be understood to include any and all sub-ranges thereof, e.g. the indication 1 to 10 should be understood to include all sub-ranges, starting from the lower limit 1 and the upper limit 10, i. all subregions begin with a lower limit of 1 or greater and end at an upper limit of 10 or less, e.g. 1 to 1.7, or 3.2 to 8.1 or 5.5 to 10.

The task underlying the independent inventive solutions can be taken from the description.

Above all, the individual in the Fig. 1, 2 ; 3 ; 4 ; 5; 6 ; 7; 8th shown embodiments form the subject of independent solutions according to the invention. The relevant objects and solutions according to the invention can be found in the detailed descriptions of these figures. <B> Reference Numbers </ b> 1 press brake 31 pressing direction 2 workpiece 32 adjusting 3 press table 33 hose assembly 4 pressing bars 34 hydraulic fluid 5 guide assembly 35 hose section 6 drive means 36 recess 7 deflection 37 midplane 8th footprint 38 bending length 9 force 39 length 10 driving force 40 cross-connector 11 forming force 41 recess 12 crown 42 Pressure fluid supply unit 13 bottom 43 Valve 14 top 44 Pulse-width modulator 15 bending die 45 height 16 punch 46 Adjustable foot 17 beam element 47 pressure segment 18 support surface 48 bottom 19 bending tool 49 top 20 clamping device 50 bearing recess 21 leg 51 sliding bearings 22 working level 52 pivot bearing 23 Base 53 slide 24 Support beam element 54 sliding surface 25 junction 55 guide recess 26 connecting element 56 Bending rod element 27 bolt 57 attachment point 28 print area 58 slot 29 print area 30 actuator

Claims (20)

1. Press table (3) or press beam (4) for a press brake (1), comprising a beam element (17) with an elongate support surface (18) for attaching a bending tool (19) or tool adapter, a support beam element (24) having approximately the same length (39) as the beam element (17), connecting points (25) on the beam element (17) mutually spaced apart in the direction of its length (39), which with reference to its length (39) are arranged symmetrically with respect to the mid-plane (37) of the press table (3), and at which the beam element (17) is connected by means of connecting elements (26) with the support beam element (24), at least one actuator (30) which acts between mutually facing pressure surfaces (28, 29) on the beam element (17) and on the support beam element (24) and which can exert an adjusting force (32) that runs approximately in the pressing direction (31) of the press brake (1) and as a result the support surface (18) of the beam element (17) is actively adjustable between a planar profile and a convex profile, characterised in that the actuator (30) comprises a hose arrangement (33) which is arranged between the mutually facing pressure surfaces (28, 29), rests against the latter and is fillable with hydraulic fluid (34), and which extends substantially in the longitudinal direction of the beam element (17).
2. Press table (3) or press beam (4) according to claim 1, characterised in that the beam element (17) and support beam element (24) are of a plate-shaped design, mutually overlap in at least certain portions and extend substantially parallel with the working plane (22) or press plane.
3. Press table (3) or press beam (4) according to claim 2, characterised in that the beam element (17) or support beam element (24) forms a U-shaped cross-section in at least some portions with a base (23) and adjoining arms (21) and the beam element (17) extends around the support beam element (24) or the support beam element (24) extends around the beam element (17) at least partially on either side by means of the arms (21).
4. Press table (3) or press beam (4) according to one of claims 1 to 3, characterised in that the hose arrangement (33) has a working length between the pressure surfaces (28, 29) which approximately corresponds to the distance between two connecting points (25) on the beam element (17).
5. Press table (3) or press beam (4) according to one of claims 1 to 4, characterised in that the hose arrangement (33) lies closer to the support surface (18) than the connecting points (25).
6. Press table (3) or press beam (4) according to one of claims 1 to 5, characterised in that the connecting points (25) are disposed, relative to the height (45) of the beam element (17), in the half adjacent to the support surface (18) in the working direction (22).
7. Press table (3) or press beam (4) according to one of claims 1 to 5, characterised in that the connecting points (25) or bolts (27) are disposed, relative to the height (45) of the beam element (17), in the half spaced at a distance apart from the support surface (18) in the working direction (22).
8. Press table (3) or press beam (4) according to one of claims 1 to 7, characterised in that a pivot bearing (52) is provided on the connecting points (25).
9. Press table (3) or press beam (4) according to one of claims 1 to 8, characterised in that a slide bearing (51) is provided on the connecting points (25).
10. Press table (3) or press beam (4) according to one of claims 1 to 7, characterised in that at least one bending-resistant element (56) extends respectively from the connecting points (25) on the beam element (17) to a fixing point (57) on the support beam element (24).
11. Press table (3) or press beam (4) according to one of claims 1 to 10, characterised in that the arms (21) of the U-shaped beam element (17) or support beam element (24) are retained by at least one cross-connector (40) at a fixed distance from one another after the hose arrangement (33) as viewed from the support surface (18).
12. Press table (3) or press beam (4) according to one of claims 1 to 11, characterised in that the hose arrangement (33) comprises at least two hose portions (35) extending parallel with one another, which are hydraulically connected in parallel.
13. Press table (3) or press beam (4) according to claim 12, characterised in that adjacent parallel hose portions (35) are connected to one another to form a hose assembly (37).
14. Press table (3) or press beam (4) according to claim 13, characterised in that the hose arrangement (33) comprises two or more hose assemblies (37) lying one above the other in the pressing direction (31).
15. Press table (3) or press beam (4) according to one of claims 1 to 14, characterised in that the pressure surfaces (28, 29) have concave recesses (36) for partially accommodating the hose arrangement (33).
16. Press table (3) or press beam (4) according to one of claims 1 to 15, characterised in that the beam element (17) is in contact with the support beam element (24) in the region of the pressure surfaces (28, 29) when the hose arrangement (33) is without pressure.
17. Press table (3) or press beam (4) according to one of claims 1 to 16, characterised in that the hose arrangement (33) comprises a hose portion (35) with a strengthening material made from a synthetic fibre braid.
18. Press table (3) or press beam (4) according to one of claims 1 to 17, characterised in that a pressurised fluid supply unit (42) connected to the hose arrangement (33) has at least one substantially leakage-free valve (43).
19. Press table (3) or press beam (4) according to claim 18, characterised in that the valve (43) comprises an electromagnetic operating unit.
20. Press table (3) or press beam (4) according to claim 19, characterised in that the valve (43) is activated by means of a pulse-width modulator (44).

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