EP0067766A2 - Flexing apparatus for the tool carrier of a press brake or the like - Google Patents

Abstract

This device for bending the tool holder of a folding press comprises structure for controlling the deformation of the wedge secured at either end, in the form of a hollow screw engaged in a socket rigid with the tool holder so that it can accomplish movements of translation within this socket, a member for fastening the screw to the wedge, a sprocket mounted coaxially to the screw on the screw-threaded shank thereof for causing the translation of the screw in the socket, and a single driving system for controlling the rotation of the set of sprockets acting at different thrust points disposed at spaced intervals along the wedge, this single wedge having a relatively great length and being therefore easily deformable under the control of the single control system.

Description

The present invention relates to a bending device of a tool holder of a press brake or the like.

It is known that a hydraulic press brake has a fixed deck and a movable deck, the fixed deck being supported at its two ends. The movable deck is actuated by jacks which are most often located also at the two ends.

The cylinders provide the force necessary to bend the sheet and this, by reaction, causes the deformation of the two decks in the opposite direction. The distance between the two decks therefore does not remain constant over their entire length during work, and this results in an irregularity in the folding angle, which is more open in the center than at the ends. As a result, the sheet is less folded in its central part than at its ends.

To overcome this drawback, various means have been devised to cause bulging on the bearing surface of the tools of one of the aprons. This bending must be adapted to the type of folding carried out. It is a function, on the one hand of the force required per unit of length to be bent, and on the other hand the length of the sheet to be bent.

The user must therefore be able to adjust this bending according to these two characteristics.

A number of different solutions have been proposed to solve this problem. Thus, French patents 1,132,633, 1,362,471 and 1,539,817 provide for mounting jacks in the central part of the press, which makes it possible to obtain deformation curves of the aprons in the same direction and of the same importance, and therefore a regular and precise folding.

French patent n ° 2 347 992 (76 10 806) describes a press brake in which one of the aprons is composed of two parts, one of which is supported or actuated at its two ends, while the other part, on which the corresponding working tool is provided, is connected to this first part by one or two common axes arranged symmetrically with respect to the median transverse plane, and relatively close to this plane.

The apron produced in two parts may include prestressing means at its ends, which make it possible initially to give the active part of this apron, that is to say that carrying the working tool, a deformation in the same direction and substantially parallel to that undergone by the other deck, when it is subjected to the folding force.

Under these conditions, one obtains for the two working edges of the fixed deck and the movable deck, deformation curves as close as possible.

Also known by the French patent _. 1 420 380 a system of shims arranged between one of the decks and the corresponding folding punch, these shims having a slope in the longitudinal direction of the tool and being individually adjustable, in order to obtain the desired bending curve. French patent 2,078,874 provides for the use of a single wedge in the form of a sloping longitudinal bar, movable laterally by means of individually adjustable screws.

Another solution is proposed by German patent 1 752 346 which describes a bending device by means of a series of shims fixed on a support along the deck and bearing on conical surfaces, all these shims having a sloping face in the longitudinal direction of the tool, and which can be adjusted by a common mechanical device placed at one end of the row of shims. Other embodiments provide hydraulic means for obtaining the bending of the tool, French patent 2,200,064 thus describing a press in which one of the tools is supported by several vertical hydraulic cylinders distributed over the length of the press and connected together in a closed hydraulic system.

Overall, these known bending devices are relatively complex and therefore expensive.

The object of the invention is to produce a particularly simple bending device, which also makes possible a single control, either manual or motorized.

According to the invention, the means for controlling the deformation of the shim comprise, at each transverse thrust point, a hollow screw engaged in a socket integral with the tool holder so as to be able to be moved in translation in this socket, a member for fixing the screw to the block, a pinion mounted coaxially to the screw on a thread thereof, in order to be able to drive it in translation in the sleeve and a unique system for controlling the rotation of the assembly of pinions and consequently of the deformation of the entire wedge by the thrusts of the hollow screws on the wedge.

This unique long block is easily deformable and particularly simple to make. It follows that the control of the deformation of this wedge requires only a relatively small effort compared to the efforts required in the above-mentioned prior embodiments.

The pinion rotation control system comprises a chain engaged with all the pinions and actuated either manually by an end wheel, or by a motor capable of being controlled by a contactor or by program in the case of '' a digital press control.

According to one embodiment of the invention, the support member is a second fixed shim extending over the entire length of the tool holder and interposed between the first movable shim and the body of the corresponding deck, and the shims are pierced holes crossed by elements for fixing the tool holder to the body of the bulkhead, for example screws, the holes in the movable wedge being formed so as to reserve transverse play on either side of the fixing elements in order to authorize a transverse movement of the wedge on its support member.

The two wedges therefore have sloping faces bearing against one another, extending in the longitudinal direction of the machine, so that the transverse deformation of the movable wedge on the fixed wedge, allows obtaining '' an appropriate corresponding bending curve of the tool holder.

• - Les figures 1 et 2 sont des vues schématiques d'une presse plieuse ou analogue, montrant respectivement les déformations subies par les tabliers pendant le pliage, et un bombage appliqué initialement à l'un des tabliers porte-outil.
• - La figure 3 est une vue en coupe partielle transversale à échelle agrandie, du tablier inférieur d'une presse plieuse suivant une forme de réalisation de l'invention.
• - La figure 4 est une vue en coupe transversale partielle analogue à la figure 3, à l'emplacement d'un des dispositifs aménagés le long de la cale pour exercer sur celle-ci des poussées transversales.
• - La figure 5 est une vue de dessus simplifiée d'une première forme de réalisation de la cale pentue déformable selon l'invention, et de son système de commande de déformation.
• - La figure 6 est une vue en perspective d'une seconde forme de réalisation de la cale déformable et de son organe de support, constituée par deux pièces identiques et représentées retournées.
• - La figure 7 est une vue en perspective des deux cales de la figure 6, la cale supérieure mobile étant appliquée sur la cale inférieure fixe par rapport à laquelle elle a été déplacée transversalement et présente de ce fait un bombage.

Other features and advantages of the invention will become apparent during the description which follows, which will be made with reference to the accompanying drawings in which two non-limiting embodiments of the device covered by the invention have been shown.

• - Figures 1 and 2 are schematic views of a press brake or the like, respectively showing the deformations undergone by the aprons during folding, and a bending applied initially to one of the tool-carrying aprons.
• - Figure 3 is a partial cross-sectional view on an enlarged scale, of the lower deck of a press brake according to an embodiment of the invention.
• - Figure 4 is a partial cross-sectional view similar to Figure 3, at the location of one of the devices arranged along the wedge to exercise on this of transverse thrusts.
• - Figure 5 is a simplified top view of a first embodiment of the deformable wedge according to the invention, and its deformation control system.
• - Figure 6 is a perspective view of a second embodiment of the deformable wedge and its support member, consisting of two identical parts and shown returned.
• - Figure 7 is a perspective view of the two shims of Figure 6, the movable upper shim being applied to the fixed lower shim relative to which it has been moved transversely and therefore has a bending.

The diagrams in Figures 1 and 2 show one; press brake comprising a fixed lower deck 1, and a movable upper deck 2, each carrying a folding tool, the deck 2 being slidably mounted on columns 3 and provided with actuating cylinders 4.

The jacks 4 develop the force necessary for bending a sheet, not shown, which causes reaction by deformation in the opposite direction of the decks 1 and 2. (Curves in phantom 5a and 5b). As a result, the distance between the latter does not remain constant over their entire length, which causes irregularities in the bending of the sheet.

To overcome this drawback, the invention aims to print one of the tools of the press an initial bending, such as that shown by the curve 6 of deformation of the punch of the upper deck 2 (Figure 2).

The bending device provided by the invention comprises a single wedge 7 (FIG. 5) extending over the entire length of one of the tool holders of the aprons, in the occurrence in this example, the lower apron 1 supporting a folding matrix not shown. The wedge 7 is placed between a table 8 forming the tool holder of the folding die, and a support member 9 of the table 8, itself placed on the horizontal upper face 11 of the body of the lower deck 1.

The upper face of the wedge 7 is horizontal, while its lower face 7a has an inclination oC on the horizontal, and is placed in abutment on an inclined face 9a of the same slope of the fixed support wedge 9. The inclinations of the lower face 7a and of the upper face 9a are oriented transversely relative to the plane of the body of the deck 1, and therefore to the longitudinal direction of the folding die.

Of course, the lower shim 9 has the same length as the sloping shim 7, these two shims as well as the upper part of the body of the deck 1 coming to fit into a corresponding housing of the tool holder 8.

The wedge 7 is pierced at different places with oblong holes 12 extending in the transverse direction, and which are crossed by elements for fixing the tool holder 8 to the body of the deck 1, constituted by screws 13. The elongation of the holes 12 in the transverse direction reserve on either side of the screws 13 a clearance which allows transverse movement of the wedge 7 by sliding on its support member 9.

Each screw 13 thus passes through the table 8, the corresponding hole 12 and that of the fixed wedge 9 to be screwed into the body of the deck 1. Elastic washers 14 are supported between the head of the screw 13 and the annular bottom 15 d '' a recess 16 formed in the table 8.

The ends of the wedge 7 are retained at two fixed points 17, between which the wedge 7 can be elastically deformed.

In the embodiment shown in FIG. 4, the means for exerting transverse thrusts on the wedge 7 comprise, at each thrust point, a hollow screw 18 with grooves 19 parallel to the axis of the screw 18 engaged in corresponding grooves a socket 21 integral with the tool holder 8, so that it can be moved in translation in this socket 21 without turning. The hollow screw 18 is coupled to the wedge 7 by a screw 22 which can be introduced into the axial housing 18a of the screw 18 and screwed into the wedge 7. The head of the screw 22 is suitably sized relative to the diameter of the housing 18a to be able to be introduced with sufficient clearance. The screw 18 can be rotated by a threaded pinion 23, mounted coaxially with the screw 18 in a housing 24 of the table 8, on a corresponding thread 25 of the screw 18.

The pinion 23 can itself be rotated by a control system comprising a chain 26 meshing with the teeth 27 of the pinion 23, the rotation of which causes the screw 18 to slide in the socket 21 and consequently the sliding of the wedge 7 on the inclined ramp 9a. Consequently, depending on whether the chain 26 drives the pinion 23 in rotation in one direction or the other, the wedge wedge 7 slides by its inclined face 7a in one direction or the other on the wedge 9, which causes this place a corresponding bending of the table 8 and the folding tool.

The control devices with screw 18 and pinion 23 of the wedge 7 are thus distributed along the latter, symmetrically on either side of its transverse axis XX, as can be seen in FIG. 5. All the pinions 23 are linked together by the single control chain 26 which can be driven manually by an end crank not shown, or by a motor, such as the motor 28 visible in FIG. 5.

The rotation of the pinions 23 allows the simultaneous advance of the screws 22 (the number of which is of course variable as a function of the length of the wedge 7), and therefore the thrust at as many corresponding points on the wedge wedge 7.

• a) donner à chaque vis 18 un filetage de pas différent, qui augmente lorsqu'on se rapproche de l'axe machine X-X,
• b) réaliser des pignons 23 de chaîne dont le nombre de dents diminue lorsqu'on se rapproche de l'axe machine X-X.

To deform it along the concave curve 29 (Figure 5) two solutions are possible:

• a) give each screw 18 a different pitch thread, which increases when approaching the machine axis XX,
• b) make chain sprockets 23, the number of teeth of which decreases when approaching the machine axis XX.

It is also possible to combine solutions a) and b) in order to give more curvature to the shim 7.

The motor 28 can be controlled, either by a contactor, or by program in the case of a digital control of the machine. Program control is particularly interesting in that it allows automatic adjustment of the bending when the characteristics of the sheet to be bent and the tools used have been displayed.

The horizontal deformation of the wedge wedge 7 is carried out so that it slides by its sloping face 7a on the corresponding sloping face 9a of the wedge 9, progressively between the fixed points 17 of the ends and the machine center. As a result, the wedge 7 also deforms in the vertical plane.

The table 8, which is constantly resting on the wedge 7 thanks to the screws 13 and the elastic washers 14, deforms in the same way, as does the folding matrix placed on the table 8.

These deformations, considered to be small compared to the longitudinal dimensions of the parts, are perfectly elastic, so that the rectilinear shape of the table 8 can be found at any time.

The initial adjustment of the bias wedge 7 makes it possible to compensate for the linearity faults of one or the other of the decks 1, 2, and to obtain a constant distance between them over their entire length.

The setting of the screws 18 against the wedge wedge 7 in its original position is done by extracting the grooved sleeve 21 and turning the screw 18 in the desired position. When this is reached, the sleeve 21 is returned to its position and locked in rotation.

An important advantage of the bending device which has just been described consists in its simplicity, thanks to the use of a single wedge 7 of great length therefore easily deformable, and this by a single control system of all the points of thrust. The fact that the control of the deformation of this wedge requires only relatively low forces allows the use of a small motor 28 of the stepping type, controlled by program.

In the second embodiment illustrated in Figures 6 and 7, the movable and deformable upper wedge 37 and its fixed support member 39 are formed by two identical parts extending from one end to the other of the tool holder (8 ). The upper wedge 37 has a lower longitudinal surface 37a with variable slope conjugate with a corresponding longitudinal surface 39a of the fixed lower wedge 39, formed on the upper face thereof.

The shims 37 and 39 are pierced with holes, not shown to simplify the drawing, similar to the holes drilled in the shims 7 and 9, and into which the screws 13 penetrate.

The two surfaces with variable slope 37a, 39a are complementary so that when the shims 37, 39 are placed one on the other so as to apply one against the other surfaces 37a, 39a, the whole of the two wedges forms a regular parallelipiped, the respective vertical faces 40 and 41 of the wedges 37 to 39 being located in the same vertical plane. Each of the surfaces 37a, 39a is defined by the grid shown in Figure 6 for the surface 39a.

The lines 43 to 49 are transverse lines on the surface 39a, extending from one end of the wedge 39 to its middle 0, through which the line 49 passes. More specifically, the lines 43 to 49 are the intersections of planes vertical parallel to each other, with the surface 39a, and it can be seen that the slope of the lines 43 to 49 on the horizontal increases progressively between the end of the wedge 39 and its center, from the value zero to the value alpha at the center of the hold. It is obviously the same between the straight line 49 and the other end of the wedge 39.

In its initial position, the movable and deformable shim 37 is placed in abutment on the shim 39 so that the surfaces with variable slope 37a, 39a are applied. one against the other at each of their points.

When exerting transverse thrusts at different points of the wedge 37, by means of the devices of FIG. 4, the wedge 37 undergoes a transverse translation on the wedge 39, and due to the displacement of the surface 37a on the conjugate surface 39a , as well as under the effect of the screws 13 and the electric washers 14, the upper wedge 37 arches to form the desired upper bending 37b (FIG. 7).

This result is obtained. Thanks to the fact that the superposition of the two surfaces 37a, 39a makes it possible to bring all the points of the latter into contact in the free state only in a single position, that in which the vertical faces 40 and 41 are in the same vertical plane (as well as the transverse vertical faces of the wedges). when one of the surfaces 37a, 39a is moved relative to the other, they cannot continue to coincide unless one of them is deformed, which in this case causes the upper face of the wedge 37 to bend.

The advantage of this embodiment consists in the fact that, to obtain the bending of the shim 37, it suffices to subject the latter to a transverse translation as a whole. This makes it possible to eliminate the fixed points at the ends of the wedge 37, and to exercise the transverse thrusts by all identical control members (screws 18 and pinions 23).

The invention is not limited to the embodiment described and may include variant embodiments. Thus, the screws 18 can have multipan heads instead of the grooves 19, cooperating with corresponding multipan sections of the sockets 21. A deformable shim such as 7 can also be mounted in the upper movable apron instead of the fixed lower apron. The support member 9 can be an integral part of the body 1 and can be machined thereon.

Claims (8)

1 - Device for bending a tool holder of a press brake comprising a fixed apron (1) and a movable apron (2), intended to keep the distance between the tools fixed on the aprons (1, 2) constant folding a sheet between them, comprising a single shim (7) extending over the entire length of one of the tool holders (8) of the aprons (1, 2), having a face (7a) inclined transversely to the folding direction and in sliding support on a support member (9), and means for exerting adjustable transverse thrusts at different points along this wedge (7) in order to elastically deform the wedge (7) in sliding it by its face; inclined (7a) and thereby bending the tool holder (8) and the associated tool, characterized in that the means for controlling the deformation of the wedge (7) comprise, at each transverse thrust point, a screw hollow (18) engaged in a socket (21) integral with the tool holder (8) so that it can be moved in translation in this socket (21), a member (22) for fixing the screw (18) to the wedge (7), a pinion (23) mounted coaxially with the screw (18) on a thread thereof, in order to be able to drive it in translation in the sleeve (21), and a single control system (26) for the rotation of the set of pinions and consequently of the deformation of the set of the block (7) by the thrusts of the hollow screws (18) on the block (7). 2 - Device according to claim 1, characterized in that the system for controlling the rotation of the pinions (23) comprises a chain (26) engaged with all of the pinions and actuated either manually by an end wheel, either by a motor (28) capable of being controlled by a contactor or by program in the case of a digital control of the press. 3 - Device according to claim 2, characterized in that the support member (9) is a second fixed wedge extending over the entire length of the tool holder (8) and interposed between the first movable wedge (7) and the body of the corresponding deck (1), and the shims (7, 9) are pierced with holes (12) traversed by elements for fixing the tool holder to the body of the deck, for example screws (13), the holes ( 12) of the mobile wedge (7) being formed so as to reserve a transverse clearance on either side of the fixing elements (13) in order to allow a transverse movement of the wedge (7) on its support member (9). 4 - Device according to claim 2, characterized in that the support member of the wedge (7) formed integral with the body of the deck (1). 5 - Device according to one of claims 1 to 4, characterized in that the pushing means on the wedge (7) are arranged so as to deform the latter along an adjustable curve (29) in order to cause the door to bulge tool (8) and the tool, either by hollow screws (18) provided with threads of increasing pitch from the ends of the wedge (7) towards its center, or by pinions (23) provided with teeth, the number of which of teeth decreases from the ends of the wedge (7) towards its center, or by both, the wedge (7) being fixed at its two ends. 6 - Device according to one of claims 1 to 5, characterized in that the hollow screw (18) is provided with a multi-panel or fluted head, engaged in a corresponding section of the sleeve (21). 7 - Device according to one of claims 1 to 3, characterized in that the movable wedge (37) and its support member (39) consist of two identical parts extending from one end to the other of the tool holder (8), and each of these shims (37, 39) has a longitudinal surface (37a, 39a) conjugate of the corresponding longitudinal surface of the other wedge and having a variable transverse slope so that when the upper wedge (37) is turned over on the lower wedge (39) with their vertical faces (40, 41) located in a same vertical plane, said conjugate surfaces (37a, 39a) are applied one against the other at all their points, and that the transverse translation of the upper wedge (37) on the surface with variable slope (39a) of the wedge lower (39) and over its entire length causes a bending of the upper wedge (37) and the corresponding deck. 8 - Device according to claim 7, characterized in that each surface with variable slope (37a, 39a) has a transverse slope on the horizontal which increases from the ends of the wedge to the middle thereof, by a value zero at an angle (α).

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