EP0387121B1 - Clamping device for a long piece such as a punch, a die or such a tool on a table of a press bending machine - Google Patents

Description

The present invention relates to an instantaneous fixing device, in accordance with safety standards, for various elongated parts and in particular for folding tools, to be fixed on the deck of a press brake.

The tool can be, for example, a punch or a press brake die hooked or fixed securely to the apron or to one or more intermediate tool holders. It must be adapted to the work carried out on the press brake, so it must be changed frequently.

Most often, it has a heel applied against a vertical face of the tool holder and clamped by flanges using a plurality of screws. When suspended, avoid dropping the tool in the event of loosening; for this purpose, the heel can be provided with a groove or a shoulder, while the straps have a reverse form. In this case, it can only be mounted or removed laterally by sliding it, which has drawbacks, especially when the tool to be changed is surrounded on each side by other tools.

In addition, the tightening time of all screws is long. As a palliative, the screws can be replaced by hydraulic or pneumatic systems, as described in patents FR-A-2,339,485 and DE-A-35 24,694, which saves time on tightening but does not do not remedy the extraction difficulties. In addition, these devices are expensive, they are restrictive because they must meet strict safety standards in order to ward off the danger of falling due to an accidental leakage of fluid.

JP-A-62 267 019 is known, which is considered to be the closest state of the art, a fixing device of another type comprising a flange pivotally mounted about an axis carried by the support of the 'tool. This flange is capable of clamping the heel for fixing the tool against one face of this support. The flange is controlled by a movable blocking member placed against the upper part thereof. However, this device is not satisfactory from the point of view of safety since it no longer retains the tool once the flange is in its tool release position.

This is why the present invention aims to provide a tool fixing device which has all the safety guarantees, which allows frontal introduction in the hooking position and which provides instant clamping to its position. work, triggering by this gesture the automatic tightening of the flange.

To this end, the subject of the invention is a fixing device for an elongated part such as a punch or die or the like on a press brake apron or on intermediate tool holders of the type comprising a movable clamping flange disposed opposite one of the faces of the corresponding support and pivotally mounted about a longitudinal axis mounted in bearings carried by the support of the tool, this flange being able to clamp against this face of the support a heel for fixing the tool, a movable blocking member being able to be placed against a flat surface formed on the rear face of the flange facing the face of the tool support, characterized in that the flange has on its rear face facing the face of the tool support, a relief in the form of a shoulder, situated in the region of the pivot axis, and a bearing surface, beyond the relief, this bearing surface being intended to cooperate with the heel of the tool.

The present invention also relates to a tool intended to be adapted on a press brake of which at least one of the aprons is equipped with a device for fixing, this tool comprising a heel intended to be engaged between a clamping flange of this fixing device and a corresponding bearing face provided on the support of this tool,
on its front face, intended to be turned towards the clamp, the tool fixing heel comprising a recess leaving an end nose, intended to be applied against a bearing surface provided on the corresponding face of the flange, characterized in that:
- At the end of its opposite face, the tool fixing heel has a convex cylindrical surface or a chamfer inscribed in this surface.

Thanks to this arrangement, a tool of the type in question can be fixed in place very quickly and with great security, thanks to a simple gesture which can be accomplished either by a man or by a robot. Indeed, the rotation of the tool-flange assembly automatically places the tool in the working position.

As for the removal of the tool, it can be carried out in two stages as a safety measure, namely: a first stage corresponding to the loosening of the flange but with retention of the tool, and a second stage corresponding to the extraction of the tool on the front by a rotational movement opposite to that of the assembly.

In an advantageous embodiment of the present device, the arrangement is such that the movable blocking member is maintained in its retracted position when the flange is open and it automatically goes into the locked position when the tool-flange assembly has pivoted completely in the direction of closing.

According to a particular characteristic, this blocking member consists of a rotary cam of such shape that by turning around its axis, its contact with the flange is practically linear and tends to spread the flange gradually.

Furthermore, the arrangement is such that this blocking member is actuated automatically when the tool is pushed, which ensures instant clamping of this tool.

In a particular embodiment, the unlocking control is carried out by a lever. In such a case, the levers of the various fixing devices, provided on the same press brake apron, can act independently of each other or be connected together and connected to a general control.

• sur sa face arrière tournée vers la face du support de l'outil, la bride conporte un relief en forme d'épaulement, situé dans la zone de l'axe de pivotement,
• le creux du talon de fixation de l'outil présente un profil semblable au relief prévu sur la bride de serrage du dispositif de fixation correspondant, et laissant substituer un nez d'extrémité, destiné à s'appliquer contre une portée d'appui prévue sur la face correspondante de la bride, au-delà du relief,
• à l'extrémité de sa face opposée, le talon de fixation de l'outil présente une surface cylindrique convexe ou un chanfrein inscrit dans cette surface.

The present invention also relates to a tool attachment device assembly comprising a piece of elongated shape such as a punch or die or similar tool on a press brake apron or on intermediate tool holders of the type comprising a movable clamping flange disposed opposite one of the faces of the corresponding support and pivotally mounted about a longitudinal axis mounted in bearings carried by the support of the tool, this flange being able to clamp against this face of the support a fixing heel of the tool, which heel has a recess disposed on its front face facing the clamping flange, a movable blocking member being able to be placed against a flat surface formed on the rear face of the flange, which is facing the face of the support of the tool after the fixing heel has been put in place, which ensures the clamping of the flange on the heel of the tool, characterized in that:

• on its rear face facing the face of the tool support, the flange has a relief in the form of a shoulder, located in the region of the pivot axis,
• the hollow of the tool fixing heel has a profile similar to the relief provided on the clamping flange of the corresponding fixing device, and allowing the substitution of an end nose, intended to be applied against a bearing surface provided on the corresponding face of the flange, beyond the relief,
• at the end of its opposite face, the tool fixing heel has a convex cylindrical surface or a chamfer inscribed in this surface.

However, the invention also relates to a press brake equipped with a device as defined above.

Other characteristics and advantages of the fixing device according to the invention will become more apparent from the following description of an exemplary embodiment given by way of non-limiting example with reference to the appended drawings in which:

Figure 1 shows, seen in profile, by way of example, the mounting of a folding punch on its tool holder by means of a fixing device according to the invention.

Figure 2 is a front view of such an assembly.

Figure 3 shows the device when the flange is loose, the punch being in the so-called safety position.

Figure 4 shows the extraction of the tool with the particularity of an arming lever located at the front.

FIG. 5 shows, seen from the rear, a system for actuating the cam in the position locked by a spring; the lever for arming the spring being integral with the cam constituting the locking member and this lever being located at the front, as in FIG. 4.

FIG. 6 shows, seen from the rear, a system for actuating such a cam in the unlocked position, the cocking lever of the spring rotating freely on the axis of the cam as in FIGS. 1 and 3.

Figure 7 illustrates a particular embodiment of the cam constituting the locking member.

As shown in Figures 1, 2, 3 and 4, the upper deck 1 receives a series of intermediate tool holders 2 fixed with flanges 3 tightened strongly by screws 4. This traditional means of clamping is, in the '' state of the art, most often reproduced for fixing the punch 5 on the tool holder 2. In this case, the heel of the tool is pinched between the front face 19 of the tool holder 2 and a similar flange to the flange 3.

On the other hand, in the device according to the invention, the clamping of the tool fixing flange 6 is ensured in a different way. Instead of being tightened by screws, it is articulated around a longitudinal axis 7 parallel to the free edge of the tool holder. This axis is formed by two journals rotating in bearings 8a and 8b fixed on the tool holder 2.

On its rear face 10, which is turned opposite the tool holder 2, this flange 6 has a shoulder 9 which can be of polygonal or cylindrical shape and which is located in the region of the pivot axis 7. On either side of this shoulder 9, there are flat surfaces 11a and 11b which will be brought into contact respectively with a blocking member and with the front face of the tool 5. However, the surface 11a is separated from the shoulder 19 by the surface 22, the role of which will be explained later.

The locking member may consist of a rotary locking cam 12 and the arrangement is such that the flange 6 acts like a lever to ensure the tightening of the tool. Furthermore, the upper edge 24 of the flange 6 is a cylindrical surface of radius R2 centered on the axis 7 or an equivalent polygonal surface. As will be explained later, this surface is intended to serve as a bearing surface for the cam 12 when the latter is in the retracted position.

The tool 5 has at its upper part a heel 15 whose face 5a located opposite the flange 6 has a relief 13 opposite and substantially the same profile as the shoulder 9 of the flange 6. At the upper end of the corresponding face of the heel 15, this recess 13 leaves a nose 21. The opposite face 17 of the recess 18, located at the base of the heel 15, is extended at its upper end by a cylindrical surface 14 of radius R1 which is tangent thereto and the center of which is at the same distance from the face 17 and the shoulder 18 of the tool as the axis of rotation 7 of the faces 19 and 20 of the tool holder.

In this way, the reference faces of the tool and the tool holder coincide when the tool is clamped. In addition, the nose 21 of the tool rests on the surface 22 of the flange, forming a bearing surface, when the tool is inserted into the tool holder.

The locking cam 12 is integral with a pin 25 itself connected to a clamping control member. This cam 12 has such a shape that it can be brought, by rotation, into a retracted position above the flange 6, position in which a part 32a of its periphery rests against the bearing surface 24 provided on the flange, while in the clamping position its active face 30 exerts its force against the face 11a of this flange.

A particular embodiment of this cam, as shown in FIG. 7, consists of a cone 30 limited by two planar faces 32a and 32b and by a cylindrical surface 31. The axis of rotation 25 is parallel to the axis 34 of the cone and located at a certain distance from this axis. Such a cam has the property of always having a rectilinear generator in a vertical plane whatever the angle of rotation, this generator gradually moving away from the base of the cone during rotation.

Figures 5 and 6 show, by way of nonlimiting example, an actuation mode of the locking cam 12. The axis 25 of rotation of this cam passes through the tool holder 2 and is extended by an eccentric crank 35 On this crankcase is coupled a spring 36 housed around a guide 37 articulated on an axis 38. In this embodiment, the orientation of the crankcase 35 relative to the cam 12 is such that the torque on the cam varies in inverse function compression of the spring. In this way, the locking cam exerts its maximum force in the clamping position while it only very slightly presses on the face 24 of the flange when it is in the retracted position.

We therefore see that, to mount the tool, we introduce it frontally and from below, as shown in Figure 4, then rotate it back and forth until it is hooked as shown in Figure 3. To obtain the clamping of the tool as shown in Figure 4, simply continue to rotate the tool according to arrow F. Indeed, the nose 21 of the upper end of the front face of the heel 15 then presses on the bearing surface 22 provided on the rear face 10 of the flange, this which causes it to pivot with the tool in the same direction. During the last phase of this movement, the upper end of the flange 6 is brought forward of the position of the clamping cam 12. Consequently, the latter is released and under the action of the spring 36, it turns on itself to engage behind the surface 11a of the flange 6. This therefore ensures the automatic tightening of the fixing heel 15 of the tool, the flange 6 then acting as a lever, as already indicated previously.

For unclamping the tool, a variety of different control modes can be devised because it suffices to rotate the cam 12 in the opposite direction to that of locking while arming the spring 36. One can, for example, use a lever located either in front of or behind the tool holder. The operation of this lever can be carried out either individually or by connecting it to similar levers of identical fixing devices which are mounted on the same tool support. In the latter case, it is possible to provide a general order.

• a) Une première position de desserrage, obtenue lorsqu'on arme le ressort 36 en tournant la came 12 au-delà du point mort constitué par l'alignement des axes 25, 35 et 38. Dans cette position stable, l'arète 43 de la came 12 vient s'encastrer derrière la bride avec un jeu autorisant le glissement latéral de l'outil.
• b) Une deuxième position d'extraction, dans laquelle la face 32a de la came est amenée, par rotation dans une position parallèle à la surface d'appui 24 prévue sur la bride, de façon à s'appuyer sur elle en autorisant la rotation de cette bride et, par suite, l'extraction frontale de l'outil.
• c) La troisième position du levier est celle qu'il prend automatiquement sous l'effet du ressort, solidairement avec la came, lorsque l'outil est bridé.

In a first particular embodiment of the invention, as shown in FIGS. 4 and 5, provision is made in particular for this lever 41 to be able to take three positions, namely:

• a) A first loosening position, obtained when the spring 36 is armed by turning the cam 12 beyond the neutral point formed by the alignment of the axes 25, 35 and 38. In this stable position, the edge 43 of the cam 12 is fitted behind the flange with a clearance allowing the lateral sliding of the tool.
• b) A second extraction position, in which the face 32a of the cam is brought, by rotation into a position parallel to the bearing surface 24 provided on the flange, so as to bear on it while allowing rotation of this flange and, consequently, the front extraction of the tool.
• c) The third position of the lever is that which it automatically takes under the effect of the spring, solidly with the cam, when the tool is clamped.

In another particular embodiment of the invention, as shown in Figures 1, 3 and 6, there is provided a lever 44 freely rotating about the axis 25 and bearing on a crank 39 secured to the crank 35 for arming spring. This solution is particularly advantageous for operating the levers of several fixing devices using a general control connected to the axes 42. In fact, in the clamping position, the cams, and consequently the cranks 35, assume varying positions from one tool holder to another due to the various factors of dispersion of the parts making up the mechanical assembly.

The examples given are not limiting and one can conceive of any other means for arming the spring.

It is also obvious that, to lock the flange, a rotary cam of another type or other means could be used without departing from the scope of the invention. Thus it would be possible to provide a movable lock comprising a blocking ramp.

The fixing device according to the invention can be used either to rigidly suspend an object, or to fix it on its base. In both cases, it allows installation and removal after a switch to the operator, which also has the advantage of avoiding interference or shock with other parts located in the same plane and close to the object handled.

It should be noted that the operations of laying and removing a tool, which are permitted by the present fixing device, are particularly suitable for manipulation by robot because they require only one simple and precise gesture. .

Furthermore, as already indicated, the invention also relates to tools, intended to equip press brakes, and whose heel is specially arranged so that these tools can be fixed in place by means of devices fixing according to the invention. The particular characteristics of the heel for fixing these tools are then those of the tool 5 previously described. Finally, the present invention further relates to press brakes equipped with fastening devices as described above.

Claims (13)

1. A clamping device for fastening an elongated part such as a punch (5), a die or a similar tool to a table of a press-bending machine or to intermediate tool-holders (2), of the type comprising a movable clamping plate (6) disposed in registry with one (19) of the faces of the respective tool-holder (2) and being mounted for swivelling about a longitudinal axle (7) mounted in bearings (8a, 8b) carried by the tool-holder, said clamping plate (6) being adapted for pressing a fixation heel (15) of the tool (5) tightly against said one face (19) of the tool-holder, and a movable blocking member (12) being adapted for being placed against a planar surface (11a) formed on the rear face (10) of the clamping plate (6) turned towards the said one face (19) of the tool-holder for the tool (5),
   characterized in that the clamping plate (6) comprises on its rear face (10) turned towards said one face (19) of the tool-holder a relief (9) shaped as a shoulder located in the zone of the swivelling axle (7), and a bearing surface (22) located beyond said relief (9), this bearing surface (22) being intended for cooperating with the heel of the tool (5).
2. A clamping device according to Claim 1, characterized in that the movable blocking member (12) bears against the corresponding face (11a) of the clamping plate (6) with a surface (30) belonging to a tightener cam, the action of which is gradual as a function of the position assigned to said cam.
3. A clamping device according to Claim 2, characterized in that the movable blocking member (12) consists of a cam having the shape of a portion of a cone (30) and which is mounted for rotating about an axis (25) being parallel with the axis (34) of said cone (30), but being offset relative thereto.
4. A clamping device according to Claim 2 or 3, characterized in that the displacement of the movable blocking member (12) towards its blocking position is effected by means of a spring (36), the arrangement being such that said spring becomes relaxed when said blocking member (12) is released out of its retracted position.
5. A clamping device according to Claim 4, characterized in that the cocking of the spring (36) acting upon the movable blocking member (12) is combined with the retracting of said blocking member, the cocking being carried out by means of an appropriate control means such as a lever (44).
6. A clamping device according to Claim 5, characterized in that the movable blocking member (12) rests, in its retracted position, against a supporting surface (24) provided on the clamping plate (6), said surface (24) presenting a convex cylindrical curvature having a radius (R2), the centre of said curvature being coincident with the rotation axis (7) of said clamping plate (6).
7. A clamping device according to Claim 5 or 6, characterized in that it is associated with further identical devices distributed, together with said device, over the whole length of the press-bending machine, and in that the means provided for cocking the springs (36) in these various clamping devices are connected to a general control means.
8. A clamping device according to any one of Claims 4 to 7, characterized in that the blocking member (12) comprises one position in which the clamping plate (6) is loosened but is allowed to swivel only very slightly, in such manner that the tool (5) having previously been fixed is held back by means of said clamping plate (6).
9. A tool intended for being adapted in a press-bending machine wherein at least one of the aprons (1) is equipped with a clamping device, said tool (5) comprising a heel (15) intended for being engaged between a clamping plate (6) of said clamping device and a corresponding supporting face (19) provided on the support (2) of said tool, while the fixation heel (15) of the tool (5) comprises, on its front face (5a) intended for being turned towards the clamping plate (6), a recess (13) allowing an end nose (21) to remain present, said nose being intended for resting against a bearing surface (22) provided on the corresponding face of the clamping plate (6),
   characterized in that the fixation heel (15) of the tool (5) presents on the end of its opposite face (17) a convex cylindrical surface or a chamfer (14) inscribed within said surface.
10. A tool according to Claim 9, characterized in that the convex surface (14) is a cylindrical surface, the central axis of which is intended to coincide with the swivelling axis (7) of the clamping plate (6) when the recess (13) of said tool (5) is pressed against the raised portion or relief (9) of the clamping plate (6).
11. A tool according to Claim 9 or 10, characterized in that it comprises at the base of the heel (15), on the face facing the recess (13), a shoulder (18) intended for coinciding with a corresponding reference surface (20) on the tool-holder (2) when the tool (5) is clamped.
12. An assembly of a clamping device and a tool comprising an elongated part such as a punch (5), a die or a similar tool on an apron (1) of a press-bending machine or on intermediate tool-holders (2) of the type comprising a movable clamping plate (6) disposed in registry with one (19) of the faces of the corresponding support (2) and being mounted for swivelling about a longitudinal axle (7) mounted in bearings (8a, 8b) carried by the tool support, said clamping plate (6) being adapted for pressing a fixation heel (15) of the tool (5) tightly against said one face (19) of the support, said heel (15) having a recess (13) disposed on its front face (5a) turned towards the clamping plate (6), a movable blocking member (12) adapted for being placed against a planar surface (11a) formed on the rear face (10) of the clamping plate (6), which rear face (10) is turned towards the face (19) of the support of the tool (5) after the fixation heel (15) of the tool has been put into place, thus ensuring the tightening of the clamping plate (6) on the heel (15) of the tool (5),
    characterized in that the clamping plate (6) comprises on its rear face (10) turned towards the face (19) of the support for the tool (5), a raised portion (9) shaped as a shoulder, located in the zone of the swivelling axis (7),

    - the recess (13) of the fixation heel (15) of the tool (5) presents a profile similar to the raised portion (9) provided on the clamping plate (6) of the corresponding clamping device and allowing an end nose (21) to remain present, said nose being intended for being pressed against a bearing surface (22) provided on the corresponding face of the clamping plate (6), beyond the raised portion (9),

    - the fixation heel (15) of the tool (5) presents on the end of its opposite face (17) a convex cylindrical surface (14) or a chamfer inscribed within said surface.
13. A press-bending machine comprising two working aprons (1) located one above the other, one of which is movable and the other one is fixed,
    characterized in that at least one of said aprons (1) is equipped with a clamping device according to one of Claims 1 to 8 for the fixation of one or several tools (5) having an elongated shape on said apron (1).

Images