EP0494633B1 - Structure for holding the forming tools of a metal plate stretch-forming machine - Google Patents

Description

The present invention relates to a support table defining a flat surface for supporting the forming tools in a machine for forming sheets by drawing.

The present invention also relates to a method of using this support table.

The invention applies especially to machines capable of stretching in the longitudinal direction of the forming tool, that is to say in the direction perpendicular to its greatest curvature, requiring jaws articulated so that '' they can curve according to the greatest curvature of the forming tool. In the following text, when it is a stretch as defined above, it will be said simply: longitudinal stretch, thus referring to the direction of positioning, on the machine, of the forming tool independently of the causes the sheet to be stretched lengthwise or widthwise. Conversely, we will speak of transverse stretching when the sheet is stretched in the direction corresponding to the greatest curvature of the forming tool.

In this case, the jaws are generally arranged in a straight line.

In longitudinal stretching, the forming tools are of a very wide variety of length, up to 12 meters, but also be very short, for example 50 centimeters. In machines specially designed for transverse drawing, with straight jaws, the maximum width of the forming tool does not generally exceed four meters and a single table or laying surface for the tools is sufficient.

In the case of longitudinal drawing, the wide range of dimensions and the light structure of the tools require the use of tool holders of variable dimensions. However, the problem can also arise for machines with transverse stretching.

• 1/ La première solution utilise des porte-outils modulaires rigides de dimensions couvrant chacun une gamme de formats d'outils. Cette solution permet de supporter sur toute leur longueur les outils, mais requiert un long temps d'immobilisation de la machine lors des changements de porte-outils. Celle-ci nécessite la manutention et le stockage de ces porte-outils, appelés parfois réhausses, très lourds et encombrants,
• 2/ La deuxième solution connue utilise des tables multiples : soit deux, soit trois.

Currently, two techniques are used:

• 1 / The first solution uses rigid modular tool holders with dimensions each covering a range of tool formats. This solution makes it possible to support the tools over their entire length, but requires a long downtime of the machine when changing the tool holders. This requires the handling and storage of these tool holders, sometimes called extensions, very heavy and bulky,
• 2 / The second known solution uses multiple tables: either two or three.

In the case of two tables, they are adjustable in spacing.

In the case of three tables, the central table is fixed and two side tables are adjustable in spacing from the central table. This solution does not fully support the forming tools and therefore requires tools having a reinforced structure as a result, which increases the cost of the tool and its weight. In addition, in this solution, there are deep voids between these movable tables that it is necessary, for imperative reasons of security to fill with movable floors. These are placed manually.

The present invention aims to overcome these drawbacks and to provide a structure which allows the use of light structure forming tools, fully supported and ensuring complete safety for personnel without requiring him to manipulate boards to fill in empty. The invention applies, in principle, to both transverse and longitudinal stretching machines, the same machine can also be mixed if its jaws can bend.

The invention thus relates to a structure for supporting the forming tools in a machine for forming sheets by drawing, characterized in that it consists of n juxtaposed table segments, mounted in a frame of the machine, at least n-1 of said table segments being equipped, each individually, with means making it possible to place said segment, either in the high working position or in the low rest position.

According to a preferred embodiment, the central table segment is a fixed station in the high working position.

According to another characteristic of the invention, each segment is equipped, at each of its two longitudinal ends, with a telescopic extension.

This characteristic makes it possible to support very wide forming tools in the direction perpendicular to the distance which separates the two stretching jaws.

As will also be seen in the following description, these extensions also make it possible to fix and tension transverse straps or else to clamp a counterform on the forming tool.

• La figure 1 est une vue schématique de dessus montrant la structure support de l'invention.
• La figure 2 est une vue schématique montrant, selon une vue parallèle aux mâchoires, l'un des segments de table de la structure selon l'invention, en position haute de travail.
• La figure 3 est une vue schématique partielle de gauche de la figure 2 montrant trois segments de table en position haute et les autres en position basse de repos.
• La figure 4 est une vue de dessus de la figure 3.
• La figure 5 est une vue schématique partielle d'un segment de table montrant comment une rallonge peut servir d'attache à une sangle transversale.
• La figure 6 correspond à la figure 2, mais montre une réalisation pratique (en demi-vue et en position basse de repos et, en traits fins en position haute de travail).
• Les figures 7 à 10 sont diverses vues schématiques transversales montrant diverses possibilités d'utilisation des rallonges.
• Les figures 11 à 15 sont diverses vues schématiques montrant, dans le sens longitudinal (d'une mâchoire à l'autre) les diverses utilisations des segments de table selon les outils de formage utilisés.

The invention will now be described with reference to the accompanying drawing in which:

• Figure 1 is a schematic top view showing the support structure of the invention.
• Figure 2 is a schematic view showing, in a view parallel to the jaws, one of the table segments of the structure according to the invention, in the high working position.
• Figure 3 is a partial schematic view on the left of Figure 2 showing three table segments in the high position and the others in the low rest position.
• Figure 4 is a top view of Figure 3.
• Figure 5 is a partial schematic view of a table segment showing how an extension can be used to attach to a cross strap.
• Figure 6 corresponds to Figure 2, but shows a practical embodiment (in half-view and in the low rest position and, in thin lines in the high working position).
• Figures 7 to 10 are various transverse schematic views showing various possibilities of using the extensions.
• Figures 11 to 15 are various schematic views showing, in the longitudinal direction (from one jaw to the other) the various uses of the table segments according to the forming tools used.

Referring to Figure 1, there is shown a structure according to the invention intended to support forming tools in a machine for forming sheets by drawing.

This figure shows the jaws 1 and 2 of the machine. These are, for example, jaws with articulated jaws 3 which can be curved.

The invention does not relate to these jaws.

The support structure of the invention is a structure with variable geometry and it is made up of n juxtaposed table segments 4. Twenty three segments have been represented in this figure 1, but this number may be different. For example, each segment can have a width of 45 cm and a length of 2.80 m.

As shown in FIG. 2, the table segments 4 are mounted in a frame 5. Each table segment, or rather preferably all except one, is equipped with means allowing it to be placed either in the high working position, as in the case of segment 4 in FIG. 2, either in the low rest position as shown in dotted lines in this same FIG. 2. The means used is for example a jack 6.

As we have just said, preferably all the segments except one have such a jack, because indeed, whatever the size of the forming tool, it must be placed on at least one segment. The central segment marked 4A is therefore preferably a fixed segment in the high working position.

In the high position, the jacks are held by latches 7 bearing on the frame 5. In the low position, each table segment rests on wedges 8.

The frame 5 is installed in a pit 9 and, in the low rest position, the level of the segments arrives at ground level 10, as can be seen in FIG. 3 which shows two segments 4 in the high working position, as well as the fixed central segment 4A bolted at its lower end to the frame 5 by bolts 11, while all the other segments 4 are in the low rest position.

Each table segment 4, like the fixed central segment 4A, has at each of its longitudinal ends a telescopic extension 12. These extensions are moved by jacks 13. These extensions allow to support forming tools, such as that 14 shown in Figure 9, very wide. To this end, shims 15 make it possible to adjust the level of the extensions at the level of the table segments 4.

In FIG. 4, which shows a partial top view, the fixed central segment 4A has been shown as well as its two neighboring segments with their extensions 12 in the extended position.

For positioning the forming tools, the table segments 4 and 4A each carry a hole 16 in which is housed positioning pins of the forming tools.

As shown in FIGS. 7 and 8, the extensions 12 can also be used to fix and tension transverse straps 17, used during longitudinal stretching with jaws in a curved position.

For this purpose, the extensions 12, as shown in FIG. 5, carry holes 18 which serve to fix towing hooks 19 to which the straps 17 can be hooked by rings 20. Thanks to the multiplicity of holes 18, the positioning of the hooks 19 is adjustable. The tension of the straps 17 is carried out by the cylinders 13 of the extensions.

FIGS. 7 and 8 thus show two cases of use of extensions for fixing straps 17.

In the case of FIG. 8, the forming tool 14 is narrow and auxiliary return rollers 21 are used.

In FIG. 10, the extensions are used to clamp a counter-form 22 on the forming tool 14. For this purpose, transverse beams 23 and tie rods 24 are used. These tie rods 24 are each articulated at the end d 'a beam 23 and at the end of an extension 12. The clamping force is also provided by the jacks 13 of the telescopic extensions 12.

Thus, these extensions can be used either to support forming tools of large transverse dimensions, or to fix and tighten straps in the case of longitudinal stretching, or even to clamp counter-forms on the forming tool. .

FIG. 6 is similar to FIG. 2, but shows a possible practical embodiment of a table segment 4.

In this view, the table segment 4 has been shown in strong solid lines in the low rest position and in fixed broken lines in the high working position. The same references correspond to the equivalent elements of the other figures.

As can be seen, the latches 7 are actuated by jacks 25. In the high position, the latches bear on the longitudinal beams 26 of the chassis 5 and a lug 27 of the latches 7 penetrates into a blind hole 28 of the longitudinal beams 26.

The table segment 4 forms a kind of box having an upper floor 29, two vertical walls 30 each having a notch 31 forming, along all the segments, a visit corridor, and a bottom 32 in two parts, separated by the notch 31. The box further comprises transverse reinforcements. The rod of the actuator 6 for operating the segment 4 is supported on a transverse reinforcement 33.

As can be seen in this figure, each extension 12 of a segment 4 is actuated by a jack 13.

In the high working position shown in thin broken lines, there is placed on the extension 12, shown in the extended position, a leveling shim 15 and also a hook 19 for attaching a transverse strap.

Figures 11 to 15 show various uses of the support structure, depending on the size of the forming tool used.

In FIG. 11, it is a tool 35 of great length, in the case of a longitudinal stretching. For ease of drawing, only five elements have been shown in the high working position, but of course there could be many more and for example all of them. There can indeed be many elements, for example twenty five or twenty seven.

In this figure, the arrows 34 indicate the direction of traction of the stretching jaws. In this example, it is a longitudinal stretching and the shape 14 has a strong curvature in the direction perpendicular to the figure, the jaws of the jaw being curved.

.In this example where the shape 14 rests on five segments and if each jaw exerts a force F in the direction of the arrows 34, the total vertical force undergone by the segments 4, 4A is: $\text{2 F sin α}$

.

FIG. 12 shows an example in which a forming tool 36 has been shown which can also be seen in FIG. 13 and which is placed in a direction corresponding to a transverse stretching in which the jaws are used in the rectilinear position and where the traction can be exerted vertically. In this case in FIG. 13, the total force exerted on the three segments 4, 4A in the working position is 2 F if each jaw exerts a force F in the direction of the arrows 37.

In Figure 12, there is also shown a shape 38 which is a long shape, normally used in longitudinal stretching, that is to say in a position 90 ° from that where it is shown, but which can be also arrange in the direction shown to stretch narrow strips used to reinforce for example the sheet which was previously stretched and formed on this form 38 placed in the longitudinal position.

FIGS. 14 and 15 show an example of transverse stretching on a form 39 placed on the single fixed central segment 4A.

The force exerted on this segment 4A is equal to 2 F if, as in the previous cases, the force exerted by each jaw in the direction of the arrows 37 is F.

(figure 11), car en étirage longitudinal, l'effort 34 n'est jamais vertical.These three examples show that the central segment 4A, which can be used alone, must be sized to be able to support the total effort 2 F on its own. The few segments 4 which surrounds it, for example three on each side, can be dimensioned more weakly, but still fairly strongly. The other segments up to each of the ends of the structure can be dimensioned more weakly because, on the one hand the forces 2 F are distributed over a greater number of segments and on the other hand, because beyond about seven segments we only do longitudinal stretching and then the vertical force exerted on the segments is reduced in the proportion of $\text{sin α}$

(Figure 11), because in longitudinal stretching, the force 34 is never vertical.

Thus, as can be seen, the support table according to the invention makes it possible to adapt to all the possible dimensions of the forming tools. In addition, this structure provides great security because there is no longer any void to fill, the unused segments remaining at ground level. Finally, the extensions 12 make it possible to place tools having a large dimension in the direction perpendicular to the direction separating the two jaws, or to be used to clamp a counterform on the forming tool or even, in longitudinal stretching, to fix and tighten cross straps.

Claims (6)

1. A support table defining a plane surface for supporting a forming tool (14, 35, 36, 38, 39) in a machine for forming metal sheet by stretching, the support table being characterized in that it comprises n juxtaposed table segments (4, 4A) mounted side-by-side in a stand (5), with at least n-1 of said table segments (4) being individually fitted with means (6) enabling said table segment to be placed either in a high, working position, or else in a low, rest position, constituting a plane surface whose length is adjustable to that of the forming tool to be supported.
2. A support table according to claim 1, characterized in that said stand (5) is placed in a cavity (9) in the ground (10) and in that, in the low, rest position, said table segments (4) are situated at ground level (10).
3. A support table according to claim 1 or 2, characterized in that the central table segment (4A) is permanently disposed in a high, working position.
4. A support table according to claim 1, 2 or 3, characterized in that each segment (4, 4A) is fitted at each of its two longitudinal ends with a telescopic extender (12).
5. A method of using the support table of claim 4, characterized in that the said telescopic extenders (12) are used to fix and to tension transverse straps (17) during longitudinal stretching.
6. A method of using the support table according to claim 4, characterized in that said telescopic extenders (12) are used to clamp a counter-form (22) against a forming tool (14) by means of transverse beams (23) placed over said counter-form (22) and each connected at each end to one of said extenders (12) by means of a tie bar (24) hinged firstly to the end of the beam (23) and secondly to said extender (12).

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