EP3335813B1 - Sheet metal forming machine by longitudinal stretching and method using such a machine - Google Patents

Description

TECHNICAL FIELD TO WHICH THE INVENTION REFERS

The present invention relates to the general field of forming or forming sheets (in particular metal sheets) by longitudinal stretching by means of drawing presses.

It relates more particularly to a machine (or press) for forming sheet metal by longitudinal stretching, this machine comprising two drawing heads located on either side of a forming tool for the sheet, which drawing heads each comprise a jaw line secured to a support structure which is associated with drawing means and which is mounted on a frame by means of a tilting axis, and at least one tilt cylinder being interposed between said frame and said support structure, to allow rotation of said support structure about said tilting axis.

BACKGROUND

The machines or longitudinal drawing presses are conventionally constituted by two drawing heads arranged vis-à-vis, each comprising a line of jaws for gripping the edges of width of the sheet that is desired to conform.

Between these two jaw lines is disposed a forming tool on the active side of which the sheet is intended to be applied by force, for the purpose of shaping. The active face of this forming tool is adapted to the profile of the part that one wishes to obtain.

The lines jaws vis-à-vis are each associated with actuating cylinders to adapt their positioning in space and to implement the desired stretching function.

For example, as described in the document EP-1,726,377 , which forms the basis of the preamble of claim 1, each jaw line is carried by a support structure equipped with drawing jacks; and this support structure is mounted on a frame by means of a horizontal tilting axis subjected to the action of one or more tilting cylinders.
The two frames which carry the jaw lines are mounted on a support frame, at least one of them slidably along an axis of displacement parallel to the axis of stretching.
In particular this document EP-1,726,377 relates to a longitudinal drawing press provided with curved jaw lines, which makes it possible to create a differential traction movement between the central jaw and the peripheral jaws, so as to tend to standardize the drawing state on the surface of the jaw. sheet metal and generate a stretching said "with edge compensation effect".

During the implementation of known longitudinal stretching machines, the forming tool located between the two drawing heads needs to be adjusted in height, by means of adapted extensions, depending on the sheet that is wish to conform and draw characteristics to apply to it.

• les outils déjà existants peuvent nécessiter dans certains cas l'utilisation de rehausses complémentaires, et
• les nouveaux outils conçus peuvent avoir des hauteurs et des masses importantes, génératrices de coûts.

Although software, supplied with the machine, allows to guide and design the forming tool to be properly positioned with respect to the kinematics of the machine and efforts to support:

• already existing tools may require in some cases the use of complementary extensions, and
• the new tools designed can have significant heights and masses, generating costs.

OBJECT OF THE INVENTION

In order to overcome the aforementioned drawbacks of the state of the art, the present invention proposes a machine for forming sheet metal by longitudinal stretching, which machine comprises two drawing heads located on either side of a forming tool for the sheet, which drawing heads each comprise a jaw line secured to a support structure which is associated with drawing means and which is mounted on a frame by means of a tilting axis, at least one tilting cylinder being interposed between said frame and said support structure, to allow rotation of said support structure about said tilting axis,
and said frame being carried by a support frame,
this machine being characterized in that it comprises means interposed between said support frame and said frame, arranged to allow adjustment of the vertical positioning of said tilting axis.

Such adjustment means make it possible to adjust the height of the jaw lines on either side of the forming tool; we can thus dispense with the presence of the systems of extensions needed in the machines of the state of the technique and thus simplify the tooling structure.
The current adjustment problems of the forming tool are reported on the drawing heads, the corresponding settings being then easier to achieve.
These particular means also confer additional adjustment and implementation possibilities. In particular, they make it possible to adjust certain angles and heights during forming, thus making the operation more fluid and improving productivity.
The versatility characteristics of the machine are further improved. And, for the machines concerned, it is also possible to implement an edge compensation on the sheet during the forming operation.

According to a first preferred embodiment, the frame is mounted on the support frame via a complementary tilt axis, parallel or substantially parallel to the tilting axis, at least one complementary tilt cylinder being interposed between said frame and said support frame to allow the rotational maneuver of said frame about said complementary tilt axis and thus allow adjustment of the vertical positioning of said tilt axis.
In this context the tilting axis and the complementary tilting axis preferably extend horizontally or substantially horizontally.
In addition, said complementary tilt axis is advantageously located on the opposite side of the tilting axis with respect to the associated jaw line.

According to a preferred embodiment, the frame is mounted on the support frame by means which allow it to move relative to said support frame parallel to itself along a vertical axis.
Said frame then advantageously consists of a vertical sliding carriage, mounted on vertical rails and operated by one or more cylinders.

• une partie de bâti mobile, qui porte lesdits moyens de réglage du positionnement vertical de l'axe de basculement, et
• une partie embase de bâti,

ladite partie de bâti mobile étant montée mobile en translation sur ladite partie embase de bâti, selon une direction perpendiculaire à l'axe de basculement et le cas échéant à l'axe de basculement complémentaire.
La partie embase de bâti est alors avantageusement commune aux deux têtes d'étirage et sert de support à l'outil de formage.According to another feature, the support frame preferably comprises:

• a moving frame part, which carries said means for adjusting the vertical positioning of the tilting axis, and
• part of a base,

said movable frame portion being movably mounted in translation on said frame base portion, in a direction perpendicular to the tilting axis and optionally to the complementary tilting axis.
The frame base portion is then advantageously common to the two drawing heads and serves as a support for the forming tool.

According to another characteristic, the machine according to the invention may comprise control means adapted to manage the displacement of the tilt cylinder or jacks and means for adjusting the vertical positioning of the tilting axis, as a function of the spatial position. desired bit lines.

The invention also relates to a method of implementing a machine as defined above, consisting in managing the displacement of the tilt cylinder (s) and means for adjusting the vertical positioning of the tilting axis, depending the desired spatial position of the jaw lines.

DETAILED DESCRIPTION OF AN EXEMPLARY EMBODIMENT

The following description with reference to the accompanying drawings, given by way of example, will make it clear what the invention consists of and how it can be achieved.

• la figure 1 est une vue schématique de côté d'une machine de formage de tôle par étirage longitudinal conforme à un mode de réalisation préféré de l'invention ;
• la figure 2 est une vue de dessus de la machine d'étirage illustrée sur la figure 1 ;
• les figures 3 à 7 sont des vues schématiques de côté qui illustrent différentes configurations spatiales possibles des têtes d'étirage de la machine d'étirage illustrée sur les figures 1 et 2 ;
• la figure 8 représente schématiquement une variante de réalisation des moyens de réglage de hauteur de l'axe de basculement, en forme de chariot guidé verticalement, ici en position basse ;
• la figure 9 est une vue schématique similaire à la figure 8, montrant le chariot guidé verticalement, en position haute.

In the accompanying drawings:

• the figure 1 is a schematic side view of a longitudinal stretch forming machine according to a preferred embodiment of the invention;
• the figure 2 is a top view of the stretching machine illustrated on the figure 1 ;
• the Figures 3 to 7 are schematic side views illustrating different possible spatial configurations of the drawing heads of the drawing machine illustrated in the drawings. Figures 1 and 2 ;
• the figure 8 schematically represents an alternative embodiment of the height adjustment means of the tilt axis, in the form of vertically guided carriage, here in the low position;
• the figure 9 is a schematic view similar to the figure 8 , showing the vertically guided carriage, in the up position.

The longitudinal stretching machine 1 according to a preferred embodiment of the invention, illustrated on the Figures 1 and 2 , comprises two stretching heads 2, 2 ', here identical, mounted facing one another on a support frame 3, on either side of a forming tool 4.

The forming tool 4 is positioned and fixed on extensions 3a which are themselves fixed on the frame 3 between the two drawing heads 2, 2 '; his active face is adapted according to the final shape of the sheet metal parts T that it is desired to obtain.

Each drawing head 2, 2 'consists of a line of jaws 5 carried by mechanical means adapted to give it the desired spatial movements.

These jaw lines 5 have the function of clamping the width edge of the worked sheet by a jaw grip. They are here each constituted of a juxtaposition of five to eleven jaws 6 (here in this case seven in number); and they are arranged in a plane perpendicular to the drawing direction (marked at 7 on the figure 2 ), or substantially perpendicular to this direction of stretching, to suitably perform their function.

Each jaw line 5 comprises means enabling it to be placed in a rectilinear, curved (concave or convex) configuration, or else in S.

On the Figures 1 and 2 , the jaw line 5 of the two drawing heads 2, 2 'is placed in horizontal straight position; but it can also be in other configurations, for example in a rectilinear position, inclined at an angle to the horizontal, in an S configuration, or in a convex curved position.
The configuration adopted is a function of the inclination and / or the curved shape that one wishes to print on the sheet, so that it can follow the profile of the edge of the tool 4 for the sake of precision of the part performed.

To fulfill their stretching function, the jaw lines 5 are each integral with a support structure 8 subjected to the action of one or more drawing jacks 9.

This support structure 8 (with the jaw line 5 and the drawing jacks 9 associated) is mounted on a frame 10 via a tilting axis 11; and at least one tilt cylinder 12 is interposed between the frame 10 and the support structure 8, to allow the pivoting operation of this support structure 8 around the tilting axis 11.

As can be seen on the Figures 1 and 2 , in the exemplary embodiment illustrated, two tilt cylinders 12 provide pivoting operation of the support structure 8 relative to the chassis 10.

The tilting axis 11 extends horizontally or approximately horizontally, perpendicularly to the direction of stretching 7.

According to the invention, the forming machine 1 comprises means which are interposed between the support frame 3 and the frame 10, arranged to allow adjustment of the vertical positioning of the tilting axis 11 (that is to say to allow adjustment of the height of the tilting axis 11 and thus the jaw line 5).

For this, as illustrated on the Figures 1 and 2 , the frame 10 is mounted on the support frame 3 via a complementary tilt axis 13, and at least one complementary tilt cylinder 14 is interposed between said frame 10 and said support frame 3, arranged to provide the maneuver in rotation of said chassis 10 about said complementary tilt axis 13.

The complementary tilting axis 13 extends horizontally, parallel or substantially parallel to the tilting axis 11.

As we can always see on the Figures 1 and 2 this complementary tilting axis 13 is situated on the opposite side of the tilting axis 11 with respect to the jaw line 5, here below the horizontal plane through which said tilting axis 11 passes.

In the present example, in the exemplary embodiment illustrated, two complementary tilt cylinders 14 provide pivoting operation of the frame 10 relative to the support frame 3.

In the embodiment of Figures 1 and 2 each drawing head 2, 2 '(with its frame 10, the complementary tilting axis 13 and the associated complementary tilting cylinders 14) is carried by a carriage-like frame portion 31, which is mounted on a mounting base portion 32 fixed.

The two carriages 31 have the possibility of moving in translation in the stretching direction 7 on the frame base portion 32, that is to say in a direction perpendicular to the tilting axis 11 and to the axis complementary tilting 13, this under the action of appropriate displacement means (eg cylinders, rack-and-pinion systems or screw-nut systems). In the embodiment of Figures 1 and 2 the displacement of each mobile frame 31 is achieved by direct action by means of a jack one part of which is fixed on said movable frame 31 and the other on the frame base 32.

The stationary base portion 32 fixed is common to both movable frame parts 31 and it also serves as support for the forming tool 4 through the extensions 3a.

The drawing machine 1 according to the invention comprises control means adapted to manage the displacement of the tilt cylinders 12, complementary tilt cylinders 14 and drawing cylinders 9, depending on the desired spatial position of the lines. of jaw 5, this simultaneously or successively.

As illustrated on the figure 3 , the tilting axis 11 of the drawing heads 2 of the drawing machine 1 according to the invention can be used conventionally, by means of the tilt cylinders 12, to rotate the jaw line 5, by example on an angular sector has of the order of 30 °.

For example, as can be seen on the figure 4 starting from a dimension of height x horizontally of the jaw lines 5 (which may correspond to a minimum low position of the jaw line), the stretching machine 1 may be adapted to rotate said jaw lines 5 between a negative angle b (for example of the order of 5 to 10 °) and a positive angle c (for example of the order of 5 to 30 °).

• pour obtenir une inclinaison du châssis 10, et donc de la ligne de mors 5 (figure 5), ou encore
• pour réaliser une compensation de bords sur la tôle (figure 6).

Starting from this low minimum position of the chassis 10, the management of the complementary tilting axis 13 by the complementary tilt cylinders 14 makes it possible to raise the tilting axis 11, as illustrated in FIGS. Figures 5 and 6 :

• to obtain an inclination of the frame 10, and therefore of the jaw line 5 ( figure 5 ), or
• to perform edge compensation on the sheet ( figure 6 ).

It is also possible to obtain a maximum horizontal high position of the jaw line 5, as illustrated in FIG. figure 7 (the height dimension x + Δ x of the jaw line 5 on the figure 7 being greater than the x-coordinate of the figure 4 ).

Any other combined management of the tilting axis 11 and the complementary tilt axis 13 can be implemented.

• les vérins de basculement complémentaires 14 permettent de lever ou d'abaisser l'axe de basculement 11 pour ajuster le niveau des lignes de mors 5, et permettent la mise en oeuvre combinée ou non d'une opération de compensation de bord ;
• les vérins de basculement 12 permettent le basculement des supports des lignes de mors 5 en fonction de l'étirage recherché, et permettent de compenser l'action des vérins de basculement complémentaires 14 ;
• les vérins d'étirage 9 sont utilisés pour étirer la tôle et/ou pour compenser l'effet de rotation des supports de lignes de mors (afin notamment de conserver la distance entre les deux lignes de mors).

In a general way :

• the complementary tilt cylinders 14 make it possible to raise or lower the tilting axis 11 to adjust the level of the jaw lines 5, and allow the combined implementation or not of an edge compensation operation;
• the tilt cylinders 12 allow the tilting of the supports of the jaw lines 5 according to the desired stretching, and make it possible to compensate the action complementary tilt cylinders 14;
• the drawing cylinders 9 are used to stretch the sheet and / or to compensate for the rotation effect of the jaw line supports (in particular to maintain the distance between the two jaw lines).

According to an embodiment variant illustrated on the Figures 8 and 9 , the carrier frame of the support structure 8 is mounted on the support frame 3 by means which allow its displacement parallel to itself along a vertical axis.

These displacement means then advantageously consist of a chassis 10 'in the form of a carriage sliding vertically along slides 15 integral with the movable frame 31, and actuated by at least one hydraulic cylinder 14'. For example two hydraulic cylinders 14 'are placed on either side of the carriage 10'. The cylinder (s) 14 'can be placed at the bottom or at the top of the mobile frame 31.

The up / down function of the support frame 8 and therefore of the jaw line 5 is performed by acting directly on the tilting axis 11 placed on the sliding frame 10 '. The height dimension x + Δ x of the jaw line 5 on the figure 9 is greater than the x rating on the figure 8 .

For this embodiment also, control means are adapted to manage the displacement of the tilt cylinders 12 and the carriage with vertical guidance, depending on the desired spatial position of the jaw lines 5, that simultaneously or successively.

• évite la présence de rehausses réglables en hauteur sur l'outil de formage (outillage et mise en oeuvre simplifiés),
• augmente la possibilité de réglage,
• permet de conformer la tôle au plus près de l'outil,
• meilleure versatilité pour le formage,
• possibilité de compensation de bord(s) pendant le formage,
• possibilité d'ajuster les angles et les hauteurs pendant le formage.

The longitudinal stretching machine according to the invention has the following advantages:

• avoids the presence of height-adjustable extensions on the forming tool (simplified tooling and implementation),
• increases the possibility of adjustment,
• makes it possible to conform the sheet as close as possible to the tool,
• better versatility for forming,
• possibility of compensation of edge (s) during forming,
• ability to adjust angles and heights during forming

Claims (10)

1. Machine for forming sheets by longitudinal stretching,
   said machine (1) comprises two stretch heads (2) located on either side of a forming tool (4) for the sheet,
   said stretch heads (2) each comprising a line of grippers (5) integral with a support structure (8) which is associated with means of stretching (9) and which is mounted on a chassis (10, 10') by the intermediary of a tipping axis (11),
   at least one tipping cylinder (12) being inserted between said chassis (10, 10') and said support structure (8), in order to allow for the maneuvering in rotation of said support structure (8) about said tipping axis (11),
   and said chassis (10, 10') being carried by a support frame (3), characterized in that it comprises means (13, 14; 15, 14'), inserted between said support frame (3) and said chassis (10, 10'), arranged to allow for an adjustment of the vertical positioning of said tipping axis (11).
2. Machine according to claim 1, characterized in that said chassis (10) is mounted on said support frame (3) by the intermediary of a complementary tipping axis (13), parallel or substantially parallel to said tipping axis (11), at least one complementary tipping cylinder (14) being inserted between said chassis (10) and said support frame (3) in order to allow for the maneuver in rotation of said chassis (10) about said complementary tipping axis (13) and as such allows for the adjusting of the vertical positioning of said tipping axis (11).
3. Machine according to claim 2, characterized in that said tipping axis (11) and said complementary tipping axis (13) extend horizontally or substantially horizontally.
4. Machine according to claim 2 or 3, characterized in that the complementary tipping axis (13) is located on the opposite side of the tipping axis (11) with respect to the associated line of grippers (5).
5. Machine according to claim 1, characterized in that said chassis (10') is mounted on said support frame (3) by the intermediary of means (15, 14') which allow for the displacement thereof in relation to said support frame (3) parallel to itself along a vertical axis.
6. Machine according to claim 5, characterized in that said chassis (10') consists of a vertically sliding carriage, mounted on vertical sliders (15) and maneuvered by one or several cylinders (14').
7. Machine according to any one of claim 1 to 6, characterized in that said support frame (3) comprises:

   - a movable frame portion (31), that carries said means for adjusting (10, 13, 14; 10', 14', 15) the vertical positioning of the tipping axis (11), and

   - a base frame portion (32),

   said movable frame portion (31) being mounted mobile in translation on said base frame portion (32), along a direction perpendicular to said tipping axis (11) and to said complementary tipping axis (13).
8. Machine according to claim 7, characterized in that it comprises a base frame portion (32) which is common to the two stretch heads (2, 2') and which is used as a support for the forming tool (4).
9. Machine according to any one of claims 1 to 8, characterized in that it comprises control means suitable for managing the displacement of said tipping cylinder or cylinders (12) and of said means (10, 13, 14; 10', 15, 14') for adjusting the vertical positioning of the tipping axis (11), according to the desired spatial position of the lines of grippers (5).
10. Method for implementing a machine according to claim 9, characterized in that it consists in managing the displacement of said tipping cylinder or cylinders (12) and of said means (10, 13, 14; 10', 14', 15) for adjusting the vertical positioning of the tipping axis (11), according to the desired spatial position of the lines of grippers (5).

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