Sheet metal stretch forming machine

Abstract

The present invention relates to a sheet metal stretching forming machine (1), which comprises two lines of jaws (7) arranged opposite each other and supported by mechanical means allowing their movement in space. This forming machine (1) is characterized in that said lines of jaws (7) have an adjustable length, each comprising: - a first group of jaws (71a), designed to allow the forming of a sheet metal by longitudinal stretching, and - a second group of jaws (72a) comprising at least two jaws (72) capable of occupying: (a) an inactive position, at a distance from the first group of jaws (71a), to allow the latter to perform said longitudinal stretching, and (b) an active position, in line with the first group of jaws (71a), to allow, together, the forming of a sheet metal by transverse stretching.

Description

Technical field of the invention

[0001] The present invention relates to the general field of shaping or forming sheets (in particular metal sheets) by means of drawing presses.

[0002] It relates more particularly to a sheet metal stretch forming machine, which machine comprises a central longitudinal axis and a frame receiving a forming tool placed between two lines of stretching jaws arranged opposite each other and carried by mechanical means allowing their movement in space. State of the art

[0003] In the field mentioned above, we know of machines called transverse drawing machines.

[0004] Transverse drawing is used to stretch sheet metal across its width, typically along the leading edges. This particular method applies a vertical force to the dies. The sheet metal is clamped in the jaws of the dies and then wraps around them during the forming process. This allows for the production of very narrow parts.

[0005] The machine configuration for this mode is defined by a straight jaw line. The drawing cylinders are extended so that the drawing head is fully retracted into the rocker arm. Oscillation and rotation are in position for this configuration. A support beam for transverse forming is positioned above the jaw line to absorb the vertical forces applied to it. The rocker arm cylinders also absorb this vertical force and allow control of the rocker arm angle during part forming.

[0006] We also know of machines called longitudinal drawing machines, designed to draw sheet metal along its length, typically fuselage components. This method allows a drawing force to be applied to the sheet metal tangential to the tool throughout the process.

[0007] To keep the sheet metal tangent to the tool as described above and maintain constant force across its entire width, the jaw line is equipped with several axes to keep it "floating." In this way, each jaw is articulated along an axis that allows the entire jaw line to curve, keeping the sheet metal tangent to the tool during forming.

[0008] Modern drawing machines are generally designed to perform either longitudinal or transverse drawing. For longitudinal drawing, the sheet metal is limited in width; and for transverse drawing, it is advantageous to have a wider line of jaws than in longitudinal drawing.

[0009] Some known machines include lines of jaws that serve both modes: longitudinal and transverse.

[0010] In this case, the jaw lines are limited to certain widths, otherwise, beyond that, forming problems will arise, in particular limits in terms of forces or radius of curvature. Presentation of the invention

[0011] To overcome the aforementioned drawback of the prior art, the present invention proposes a sheet metal forming machine by drawing, which machine comprises a machine frame having a central longitudinal axis, equipped with a table structure for receiving a forming tool placed between two lines of drawing jaws arranged opposite each other and supported by mechanical means allowing their movement in space. This machine is characterized in that said lines of jaws have a variable length, each of said lines of jaws comprising: a first group of jaws arranged in a line, which first group of jaws is designed to allow the forming of a sheet by longitudinal drawing, the line of jaws of said first group of jaws, called the central line of jaws, comprising two end jaws, and a second group of jaws comprising at least two jaws capable of occupying: (a) an inactive position in which the jaws of said first group of jaws are positioned at a distance from the jaws of said second group of jaws, to allow said central line of jaws to perform the forming of a sheet by longitudinal drawing, and (b) an active position, in which the jaws of said first group of jaws are positioned in line between the jaws of the second group of jaws, in line with the two end jaws of said first group of jaws,

[0012] the resulting jaw line, called the complete jaw line, comprising said first group of jaws and said second group of jaws, being designed to allow the forming of a sheet by a transverse type drawing.

[0013] By its structure, such a drawing machine can therefore achieve, under optimal conditions, either transverse or longitudinal drawing.

[0014] The principle of the present invention is to propose two possible configurations of the bit lines, namely: a configuration adapted to the longitudinal drawing mode, including an incurvable jaw line, and a configuration adapted to the transverse drawing mode, including a straight jaw line, composed of the incurvable jaw line in a straight position (jaws aligned) in the center and 2 fixed parts on either side of the central jaw line.

[0015] Other non-limiting and advantageous features of the forming machine according to the invention, taken individually or in all technically possible combinations, are as follows: the central jaw line is supported by a central jaw line frame, the second group of jaws is supported by a second group of jaws frame, and the machine includes means for the relative movement of said central jaw line frame and said second group of jaws frame, so as to allow said second group of jaws to occupy the aforementioned active and inactive positions;the second group of jaws frame includes a base which extends into two lateral extensions at the distal ends of which are provided the jaws of said second group of jaws, said central jaw line frame includes a cylindrical guide column, centered or approximately centered on said central longitudinal axis and which slides through the base of said second group of jaws frame, translational maneuvering means, constituting said means of movement, and rotational maneuvering means of said guide column are interposed between the base of said second group of jaws frame and the free end of said guide column, located on the other side of said base of the second group of jaws frame with respect to the central jaw line frame;the distal ends of the lateral extensions of the second group of jaws frame are carried by movable support carriages along two longitudinal beams, constituting said machine frame, which extend parallel to said central longitudinal axis, which support carriages are maneuverable along the length of said longitudinal beams by means of carriage jacks; the central jaw line frame and the second group of jaws frame together form a rocker arm which is articulated around a horizontal axis passing through the rocker arm / carriage connecting shafts, which rocker arm is rotated by rocker arm jacks interposed between itself and the connecting shafts; the central jaw line is carried by a jaw-carrying head, itself carried by the central jaw line frame by means of an oscillation axis associated with one or more oscillation jacks interposed between said central jaw line frame and said jaw-carrying head;The jaw-carrying head includes bending cylinders for bending the central jaw line; the drawing machine includes a support beam arranged to bear on the top of said complete jaw line configured in a straight line, to absorb the vertical forces applied thereto.

[0016] Of course, the different features, variants and embodiments of the invention can be combined with each other in various ways as long as they are not incompatible or mutually exclusive. Detailed description of the invention

[0017] Furthermore, various other features of the invention become apparent from the attached description made with reference to the drawings which illustrate one, non-limiting, embodiment of the invention and where: [ Fig. 1] is a schematic side view of a possible embodiment of a sheet metal drawing forming machine according to the invention, here without a forming tool, with the jaw lines spread apart, and in a transverse drawing configuration; Fig. 2 ] is a schematic top view of the forming machine illustrated on the figure 1 ; Fig. 3 ] is a schematic cross-sectional, front view of the forming machine illustrated on the Figures 1 And 2 ; Fig. 4 ] is a schematic cross-sectional, side view of the forming machine illustrated on the figures 1 to 3 , in a transverse drawing configuration, equipped with a forming tool, and with two closely spaced jaw lines; [ Fig. 5 ] is a schematic top view of the forming machine illustrated on the figure 4 ; Fig. 6 ] is a schematic cross-sectional, side view of the same forming machine, here in longitudinal drawing configuration and equipped with a forming tool; [ Fig. 7[ ] is a schematic top view of the forming machine of the figure 6 (with forming tool and in longitudinal stretching configuration); [ Fig. 8 ] is a partial schematic top view of the machine figures 6 And 7 (longitudinal stretch configuration) illustrating the possible oscillating movement of the jaw lines; [ Fig. 9 ] is a partial schematic top view of the machine figures 1 to 5 (transverse stretch configuration) illustrating the possible angulation movement of the bit lines; [ Fig. 10 ] is a schematic cross-sectional, front view of the machine figures 6 And 7 (longitudinal stretch configuration) illustrating the possible rotational movement of the jaw lines; [ Fig. 11 ] is a schematic view that illustrates the possibilities of curvature of the bit lines in longitudinal stretching configuration.

[0018] The sheet metal stretch forming machine 1 illustrated in the attached figures is structured so that it can be configured in longitudinal stretching mode or in transverse stretching mode.

[0019] This forming machine 1 comprises a machine frame 2, having a central longitudinal axis 3 and a central transverse axis 4.

[0020] The machine frame 2 is equipped with a table structure 5 for receiving a forming tool 6 placed between two lines of drawing jaws 7 arranged opposite each other and supported by mechanical means 8 allowing their movement in space.

[0021] The sheet metal drawing means, located on either side of the table structure 5 equipped with the forming tooling 6, are identical or similar.

[0022] The table structure 5 here includes a central table 51 positioned on the central transverse axis 4 and bordered by two auxiliary tables 52.

[0023] The central table 51 and the two auxiliary tables 52 are controlled in vertical movement by guides 53 and operating cylinders 54.

[0024] The active face of the forming tool 6 is adapted according to the final shape of the sheet metal parts to be obtained. figures 4 And 5 illustrate a forming tool 6 adapted for transverse stretching; and the figures 6 And 7 illustrate a forming tool 6 adapted for longitudinal stretching.

[0025] The means for stretching the sheet metal consist of two lines of jaws 7 facing each other, carried by mechanical means 8 which are adapted to give it the desired spatial movements.

[0026] These jaw lines 7 are designed to clamp the width edge of the sheet metal being worked, by gripping it. Here, each one consists of a juxtaposition of jaws 71, 72 and they are arranged in a plane perpendicular to the direction of drawing, or substantially perpendicular to this direction of drawing (this direction of drawing being placed on the central longitudinal axis 3), to properly fulfill their function.

[0027] According to the invention, the bit lines 7 have an adjustable length, and each of them comprises: a first group of jaws 71a arranged in a line, which first group of jaws 71a is designed to allow the forming of a sheet by longitudinal drawing, the line of jaws of this first group of jaws 71a, called the central line of jaws 71a, comprising two end jaws 71b, and a second group of jaws 72a comprising at least two jaws 72 capable of occupying: (a) an inactive position in which the jaws 71 of the first group of jaws 71a are positioned at a distance from the jaws 72 of the second group of jaws 72a, to allow the central line of jaws 71a to perform the forming of a sheet by longitudinal drawing, and (b) an active position in which the jaws 72 of the second group of jaws 72a are positioned in a line on either side of said first group of jaws 71a, in line with the two jaws end 71b of the first group of jaws 71a, the resulting jaw line, called the complete jaw line 7c, comprising said first jaw group 71a and said second jaw group 72a, being designed to allow the forming of a sheet by a transverse drawing.

[0028] The jaws 71 of the central jaw line 71a are carried by a jaw-carrying head 10, itself carried by a central jaw line frame 11 by means of a vertical or approximately vertical oscillation axis 12, associated with oscillation cylinders 13. These oscillation cylinders 13 are designed to allow the jaw-carrying head 10 to rotate about the oscillation axis 12.

[0029] The bit-holder head 10 includes bending cylinders 101 for bending the central bit line 71a, as illustrated in the figure 11 . For this purpose, the juxtaposed jaws 71 of this central jaw line 71a are articulated in pairs and subjected in pairs to the action of a bending cylinder 101.

[0030] The central jaw line frame 11 has a rear extension (opposite the associated jaw line 71a), in the form of a cylindrical guide column 14 with a horizontal or approximately horizontal axis.

[0031] This guide column 14 is centered or approximately centered on the central longitudinal axis 3.

[0032] For their part, the jaws 72 of the second group of jaws 72a are supported by a frame of the second group of jaws 15 in the general shape of a U.

[0033] This second group of jaws 15 frame includes a base 151 which extends into two lateral extensions 152 at the distal ends of which are provided the jaws 72 of the second group of jaws 72a.

[0034] Each of these distal ends supports at least one bit 72. For example, each of these distal ends supports two juxtaposed bits 72, fixed to said distal ends ( Figure 10 especially).

[0035] The cylindrical guide column 14 of the central jaw line frame 11 slides and rotates through the base 151 of the second group of jaws frame 15, and the forming machine 1 comprises: translational maneuvering means 16, interposed between the base 151 of the second group of jaws frame 15 and the free end of the guide column 14 (located on the other side of the base 151 of the second group of jaws frame 15 with respect to the central jaw line frame 11), and rotational maneuvering means 17 of the guide column 14, also interposed between the base 151 of the second group of jaws frame 15 and the free end of the guide column 14.

[0036] The translational maneuvering means 16 consist of cylinders, for example two of them. They allow the two groups of jaws 71a and 72a to be moved closer together or further apart to obtain the aforementioned active and inactive positions.

[0037] They constitute the aforementioned means of movement, for the relative movement of the central jaw line frame 11 and the second group of jaws frame 15.

[0038] These cylinders 16, also known as 16 drawing cylinders, are also used for sheet metal drawing operations, in longitudinal drawing mode.

[0039] The means of rotational maneuvering 17 here consist of a single cylinder 17. Alternatively, several cylinders 17 can be used.

[0040] The distal ends of the lateral extensions 152 of the second group of jaws frame 15 are carried by support carriages 18, movable along two longitudinal beams 21, constituting the machine frame 2, and which extend parallel to the central longitudinal axis 3.

[0041] The support trolleys 18 are maneuverable along the length of the longitudinal beams 21 by means of trolley jacks 181.

[0042] The central jaw line frame 11 and the second group of jaws frame 15 together form a rocker arm which is articulated around a horizontal (or approximately horizontal) axis passing through rocker arm / carriage linkage means, in the form of connecting shafts 182, 183.

[0043] This balance wheel 11-15 is operated in rotation by balance wheel jacks 19 interposed between itself and the connecting shafts 182, 183.

[0044] The forming machine 1 further includes a support beam 20 arranged to bear on the top of each complete line of jaws 7c (with all jaws 71 and 72 aligned in a straight line), for operation in transverse stretching mode.

[0045] This support beam 20 allows the vertical forces applied to the complete jaw line 7c to be absorbed during forming operations. It is secured to the distal ends of the lateral extensions 152 in the forming configuration by a transverse stretching.

[0046] Such a configuration, with the support beam 20 in the active position, is illustrated in particular on the Figures 1 , 3 and 4 .

[0047] The sheet metal stretching forming machine 1 according to the invention is illustrated in a transverse stretching configuration on the figures 1 to 5 And 9 .

[0048] In this transverse drawing configuration, the jaws 71 of the first group of jaws 71a are aligned; and the jaws 72 of the second group of jaws 72a extend the two end jaws 71b and are aligned with them. This results in a complete, straight line of jaws 7c. The support beam 20 is positioned resting on top of this complete line of jaws 7c.

[0049] This alignment of the first and second groups of jaws 71a, 72a is obtained by the operation of the stretching cylinders 16 and the appropriate configuration of the jaw line frames in rotation and oscillation.

[0050] Starting from a position far from the two bit lines 7 facing each other, as illustrated on the Figures 1 And 2 The two jaw lines 7 are brought together by means of the carriages 18 actuated by the carriage cylinders 181, to obtain the close position illustrated on the figures 4 And 5 , on either side of the forming tooling 6.

[0051] The edges of the sheet metal to be formed can then be supported by the two jaw lines 7; and this sheet metal can be formed on the forming tooling 6 using: the rocker arm cylinders 19 and the table cylinders 54, for vertical movements and rotation around the central longitudinal axis 3, the stretch cylinders 16 and the carriage cylinders 181, for horizontal movements, and the carriage cylinders 181 for angular movements, by a different movement of the carriages 18, as illustrated on the figure 9 (rotational movement around a vertical axis of a carriage called a "reference carriage").

[0052] The sheet metal stretching forming machine 1 according to the invention is illustrated in a longitudinal stretching configuration on the figures 6 , 7 , 8 10 and 11 .

[0053] In this longitudinal stretching configuration, only the jaws 71 of the first group of jaws 71a are used; and these jaws 71 of the first group of jaws 71a are separated from the jaws 72 of the second group of jaws 72a, the latter being positioned in the background.

[0054] This retraction of the jaws 72 of the second group of jaws 72a is obtained by a maneuver of the stretching cylinders 16, guided by the guide column 14 and the appropriate configuration of the frames 8 of jaw lines 7 in rotation and oscillation.

[0055] Starting from a position far apart from the two jaw lines 7, the two jaw lines 7 are brought closer together by means of the carriages 18 actuated by the carriage cylinders 181, to obtain the close position illustrated in the figures 6 And 7 , on either side of the forming tooling 6.

[0056] The edges of the sheet metal to be formed can then be supported by the two jaw lines 7; and this sheet metal can be formed on the forming tooling 6 using: the rocker arm cylinders 19 and the table cylinders 54, for vertical movements and rotation around the central longitudinal axis 3, the drawbar cylinders 16 and the carriage cylinders 181, for horizontal movements, the oscillating cylinders 13, for the oscillating movement of the jaw lines 71a with the constituent jaws 71 aligned, around the oscillating axis 12 (as illustrated on the figure 8 ), the rotation cylinder(s) 17, for the rotational movements of the jaw lines around the axis of the guide column 14 (as illustrated on the Figure 10 ), the bending cylinders 101, for bending the central jaw lines 71a (as illustrated on the figure 11 ).

[0057] The result is a sheet metal forming machine that is particularly versatile and very easy to configure for transverse or longitudinal stretching.

[0058] In particular, it allows for small radii of curvature for longitudinal drawing while maintaining a significant jaw line length for transverse drawing.

Claims

1. Sheet metal forming machine by drawing (1), which forming machine (1) comprises a machine frame (2) having a central longitudinal axis (3), equipped with a table structure (5) for receiving a forming tool (6) placed between two lines of drawing jaws (7) arranged opposite each other and carried by mechanical means (8) allowing their movement in space, characterized in thatsaid jaw lines (7) have an adjustable length, each of said jaw lines (7) comprising: - a first group of jaws (71a) arranged in a line, which first group of jaws (71a) is designed to allow the forming of a sheet by longitudinal drawing, the jaw line of said first group of jaws, referred to as the central jaw line (71a), comprising two end jaws (71b), and - a second group of jaws (72a) comprising at least two jaws (72) capable of occupying: (a) an inactive position, in which the jaws (71) of said first group of jaws (71a) are positioned at a distance from the jaws (72) of said second group of jaws (72a), to allow said central jaw line (71a) to perform the forming of a sheet by longitudinal drawing, and (b) an active position, in which the jaws (71) of said first group of jaws (71a) are positioned in line between the jaws (72) of the second group of jaws (72a),extending from the two end jaws (71b) of said first group of jaws (71a), the resulting line of jaws, referred to as the complete line of jaws (7c), comprising said first group of jaws (71a) and said second group of jaws (72a), is designed to allow the forming of a sheet by transverse drawing.

2. Sheet metal forming machine (1) according to claim 1, characterized in that said central jaw line (71a) is supported by a central jaw line frame (11), in that said second group of jaws (72a) is supported by a second group of jaws frame (15), and in that the forming machine (1) includes means of movement (16) for the relative movement of said central jaw line frame (11) and said second group of jaws frame (15), so as to allow said second group of jaws (72a) to occupy said active and inactive positions.

3. Sheet metal forming machine (1) according to claim 2, characterized in thatsaid second group of jaws frame (15) includes a base (151) which extends by two lateral extensions (152) at the distal ends of which are provided the jaws (72) of said second group of jaws (72a), said central jaw line frame (11) including a cylindrical guide column (14), centered, or approximately centered, on said central longitudinal axis (3) and which slides through the base (151) of said second group of jaws frame (15), translational maneuvering means (16), constituting said movement means, and rotational maneuvering means (17) of said guide column (14) being interposed between the base (151) of said second group of jaws frame (15) and the free end of said guide column (14), located on the other side of said base (151) of the second group of jaws frame (15) with respect to the central jaw line frame (11).

4. Sheet metal forming machine (1) according to claim 3, characterized in thatsaid distal ends of the lateral extensions (152) of the second group of jaws frame (15) are carried by support carriages (18) movable along two longitudinal beams (21), constituting said machine frame (2), which extend parallel to said central longitudinal axis (3), which support carriages (18) are maneuverable along the length of said longitudinal beams (21) by means of carriage jacks (181).

5. Sheet metal forming machine (1) according to claim 4, characterized in that The central jaw line frame (11) and the second group of jaws frame (15) together form a rocker arm which is articulated around a horizontal axis passing through the rocker arm / carriage connecting shafts (182, 183), which rocker arm is operated in rotation by rocker arm cylinders (19) interposed between itself and the connecting shafts (182, 183).

6. Sheet metal forming machine (1) according to any one of claims 3 to 5, characterized in thatthe central jaw line (71a) is carried by a jaw-carrying head (10), itself carried by said central jaw line frame (11) by means of an oscillation axis (12) associated with one or more oscillation cylinders (13) which are interposed between said central jaw line frame (11) and said jaw-carrying head (10).

7. Sheet metal forming machine (1) according to claim 6, characterized in that said jaw-carrying head (10) includes bending cylinders (101) for bending the central jaw line (71a).

8. Sheet metal forming machine (1) according to any one of claims 1 to 7, characterized in that It includes a support beam (20) arranged to bear on the top of said complete jaw line (7c) configured in a straight line, to take up the vertical forces applied thereto.

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