Sheet metal stretch forming machine

Abstract

The present invention relates to a sheet metal forming machine by drawing (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 drawing, 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 forming by longitudinal drawing, 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 drawing. Figure for the abstract: Figure 7

Description

Title of the invention: Sheet metal stretch forming machine 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 forming machine by drawing, which machine comprises a central longitudinal axis and a frame receiving a forming tool placed between two lines of drawing jaws arranged opposite each other and carried by mechanical means allowing their movement in space. State of the art

[0003] In the above field, there are known machines called transverse drawing machines.

[0004] Transverse drawing is designed to draw sheet metal across its width, typically along the leading edges. This particular method allows a vertical force to be applied to the die line. The sheet metal is clamped in the jaws of the die line and then wraps around the die during forming. This makes it possible to produce 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 workpiece forming.

[0006] Longitudinal drawing machines are also known, 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 a constant force across the entire width of the sheet, the jaw line is equipped with several axes so as to keep it "floating". In this way, each jaw is articulated along an axis allowing the entire jaw line to be curved to keep the sheet metal tangent to the tool during forming.

[0008] Current drawing machines are generally structured to perform either longitudinal drawing or transverse drawing.

[0009] For the "longitudinal drawing" mode, the sheets are limited in width; and for the "transverse drawing" mode, it is advantageous to have a wider jaw line than in longitudinal drawing.

[0010] Some known machines include lines of jaws which serve both modes: longitudinal and transverse.

[0011] 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

[0012] In order to remedy 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,

[0013] This machine being characterized by the fact that said jaw lines have a variable length,

[0014] each of said bit lines comprising:

[0015] - a first group of jaws arranged in a line, which first group of jaws is designed to allow the forming of sheet metal by longitudinal drawing, the jaw line of said first group of jaws, called the central jaw line, comprising two end jaws, and

[0016] - a second group of jaws comprising at least two jaws capable of occupying:

[0017] (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 a forming of a sheet by longitudinal drawing, and

[0018] (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, extending from the two end jaws of the said first group of jaws,

[0019] the resulting jaw line, referred to as 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 drawing.

[0020] By its structure, such a drawing machine can therefore achieve, under optimal conditions, either transverse drawing or longitudinal drawing.

[0021] The principle of the present invention is to propose two possible configurations of the bit lines, namely:

[0022] - a configuration adapted to the longitudinal drawing mode, comprising a line of inflexible bit, and

[0023] - a configuration adapted to the transverse stretching mode, comprising a line of straight bit, composed of the incurvable bit line in the straight position (bites aligned) in the center and 2 fixed parts on either side of the central bit line.

[0024] 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:

[0025] - the central jaw line is supported by a central jaw line frame, the second group of jaws is carried by a second group of jaws frame, and the machine includes means of movement 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;

[0026] - the second group of jaws frame comprises a base which extends into two lateral extensions at the distal ends of which are formed the jaws of said second group of jaws,

[0027] said central jaw line frame comprises a cylindrical guide column, centered or approximately centered on said central longitudinal axis and which slides through the base of said second jaw group frame,

[0028] means of maneuvering in translation, constituting said means of movement, and means of maneuvering in rotation 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;

[0029] - the distal ends of the lateral extensions of the second group of jaws are carried by mobile support trolleys along two longitudinal beams, constituting said machine frame, which extend parallel to said central longitudinal axis, which support trolleys are maneuverable along the length of said longitudinal beams by means of trolley jacks;

[0030] - the central jaw line frame and the second group of jaws form together a balance wheel which is articulated around a horizontal axis passing through the balance wheel / carriage connecting shafts, which balance wheel is operated in rotation by balance wheel cylinders interposed between itself and the connecting shafts;

[0031] - the central bit line is carried by a bit-holder head, itself carried by the central jaw line frame via an oscillation axis associated with one or more oscillation cylinders interposed between said central jaw line frame and said jaw-holding head;

[0032] - the bit-holder head includes bending cylinders for maneuvering in curvature of the central bit line;

[0033] - the drawing machine includes a support beam arranged to take support on the top of said complete jaw line configured in a straight line, to take up the vertical forces applied thereon.

[0034] Of course, the various features, variants, and embodiments of the invention can be combined in various ways, provided they are not incompatible or mutually exclusive. Detailed description of the invention

[0035] In addition, 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:

[0036] [Fig-1] is a schematic side view of a possible embodiment of a sheet metal forming machine by stretching according to the invention, here without forming tool, jaw lines spread apart, and in transverse stretching configuration;

[0037] [Fig.2] is a schematic top view of the forming machine illustrated in [Fig.1];

[0038] [Fig.3] is a schematic cross-sectional, front view of the forming machine illustrated in Figures 1 and 2;

[0039] [Fig.4] is a schematic cross-sectional, side view of the forming machine illustrated in Figures 1 to 3, in transverse drawing configuration, equipped with a forming tool, and with two closely spaced jaw lines;

[0040] [Fig.5] is a schematic top view of the forming machine illustrated on the [Fig.4];

[0041] [Fig.6] is a schematic cross-sectional view, from the side, of the same forming machine, here in longitudinal drawing configuration and equipped with a forming tool;

[0042] [Fig.7] is a schematic top view of the forming machine of [Fig.6] (with forming tool and in longitudinal drawing configuration);

[0043] [Fig.8] is a partial schematic top view of the machine in Figures 6 and 7 (longitudinal drawing configuration) illustrating the possible oscillating movement of the jaw lines;

[0044] [Fig.9] is a partial schematic top view of the machine in Figures 1 to 5 (transverse drawing configuration) illustrating the possible angulation movement of the jaw lines;

[0045] [Fig. 10] is a schematic cross-sectional, front view of the machine in Figures 6 and 7 (longitudinal drawing configuration) illustrating the possible rotational movement of the jaw lines;

[0046] [Fig. 11] is a schematic view that illustrates the possibilities of bending the jaw lines in longitudinal stretching configuration.

[0047] The sheet metal stretching 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.

[0048] This forming machine 1 comprises a machine frame 2, having a central longitudinal axis 3 and a central transverse axis 4.

[0049] 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.

[0050] The sheet metal drawing means, located on either side of the table structure 5 equipped with the forming tooling 6, are identical or similar.

[0051] The table structure 5 here comprises a central table 51 positioned on the central transverse axis 4 and bordered by two auxiliary tables 52.

[0052] The central table 51 and the two auxiliary tables 52 are controlled in vertical movement by guides 53 and operating cylinders 54.

[0053] 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 drawing; and Figures 6 and 7 illustrate a forming tool 6 adapted for longitudinal drawing.

[0054] 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.

[0055] These jaw lines 7 have the function of clamping the width edge of the sheet metal being worked, by gripping it. Here, each one is made up 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), in order to properly fulfill their function.

[0056] According to the invention, the bit lines 7 have an adjustable length, and each of them comprises:

[0057] - 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 metal by longitudinal drawing, the jaw line of this first group of jaws 71a, called the central jaw line 71a, comprising two end jaws 71b, and

[0058] - a second group of jaws 72a comprising at least two jaws 72 capable of occupying:

[0059] (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 to the central jaw line 71a to perform a sheet metal forming by longitudinal drawing, and

[0060] (b) an active position in which the jaws 72 of the second group of jaws 72a are positioned in line on either side of said first group of jaws 71a, in line with the two end jaws 71b of the first group of jaws 71a,

[0061] the resulting jaw line, referred to as 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.

[0062] 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 around the oscillation axis 12.

[0063] The jaw-holder head 10 includes bending cylinders 101 for bending the central jaw line 71a, as illustrated in [Fig. 1 1].

[0064] 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.

[0065] 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.

[0066] This guide column 14 is centered or approximately centered on the central longitudinal axis 3.

[0067] For their part, the jaws 72 of the second group of jaws 72a are supported by a second group of jaws frame 15 in the general shape of a U.

[0068] 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.

[0069] Each of these distal ends supports at least one jaw 72. For example, each of these distal ends supports two juxtaposed jaws 72, attached to said distal ends ([Fig. 10] in particular).

[0070] 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:

[0071] - means of maneuvering in translation 16, interposed between the base 151 of the frame of second group of jaws 15 and the free end of the guide column 14 (located on the other side of the base 151 of the frame of the second group of jaws 15 relative to the central jaw line frame 11), and

[0072] - means for rotating the guide column 14 17, also interposed between the base 151 of the frame of the second group of jaws 15 and the free end of the guide column 14.

[0073] 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.

[0074] 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.

[0075] These cylinders 16, also called drawing cylinders 16, are also used for sheet drawing operations, in longitudinal drawing mode.

[0076] The rotational maneuvering means 17 here consist of a single cylinder 17. Alternatively, several cylinders 17 can be used.

[0077] 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.

[0078] The support trolleys 18 are maneuverable along the length of the longitudinal beams 21 by means of trolley jacks 181.

[0079] 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.

[0080] This balance wheel 11-15 is operated in rotation by balance wheel cylinders 19 interposed between itself and the connecting shafts 182, 183.

[0081] 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 drawing mode.

[0082] This support beam 20 allows the vertical forces applied to the complete jaw line 7c to be absorbed during the forming maneuvers.

[0083] It is made integral with the distal ends of the lateral extensions 152 in forming configuration by a transverse stretching.

[0084] Such a configuration, with the support beam 20 in the active position, is illustrated in particular in Figures 1, 3 and 4.

[0085] The sheet metal stretching forming machine 1 according to the invention is illustrated in transverse stretching configuration in Figures 1 to 5 and 9.

[0086] In this transverse stretching 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 The end jaws 71b 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.

[0087] 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.

[0088] Starting from a position far apart from the two lines of jaws 7 facing each other, as illustrated in figures 1 and 2, the two lines of jaws 7 are brought together by means of the carriages 18 operated by the carriage cylinders 181, to obtain the close position illustrated in figures 4 and 5, on either side of the forming tooling 6.

[0089] 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:

[0090] - the rocker arm cylinders 13 and the table cylinders 53, 54, for the movements vertical and rotation around the central longitudinal axis 3,

[0091] - the stretching cylinders 16 and the carriage cylinders 181, for the movements horizontal, and

[0092] - the carriage cylinders 181 for angular movements, by a movement different from the carriages 18, as illustrated in [Fig.9] (rotational movement around a vertical axis of a carriage called "reference carriage").

[0093] The sheet metal stretching forming machine 1 according to the invention is illustrated in longitudinal stretching configuration in Figures 6, 7, 8, 10 and 11.

[0094] 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 recess.

[0095] 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.

[0096] Starting from a position far from the two lines of jaws 7 facing each other, the two lines of jaws 7 are brought together by means of the carriages 18 actuated by the carriage cylinders 181, to obtain the close position illustrated in figures 6 and 7, on either side of the forming tooling 6.

[0097] 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:

[0098] - the rocker arm cylinders 19 and the table cylinders 54, for vertical movements and the rotation around the central longitudinal axis 3,

[0099] - the stretching cylinders 16 and the carriage cylinders 181, for the movements horizontal,

[0100] - the oscillating cylinders 13, for the oscillating movement of the jaw lines 71a with the constituent jaws 71 aligned around the oscillation axis 12 (as illustrated in [Fig.8]),

[0101] - the rotation cylinder(s) 17, for the rotational movements of the jaw lines around the axis of the guide column 14 (as illustrated in [Fig.10]),

[0102] - the bending cylinders 101, for bending the jaw lines central 71a (as illustrated in [Fig. 11]).

[0103] A particularly versatile sheet metal forming machine is obtained which is very easy to configure for transverse or longitudinal drawing.

[0104] In particular, it allows for small radii of curvature to be achieved for longitudinal drawing while maintaining a significant jaw line length for transverse drawing.

Claims

Demands

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 supported by mechanical means (8) allowing their movement in space, characterized in that said lines of jaws (7) have a variable length, each of said lines of jaws (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 metal by longitudinal drawing, the line of jaws of said first group of jaws, 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) suitable for 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 line of jaws (71a) to perform sheet metal forming 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), in line with 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), being designed to allow sheet metal forming 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) comprises movement means (16) for the relative movement of said central jaw line frame. central jaw (11) and said second group jaw frame (15), so as to allow said second group jaw (72a) to occupy said active and inactive positions.

3. Sheet metal forming machine (1) according to claim 2, characterized in that said second group of jaws frame (15) comprises 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) comprising 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) relative to the central jaw line frame (11).

4. Sheet metal forming machine (1) according to claim 3, characterized in that said 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 cylinders (181).

5. Sheet metal forming machine (1) according to claim 4, characterized in that the central jaw line frame (15) 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 that the central jaw line (71a) is carried by a jaw-carrying head (10), itself carried by said central jaw line frame (11) via 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 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 comprises 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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