FR2683470A1 - ACCOMPAGNATOR OF TOLE FOR PRESS-PLY. - Google Patents

Abstract

Metal-sheet-following device for a bending press, including a pivoting support (6) actuated by one or more articulated systems, each of them being constituted by at least two levers (9),(10) and two links (15),(17) forming, together with the support, at least two parallelograms which can be deformed in the manner of a pantograph. The fixed articulation points (7),(8) of the two levers on the one hand, and the articulation points (16),(18) of the links on the support on the other hand, are aligned with the point which is coincident with the axis of rotation of the metal sheet about the die edge. Rotational actuation of the assembly follows the movement of the moving table of the press by means of a control mechanism of the "master-slave" type which has the effect of minimising the following error in the metal sheet which is being bent. The metal sheet (5) is rendered integral with the support (6) but the latter may slide slightly in relation to its articulation points so as to follow the sliding of the metal sheet during the bending. The support may either be a plate or a set of arms, the spacing of which may be adjusted. The arms may be integral or independent.

Description

The present invention relates to a device accompanying the sheet metal

  During this operation, the sheet is pinched between an elongated punch called counter-vee, fixed to the upper deck and a matrix of the same length in the shape of a vee attached to the lower deck The bringing together of these two tools causes a bending of the sheet between the two edges of the vee then a permanent deformation which is the fold to achieve the desired angle. During this operationi the fold to achieve is located near one of the edges of the sheetelçaissant his largest part in front of the press, this part rotates in the surrounding space with a sudden acceleration to reach an angular speed which is even greater than the vé is small 15 Under these conditions, the moment created by the weight of the sheet whose center gravity is away from the support line formed by the edge of vee, causes a bending of this sheet and a permanent deformation called counter-fold To overcome this inc disadvantage, we must accompany the sheet metal in its movement which requires the action of two operators standing on each side of the sheet and trying to follow its movement But the synchronization of the arms of the operators with the movement of the sheet is difficult and very fatiguing, even dangerous.25 Apparatuses of various types have been made to provide a solution to the problem but they are not entirely satisfactory because they are either complex, such as the apparatus described in US Patent 3 855 The difficulty encountered in finding an effective solution stems from the fact that the sheet metal support must be rotated about an axis corresponding to the edge of the vee and that it is not necessary. not possible to materialize this axis. The apparatus forming the subject of the present invention is a sheet metal follower comprising a pivoting support actuated by one or more articulated systems, each of them being constituted by at least two levers and two links forming with the support, at least two deformable parallelograms. The way of a pantograph The fixed points40 of articulation of the two levers are aligned with the poiht 2 -

representative of the matrix edge.

  The rotation control of the assembly is slaved to the movement of the movable apron of the press according to a law identical to that which governs the angular rotation speed of the sheet around the die edge during folding. This rotation command is obtained by a servo-control of the 'master-slave' type which has the effect of minimizing the accompanying error of the sheet being bent. The accompanying error is obtained by comparison10 between the value given by a sensor linked to the mobile apron and that given by another sensor indicating the movement

  of the accompaniment system The coherence of the values (angular or linear) read on the two sensors is obtained either mechanically or electronically.

  The driving force of rotation of the support can be

  electric, hydraulic or pneumatic, without affecting the choice of measuring system adopted.

  Several articulated systems may be placed side by side or at a distance from one of the other systems having their own support or being connected to a common plate, the driving force and / or the measuring means being able to be clean. to each system be common. The sheet is made integral with the support by any appropriate means such as suction cups, magnets, clamps, etc., and the support is connected to the articulated system by a link

  elastic able to follow the slight sliding of the sheet during folding.

  The attendant can be mounted on a carriage with elastic suspension capable of following the approach movement of the lower deck when it is movable It is fixed to this lower deck at constant horizontal and vertical distances from the edge of vee by the intermediate vernier stops or wedges to adapt it to the different widths of vés.35 Other features and advantages of the accompanying sheet metal according to the invention will still appear

  through the following description of an exemplary embodiment given by way of indication and not limitation with reference to the accompanying drawings, in which: FIG. 1 shows in front views and in profile, a

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  press brake while folding and forming the counter

  fold on a sheet of large format. FIG. 2 is a diagrammatic enlargement of the folding zone. FIG. 3 is a profile view of the front of the press equipped with the following sheet metal follower

1 invention.

  FIG. 4 is a block diagram of an electronic servocontrol of the "master-slave" type adapted to the attendant.

  Figure 5 shows schematically an alternative embodiment of the control and the measurement of the movement.

  Figure 6 is a top view of a sheet attendant consisting of two independent arms.

  Figure 7 is a top view of an attendant

plate-shaped sheet.

  Figure 8 shows a detail of the articulation of an actuating rod on the support.

  As shown in FIG. 1, the press brake essentially consists of a frame (1), an upper deck carrying a punch (2) and a lower deck carrying a generally V-shaped die (3). one of the two aprons is movable, which brings the tools closer together and folds the sheet (5) together, as shown in FIGS. 2 and 3. If the sheet has a large dimension in front of the press and is not supported. it flexes and forms during folding a counter-fold (26) resulting from the "whiplash" caused by its acceleration at the beginning of folding and the moment created by its weight. The principle of operation of the attendant as described in Figure 3 is similar to that of the pantograph The fixed points (7) and (8) integral with the frame (20) of the apparatus are aligned with the edge of the matrix ( 4); around these fixed points can pivot two levers (9) and (10), the lever (9) has two pivot points (11) and (12); the lever (10) has a pivot point (13) and a light (14) A rod (15) connecting the hinge points (11) and (13) articulates (16) on the support (6) while a second link (17) connects the point ( 12) from the lever (9) to a second pivot point (18) of the support (6) The points (16) and (18) are aligned 4 - with the die edge (4) The two parallelograms formed by the points (7), (8) (13 a), (ia) on the one hand and (11 a), (12 a) (18 a), (16 a) on the other hand can be deformed to take the respective positions (7), (8), (13b), (lib) and (ilb) (12b), (18b) (16b) so that the points (18b), (1i 6b) in solidarity of the plate (6) always remain aligned with the edge of vee and at a constant distance from this edge when the levers (9) and (10) are rotated by any angle ue. In the example of Figure (3) the rotation of the lever (9), therefore the lever (10) which remains parallel, is obtained by a cylinder (19) articulated in (8) and whose rod is connected in (8). Cl) at the lever (9) and the rod (I 5) This jack can be hydraulic, as shown in the figure, pneumatic or electric In all cases, it is controlled by a power member, not shown but which, in the example described comprises a hydraulic distributor delivering to the

  cylinder an oil flow rate proportional to an electrical setpoint, this being determined by the servo system so that the angle of rotation of the support (6) is constantly equal to the rotation angle a sheet at the same time during folding.

  For this purpose, the companion is electrically connected to the press This has, or originsoit add an incremental measurement rule (21) whose slider (22) 25 indicates the position and speed of the moving apron (23). At the same time, the companion is equipped with an incremental rule (24) whose size is related to the angular displacement of the lever (10). This rule (24) has a slider (25) guided on the ruler and controlled by the rider. lever (10) with a sliding connection represented by the light (14) The ruler (24) is mounted on

  the frame (20) in position perpendicular to the lever (10) when it is at rest. It can be seen that the movement of the slider (25 a) to (25 b) is proportional to that of the slider (22) of the press since this one measures the penetration of the punch in the matrix and that, geometrically-

  the triangle formed by the points (25a), (25b), (8) is similar to that formed by the apex of the punch, in its initial (27a) and final (27b) positions, and the edge 40 matrix (4) shown in FIG. 2 Thus, in this embodiment, the coherence of the values read on the two sensors is purely mechanical. The servo-control principle is described in the diagram of FIG. 44) and (45) process the signals complemented by the sliders (22) and (25) to obtain on a output a positive counting signal if the cursor moves in the folding direction and, on another output, a signal of Negative counting if the cursor moves in reverse.10 The frequency-voltage converter (46) outputs a setpoint voltage proportional to the counting frequency of the adapter (44), positive if the count is positive and negative in the case opposite. The preselecting member of the folding vee (47) outputs a division ratio corresponding to the matrix chosen from an interface of the coding wheel or other type. The dividing block (48) receives the counting signals from the adapter (45) and outputs a quantity of pulses

  proportional to the division ratio of the preselection member (47).

  The counting signals coming from the adapter (44) and the division block (48) are transmitted to the block (49) which outputs a signed digital value representative of the tracking error of the attendant relative to the moving deck. The converter (50) converts this digital value into an analog voltage. Thus, the outgoing reference voltages

  the converter (46) and the converter (50) enter a P I D block (51) (proportional, integral and differential) to generate, at the output, a control signal from the power device.

  Another embodiment shown in FIG. 5 and indicated as a second nonlimiting example consists in driving the lever (9) or the lever (10) in rotation with the aid of a motor (electric or other) (28). ) 35 of a transmission (29) and to measure the angle of rotation of this lever, and thus of the support (6), by means of a rotary encoder (30) placed in one of the drive shafts (7) or (31) In this case, the consistency between the linear measurement of the tool displacement and the rotational measurement of the rotation of the support is obtained electronically but the principle 6 -

enslavement remains the same.

  The sheet metal follower may be in various forms and two examples of embodiments are given in FIGS. 6 and 7.5 In FIG. 6 each articulated system has its own support arm (32), (33), the arms may be rejected

  depending on the width of the sheet 181, they may slide along the apron (34) of the press and find a place in the extension of this apron when they are not used. Their drive may be independent or common, for example by means of a splined shaft (35).

  In Figure 7, the support is a plate (36) driven by at least two articulated systems, the assembly, which can be bulky and heavy, is mounted on a carriage of the type shown in Figure 3 This carriage has a setting in height (37) to bring it to the plane level

  horizontal of the matrix and an elastic suspension (38) for the purpose of relieving the load to be lifted, that is to say the attendant and the sheet during the approaching movement of the apron when it is the lower apron which is movable as in Figure 3.

  In all cases, the apparatus is fixed rigidly to the lower deck at horizontal and vertical distances

  This can be achieved by means of wedges (39) matching the type of matrix used or by means of vernier-readable stops.

  In order not to slip accidentally on the support during the folding the sheet is kept on him by

  example using suction cups (40) or any other means such as electromagnets or clamps.

  During folding, the plate pivots around the die edge (4) but it can be seen in FIG. (2) that it slides on this edge since the segment (4) - (27b) is longer than the segment (4) - (27 a) The apparatus therefore comprises, according to FIG. 8, a possibility of longitudinal sliding between the support (6) and the connecting pins (16) and (18). For this purpose the clevises (41) on the links (15), (17) are slidably mounted on the plate (6) and are connected thereto by means of resilient elements such as the springs (42) and 7 - held by screws (43) It is obvious that this solution is given by way of example, and that the apparatus can be adapted to slide the sheet in another way such as for example a sliding mounting of the holding members on the plate. The principle of the sheet metal guide can be used on all types of apron press brakes

  Mobile upper or lower Due to its high operating accuracy it is particularly suitable for folding10 thin or fragile sheets.

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Claims (5)

ReCEND i CATI ONS   1 Plate support unit for press-   folder, having a support (6) which pivots about an axis parallel to the die (3) to support the sheet (5) during the folding operation; characterized in that: S -The support is actuated by a or more articulated systems each of them being constituted by at least two levers (9 Y, (10) and at least two links (15), 1 (7) forming with the support at least two parallelograms   deformable in the manner of a pantograph.   -The fixed points of articulation (7 C, (8) of the levers are aligned with the representative point of the die edge (4) -The rotation control of the assembly is slaved to the displacement of the moving apron of the press following a identical law to that which governs the angular speed of rotation of the tale around the edge of the matrix during folding 2 Apparatus accompanying sheet according to claim 1 characterized in that: -The control of rotation is obtained by a servocontrol of the type "master-slave" which has the effect of minimizing   the accompanying error of the sheet being bent.   -The accompanying error is obtained by comparison between the value given by a sensor (21), (22) linked to the moving deck and that given by another sensor (24>, (25) indicating the movement of the system of accompaniment.-The coherence of the values (angular or linear) read on the two sensors is obtained either mechanically or electronically.   3 Apparatus according to the preceding claims   characterized in that the type of driving force (19) actuating the rotation of the support has no effect on the choice of the means of measurement adopted.   4 Apparatus according to the preceding claims   characterized in that a plurality of articulated systems can be placed side by side or at a distance from each other, each system being provided with its own support (32), (33) or being connected to a common tray (36). ) the driving force and / or the measuring means that may be suitable for each system is common.   S Apparatus according to the preceding revendio characterized in that the tble east made integral with the support by any appropriate means such as suction cups (40)   or magnets, cited as non-limiting examples.   Apparatus according to the preceding claims   characterized in that the support is connected to the articulated system via an elastic connection (4 I), (42), (43) oriented in the sliding direction of the sheet.   Apparatus according to the preceding claims   characterized in that: -I 1 is mounted on a carriage with elastic suspension (38) capable of following the approach movement of the apron   lower when it is mobile.   -It attaches to this lower deck at distances   Horizontal and vertical constants of the matrix edge.   Apparatus according to the preceding claims   characterized in that the adjustment of the above-mentioned horizontal and vertical distances is achieved by means of stops or positioning wedges (39) attached to the apparatus or the press.