EP0893174A1 - Sheet edge prehemming and final hemming unitk - Google Patents

Abstract

The machine pre-crimps and crimps the edge (11) of sheet metal (10) which is supported by a fixed die (14). This has two moving heads, one for pre-crimping (2), the other (3) for crimping, which are displaced in step so that they squeeze the edge of the sheet one after the other and disengage. The heads have a common driving shaft (90) which has a crimping head (100) that is also movable. It is displaced by at least one air piston (1000) so that it squeezes the area (13) of the sheet adjacent to the crimping zone before operation and is disengaged after operation.

Description

The present invention relates to a pre-crimping and crimping unit from the edge of a sheet which is supported by a fixed die.

It also relates to a tool composed of a set of several units of this kind, juxtaposed.

More specifically, the present invention relates to a unit of the type described in French patent application No. 95 07113 (Publication No. 2,735,049).

This known unit comprises two movable heads, one used for pre-crimping and the other crimping, which are moved synchronously to come one after the other press the edge of the sheet and get free, the displacements of the two heads being controlled by a common motor shaft.

It is remarkable by the fact that the crimping head described, during pressing, a curvilinear trajectory whose instantaneous center of rotation is close to the sheet bending zone, and whose tangent at the end of crimping is substantially orthogonal to the plane of the sheet, the active face of the crimping head (which is applied against the sheet) remaining substantially parallel to itself during this movement.

This particular movement of the crimping tool makes it possible to work with regular and controlled quality, avoiding the formation of a ripple on the panel outside of the sheet, matrix side.

According to an additional characteristic of the known unit, the displacement of the presetting head is done during pressing - and in particular at the end of pressing - in a direction orthogonal or substantially orthogonal to the plane of the sheet.

Thus, the parasitic forces, likely to cause the winding of the edge of sheet metal and inadvertently moving the part on the matrix, are eliminated, or practically eliminated.

In a preferred embodiment of this known unit, the two heads are driven by a common motor shaft, which always rotates in the same sense, and whose movement is transmitted to the heads via a mechanism to eccentric.

The motor shaft is rotated by an electric motor with reducer incorporated speed (gearmotor).

• la tête de sertissage est montée en partie haute d'un bras oscillant approximativement vertical, dont l'extrémité inférieure porte un premier tourillon par lequel il s'articule sur une biellette pouvant pivoter librement autour d'un axe fixe, tandis que sa portion médiane porte un second tourillon s'articulant sur un levier de commande ;
• la tête de présertissage est portée par un bras oscillant, approximativement vertical, dont l'extrémité inférieure porte un premier tourillon par lequel il s'articule sur une biellette pouvant pivoter librement autour d'un axe fixe, tandis que sa partie supérieure porte un second tourillon s'articulant sur un levier de commande ;
• la tête de sertissage est située au-dessous de la tête de présertissage.

In one embodiment of the device, in which the plane of the sheet is substantially horizontal:

• the crimping head is mounted in the upper part of an approximately vertical oscillating arm, the lower end of which carries a first pin by which it is articulated on a rod which can pivot freely around a fixed axis, while its median portion carries a second journal articulated on a control lever;
• the presetting head is carried by an oscillating arm, approximately vertical, the lower end of which carries a first pin by which it is articulated on a rod which can pivot freely around a fixed axis, while its upper part carries a second pin hinged on a control lever;
• the crimping head is located below the pre-crimping head.

The pre-crimping and crimping head drive is carried out from of the common motor shaft via an eccentric crank pin system and a connecting rod a pivoting spreader, articulated on a fixed axis.

In general, this kind of unit is satisfactory.

It is simple and allows you to work at high speed.

In use, however, it turned out that defects in the quality of the crimping could appear, especially at high speed, which are linked to a slight movement of the sheet during the pre-crimping and / or crimping operation.

The present invention aims to solve this problem.

This is achieved thanks to the fact that the pre-crimping and crimping has a clamping head, also movable, which is moved by at least a pneumatic cylinder so as to press the zone of the sheet adjacent to the zone of crimping before the operation, and which is released after the operation.

Preferably, the clamping head is carried by a pivoting arm.

In the case where the pre-crimping and crimping heads are worn all two by approximately vertical swing arms, the crimping head being located below the presetting head, the swivel arm which carries the clamping head affects substantially the shape of an inverted "U" which comes to kiss from above the arm of pre-pressing.

In the case where the drive of the pre-crimping and crimping heads is made from the common motor shaft via an eccentric crank pin system and connecting rod connected to a pivoting lifting beam, the pivoting arm carrying the clamping head, and this Swivel lifting beam, are articulated on the same fixed axis.

The present invention also relates to a preserting assembly and crimping for long sheet metal, this assembly being composed of several juxtaposed units as described above.

In an embodiment more particularly intended to work on a curved sheet, at least some of said units have an offset angular positioning compared to that of the others, the arrangement being such that the directions at the end of the race different clamping, pre-crimping and crimping heads are in all areas substantially orthogonal to the surface of the sheet.

Other characteristics and advantages of the invention will become apparent from the description and attached drawings which represent a preferred embodiment.

• la figure 1 est une vue partielle et schématique de l'unité, qui représente la pièce à sertir montée sur une matrice, ainsi que la partie d'outillage servant au serrage, avant l'opération;
• la figure 2 est une vue similaire à la figure 1, représentant ces mêmes éléments en cours de serrage ;
• les figures 3 et 4 sont des vues schématiques similaires aux figures 1 et 2 respectivement, montrant la partie d'outillage réalisant le présertissage ;
• les figures 5 et 6 sont des vues schématiques similaires, montrant la partie d'outillage réalisant le sertissage ;
• la figure 7 est une vue de face d'une unité conforme à l'invention, représentée en position ouverte, les têtes de présertissage et de sertissage dégagées, mais avec la tête de serrage en position basse, active.

In the drawings:

• Figure 1 is a partial and schematic view of the unit, which shows the piece to be crimped mounted on a die, as well as the tooling part used for clamping, before the operation;
• Figure 2 is a view similar to Figure 1, showing these same elements during tightening;
• Figures 3 and 4 are schematic views similar to Figures 1 and 2 respectively, showing the tooling part carrying out the pre-crimping;
• Figures 5 and 6 are similar schematic views showing the tooling part carrying out the crimping;
• Figure 7 is a front view of a unit according to the invention, shown in the open position, the pre-crimping and crimping heads released, but with the clamping head in the low, active position.

It will be noted that in the schematic views of FIGS. 1 to 6, on the one hand, and in the more elaborate view of FIG. 7, on the other hand, the same reference signs have been used to denote the same parts.

In FIGS. 1 to 6, the clamping tools have been given artificially, of pre-crimping and, respectively of crimping, simple shapes, and these three tools were considered independently of each other, so as to allow a better understanding of how they work.

However, as shown in Figure 7, these two tools are nested one inside the other, which requires parts of more elaborate shape, avoiding interference of the different components of the tools during a cycle complete clamping, pre-crimping, crimping, loosening and unloading / loading pieces.

Finally, in these same figures, the piece to be crimped and the active faces of the heads of work (which come to press against the sheet) have been artificially represented to scale significantly larger than that of the rest of the elements, in order to better illustrate the operations. The part to be crimped is not shown in FIG. 7.

In Figures 1 to 6, there is designated by the reference 1 a piece to be crimped composed of two sheets 10 and 12, only the border area of this part being the subject of the crimping operation having been shown.

The part 1 is supported by a fixed matrix 14 whose support plane 15 is horizontal. This horizontal support plan will be conventionally called in the rest of the description and in the claims "sheet plan". The lower sheet, which rests on the matrix 14 has a width greater than that of the other sheet 12; she presents a flange 11 folded at right angles to the rest of the sheet, and therefore disposed vertically. The initial folding of the flange 11 was carried out using a separate tool, by example in press. It is this rim 11 which must be folded back against the border zone 13 of the other sheet 12 to perform the assembly by crimping the two sheets.

The clamping tool illustrated in Figures 1 and 2 includes a clamping 100 having a clamping member - or tool 101 which has a working face 1010 plane. The head 100 is carried by a frame, or arm, 102 having the general shape of a "U" overturned (opening downwards). The end of this frame, which is opposite the tool 101, is articulated around a fixed horizontal axis 530. This axis is positioned, and the armature sized, so that in the low position - shown at Figure 2 - the face 1010 is applied against a zone 13 'of the sheet 12 adjacent to the zone 13, outer side with respect to the crimping unit (left side of the figure).

The working face 1010 is inclined relative to the general direction of the tool 101, forming a bevel at approximately 45 °.

Thus, in the clamping position (Figure 2), the space above zone 13 is well cleared, allowing the free passage of the pre-setting tools and crimping; in fact, the tool 101 extends obliquely, towards the outside, above the matrix 14.

The upward (Figure 1) and downward (Figure 2) movements of the head tightening 100 are controlled by a pneumatic cylinder 1000 whose body is articulated around a fixed horizontal axis 104, and the end of the rod 1001 of which is articulated arm 102 by an axis 103 situated above the level of the axis 530.

The extension of the jack (arrow K ) causes the head 100 to pivot in the direction of lowering, for tightening (arrow L ).

The pneumatic pressure of the cylinder allows to maintain a tightening force permanent face 1010 on the part, which immobilizes it correctly before and during the pre-crimping and crimping operations.

The pre-crimping tool comprises a head 2 having a working face - or active face - flat 20, carried by a moving part formed by an arm 22 and a upper intermediate part 21. The arm 22 stands in a position close to the vertical, slightly tilted outwards from this vertical direction.

At its lower end, the arm 22 carries a first pin 24, by which it is articulated to a link 4 articulated on a fixed axis 40, that is to say carried by the frame of the unit (not shown in Figures 1 to 4). Part 21 carries a second pin 23 by which it is articulated on a control lever 5, of approximately shape triangular. The latter pivots freely around a fixed axis 50, and carries a journal 51 by which it is articulated on a control rod 52. The rod 52 is curved, and its opposite end carries a pin 53 by which it is connected to the eccentric and connecting rod control, which will be described later. Trunnion 53 is subjected to a back and forth movement along a circular arc path, with center 530. The low 4 and high 52 links are arranged towards the outside (relative to the matrix 14). The points corresponding to axes 23, 50, 40 and 24 constitute the angles of a quadrilateral fictitious deformable of which one of the sides is materialized by the part 21, 22 carrying the head 2.

The different axes are positioned, and the lever arms chosen, such so that the movement of the active face 20 during the operation is done according to a substantially vertical direction, perpendicular to the plane 15.

This face 20 is in a plane inclined at 45 ° relative to the plane 15, when it is at the end of the working stroke (Figure 4).

The preserting operation results from the upward movement of the pin 53 around the point 530 (arrow I ₁ , FIG. 4), which causes the lever 5 to tilt downwards, around the point 50 (arrow I ₂ ), and the deformation of the quadrilateral mentioned above.

During the operation, the part 1 is perfectly immobilized by the pressure exerted on the zone 13 ′ by the tightening tool 101.

At the end of the race, the lines L1 and L2 which respectively connect the points 23 and 50 on the one hand, and 24 and 40 on the other hand, are both parallel to the bearing face 15 (sheet metal plane), c that is to say horizontal (Figure 4).

The flange 11, once folded at 45 °, is referenced 11 '.

The crimping tool shown schematically in Figures 5 and 6 comprises a working head 3 which is carried by an arm 31 approximately vertical and has an active lower face - working face - 30 whose function is to press the partially folded edge 11 'to fold it completely and bring it in contact with the edge zone 13 of the sheet 12, so as to ensure complete crimping from room 1.

The arm 31 has, on the inner side, a middle portion 32 lying in overhang below the active face 30, substantially perpendicular to the latter.

Like the arm 21, the arm 31 is provided at its lower end with a first pin 33, by which it is articulated on a link 6 which can pivot freely around a fixed axis 60.

Part 32 carries a second pin 34 by which it is articulated the end of a lever 7. It is a slightly bent lever, the opposite end (outer side) carries a pin 70. The latter is articulated on two rods 73, 74. The rod 73, approximately horizontal, can pivot freely around a fixed axis 730. The rod - or tie rod - 74, approximately vertical, extends upwards, and its opposite end (upper end) carries a pin 75.

This ensures its connection to the eccentric drive system and connecting rod, which will be described later. Trunnion 75 can follow a back-and-forth trajectory in a semicircle around point 530.

In its central (angled) zone, the lever 7 carries a pivot 71 hinged on a link 72 able to pivot freely around a fixed axis 720.

The lever 7 and the link 6 are approximately horizontal, directed towards outside.

The rod 72 extends downward (relative to the lever 7), and it has a approximately vertical direction.

It will be understood, on examining FIGS. 5 and 6, that the crimping tool 3 describes a complex movement, the trajectory of which is imposed by the semi-circular trajectories pins 70, 71 and 33 around axes 730, 720 and 60 respectively.

Before the operation, the pin 75 is in the low position, which has the effect to keep the head 3 tilted outwards, free with respect to the part 1 (figure 5).

The upward movement of the pin 75 (arrow J ₁ , FIG. 6), deforms the assembly of the connecting rods and levers mechanism and causes the head 3 to tilt towards the part 1, which ensures crimping (arrow J ₂ ).

This mechanism is arranged, and the various lever arms determined, to such that the active face 30 follows, as soon as it comes into contact with the edge of sheet 11 ′, a curvilinear trajectory, the established center of rotation (in mobile position) is very close to the fold-back zone (top of the bending angle) of the sheet, this face 30 is further moving parallel to itself from the moment it came into contact with the sheet metal, until the end of the screening. The tangent to this trajectory is, at the end of stroke, normal to the sheet (perpendicular to face 15). At the start of crimping, the points 730, 70 and 71 are almost aligned; point 71 is progressing slower and slower, while points 34 and 33 go down. The linkage produces a knee brace effect which develops a very high pressing effort during work.

The crimping head 3 follows, during operation, a curvilinear trajectory centered in an area corresponding to the bending angle of the sheet. At the end of the operation, this trajectory is perpendicular to surface 15.

The shape of this trajectory, added to the fact that the part is immobilized constantly by the action of the clamping tool 101, allows working in optimal conditions in terms of quality.

The crimped edge is referenced 11 ".

As seen in Figure 7, the different fixed axes (shown hatched) are carried by a frame 8, which also supports a motor shaft 90, driven in rotation - in a single direction symbolized by the arrow R - by means of an electric gear motor 9.

The shaft 90 is connected, via an eccentric pin, to the axis 910 of a connecting rod 91. The opposite end of the latter carries a journal 92 by which it is articulated to a spreader 93. This is pivotally mounted around the fixed axis 530 already mentioned, which also serves as a pivot axis of the arm 102.

This lifter carries the pins 53 and 75 for driving the connecting rod control 52 (of the presetting tool) and of the tie rod 74 (of actuation of the crimping), respectively.

The arm 102 which carries the clamping head is shaped to embrace by the above the arm 22 carrying the presetting head 2, which overhangs the crimping head 3.

In the embodiment shown, the axis 104 of articulation of the jack 1000 is carried by the gear motor 9.

In the cycle start position, favorable for removing the crimped part and when a new part is put in place, the lifter 93 is in a position angular mean ensuring the clearances of the two heads 2 and 3, while the head of tightening is raised, cylinder 1000 retracted.

The raised position of the clamping head is illustrated in FIG. 7 by a dashed line, and the corresponding elements are preferably assigned the "prime" index.

When a new part is put in place, the jack 1000 is put in extension (arrow K ), and the arm 102 pivots down around the axis 530 (arrow L ), until the tool 101 applies against the part. The axis 103 follows a circular arc T , centered on the axis 530.

In synchronism with the clamping action, heads 2 and 3 are actuated, successively carrying out the pre-crimping and crimping operations, then are retracted, after which the cylinder 1000 is retracted for the evacuation of the crimped part.

The pre-crimping and crimping operations are described in a way exhaustive in the aforementioned FR-A-2 735 049, which can be referred to if necessary.

If the head 100 has a great length (dimension in a direction perpendicular to the plane of the figures), it is possible to provide two or more jacks placed side by side and connected in parallel, acting on the arm 102.

Of course, the unit is controlled by an appropriate control system such than a programmable controller or a microcomputer, which ensures good sequencing of the different operations.

It goes without saying that such a unit can only work over a length limited sheet metal. To treat a very long sheet, and in particular its entire periphery, it is possible to juxtapose a set of units such as the one described above, which will be operated jointly and synchronously, to ensure crimping on a great length, for example over the entire perimeter of the sheet. Furthermore, when we have case of a curved sheet, it is possible to orient all or part of the angularly of these units in a different way, so that each working head comes to attack orthogonally the sheet in the area assigned to it. For this purpose the units are adjustable mounting on a frame.

As a field of application of the invention, mention may be made, by way of non-limiting example, the automotive industry for the crimping of various parts such as doors, hoods and shutters.

Claims (6)

Pre-crimping and crimping unit for the edge (11) of a sheet (10) which is supported by a fixed matrix (14), comprising two movable heads, one (2) of pre-crimping, and the other (3) crimping, which are moved synchronously to come one after the other, press the edge of the sheet (11) and release it, these two heads being driven by a common drive shaft (90), characterized in that it comprises a clamping head (100), also movable, which is moved by at least one pneumatic cylinder (1000) so as to press the zone (13 ') of the sheet adjacent to the zone of crimping before the operation, and which is released after the operation. Unit according to claim 1, characterized in that the head of clamping (100) is carried by a pivoting arm (102). Unit according to claim 2, in which the pre-press heads (2) and crimping (3) are both carried by swinging arms (22, 31) approximately vertical, the crimping head (3) being located below the pre-crimping head (2), characterized in that the pivoting arm (102) which carries the clamping head (100) substantially affects the shape of an inverted "U" which comes to kiss from above the preserting arm (22). Unit according to claim 2 or 3, in which the drive of pre-crimping heads (2) and crimping heads (3) are made from the common motor shaft (90) via an eccentric crank pin and connecting rod system (91) connected to a lifting beam swivel (93), characterized in that the swivel arm (102) carrying the clamping head (100), and this pivoting spreader (93), are articulated on the same fixed axis (530). Pre-crimping and crimping kit for large sheet metal length, which includes several juxtaposed units conforming to at least one of the previous claims. Assembly according to claim 5, characterized in that certain at least of said units have an angular positioning offset from that of other.

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