EP1998910B1 - Device and method for joining metal sheets by means of riveting - Google Patents

Abstract

A device (1) for assembling panels using riveting which includes a riveting system (6) together with a drilling system (4). According to the invention, the device includes components for setting the riveting head (38) in motion relative to a carriage (34) of the riveting system, where these components are designed to be capable of moving this riveting head (38) between an at-rest position in which the drilling head axis and the riveting head axis (16, 40) are distinct, and a working position in which the same axes (16, 40) coincide.

Description

TECHNICAL AREA

The present invention relates generally to the field of joining by riveting thin metal sheets or structures, this technique is widely used in aeronautical construction activities.

The invention indeed has a preferred but non-limiting application in the field of robotic assembly by riveting aircraft sheets having a drilling surface / riveting high curvature, such as the leading edge of a wing , or of lower curvature, like an aircraft fuselage panel.

STATE OF THE PRIOR ART

Devices for assembling sheets by riveting have already been widely developed in the prior art. An exemplary embodiment is known from the document US 2,978,791 , on which the preamble of claims 1 and 21 is based.

In the aerospace industry, these devices generally include a frame carrying a drilling system, a riveting system, and a press-plate system. The press-plate system is usually driven first in order to make contact with the sheets to be assembled, then it is the turn of the drilling system to break through the holes. sheet to obtain a hole in which is then inserted a rivet, issued by the riveting system. As an indication, it is noted that the sheet-metal press system can possibly be doubled by a second press-plate system in order to pressurize both sides of the sheet assembly. On the other hand, depending on the possibilities of access to this structure, the rivets are set up from one side of the sheets to be assembled, or from both sides of them.

The assembly formed by the chassis carrying the various systems mentioned above is usually placed at the end of a robotic arm of the device, which thus makes it possible to bring this assembly to the desired location relative to the sheets to be assembled.

Drilling and riveting systems of known devices, as described in the document EP 1 329 270 , are generally controlled so that the riveting head and the piercing head are alternately brought into the working axis of the device, in order to perform one or more operations specific to them and involving other sets in motion .

This way of operating which therefore requires the sequential movement of drilling and riveting systems, requires the presence of a relatively complex drive kinematic chain combining a multitude of means of rotation and translation, and which not only translates into high mass and bulk important overall, but especially by a lack of precision in drilling.

Indeed, it has been found a lack of rigidity of the drilling head resulting from the large number of moving means with which it is associated, but also due in particular to the fact that this plurality of moving means is conducive the appearance in time of internal kinematic variations specific to the tools, which encourage the appearance of games. These variations, combined with the flexibility of the robotic arm carrying these systems, naturally does not allow the drilling system to have sufficient rigidity in the drilling axis, capable of ensuring the formation of a perfectly circular hole and / or 'regular milling.

STATEMENT OF THE INVENTION

The object of the invention is therefore to provide a device and a method for the riveting assembly of sheet metal remedying the problems mentioned above, and relating to the embodiments of the prior art.

To this end, the subject of the invention is a device for the joining by riveting of sheets, as defined in the independent claim 1.

Advantageously, the device according to the invention provides a better precision in the drilling, since the driving kinematic chain associated with the drilling system can be simplified compared with that encountered in the prior art. Indeed, it is now no longer necessary to move the drilling system to ensure the alternative establishment in the working axis, riveting and drilling systems.

This is explained by the fact that the proposed solution implies that the piercing head remains permanently in the working axis of the device, whether during the drilling operation or during the riveting operation, since it is the riveting system itself which is designed so that its riveting head is in turn disengaged from the working axis, and oriented according to it, being located forward with respect to the piercing head with which this head riveting is then also aligned.

Therefore, the proposed arrangement provides a very high rigidity in the drilling axis, capable of ensuring the formation of a perfectly circular hole and a regular milling.

In addition, it is noted that the simplification of the driving kinematic chain associated with the drilling system is not only intended to reduce the risk of occurrence of internal kinematic variations specific to the tooling and favoring the appearance games, but also leads advantageously to decrease the mass of the device and its overall size.

In addition, the use of a deformable parallelogram overall makes it possible to further simplify the design of the device.

The use of a deformable parallelogram, similar to a pantograph, generally provides a simplified sequencing of the riveting operation that follows the drilling operation, thus provides better efficiency to the device. Indeed, as will be detailed later, it is noted that the parallelogram is designed to deform in order to bring the riveting head into its working position in which the drill head axis and rivet head axis are combined, this deformation can advantageously be carried out automatically during a simple movement of the second carriage, preferably parallel to the drill head axis.

In addition, as indicated above, it is preferably provided that the parallelogram is deformed in a predetermined manner during a simple movement of the second carriage in a sliding direction, preferably identical to the direction of movement of the riveting head. at the end of riveting operation, that is to say in a direction of the working axis of the device, itself parallel to the direction of the drill head axis. Therefore, this preferred embodiment is remarkable in that the sequencing of the riveting operation is simplified to the extreme, since it consists only of moving the second carriage in motion in the direction of sliding.

According to the invention, the mechanical deformation system is a guiding system comprising a pin integral with one of the two parallel arms, the pin sliding in a switching groove when the second carriage moves in the direction sliding. The groove, similar to a ramp or a routing track, has a suitable shape ensuring the deformation of the desired parallelogram.

As such, it is noted that the routing groove preferably has successively a first portion to maintain the parallelogram in its first configuration placing the riveting head in its rest position, a second portion for deforming progressively the parallelogram until it adopts its second configuration placing the riveting head in its working position, and a third portion to maintain the parallelogram in its second configuration, to allow a riveting operation. The three adjoining portions are preferably each rectilinear, respectively oriented along three distinct lines. In this regard, it is preferably provided that the first and third portions are parallel to each other and parallel to the working axis, while the second portion is inclined relative thereto in order to ensure the progressive approximation of the head of the riveting towards the working axis. Finally, it is indicated that the routing groove, which is preferably in a plane, may not include the first portion mentioned above, but only the other two portions respectively first of all the deformation of the parallelogram in order to bring the riveting head in its working position, and then maintaining the deformed parallelogram to put the head in translation to complete the riveting operation along the working axis.

Preferably, the device comprises a frame carrying the routing groove and on which are mounted each of the riveting system and drilling system, the first and second carriages being each arranged so as to be able to slide rectilinearly with respect to the frame according to the same sliding direction, the drilling system comprising means for moving the first carriage in the sliding direction, and the riveting system also having means for moving the second carriage in the sliding direction.

Alternatively, one could predict that the first and second carriages slide respectively in two different directions, namely not parallel to each other. On the other hand, another possibility would be to use the same moving means for moving the first and second carriages, in the same or similar manner to that described above incorporating coupling means.

In order to limit as much as possible the overall bulk of the device, the means for setting the second carriage in motion in the sliding direction comprise a rodless jack, of a conventional design and known to those skilled in the art. An alternative solution could for example have been to use a linear motor, as it is preferentially retained to achieve the means for moving the first carriage. In such a case, the linear motor employed is of the type of those commercially available.

Still preferentially, whatever the preferred embodiment considered, the first carriage is mounted on two guide rails secured to the frame, with the aid of a plurality of stirrup-shaped pads cooperating with the two rails of guiding and being integral with the first carriage. One can then provide that each of these two guide rails of the first carriage has a core arranged respectively in two inclined planes forming together a V in section taken orthogonally to the drill head axis.

Thus, the activation of the solenoid of a primary element of the linear motor makes it possible to create electromagnetic forces ensuring the displacement on the rails of the first carriage, and also an attraction thereof to a secondary element usually taking the form of a track of permanent magnets. This attraction has the effect of creating a plating of the first carriage on the guide rails, which, because of their V arrangement, strongly help maintain a centering of the drilling head in the working axis. Indeed, in operation, these support forces permanently maintain the first carriage on the rails arranged in V, thereby avoiding the appearance of vibration generating sets that would be extremely detrimental to the drilling accuracy.

As an indication, each of the two guide rails of the first carriage preferably has an I-shaped cross section.

Furthermore, it is preferably provided that the first carriage is equipped with a first read head adapted to cooperate with an optical ruler placed on the chassis. This makes it possible to carry out controlled micrometric displacements of the first carriage on the chassis of the device, and thus to envisage the realization of holes / millings of extremely precise dimensions.

The second carriage of the riveting system is preferably mounted on a rail of guide secured to the frame and also oriented in the direction of sliding, with the aid of at least one stirrup-shaped pad cooperating with the guide rail and being secured to the second carriage. Preferably, it is expected that this rail is separate from the two guide rails on which is secured the first carriage of the drilling system. As an indication, the aforementioned rail is used both for the case where the riveting head is mounted on means for rotating, as for the case where it is carried by a deformable parallelogram.

The device further preferably comprises a steel press system arranged to be slidable in a rectilinear manner with respect to the frame, in the direction of sliding. The sheet metal press system preferably comprises a third carriage mounted on the frame, as well as means for moving this third carriage in the sliding direction.

In this respect, it is preferably provided that the means for moving the third carriage take the form of a linear motor, which may be such that it has in common with the linear motor of the first carriage the same fixed secondary element, know the permanent magnet track placed between the two guide rails of the first carriage. This specificity also makes it possible to reduce the number of kinematic elements within the device, resulting in a further reduction in the overall weight and bulk of the device.

As such, it is also possible that the third carriage is mounted on the two guide rails guiding the first carriage, with the aid of a plurality of stirrup-shaped pads cooperating with these two guide rails and being secured. of the third carriage.

Here again, the third carriage is equipped with a second read head adapted to cooperate with an optical ruler placed on the chassis, which is of course preferably identical to that cooperating with the first read head equipping the carriage of the drilling system. . As mentioned above, this advantageously makes it possible to envisage carrying out micrometric displacements of the third carriage on the chassis.

On the other hand, it is indicated that the sheet-metal press system has a sheet-metal press head mounted on the third carriage and defining a sheet-metal press head axis coinciding with the drilling head axis.

It is preferably provided that the frame is mounted on a robotic arm of the device, for example by means of a five-axis head.

Furthermore, the device preferably also comprises a control system provided with means making it possible to deliver an advance speed setpoint of a drilling tool of the device, along the axis of the piercing head, as well as a setpoint of rotation speed of this tool, these instructions being based on information on the local stiffness of plates at a hole to be drilled for receiving a rivet.

Thus, taking into account information on the local stiffness of the sheets for controlling the drilling operation of a hole, which in a conventional but non-limiting manner comprises the production of this hole and preferably that of a countersink for housing of the rivet head, it is then advantageously possible to ensure the formation of a perfectly circular hole and without delamination in the drilling of a composite, and a regular milling at the end of this hole.

Finally, the subject of the invention is also a method of joining by riveting of sheets implemented using a device such as that which has just been described.

Other advantages and features of the invention will become apparent in the detailed non-limiting description below.

BRIEF DESCRIPTION OF THE DRAWINGS

• la figure 1 représente une vue en perspective d'une partie d'un dispositif pour l'assemblage par rivetage de tôles non couvert par l'invention, mais utile à la compréhension de celle-ci ;
• la figure 2 représente une vue éclatée en perspective du dispositif montré sur la figure 1 ;
• la figure 3 représente une vue en coupe prise selon le plan P de la figure 1 ;
• les figure 4 à 6 représentent des vues schématiques de différentes parties d'un système de commande équipant le dispositif montré sur les figures 1 à 3 ;
• les figures 7a à 7i montrent le dispositif des figures 1 à 3 à différents stades lors de la mise en oeuvre d'un procédé d'assemblage par rivetage de tôles ;
• la figure 8 représente une vue en perspective d'une partie d'un dispositif pour l'assemblage par rivetage de tôles, selon un mode de réalisation préféré de la présente invention ;
• la figure 9 représente une vue de face du dispositif montré sur la figure 8 ;
• la figure 10 représente une vue éclatée en perspective d'une partie du dispositif montré sur les figures 8 et 9, détaillant plus spécifiquement la conception du second chariot portant le tête de rivetage ;
• la figure 11 représente une vue schématique de dessus illustrant la gorge d'aiguillage servant à la déformation d'un parallélogramme déformable équipant le dispositif montré sur les figures 8 à 10 ; et
• les figures 12a et 12b montrent le dispositif des figures 8 à 11 à différents stades lors de la mise en oeuvre d'un procédé d'assemblage par rivetage de tôles selon un mode de réalisation préféré de la présente invention.

This description will be made with reference to the appended drawings among which;

• the figure 1 is a perspective view of a portion of a device for riveting sheet metal not covered by the invention, but useful for the understanding thereof;
• the figure 2 represents an exploded perspective view of the device shown on the figure 1 ;
• the figure 3 represents a sectional view taken along the plane P of the figure 1 ;
• the figure 4 to 6 represent schematic views of different parts of a control system equipping the device shown on the Figures 1 to 3 ;
• the Figures 7a to 7i show the device of Figures 1 to 3 at different stages during the implementation of a joining process by riveting metal sheets;
• the figure 8 is a perspective view of a portion of a device for riveting sheet metal, according to a preferred embodiment of the present invention;
• the figure 9 represents a front view of the device shown on the figure 8 ;
• the figure 10 represents an exploded view in perspective of a part of the device shown on the figures 8 and 9 , detailing more specifically the design of the second carriage carrying the riveting head;
• the figure 11 represents a schematic top view illustrating the routing groove used for the deformation of a deformable parallelogram equipping the device shown on the Figures 8 to 10 ; and
• the figures 12a and 12b show the device of Figures 8 to 11 at different stages in the implementation of a sheet riveting method according to a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

With reference first of all to the Figures 1 to 3 , we see a part of a device 1 for the riveting assembly of sheets not covered by the invention, but useful for the understanding thereof, which will be described with reference to Figures 8 to 12b .

The sheets concerned being of the metal type or made of any other material such as composite material.

This device 1 like the present invention, finding a preferred application in the field of aeronautical constructions, can be adapted to allow the automatic installation of any type of rivets, such as rivets to shoot, and / or rivets struck, and / or crushed rivets, without departing from the scope of the invention. Nevertheless, it is noted that the device 1 is preferably designed to work blindly, with rivets to shoot.

The part of the device 1 represented on the Figures 1 to 3 concerns only a terminal portion of this device, and is preferably a mountable / dismountable tool intended to be assembled at the end of a robotic arm (not shown) preferably forming part of this device. As a guide, it is noted that the junction between the end of this robotic arm, and the tool part which will now be described, may be constituted by a five-axis head known to those skilled in the art and allowing a very high orientation. precise of this tool in space.

For the sake of clarity, the description of the device 1 will be made with reference to a system of axes of this device, which is specifically attached to a chassis 2 of the latter, also called chassis of the tool. Thus, X is referred to as the longitudinal direction of the device, Y is the direction transversely oriented relative to this device, and Z is the vertical or height direction, these three directions being orthogonal to each other. Naturally, it should be understood that the aforementioned axis system moves in the same movement as that of the chassis 2, driven by the robotic arm.

The device 1 thus comprises generally, attached to the frame 2, three systems intended to provide different functions, namely a drilling system 4, a riveting system 6, and a press-plate system 8. For information purposes, it is indicated that these systems are also called actuators, or even effectors.

With regard to the drilling system 4, the latter has a first carriage 10 supporting the whole of the piercing spindle 12, which has at its front part a piercing head 14 equipped with a piercing tool 17 and defining a drill head axis 16, also called drilling tool axis, wherein is arranged the same tool. More specifically, the pin 12 is fixedly mounted on the carriage 10, so that the relative position between the axis of the drilling head 16 oriented in the direction X, and the same carriage 10, is intended to remain identical throughout. a riveting assembly cycle. By way of indication, the piercing head 14 conventionally comprises the piercing tool 17, as well as the support of this tool, of the mandrel type or the like.

The first carriage 10 is mounted on the frame 2 so as to be able to slide rectilinearly with respect thereto, in a direction of sliding 18 parallel to the direction X. To do this, the carriage 10 is slidably mounted on two rails. 20 oriented guideways in the direction X, and therefore consequently also in the direction of sliding 18, these two rails 20 being spaced apart from each other in the direction Y.

More specifically with reference to the figure 3 showing a cross-section in a plane P oriented in directions Y and Z and passing through the piercing system 4, it can be seen that the two rails 20, for example having an I-shaped cross section, are arranged in such a way as to that the two souls of these I are respectively in two inclined planes P1, P2 together forming a V. In addition, the upper flanges of these two rails 20 are therefore also respectively in two inclined planes P3, P4 jointly forming a V , the tip of the latter V being oriented in the Z direction, downwards. It is noted that these two V each have two branches symmetrical to each other with respect to a vertical plane XZ passing through the axis 16, and together forming an angle of about 90 °.

The V arrangement of the upper flanges of the rails 20 allows easy and precise adjustment of the carriages arranged on these rails, and generally makes it possible to very satisfactorily block any parasitic movements of these carriages when they are in translation on the rails.

To allow lashing on the rails 20, the carriage 10 is equipped with a plurality of yoke-shaped ball bearings 22, for example four in number, with two of them associated with one of the rails 20, and the remaining two associated with the other of these rails. Each of these pads 22 therefore encloses the upper branch of the I of one of the two rails 20, as is best seen on the figure 3 .

To enable displacement in the sliding direction 18 of the first carriage 10 relative to the frame 2, the drilling system 4 incorporates moving means 24 which preferably take the form of a linear motor incorporating a movable primary element 26 embedded on the first carriage 10, and a fixed secondary element 28 mounted on the frame 2.

As is clearly visible in the figures, the frame 2 has in section on a YZ plane of a general shape of U, at the two ends of which are fixed the two rails 20. Between the two branches of this U, there is provided a magnetic track consisting of rare earth permanent magnets, alternating along the same track the North and South polarizations. This track, placed under the first carriage 10, then constitutes the fixed secondary element 28 of the linear motor 24.

Thus, the activation of the solenoid equipping the movable primary element 26 of the linear motor 24 makes it possible to create electromagnetic forces ensuring on the one hand the displacement in the X direction of the first carriage 10 on the rails 20, and on the other hand an attraction in the direction Z of the same carriage 10 to the fixed secondary element 28.

In order to obtain a micrometric precision in the displacement of the carriage 10, it is expected that the latter is equipped with a read head 30 cooperating with an optical ruler 32 placed on the frame 2, in the direction X. Preferably, this rule 32 consists of a glass bar bearing graduations of very high precision. Thus, the read head 30 converts into electronic signals the detection of engravings read on the ruler 32 during the passage of the carriage 10, to give its exact position on the guide rails 20.

The description of the drilling system 4 which has just been carried out shows a specificity, namely that the axis of drilling head 16 is provided to remain permanently in the working axis of the device, and is therefore not no case intended to be animated by a movement relative to the chassis 2 during operation of the device.

Always referring to Figures 1 to 3 , the riveting system 6 comprises meanwhile a second carriage 34 supporting the assembly of the riveting tool 36 or riveting machine, which comprises in its front portion a riveting head 38, which in turn defines a rivet head axis 40 More precisely, the riveting head 38, and more generally the riveting tool assembly 36, is integrally mounted at the front of a deportation arm 42 extending generally along the X direction, and whose the rear part is mechanically connected to the carriage 34.

The aforementioned mechanical connection is made using means of movement (hidden in the figures) designed to be able to put the arm 42 and the head 38 secured to it in rotation relative to the carriage 34 about an axis of rotation 44, for the purpose of moving the same riveting head 38 between a rest position in which the drill head axis 16 and the rivet head axis 40 are separate and parallel as shown in FIGS. figures 1 and 3 , and a working position in which these axes 16, 40 are merged, as will be explained later. The moving means then preferably takes the form of a conventional rotary motor, the axis of rotation 44 of which is preferably parallel to the X and 18 directions, and of course distinct from the axes of the piercing head and the rivet headpiece 16, 40. As a result, the start of the rotary motor causes the head 38 to move relative to the carriage 34, this movement describing a trajectory corresponding to a portion of a circle situated in a plane YZ.

The second carriage 34 is mounted on the frame 2 so as to slide rectilinearly with respect to the latter in the sliding direction 18. To do this, the second carriage 34 is slidably mounted on a guide rail 46, preferably separate from the two guide rails 20 of the carriage 10, but also oriented in the directions X and 18. As shown in FIG. figure 2 , the rail 46 of H-shaped cross-section is integrally mounted on an outer lateral surface of one of the legs of the U formed by the frame 2.

To allow stowage on the rail 46, the carriage 34 is equipped with one or a plurality of yoke-shaped ball bearings 48, for example, provided at the number two, spaced in the X direction. pads 48 thus encloses the free lateral branch of the H which is opposed to the other lateral branch fixed integrally on the frame 2.

Preferably, the carriage 34 of the riveting system 6 does not comprise any translational means of its own, but is provided to be able to couple with the carriage of the drilling system 4, and is therefore likely to be set in motion in the direction 18 under the effect of the start of the first linear motor 24 described above.

Indeed, there are provided coupling means 50 allowing, when in an activated state, to couple in translation in the direction 18, one to the other of the carriages 10, 34, and, when are in a deactivated state, to allow relative sliding between these same carriages.

To do this, provision is made for example that these means 50 comprise a guide rail 52 integral with the first carriage and arranged in the X and 18 directions, and at least one actuatable brake caliper 54, integral with the second carriage 34, and more particularly of an inclined upper part of the latter which tends to move closer to pin 12 to limit the overall size. Thus, according to whether or not it is desired to couple the two carriages in translation in the direction 18, the brake callipers 54, permanently secured to the free upper part of the I-shaped cross section rail 52, are actuated accordingly. , for example electromagnetically. In this regard, it is noted that in the case envisaged where the riveting system 6 is equipped with its own means of translation, they can then take any form known to those skilled in the art, such as for example incorporating a hydraulic cylinder.

The coupling described above makes it possible, of course, to obtain also a micrometric precision in the displacement of the carriage 34, thanks to the read head 30 equipping the carriage 10 and the optical ruler 32 placed on the frame 2.

With regard to the sheet metal press system 8, the latter has a third carriage 60 supporting a sheet metal press head 62, also known as pressurizing gun, which defines a sheet metal press head axis 64 oriented in directions X and 18. In a manner known to those skilled in the art, the head 62, intended to contact the sheets to be assembled during the drilling and riveting operations, is provided with a through orifice 66 arranged according to the the axis of the press head 64 and intended to be alternately traversed by the drilling tool 17, and the riveting head 38. More specifically, this head 62 or barrel is fixedly mounted on the carriage 60, so that the position relative between the head axis X-oriented sheet-metal press, and the same carriage 60, is intended to remain identical throughout a riveting assembly cycle.

In addition, one of the peculiarities of this preferred embodiment lies in the fact that the pins 64 and 16 are permanently merged during a riveting assembly cycle.

The third carriage 60 is mounted on the frame 2 so as to be able to slide rectilinearly with respect to the latter in the sliding direction 18. To this end, the carriage 60 is slidably mounted on the two guide rails 20 arranged in V previously described, forward with respect to the first carriage 10 of the drilling system, naturally understood that the front and the back are here determined according to the orientation of the drilling tool used by the system 4.

To allow the lashing on the rails 20, the carriage 60 is equipped with a plurality of ball bearings 68 in the form of a stirrup, for example two in number, each associated with one of the two rails. Each of these shoes 68 thus encloses the upper branch of the I of one of the two rails 20.

To enable displacement in the sliding direction 18 of the third carriage 60 with respect to the frame 2, the sheet-ironing system 8 incorporates moving means 70 which preferably take the form of a linear motor incorporating a primary element mobile 72 on the third carriage 60, and a fixed secondary element 28 mounted on the frame 2, and which is preferably the same as that used for the first linear motor, in order to limit as much as possible the number of kinematic components necessary for the operation of the device 1.

Thus, here too, the activation of the solenoid equipping the movable primary element 72 of the linear motor 70 makes it possible to create electromagnetic forces ensuring on the one hand the displacement in the X direction of the third carriage 60 on the rails 20, and of on the other hand, an attraction along the Z direction of this same carriage 60 towards the fixed secondary element 28 of the permanent magnet track type.

To also obtain a micrometric precision in the movement of the carriage 60, it is expected that the latter is equipped with a read head 74 cooperating with the optical ruler 32 above, placed on the frame 2. As a result, it is therefore possible to perfectly control the relative spacing of the two carriages 10 and 60, which has the advantage of having a great deal of control of the depth of the holes and milling performed using the drilling tool.

To be able to control this device 1 in the desired way, it is also equipped with a control system 83 shown schematically on the Figures 4 to 6 . Overall, this system 83 comprises first control means 84 which are associated with the sheet metal press system 8, as well as second control means 86 which are associated with the piercing system 4, these means 84, 86 being able to be naturally grouped at the same time. within the same equipment.

Regarding the first means 84 shown on the figure 4 , these comprise a first digital control unit 88 connected to a servo-control card 90 of the linear motor 70 of the sheet-iron press system 8. The unit 88 is thus capable of delivering position, speed and speed commands. Advance and power to the card 90, which then performs a control in position, speed and power, delivering a suitable current to the motor 70 to which the card 90 is connected.

In return, the servo card 90 receives from the read head 74 information on the actual position of the carriage 60, this information being returned to the unit 88. Moreover, this servo card 90 is also capable of restoring the unit 88 measures the speed of advance of the carriage 60 and the effective power, this effective power allowing the unit 88 to determine the engine power absorbed by the system 8 during the docking and clamming operations.

Regarding the second means 86 shown on the figure 6 these comprise a second digital control unit 92 connected to a servo-control card 94 of the linear motor 24 of the drilling system 4. The unit 92 is thus capable of delivering position, speed and feed instructions. power card 94, which then performs a control in position, feed rate and power, delivering a current appropriate to the motor 24 to which the card 94 is connected. In return, the servo card 94 receives from the read head 30 information on the actual position of the carriage 10, this information being returned to the unit 92. Moreover, this servo card 94 is also able to restore the unit 92 measures concerning the speed of advance of the carriage 10 and possibly the effective power.

In addition, the digital control unit 92 is also connected to a servocontrol card 96 of the rotary motor of the pin 12. The unit 92 is thus capable of delivering rotational speed and power instructions to the card 96. , which then realizes a servocontrol in rotational speed and in power, by delivering a current appropriate to the rotary motor to which this card 96 is connected. In return, it may be provided that this servo card 96 returns to the unit 92 measures concerning the speed of rotation of the tool 17 and the effective power.

In this regard, it is indicated that the unit 92 comprises means 82 for delivering, respectively to the cards 94 and 96, setpoints of the tool advance speed and setpoint of rotation speed of this tool which are function information on the local stiffness of the sheets at the hole to be drilled for receiving a rivet, this information being called Info stiffness.

More specifically with reference to the figure 5 it can be seen that these means 82 take for example the form of a correction matrix of the two aforementioned setpoints, this matrix thus taking into account not only information Info_raideur previously determined, but also possibly the nature of the material and the type of the drilling tool whose data are pre-recorded in a specific program. Of course, this correction matrix is designed so that the instructions of speed of advance and rotation that it delivers to the cards 94, 96 make it possible to carry out a drilling with a quality and a precision as high as possible.

It will now be described with reference to Figures 7a to 7f the method of assembly by riveting implemented using the device 1 presented above, this method generally comprising a step of determining information on the local stiffness of the sheets at the hole to be drilled, followed by a drilling step to achieve the hole and the milling associated with it, then finally a step of setting up a rivet in said drilled hole, these three steps being repeated as many times as there are rivets to lay on the sheets to be assembled.

As shown in figure 7a , the frame is first positioned relative to the plates 80 to be assembled according to the point thereof where the rivet must be placed, the three systems 4, 6, 8 are each in their rest position.

More specifically with reference to the figure 7b it can be seen that the frame 2 is first brought by the robotic arm close to the sheets 80 to be assembled, so that the front end of the sheet metal press head 62 is at a standard distance D_stand of the sheets 80 according to the sliding direction 18 and that of the axis 64, this distance may be of the order of 15 mm. At this stage, the carriage 60 is in a position such that its central point C is at a reference point R of the optical ruler 32.

Then, the docking operation is initiated by controlling a linear displacement of the carriage 60 with the unit 88, in order to obtain a contact between the head 62 and the plates 80. It is noted that as soon as the aforementioned contact is established , the control unit 88 periodically determines the value of the absorbed motor power P1 absorbed by the system 8, this absorbed value P1 being then converted by a converter integrated to the unit 88 in order to obtain a value of the resistance strength of the plates. at the F1 docking. As an indication, it is noted that this force F1, updated every 5 ms, also corresponds in value to a driving force of the press-plate system 8 against the plates 80.

The control of this docking operation is provided so that the movement of the system 8, and more specifically that of its carriage 60, is completed when the determined force F1 has reached a target value F1_target, which can for example be fixed to a low value of the order of 1 N. As shown in Figure 7c at the end of the docking operation, the carriage 60 thus traveled a distance D1_final between the point R and a point C1 of the rule 32 at which the point C of the carriage 60 is located, the value of this measured distance D1_final using rule 32 being restored to the unit 88. In addition, at this moment, the value of the resistance force of the plates at the end of the docking, called F1_final, which is of course natural, is known and recorded via the unit 88. substantially identical to the force F1_cible.

Furthermore, it is also possible to perform an error detection using the value of the recorded distance D1_final. Indeed, if this value is not within a predetermined range, it can then be concluded that the device is poorly positioned relative to the sheets, or while these sheets have a form out of tolerance.

Then, we initiate the clamming operation, which is started at the end of the docking operation, possibly with a stopping time between these two operations. In the same way as that encountered in the context of the preceding operation, the clamming is carried out by controlling a linear displacement of the carriage 60 with the unit 88, in order to obtain a reinforced adhesion between the head 62 and the sheets 80 contact. It is noted that during this operation, the control unit 88 periodically determines, on the one hand, the value of the absorbed motor power P2 absorbed by the system 8, this absorbed value P2 being then converted by the converter in order to obtain a value of the resistance force of the laminations F 2, and secondly the clamping distance D_clamage corresponding to the actual distance traveled by the point C of the carriage between the point of the optical ruler 32 at which it is located at the moment t considered, and the point C1 of this rule. Here again, it is specified that the force F2, updated every 5 ms as well as the value D_clamage, also corresponds in value to a driving force of the press-plate system 8 against the plates 80.

The control of this clamping operation is provided so that the movement of the carriage 60 is completed when the determined force F2 has reached a target value F2_cible, or when the clamping distance D_clamage has reached a target value D_clamage_cible, the clamping operation thus being completed as soon as any one of these two target values has been reached.

As an indication, the target value F2_cible can for example be set at a value of the order of 150 N, and the target value D_clamage target can even example be set to a value of the order of 500 microns. As shown in figure 7d at the end of the clamping operation, the carriage 60 thus traveled a distance D2_final between the point R and a point C2 of the rule 32 at which the point C of the carriage 60 is located, the value of this distance D2_final measured at With the aid of rule 32 being returned to unit 88. This then makes it possible to obtain the final clamming distance D_clamage_final actually traveled by system 8, by subtracting D1_final from D2_final. In addition, the knowledge on the one hand of the dimensions of the system 8 and on the other hand of the real position of the latter on the frame 2 at the end of the clamping operation makes it possible to determine the exact position of the stressed plates 80 relative to the frame 2. In this regard, the unit 88 can then determine and store the distance T_tôles_final corresponding to the distance in the direction 18 between the point R of the rule 32 and the front end of the head of press-plates 62 at the end of the clamming operation.

This specificity is advantageous since it makes it possible to optimally optimize the linear displacement of the drilling system 4 during the subsequent drilling step, insofar as this system 4 can be driven at a high speed over a precise distance set as a function of the distance T_tôles_finale, before being slowed down to the speed of advance of the previously determined tool. Furthermore, the knowledge of this distance T_tôles_finale, of the order of 200 mm, allows to fix precisely the rotational speed change distance of the drilling tool for the attack of milling, when a storied tool driller- miller is used. Finally, another advantage lies in the fact that the depth of the countersink can be perfectly respected. As such, it is indicated that the subsequent milling stroke can also be corrected according to information Info_raideur determined as described below, and also possibly depending on the various characteristics of the rivets employed. In this respect, it is noted that the lower the local stiffness of the sheets, the more the latter are deformed by the thrust of the sheet-metal press head, and therefore the center of this sheet-metal press head is far from these same. deformed sheets. So, the more the local stiffness of the sheets is low, the greater the milling stroke compared to the press-plate system, to obtain a determined depth of milling, will be important.

Moreover, it is also possible to perform an error detection using the value of the recorded distance D_clamage_finale. Indeed, if this value is not within a predetermined range, it can then be concluded that the device is poorly positioned relative to the sheets, or while these sheets have a form out of tolerance. In addition, at the end of the clamming operation stopped when target value D_clamage_cible has been reached, the value of the resistance strength of the plates at the end of clamoring is known and recorded via unit 88. called F2_final. If this value is too low, then it can be considered that the structure formed by the sheets is non-existent.

With the value of the resistance force of the plates at the end of the clamage F2_final, it is then possible to determine, again using the unit 88, the information Info_raideur by establishing the following report: $$\mathrm{Info\_stiffness}=\left(\mathrm{F}2\mathrm{\_final}-\mathrm{F}1\mathrm{\_final}\right)/\mathrm{D\_clamage\_finale}$$

This information on the local stiffness of the sheets, whose value is for example of the order of 30 kg / mm, is then delivered to the second control means 86 associated with the drilling system 4, and more particularly to the correction matrix 82 equipping the unit 92. As previously indicated, this Info_raideur information is provided to predispose the instructions of speed of advance and speed of rotation of the tool 17 used when ordering the drilling step which will now be described .

Firstly, it is specified that this drilling step is initiated with the system 8 in its position as shown in FIG. figure 7d , and the systems 4 and 6 in their positions as shown on the figure 7a , as is globally represented on the figure 7e .

This drilling operation consists in moving the carriage 10 of the drilling system 4 so that it passes through the sheet-iron press system 8, and also passes through the two plates 80 to be assembled.

The advancement required in the sliding direction 18 is performed using the first motor 24. In this regard, it is noted that this operation is preferably not only to practice a through hole in the two sheets 80 superimposed, but also to make a countersink to accommodate the rivet head that will be laid later. As shown on the figure 7f , it is noted that the setting in motion of the carriage 10 of the drilling system in the direction 18 did not cause any movement of the carriage 34 of the riveting system 6, since this operation was carried out with the brake callipers 54 in a deactivated state, that is to say without securing between the brake calipers 54 and the rail 52. Therefore, it is noted that during the movement of the first carriage 10, the second carriage 34 remains stationary relative to the chassis 2.

More specifically, the drilling is carried out by controlling the linear displacement of the carriage 10 with the feed speed setpoint of the tool as previously determined and coming from the die 82, and simultaneously controlling the rotation of the pin 12 with the reference speed of rotation of the tool also coming from this matrix 82, these instructions being respectively delivered to the servocontrol cards 94 and 96.

During this piercing step, the value of a resistance force of the sheets F3 resulting from the support of the press-ironing system 8 on the sheets 80 is periodically determined. This determination of F3 is preferably carried out in the same way as that adopted for the determination of F1 and F2. As such, it is indicated that the engine associated with the trolley 60 of the ironing system continues to be fed during drilling, and that it is slaved in position so that the carriage 60 retains its C2 position on the chassis 2.

As an indication, F3 is updated every 5 ms and corresponds in value to a driving force of the sheet metal press head 62 in the sheets 80 during drilling.

This then makes it possible to compare periodically during the drilling, using the unit 92, the value of this force F3 to a minimum value F3_min, the minimum value F3_min can for example be set at 5 N.

When it is detected that F3 is less than F3_min, then it is ordered a decrease in the advance speed setpoint of the drilling tool via the matrix 82, so that the value of the force F3 returns to the above the minimum value F3_min. Thus, this way of operating advantageously makes it possible for the sheet-metal press head 62 not to lose contact with the sheets 80 during the drilling operation, following excessive thrust of the piercing tool 17 on these sheets.

At the end of this piercing step, as shown in figure 7g , the carriage 10 is again driven so as to move back on the rails 20 until it reaches a position farther away than the starting position shown on FIG. figure 7a . Indeed, it is sought a relative spacing in the direction 18 between the carriage 34 and the carriage 10, so that the riveting head 38 can come without problems of space in front of the piercing head 14, as this will be described later.

The method is continued by a step of placing the rivet in the hole obtained, this step beginning with a displacement of the riveting head 38 in the axis of the piercing head 14, in front of it.

To align these two axes 16, 40 and thus ensure that the riveting head 38 is in the working axis, the means for rotating this head 38 and the arm 42 are actuated until the position desired, as shown on the figure 7h . At the same time, the means 50 of the two carriages 10 and 34 are controlled so as to go into the activated state allowing them to be coupled in translation in the direction 18.

Then, it is undertaken a displacement of all of the two carriages 10, 34 with the first linear motor 24, as visible on the figure 7i . During this movement, the riveting head 38 located in front of the piercing head 14 penetrates inside the metal press head 62 and is therefore positioned very close to the two plates 80 to be assembled, on which the rivets removal operation is performed in a conventional manner, known to those skilled in the art.

Once the rivet is placed, the three carriages 10, 34, 60 are piloted so that they find their rest positions as shown on the drawing. figure 7a .

Referring now to Figures 8 to 11 a part of a device 1 for the rivet joining of sheets can be seen according to a preferred embodiment of the present invention. It has for some parts of a design identical or similar to that of the device 1 described above, and in this respect, it is noted that in the figures, the elements bearing the same reference numerals correspond to identical or similar elements . Therefore, it can be seen that the noticeable difference between the two devices 1 lies in the design of the riveting system 6, and more particularly in the design of the means for moving the riveting head 38 relative to the second carriage, still designed to be able to move the same riveting head between the rest position in which the drill head axis and the rivet head axis 16, 40 are distinct, and a working position in which the axis of drilling head and axis of riveting head 16, 40 are merged. On the other hand, the frame 2, the drilling system 4 and the sheet-iron press system 8 are identical or similar to those previously presented.

More particularly with reference to figures 8 and 9 , the riveting system 6 comprises the second carriage 34 supporting the assembly of the riveting tool 36 or riveting machine, which comprises in its front part the riveting head 38, which in turn defines the rivet head axis 40 parallel at directions X and 18. The riveting head 38, and more generally the riveting tool assembly 36, is mounted mechanically at its rear portion on the carriage 34 via a deformable parallelogram 102, which will be described below.

The second carriage 34 is mounted on the frame 2 so as to slide rectilinearly relative thereto in the sliding direction 18. To do this, the second carriage 34 is slidably mounted on the guide rail 46 preferably separate from the two guide rails 20 of the carriage 10, but also oriented in the directions X and 18. As shown in FIG. figure 9 , the rail 46 of H-shaped cross section is mounted solidarily on an outer lateral surface of one of the branches of the U formed by the frame 2.

To allow stowage on the rail 46, the carriage 34 is equipped with one or a plurality of yoke-shaped ball bearings 48, for example, provided at the number two, spaced in the X direction. pads 48 thus encloses the free lateral branch of the H which is opposed to the other lateral branch fixed integrally on the frame 2.

Preferably, the riveting system 6 also comprises means for moving the second carriage 34 in the sliding direction 18, these means therefore preferably being different from the moving means 24 of the first carriage 10, although this could in to be otherwise, without departing from the scope of the invention. The means for moving the second carriage 34 preferably takes the form of a rodless jack 104 of the type commercially available, arranged in the direction 18. Generally, the latter has a hollow body 106 fixed relative to to the frame 2, and a movable cylinder slider 108 adapted to be moved in the direction 18 relative to the hollow body 106 in which it is partially housed.

As mentioned above, one of the remarkable features of this preferred embodiment lies in the presence of the deformable parallelogram 102 establishing the mechanical connection between the rear portion of the riveting tool 36, and the carriage 34. This parallelogram 102 thus makes integral part of the means for moving the head riveting 38 relative to the second carriage, since it is easily capable of providing the movement of the same riveting head 38 between the rest position and the working position.

To do this, the parallelogram 102 comprises two parallel arms 110, each articulated at its rear end on the second carriage 34 along an axis 112, and articulated at its front end to the rear portion of the riveting tool 36 along an axis 114 , and more specifically articulated on a support block of the riveting head 38. In this respect, the axes 112, 114 are arranged parallel to the direction Z, so that the parallelogram 102 is deformed in an XY plane parallel to the direction of In addition, it is noted that the other two sides of the parallelogram 102 are physically constituted by the second carriage 34 and the riveting tool.

To complete the means for setting the riveting head 38 in motion, a mechanical deformation system of the parallelogram is provided. This system is generally designed so as to generate automatically, when the second carriage 34 is set in motion in a direction 18 by means of the jack 104, a deformation of the parallelogram 102 of a first configuration shown on the figures 8 and 9 placing the riveting head 38 in its rest position spaced from the working axis, to a second configuration which will be described later, placing the head 38 in its working position.

To do this, the mechanical deformation system 116 takes the form of a guiding system comprising a pin or roller 118 integral with one of the two parallel arms 110, preferably the arm located the outermost as shown, the pin 118 sliding in a switch groove 120 during a setting in motion of the second carriage 34 in the direction 18. The groove 120 fixed to the frame 2 is preferably located in a plane parallel to that in which the parallelogram is provided to deform.

Thus, the throat 120 which will be detailed later has a suitable shape ensuring the desired deformation of the parallelogram, namely that allowing the controlled approximation of the riveting head 38 to the working axis of the device, and also ensuring a maintenance of the rivet head axis 40 always parallel to the direction 18 during the movement of this head 38.

With reference to the figure 10 it can be seen that the carriage 34 may be composed of several elements that can be quickly dismounted relative to one another. Indeed, the part of the carriage 122 fixedly supporting the caliper-shaped shoe 48 and cooperating with the guide rail 46 is intended to remain permanently on this rail, while another carriage part 124 carrying the parallelogram 102 is intended to be mounted by quick attachment to the aforementioned part 122. In other words, the piece 124 is a key interface piece of a fast assembly and disassembly function of the parallelogram .102. Overall, it comprises two axes or shafts 126, 128 located one above the other, and parallel to the direction X. These two axes 126, 128 are respectively intended to rest in a V-shaped groove 130 and a U-shaped groove 132 made on the part 122 directly fixed on the shoe 48.

On the other hand, the carriage 34 is also equipped with a workpiece 134 establishing the mechanical connection between the workpiece 124 and the slider 108, this workpiece 134 actually having two distinct functions. The first function is to ensure the securing of the workpiece 124 on the part 122, namely to cooperate each of the two axes 126, 128 with their respective grooves 130, 132. This is done in a simple manner by turning the lower pin 128 carrying the connecting piece 134, which axis has an eccentric form provided for this purpose. More precisely, the axis 128 is introduced first into the depth of the U-shaped groove 132, then the axis 126 is tilted vertically from the V-groove 130, and finally, the part 134 is pushed by pivoting against a piece 138 which will be presented below. The locking is then simultaneously ensured by the eccentric support of the joining piece 134 against the groove 132.

The second function resides in the mechanical coupling with the slider of the cylinder 108. In fact, the H-shaped part 134 comes to couple quickly at the two lower branches of the H between the forks of a part of the cylinder. 138 home U screwed on the slider 108. To do this, the U-shaped part 138 carries spring ball screws 140 to retain the two lower branches of the H in the closed / locking position, ensuring this is a stop for the piece H-shaped 134 participating in the mechanical coupling of the carriage 34. on the rodless cylinder 104.

On the figure 11 , it has been shown in plan view the diverter groove 120 in which the pin 118 is intended to slide during the setting in motion of the carriage 34 in the direction 18. First, it can be seen that in the first direction 144 of the sliding direction 18 going towards the front of the device 1, this groove 120 comprises three distinct portions connected to each other. There is a first portion 148 extending along an axis 149 parallel to the direction 18, this first portion 148 for generally moving the riveting head 38 by keeping it away from the working axis of the device. In this regard, it is noted that as the pin 118 remains in the first portion 148, the riveting head 38 moves in the direction 18 without the position of its axis 40 is changed. Thus, it should be understood that the parallelogram 102 does not deform during this portion of the movement of the riveting tool 36. Next, the groove 120 includes a second portion 150 whose function is to lead to a progressive deformation of the parallelogram 102 until it adopts a configuration to place the riveting head in its working position, namely to align the rivet head axis 40 with the drill head axis 16.

To do this, in the embodiment described, this second portion 150 extends along an axis 151 located in the horizontal plane of the groove 120, and inclined relative to the direction 18 and the axis 149 of the first portion. Then, the groove 120 ends with a third portion 152 similar in shape to the first portion 148, since it is oriented along an axis 153 parallel to the direction 18. This third portion keeps the parallelogram 102 deformed and allow the movement of the riveting head 38 along the working axis, with the rivet axis 40 parallel to the drill head axis 16.

In view of the foregoing, it is noted that the profile of the groove 120 is similar to that of a driver who changes lanes, insofar as it passes from a straight path to a progressive shift and then rejoins a lane. new straight path, offset from the first. Of course, to avoid jerks and fluidize the movement of the pin 118, the junctions 154 and 156 between the three portions 148, 150, 152 are provided substantially rounded shape.

It is noted that the position of the pin 118 near the rear end of the outer arm 110, namely close to the axis of rotation 112, plays the role of amplifying the offset traced by the second portion 150 of the throat . Typically, the center distance of the joints 112, 114 measuring 240 mm, the distance from the pin 118 to the axis 112 being approximately 30 mm, we obtain an amplification of the offset in the ratio 240/30, ie eight times the offset engraved in the throat. Thus, with a 24 mm offset engraved in the throat, one gets 192 mm of offset between the disengaged axis and the working axis.

It will now be described the method of assembly by riveting implemented using the device 1 presented above.

First of all, it is indicated that this method generally comprises the same steps as those indicated for the preceding embodiment, namely a step of determining information on the local stiffness of the sheets at the hole to be drilled, followed by a drilling step to achieve the hole and the milling associated with it, then finally a step of setting up a rivet in the drilled hole. Since the first two steps are identical to those mentioned previously, they will not be described further. On the other hand, since the riveting step is substantially different, in particular in the manner in which the riveting tool 38 is brought into the working axis, this will now be detailed.

With reference to the figure 8 it can be seen that at the end of the piercing operation, the rivet carriage 34 is translated in the direction 18, implying movement of the peg. 118 in the first portion 148 of the throat. During this movement, the riveting head 38 is moved forward in the direction 144 of the direction 18, with its axis 40 undergoing no movement due to the maintenance of the parallelogram 102 in the first configuration. Thus, this first part of the displacement of the riveting head 38 makes it possible to maintain it in its rest position, while bringing it towards the front of the device. Then, when the rodless cylinder 104 continues its movement, the pin 118 enters the second portion 150 of the groove, leading to a progressive deformation of the parallelogram 102 to its second configuration in which it places the riveting head 38 in the groove. axis of work to enable it to provide the desired riveting operation. Therefore, as mentioned above, the alignment of the riveting head in the working axis is by the deformation of the parallelogram 102, this kinematic solution to ensure a safe and fast engagement in the system press-plate provided for this purpose. As such, the figure 12a shows the riveting system during the movement of the pin 118 within the second portion 150.

This purely mechanical solution has the advantage of no longer depend on a motorized system for the progressive engagement of the riveting system, nor more sensors position and control of the automata associated with the engine. Thus, it ensures a better engagement of the riveting system in the working axis, this engagement by mechanical process, the pantograph type, being unconditional, fast, simple and reliable.

The last part of the advance of the carriage 34, carried out with the pin 118 borrowing the third portion 152, causes the riveting head 38 to move in the direction 18, parallel to the working axis, until produce the introduction rivet in the drilled hole schematized on the figure 12b .

In addition, it is realized in precise re-centering at the end of the introduction of the riveting head 38 in the barrel 62 of the sheet-iron press system 8, thanks to the tolerancing of the through orifice 66 with the riveting head 38, preferably in diameter 18 H7 g6. In addition, it is preferably provided an initial conical entry on the barrel 62 of the press-plates.

Once this is achieved, the slider 108 of the cylinder 104 can be moved in the opposite direction 146, rearwardly, in order to put the device back into the configuration shown in FIG. figure 8 .

Claims (21)

1. A device (1) for assembling metal sheets (80) by riveting, the device including a riveting system (6) as well as a drilling system (4), said drilling system (4) including a first carriage (10) as well as a drilling head (14) mounted on the first carriage (10) and defining a drilling head axis (16), and said riveting system (6) comprising a second carriage (34) as well as a riveting head (38) mounted on said second carriage (34) and defining a riveting head axis (40),
   the device further including means for setting said riveting head (38) into motion relative to the second carriage (34) designed so as to be capable of moving this same riveting head (38) between a rest position in which said drilling head axis and riveting head axis (16, 40) are distinct, and a working position in which said drilling head axis and riveting head axis (16, 40) coincide, said means for setting said riveting head (38) into motion relative to the second carriage (34) comprising a deformable parallelogram (102),
   characterized in that said means for setting said riveting head into motion relative to the second carriage (34) comprise:

   - two parallel arms (110) forming said deformable parallelogram (102), each articulated at one of its two ends on said second carriage (34) and articulated at the other of its ends on said riveting head (38);

   - a mechanical system (116) for deforming the parallelogram (102) designed so as to cause, during the setting of said second carriage (34) into motion along a slide direction (18), deformation of said parallelogram (102) from a first configuration placing said riveting head (38) in its rest position to a second configuration placing said riveting head (38) in its working position, and vice versa,

   and in that said mechanical deformation system (116) is a guide system comprising a pin (118) firmly attached to one of said two parallel arms (110), said pin (118) sliding in a guide slot (120) during the setting of said second carriage (34) into motion along said slide direction (18).
2. The device (1) according to claim 1, characterized in that said guide slot (120) successively exhibits a second portion (150) which allows said parallelogram (102) to gradually deform until it adopts its second configuration placing said riveting head (38) in its working position, and a third portion (152) for maintaining said parallelogram (102) in its second configuration, so that said riveting head (38) is set into a translational movement while retaining its working position in order to accomplish the riveting operation.
3. The device (1) according to claim 1, characterized in that said guide slot (120) successively exhibits a first portion (148) allowing said parallelogram (102) to be maintained in its first configuration placing said riveting head (38) in its rest position, a second portion (150) allowing said parallelogram (102) to gradually deform until it adopts its second configuration placing said riveting head (38) in its working position, and a third portion (152) allowing said parallelogram (102) to be maintained in its second configuration, so that said riveting head (38) is set into translational movement while retaining its working position in order to accomplish the riveting operation.
4. The device (1) according to any of claims 2 and 3, characterized in that it comprises a chassis (2) bearing said guide slot (120) and on which are mounted each of said riveting system (6) and drilling system (4), said first and second carriages (10, 34) each being arranged so as to be capable of sliding rectilinearly relative to the chassis (2) along said same slide direction (18), said drilling system (4) including means (24) for setting the first carriage (10) into motion in said slide direction (18), and said riveting system (6) also including means (104) for setting the second carriage (34) into motion in said slide direction (18).
5. The device (1) according to claim 4, characterized in that said means for setting the second carriage (34) into motion in said slide direction (18) comprises a rodless piston (104).
6. The device (1) according to any of claims 4 or 5, characterized in that said means (24) for setting the first carriage (10) into motion assume the form of a linear motor.
7. The device (1) according to any of claims 4 to 6, characterized in that said first carriage (10) is mounted on two guide rails (20) firmly attached to said chassis (2), by means of a plurality of pads (22) in the form of calipers cooperating with said two guide rails (20) and being firmly attached to said first carriage (10).
8. The device (1) according to claim 7, characterized in that each of said two rail guides (20) of the first carriage (10) has a core, both cores being respectively arranged in two inclined planes (P1, P2) forming together a V in a section taken orthogonally to said drilling head axis (16).
9. The device (1) according to claim 7 or claim 8, characterized in that each of said two guide rails (20) of the first carriage (10) has a transverse section in the form of an I.
10. The device (1) according to any of claims 4 to 9, characterized in that said first carriage (10) is equipped with a first reader head (30) capable of cooperating with an optical rule (32) placed on said chassis (2).
11. The device (1) according to any of claims 4 to 10, characterized in that said second carriage (34) is mounted on a guide rail (46) firmly attached to said chassis (2) and oriented along the slide direction (18), by means of at least one pad (48) in the form of calipers cooperating with said guide rail (46) and being firmly attached to said second carriage (34).
12. The device (1) according to any of claims 4 to 11, characterized in that it further includes a sheet-clamping system (8) arranged so as to be able to slide rectilinearly relative to the chassis (2), along said slide direction (18).
13. The device (1) according to claim 12, characterized in that the sheet-clamping system (8) comprises a third carriage (60) mounted on said chassis (2), as well as means (70) for setting this third carriage (60) in motion in said slide direction (18).
14. The device (1) according to claim 13, characterized in that said means (70) for setting the third carriage (60) in motion assume the form of a linear motor.
15. The device (1) according to claim 14 combined with claim 8, characterized in that the linear motors (24, 70) of the first and third carriages (10, 60) have a same fixed secondary element (28) in common.
16. The device (1) according to any of claims 13 to 15 combined with any of claims 9 to 11, characterized in that said third carriage (60) is mounted on said two guide rails (20) guiding said first carriage (10), by means of a plurality of pads (68) in the form of callipers cooperating with said guide rails (20) and being firmly attached to said carriage (60).
17. The device (1) according to any of claims 13 to 16, characterized in that said third carriage (60) is equipped with a second reader head (74) capable of cooperating with an optical rule (32) placed on said chassis (2).
18. The device (1) according to any of claims 13 to 17, characterized in that said sheet-clamping system (8) has a sheet-clamping head (62) mounted on said third carriage (60) and defining a sheet-clamping head axis (64) coinciding with the drilling head axis (16).
19. The device (1) according to any of claims 4 to 18, characterized in that said chassis (2) is mounted on a robotic arm of the device.
20. The device (1) according to any of the preceding claims, characterized in that it includes a control system (83) comprising means (82) for delivering an advance speed setting for a drilling tool (17) of the device, along the drilling head axis (16) as well as a rotation speed setting for this tool, these settings depending on information on the local stiffness of the metal sheets (Info_raideur) at a hole to be drilled intended to receive a rivet.
21. A method for assembling metal sheets by riveting, characterized in that it is applied by means of a device (1) according to any of the preceding claims.

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