EP0687578A1 - Device for marking thin plates, in particular for body sheets in the vehicle industry - Google Patents

Abstract

The marker consists of a frame (9) equipped with a gripper (22) for the sheet metal component to be marked, a first carriage (10) which travels along the frame (9) parallel to the component's surface, and a second carriage (11) with a marking wheel (16) which has a series of engraves plates round its rim. The marking wheel is rotatable on the second carriage about a shaft (17) lying parallel to the surface of the component to be marked, so that the appropriate engraved plate can be positioned against it. The force applied by the marking wheel is regulated to a level which is sufficient to imprint the desired motif, with each engraved plate having a flat base surface from which the motif projects and which acts as a stop to limit penetration into the component being marked. The marking wheel is rotated by a step motor (18) through a drive mechanism (19) with reduction gears.

Description

The present invention relates to a device for marking thin metal parts, in particular sheets for the automotive industry.

The marking of industrial products, in particular of sheet metal for motor vehicles, is an increasingly widespread necessity in order to combat theft in particular.

With this in mind, it is necessary to make a marking on each part which is both readable and difficult to falsify.

In addition, this marking must withstand the manufacturing steps to which the part which has been marked is subjected.

A marking device is already known in which an engraved plate comprising an embossed pattern is applied by force against a thin part of the part to print said pattern on it.

This known device has the major drawback that it requires a very large power to apply the engraved plate against the part to be marked, which poses problems of cost and ease of handling the device.

In addition, depending on the size of the pattern, the pressure to be applied to the engraved plate differs considerably, which limits the possibilities of marking.

Also known from US-A-4,431,321 is a device for marking thin metal parts, in particular sheets for the automotive industry, comprising a chassis provided with means of attachment to a metal part to be marked, a first carriage, movable in translation on the chassis parallel to the surface of the part to be marked, and a second carriage, supporting a wheel which comprises, at its periphery, a plurality of plates each engraved with a pattern, said wheel being rotatably mounted on the second carriage around an axis parallel to the plane of the surface of the workpiece to be marked, and being capable of bringing one of its engraved plates facing the surface of the workpiece to be marked, said second carriage being movable by relation to the first carriage between a rest position in which the wheel is moved away from the surface of the part to be marked and a printing position in which the wheel applies said engraved plate against the surface of the part to be marked, exerting sufficient pressure to print the pattern.

The selection of a pattern is carried out by rotation of the wheel and the printing of the pattern is carried out by translation of the second carriage carrying said wheel in a direction perpendicular to the surface of the part to be marked.

This device operates in the following manner.

It is first of all attached to the part to be marked by its attachment means.

The first carriage is then placed in the starting position, at one end of its translation travel parallel to the surface of the part to be marked.

The second carriage being in the rest position, the engraved plate comprising the first pattern to be printed is brought opposite the surface of the part to be marked by rotation of the wheel.

The second carriage is then moved in translation towards the surface of the part to be marked, it then takes its printing position in which the engraved plate of the wheel exerts sufficient pressure on the part to be marked to print the desired pattern there. .

The second carriage is then returned to the rest position by a translational movement opposite to the previous one.

The first carriage can then be moved by a distance corresponding to the width of a pattern, possibly increased by a desired spacing between two successive patterns, then, by rotation of the dial and translation of the second carriage, a second pattern is printed. on the surface of the part to be marked.

By repeating these operations several times, it is possible to successively print on the part to be marked different contiguous patterns to form a marking consisting of a variable number of patterns.

This known device nevertheless has certain drawbacks.

Among these, there may be mentioned in particular the fact that the wheel is applied against the surface of the part to be marked with a substantially constant force, whatever the pattern to be printed.

However, depending on whether a simple pattern is printed, that is to say comprising few relief shapes, or a complex pattern, that is to say comprising many relief shapes, the force necessary for the the pattern varies.

Therefore, if a constant force is applied, the depth of the print varies from one pattern to another, which leads to irregular prints, of lower quality than if one used an engraved plate comprising all patterns to print simultaneously.

The present invention aims to provide a device for marking thin metal parts, in particular sheet metal for the automotive industry, which does not in particular have this drawback.

The present invention is characterized by the fact that the force exerted on the dial, when printing a pattern, is adjusted to a constant value, sufficient to print the most complex pattern, and by the fact that each engraved plate of the wheel has a flat base surface, from which a pattern projects, and which serves as a stop limiting the insertion of said plate into the surface of the part to be marked.

In a preferred embodiment of the invention, the chassis includes operating handles and is suspended from a winch with constant torque which allows it to move in space.

Advantageously, the device according to the invention is connected to an electronic control cabinet which controls the various organs of the device according to the desired marking.

In particular, this control cabinet can control the attachment of the chassis to the part to be marked, the movement of the first carriage, the rotation of the wheel, and the translation of the second carriage for printing a pattern.

• la figure 1 représente un poste de marquage équipé d'un dispositif selon l'invention,
• la figure 2 est une vue en coupe et en élévation du dispositif de la figure 1,
• la figure 3 est une vue en coupe selon III-III de la figure 2,
• la figure 4 est une vue en coupe selon IV-IV de la figure 3,
• la figure 5 est une vue de détail de la figure 3 pendant une opération d'impression,
• la figure 6 est une vue de détail de la figure 2, et
• la figure 7 est une vue en coupe selon VII-VII de la figure 6.

In order to better understand the invention, we will now describe an embodiment given by way of non-limiting example, with reference to the accompanying drawing in which:

• FIG. 1 represents a marking station equipped with a device according to the invention,
• FIG. 2 is a view in section and in elevation of the device of FIG. 1,
• FIG. 3 is a sectional view along III-III of FIG. 2,
• FIG. 4 is a sectional view along IV-IV of FIG. 3,
• FIG. 5 is a detailed view of FIG. 3 during a printing operation,
• FIG. 6 is a detailed view of FIG. 2, and
• FIG. 7 is a sectional view along VII-VII of FIG. 6.

In the marking station of a motor vehicle production line in FIG. 1, an operator 1, standing in front of a vehicle 2, manipulates a device 3 according to the invention.

The device 3 is suspended by a cable 4 from a constant torque winch 5 which allows the operator 1 to raise or lower the device 3 at will.

The winch 5 is mounted on a rail system 6 which allows it to be moved in all directions.

An electrical harness, not shown, connects the device 3 to a control cabinet 7, while hydraulic lines, not shown, connect the device 3 to a hydraulic unit 8.

The device 3 is shown in section in FIG. 2, apart from the lifting member and the handles that can be seen in FIG. 1.

The device comprises a chassis 9, a first carriage 10 movable relative to the chassis 9 in the direction X and a second carriage 11 movable relative to the first carriage 10 in the direction Y.

Slides 12 allow the first carriage 10 to slide relative to the chassis 9.

As seen in the sectional view of Figure 3, the movement of the first carriage 10 is provided by an electric stepper motor 13, which is mounted on the frame 9, and whose rotation shaft is integral with a threaded rod 14, which cooperates with a thread, not shown, provided in the first carriage 10.

Presence detectors 15 make it possible to detect the arrival at the end of the travel of the first carriage 10.

On the second carriage 11, a thumbwheel 16 is mounted, the periphery of which supports a plurality of plates engraved with different patterns.

The thumbwheel 16 is rotatably mounted around an axis 17 which is perpendicular to the directions of movement X of the first carriage 10 and Y of the second carriage 11.

A second electric motor 18 is housed on the second carriage 11 above the wheel 16, and allows, via a drive mechanism 19, to rotate said wheel 16 to bring an engraved plate bearing a pattern desired at its bottom.

A hydraulic cylinder 20, mounted at the top of the first carriage 10 is able to move the second carriage 11 along slides 21 which are visible in FIG. 4.

At its lower part, the device according to the invention comprises a jaw 22 articulated on the chassis 9 around an axis 23 parallel to the direction X of movement of the first carriage 10.

The jaw 22 is located below the first carriage 10, and supports a reaction "pile" 23 placed opposite the lower part of the wheel 16.

A toggle mechanism 24, actuated by a jack, not shown, makes it possible to move the jaw 22 between an open position, which is shown in broken lines in FIG. 2, and a closed position, shown in solid lines, in which it achieves the attachment of the device according to the invention to the metal part to be marked.

To this end, the chassis 9 includes stops 25 against which the metal part comes to bear while being pinched between its stops 25 and the reaction pile 23.

The operation of the device is as follows.

Initially, the first carriage 10 is in the rest position shown in FIG. 3.

The motor 18, via the drive mechanism 19, rotates the thumbwheel 16 to bring to its lower part an engraved plate bearing the first pattern of the marking to be printed on the metal part.

The jack 20 is then actuated to lower the second carriage 11 downward, so as to apply the desired engraved plate against the metal part.

FIG. 5 shows a metal part 26 trapped between a plate 27 of the thumb wheel 16 and the reaction "pile" 23.

The pressure exerted by the jack 20 is advantageously adjusted so as to correspond to the pressure necessary to print the most complex pattern of all those which are carried by the wheel 16.

To prevent a plate bearing a simpler pattern from sinking too strongly into the metal part 26, each engraved plate has a flat base surface 28 which limits its sinking, as seen in FIG. 5.

Furthermore, the device comprises a locking member of the wheel, which automatically immobilizes the latter in its current angular position, when the second carriage moves from its rest position to its printing position.

In the embodiment described, the blocking member is constituted by a lever 29, visible in FIG. 2, which is articulated on the second carriage 11 around an axis perpendicular to the movement of the latter and projects from the face of this second carriage 11 adjacent to the first carriage 10.

A cam 30 projecting from this face of the first carriage 10 cooperates with the lever 29.

In the high position or the rest position of the second carriage 11, as shown in FIG. 2, the cam 30 pushes the lever 29 back into its rest position which is moreover imposed by the torsion spring 31.

In the low position or printing position of the second carriage, the cam 30 pivots the lever 29, which causes its lug 29 a to engage in a not shown groove provided for this purpose on the thumbwheel 16.

Thus, it is understood that, when the second carriage descends, the wheel stops in rotation so as to ensure proper application of the engraved plate 27.

After printing the first pattern, the second carriage 11 rises to the rest position and the motor 13 moves the carriage 10 a distance slightly greater than the width of a pattern.

A second pattern can thus be printed on the metal part 26, next to the first pattern, by repeating the operations described above.

During the entire marking operation, the patterns are successively printed on the surface of the metal part, without the jaw 22 being unlocked from its hooking position on the metal part 26.

The device according to the invention has the essential advantage that it allows the printing of markings of different lengths always using the same printing power.

Figures 6 and 7 show the drive mechanism 19.

In Figure 6, there is shown in broken lines the motor 18, its drive shaft 32, a first belt 33 connecting said drive shaft 32 to a reduction gear 34, a second belt 35 and the drive shaft 17 wheel 16.

The drive mechanism 19 also comprises two safety members 36 and 37 which have the role of constantly monitoring the correct tension of the belts 33 and 35.

Each safety member comprises a lever 38 mounted pivoting about an axis 39 perpendicular to the plane of the belts.

The lever 38 comprises, in its middle part, a caster 40 carried by an axis 41 also perpendicular to the plane of the belts.

A torsion spring 42 exerts a torque on the lever 38 in the direction of support of the caster 40 on the corresponding belt 33 or 35.

When the belts are properly tensioned, the end of each lever 38 is situated opposite a corresponding proximity sensor 43, 44.

As long as the proximity sensor 43, 44 detects the presence of the end of the lever 38, it is understood that the belts 33 and 35 are suitably tensioned.

On the other hand, in the event of a rupture or incorrect tension of one of the belts, the lever 38 pivots about its axis 39 and the corresponding proximity sensor 43,44 signals this anomaly to the operator and / or to a safety device which neutralizes the operation of the device according to the invention.

It is understood that the embodiment which has just been described has no limiting character and that it can receive any desirable modifications without departing from the scope of the invention.

Claims (5)

1 - Device for marking thin metal parts, in particular sheets for the automotive industry, comprising a chassis (9) provided with attachment means (22) to a metal part to be marked (26), a first carriage (10 ) movable in translation on the chassis (9) parallel to the surface of the part to be marked (26) and a second carriage (11), supporting a wheel (16) which comprises, at its periphery, a plurality of plates each engraved with 'a pattern (27), said wheel being rotatably mounted on the second carriage (11) about an axis (17) parallel to the plane of the surface of the workpiece (26), and being capable of bringing one of its engraved plates (27) facing the surface of the part to be marked (26), said second carriage (11) being movable relative to the first carriage (10) between a rest position in which the wheel (16) is away from the surface of the workpiece (26) and a printing position in which the mole head (16) applies said engraved plate (27) against the surface of the workpiece (26) by exerting sufficient pressure to print the pattern, characterized in that the force exerted on the wheel (16) during the printing of a pattern, is set to a constant value, sufficient to print the most complex pattern, and by the fact that each engraved plate (27) of the dial has a flat base surface (28), of which a pattern protrudes, and which serves as a stop limiting the sinking of said engraved plate in the surface of the part to be marked (26). 2 - Device according to claim 1, characterized in that the engraved wheel is rotated by a stepping motor (18) via a drive mechanism (19). 3 - Device according to claim 2, characterized in that the drive mechanism (19) comprises a reduction gear (34). 4 - Device according to claim 3, characterized in that it comprises safety members (36,37) which constantly monitor the correct tension of belts (32,35) of the drive mechanism (19). 5. Device according to any one of claims 1 to 4, characterized in that it comprises a blocking member (29) of the wheel (16), which automatically immobilizes the latter in its current angular position, when the second carriage (11) passes from its rest position to its printing position.

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