TOOL FOR CHECKED FOR THE COAXIALITY OF THE ELECTRODES OF A SPOT WELDING DEVICE

Abstract

TOOL FOR VERIFYING THE COAXIALITY OF ELECTRODES IN A SPOT WELDING APPARATUS The present invention relates to a tool (1) for adjusting the coaxiality between two electrodes (4, 6) of a spot welding apparatus (2), notable in that said tool comprises: - a first sleeve (8) adapted to be inserted onto one of the two electrodes and comprising a first front face; - a second sleeve (10) adapted to be inserted onto the other of the two electrodes and comprising a second front face; the first and second front faces being intended to be opposite each other and comprising visual markers (8.2, 12) indicating coaxiality. (Figure to be published with the abbreviation: Figure 4)

Description

Title of the invention: TOOL FOR CHECKING THE COAXIALITY OF THE ELECTRODES OF A SPOT WELDING DEVICE Technical field

[0001] The present invention relates to the field of motor vehicles, more particularly the field of spot welding devices used during the assembly of sheet metal of motor vehicles. Prior art

[0002] To assemble sheet metal parts, particularly those found in the structures of motor vehicles, spot welding using electric clamps is the technique most generally used during the production of motor vehicles.

[0003] These pliers allow the creation of a welding point thanks to the combination of an electric current with a mechanical force. When the current passes, the metal melts at the electrodes, thus forming a weld joining the two sheets.

[0004] However, it has been observed that the electrodes are subject to coaxiality problems due to misalignment of the axes of the electrodes or to a perpendicularity problem presented between the axis of one of the electrodes with the sheets to be welded.

[0005] If the coaxiality of the welding electrodes is not precisely respected, the current transfer surface decreases, which leads to non-conformity of the welding point. This has undesirable consequences both on the structure of the motor vehicle and on the environment in which it is produced.

[0006] For example, a problem of coaxiality of the welding electrodes can cause defects in the bodywork, or lead to weld projections which can damage any glue beads located near the weld. Such a coaxiality problem can, in addition, cause pollution with very fine metal particles which are bad for neighboring installations and which present a danger, particularly respiratory, for operators working nearby.

[0007] Published patent document US 2016 / 0221110 A1 discloses a spot welding apparatus comprising an elastic element coupled to each of the two electrodes, so as to apply pressure and ensure good contact with metal sheets during welding.

[0008] However, the solution proposed by the document does not make it possible to overcome the technical problem stated above; in fact, no element of the welding apparatus makes it possible to ensure good coaxiality between the two electrodes prior to welding. Statement of the invention

[0009] The present invention aims to overcome at least one of the drawbacks of the aforementioned state of the art. More particularly, the invention aims to propose a simple, efficient and economical solution for ensuring coaxiality between two electrodes of a spot welding apparatus.

[0010] To this end, the invention relates to a tool for adjusting coaxiality between two electrodes of a spot welding apparatus, remarkable in that said tool comprises: - a first sheath capable of being plugged onto one of the two electrodes and comprising a first front face; - a second sheath capable of being plugged onto the other of the two electrodes and comprising a second front face; the first front face and the second front face being intended to be opposite each other and comprising visual markers revealing coaxiality.

[0011] According to one embodiment, the visual markers comprise a circle on the second face and an outline on the first face capable of being inscribed in the circle.

[0012] Advantageously, the inscription of the contour in the circle corresponds to a positioning of said contour directly opposite said circle, said positioning is preferably observed visually.

[0013] According to one embodiment, the circle is made by a groove on the second face.

[0014] According to one embodiment, the groove comprises a thickness presented between an internal periphery and an external periphery of said groove, said thickness being between 1 and 5 mm.

[0015] According to one embodiment, the contour comprises radial points with ends capable of being inscribed in the circle.

[0016] According to one embodiment, the contour comprises at least three radial points distributed angularly and homogeneously around the first sheath.

[0017] According to one embodiment, the radial points correspond to ribs extending axially and from an external face of the first sheath.

[0018] The invention also relates to a method for adjusting the coaxiality of the electrodes of a spot welding apparatus intended for welding sheet metal plates, in particular of a motor vehicle structure, the welding apparatus comprising a first electrode and a second electrode movable relative to the first electrode, remarkable in that the method comprises the use of a tool according to the invention.

[0019] According to one embodiment, said method comprises the following steps: - plugging the first sheath onto the first electrode; - plugging the second sheath onto the second electrode; - bringing the second electrode closer to the first electrode until the first and second front faces come into contact; - observation of the visual markers and in the event of a coaxiality defect, adjustment of the position of at least one of the first electrode and second electrode until the visual markers reveal the coaxiality.

[0020] According to one embodiment, the adjustment of the position of at least one of the first electrode and second electrode is good when the end of each of the radial tips is strictly between an inner periphery and an outer periphery of the groove on the second face.

[0021] The measures of the invention are advantageous in that the tool for adjusting the coaxiality between the two electrodes allows for a rapid and precise visual check of the coaxiality prior to adjusting the position of at least one of the first electrode and second electrode. The tool is effective, inexpensive and simple to set up.

[0022] The method of adjusting the coaxiality of the electrodes of the welding apparatus according to the invention makes it possible to ensure good perpendicularity of each of the two electrodes with the sheet metal during welding, and adequate coaxiality of said two electrodes, thus making it possible to obtain a compliant spot weld, which makes it possible to guarantee compliant assembly of motor vehicles. Brief description of the drawings

[0023] [Fig.l] represents a schematic illustration of two electrodes of a spot welding apparatus, said electrodes having a coaxiality problem requiring adjustment by means of a tool according to the invention;

[0024] [Fig.2] represents a perspective view of a first sheath of the adjustment tool of the invention, capable of being plugged onto one of the two electrodes illustrated in [Fig.l];

[0025] [Fig.3] represents a perspective view of a second sheath of the tool of adjustment of the invention, capable of being plugged onto the other of the two electrodes illustrated in [Fig.l];

[0026] [Fig.4] represents a sectional view of the two electrodes of [Fig.l], comprising respectively the second sheath and the first sheath having visual markers revealing the coaxiality of said two electrodes. Detailed description

[0027] [Fig.l] represents a schematic illustration of a spot welding apparatus 2, intended for welding sheet metal plates, in particular of a motor vehicle structure, comprising a first electrode 4 and a second electrode 6 movable by relative to the first electrode 4.

[0028] It can be seen that the two electrodes 4, 6 have a coaxiality problem represented by a misalignment of the axes 4.1 and 6.1, requiring adjustment. In this regard, the present invention proposes a tool for adjusting the coaxiality of the electrodes.

[0029] The coaxiality adjustment tool comprises a first sheath 8 shown in [Fig. 2], which is capable of being plugged onto one of the two electrodes 4 or 6, more preferably, said first sheath 8 comprising a hole 9 capable of being plugged around the second movable electrode 6. The tool also comprises a second sheath 10 shown in [Fig. 3], which is capable of being plugged onto the other of the two electrodes 4, 6, and preferably, said second sheath 10 comprising a hole 11 capable of being plugged around the first fixed electrode 4.

[0030] The first and second sheaths 8, 10 respectively comprise a first front face 8.1 and a second front face 10.1 intended to be opposite each other to adjust the coaxiality of the electrodes 4, 6 and comprising visual markers revealing coaxiality, which will be detailed below.

[0031] With reference to [Fig.2], the first sheath 8 comprises a contour 8.2 on the first front face 8.1, forming radial points 8.3 preferentially corresponding to ribs 8.3 extending axially and from a substantially cylindrical external face 8.4 of the first sheath 8.

[0032] The axial and radial directions refer to a main axis of revolution (not shown) of the first sheath 8.

[0033] The contour 8.2 comprises at least three radial points 8.3 distributed angularly and homogeneously around the first sheath 8, and more preferably four radial points 8.3 having identical dimensions.

[0034] Advantageously, each radial point 8.3 ends with an end 8.5 intended to fit into a circle arranged on the second front face of the second sheath during adjustment of the coaxiality.

[0035] With reference to [Fig.3], we can see the circle 12 arranged to the right of the second face 10.1 of the second sheath 10.

[0036] Preferably, the circle 12 corresponds to a groove 12 made directly on the second face 10.1, said groove 12 comprising a thickness e presented between an internal periphery 12.1 and an external periphery 12.2 of said groove 12, the thickness e being between 1 and 5 mm, and more preferably between 0.5 and 3 mm.

[0037] [Fig.4] represents a sectional view of the two electrodes 4 and 6 of [Fig.l], respectively comprising the second sheath 10 and the first sheath 8 having visual markers 8.3, 12 revealing the coaxiality of said two electrodes.

[0038] After inserting the sheaths 8 and 10 until their respective front faces 8.1, 10.1 are coplanar with one end of the corresponding electrode, the second mobile electrode 6 was brought closer to the first fixed electrode 4, until the two front faces 8.1, 10.1 came into contact.

[0039] In this configuration, the state of the coaxiality of the electrodes 4, 6 depends on the coaxiality between the contour 8.2 and the groove 12, which is to be assessed visually. Indeed, the coaxiality between the electrodes 4 and 6 will only be good if all the ends 8.5 of the radial tips 8.3 are inscribed in the thickness e of the groove 12, as illustrated in [Fig.4], in which the coaxiality is correctly adjusted, and the axes 4.1 and 6.1 of the two electrodes are merged.

[0040] Advantageously, the thickness e makes it possible to define the precision of the adjustment of the coaxiality. Indeed, when all the ends 8.5 of the radial tips 8.3 are inscribed in the groove 12, the more the latter comprises a reduced thickness, the more precise the coaxiality will be.

[0041] Preferably, the adjustment is to be made prior to welding, so the sheaths 8 and 10 are to be removed before starting welding, as soon as the coaxiality between the two electrodes is correctly adjusted.

Claims

Claims

1. Tool (1) for adjusting coaxiality between two electrodes (4, 6) of a spot welding apparatus (2), characterized in that said tool (1) comprises: - a first sheath (8) capable of being plugged onto one of the two electrodes (4, 6) and comprising a first front face (8.1); - a second sheath (10) capable of being plugged onto the other of the two electrodes (4, 6) and comprising a second front face (10.1); the first front face (8.1) and the second front face (10.1) being intended to be opposite each other and comprising visual markers (8.2, 12) revealing coaxiality.

2. Tool (1) according to claim 1, wherein the visual markers (8.2, 12) comprise a circle (12) on the second face (10.1) and an outline (8.2) on the first face (8.1) capable of being inscribed in the circle (12).

3. Tool (1) according to claim 2, wherein the circle (12) is made by a groove (12) on the second face (10.1).

4. Tool (1) according to claim 3, wherein the groove (12) comprises a thickness (e) presented between an inner periphery (12.1) and an outer periphery (12.2) of said groove (12), said thickness (e) being between 1 and 5 mm.

5. Tool (1) according to one of claims 2 to 4, in which the contour (8.2) comprises radial points (8.3) with ends (8.5) capable of fitting into the circle (12).

6. Tool (1) according to claim 5, in which the contour (8.2) comprises at least three radial points (8.3) distributed angularly and homogeneously around the first sheath (8).

7. Tool (1) according to one of claims 5 and 6, in which the radial tips (8.3) correspond to ribs (8.3) extending axially and from an external face (8.4) of the first sheath (8).

8. Method for adjusting the coaxiality of the electrodes (4, 6) of a spot welding apparatus (2) intended for welding sheet metal plates, in particular of a motor vehicle structure, the welding apparatus (2) comprising a first electrode (4) and a second electrode (6) movable relative to the first electrode (4), characterized in that the method comprises the use of a tool (1) according to one of claims 1 to 7.

9. Method according to claim 8, comprising the following steps: - plugging the first sheath (8) onto the first electrode (4); - plugging the second sheath (8) onto the second electrode (6); - bringing the second electrode (6) towards the first electrode (4) until the first (8.1) and second (10.1) front faces make contact; - observing the visual markers (8.2, 12) and in the event of a co-axiality defect adjusting the position of at least one of the first electrode (4) and second electrode (6) until the visual markers (8.2, 12) reveal the coaxiality.

10. Method according to claim 9, characterized in that the tool (1) is according to claims 4 and 5, and in that the adjustment of the position of at least one of the first electrode (4) and second electrode (6) is good when the end (8.5) of each of the radial tips (8.3) is strictly between an inner periphery (12.1) and an outer periphery (12.2) of the groove (12) on the second face (10.1).

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