Metal sheet metal edge welding machine

Abstract

The invention relates to a welding machine (20) for at least two raised edges (12), the welding machine (20) comprising at least one frame (22) carrying a clamping member (224) for clamping the raised edges (12) against each other, the clamping member (224) being positioned, in the direction of travel (SA), at the front of a feed means (222) of the machine, the latter comprising at least one welding element (24) having a welding torch (242), characterized in that the welding element (24) is disposed, in the direction of travel (SA), between the clamping member (224) and the feed means (222), said welding element (242) comprising a detection device (246) configured to determine a distance (D) separating said detection device (246) from a free end (13). of at least one of the raised edges (12),the welding machine (20) comprising a positioning element (245) for the welding torch configured to place the welding torch (242) at a distance from the free end (13) according to the distance (D) determined by the detection device (246). (Figure 4),

Description

Title of the invention: Machine for welding raised edges of metal sheets

[0001] The present invention relates to welding machines for welding together constituent parts of a transport and / or storage tank, for example of liquefied gas.

[0002] The component parts of transport and / or storage tanks are typically metal sheets. Generally, these metal sheets comprise a main portion extending in a plane and at least one raised edge extending, to a certain height, in a plane substantially perpendicular to the plane in which the main portion extends. In order to form the transport and / or storage tanks, the metal sheets are welded together. More precisely, a raised edge of one metal sheet is welded to a raised edge of an adjacent metal sheet.

[0003] Gas transport and / or storage tanks have varying volumes, ranging up to very large dimensions, sometimes exceeding one hundred thousand cubic meters. Manual welding of upturned edges in these tanks is complicated. To reduce this complexity, solutions exist that use welding machines to automate the welding process and thus accelerate the welding speed of the metal sheets, thereby speeding up the construction of gas transport and / or storage tanks.

[0004] Over a large portion of the tank, the upturned edges are generally of a constant height. Welding machines then present no particular difficulty in welding these upturned edges using a weld bead positioned halfway up the upturned edges. However, in certain areas of these transport and / or storage tanks, for example at the ends of the tank strakes, the upturned edges vary in height. On such upturned edges, prior art welding machines cannot be used. Indeed, the variable height prevents the welding machine from welding the entire upturned edge.

[0005] Furthermore, the raised edges at the ends of the strakes can also have a variable thickness. For example, in some places, two raised edges are welded together, while in other places, four raised edges are welded together. This variation in thickness resulting from this stacking of raised edges prevents the use of prior art welding machines.

[0006] In this context, the areas of the tank where the raised edges have varying heights and / or thicknesses are welded manually, which considerably slows down the manufacture of such a transport and / or storage tank. For example, on a tank of 173,000 m3, there are approximately 3,000 strake ends, which represents approximately 1,500 meters of welding to be carried out manually.

[0007] There is therefore a real need for a welding machine that can adapt to variations in the height and / or thickness of raised edges in order to accelerate the manufacture of gas transport and / or storage tanks. The objective of the invention described in this document is therefore to overcome the drawbacks of the prior art by providing a welding machine capable of welding raised edges with varying heights and / or thicknesses.

[0008] The present invention thus has as its main object a welding machine for at least two metal sheets, each comprising a main part and at least one raised edge extending substantially in a plane intersecting a plane in which the main part extends, the welding machine comprising at least one frame carrying a means for advancing the welding machine on the metal sheets in a direction of advancement, said frame carrying a clamping member intended to clamp the raised edges against each other, the clamping member being positioned, in the direction of advancement, in front of the advancement member, the welding machine comprising at least one welding element comprising a welding torch configured to weld at least the raised edges together, characterized in that the welding torch is disposed, in the direction of advancement, between the clamping member and the advancement member,said welding element comprising a detection device configured to determine a distance separating said detection device from a free end of at least one of the raised edges, the welding machine comprising a welding torch positioning device configured to place the welding torch at a distance from the free end according to the distance determined by the detection device.

[0009] It should be noted that the technical field of application for such a welding machine is that of liquefied natural gas transport and / or storage tanks, in particular tanks with sealed and thermally insulated membranes. Given the dimensions of such tanks and the liquid they contain, no leakage can be tolerated. This field also justifies the means implemented in the welding machine according to the invention.

[0010] The advancement means may, for example, consist of drive rollers, for example two or more. In the case of drive rollers, these rollers exert a mechanical force on the raised edges, advancing the welding machine, at least in the direction of travel. It is thus understood that the welding machine moves on the metal sheets by resting on them, along the raised edges, these raised edges forming a guide for the movement of the welding machine. It will be understood that the drive wheels are used in pairs on either side of the raised edges.

[0011] The clamping element may, for its part, consist of at least two clamping rollers. This clamping element, when made up of clamping rollers, exerts a compressive force on the raised edges, which clamps the raised edges and thus facilitates their welding.

[0012] The clamping device is therefore positioned in front of the weld element, so that the raised edges are clamped before welding. Optionally, the welding machine may include one or more clamping devices in addition to the clamping device mentioned above; these devices may, for example, be positioned before or after the welding torch, in particular to initiate a bringing together of the raised edges before they are clamped by the clamping device, in the case of a clamping device positioned in front of the clamping device, or to limit the forces on the weld that has just been made by the welding torch, in the case of a clamping device positioned after the welding torch.

[0013] The welding torch can use different technologies to weld the ends of the raised edges, for example TIG, plasma, wire laser, and scanning laser technology.

[0014] It should be noted that, in order to weld the raised edges together, the welding torch actually welds the free ends of the raised edges together. Therefore, the welding torch must be positioned relatively close to these free ends to weld them correctly. Thus, when the raised edges vary in height, the welding torch must follow this height in order to weld the free ends of the raised edges together. It is understood here that the height of a raised edge corresponds to the distance separating the free end of said raised edge from a plane in which the main part of the metal sheet extends.

[0015] It is understood here that, since the welding torch welds together the free ends of the raised edges, it differs from welding machines of the prior art, which are designed to weld the raised edges approximately halfway up the raised edges.

[0016] To enable the welding torch to follow the height, the detection device is connected directly or indirectly to the welding torch and determines the distance separating it from the free end. Based on this distance, the positioning element adjusts the position of the welding torch, allowing it to follow the profile of the free end and weld the free ends even if the height of the raised edges changes.

[0017] The determination of this distance can be by an in situ measurement or any other direct or indirect means allowing this distance to be determined.

[0018] It should also be noted that the use of the term "the raised edges are welded together" in this application covers both raised edges that are directly and indirectly welded together. For example, when welding the raised edges, a tab attached to an insulating layer of the tank may be placed between the two raised edges. Thus, by welding the raised edges to the tab, they are joined to each other and to the tab, which is itself joined to the insulating layer of the tank. This situation corresponds to welding three layers. In another example, at the junction between a first, second, third, and fourth raised edge, there may be up to five layers, including the tab.

[0019] The detection device can also determine a weld width corresponding to the resulting thickness of the stacked raised edges. This weld width can vary depending on the thickness of each raised edge and the number of raised edges welded together. The welding machine can then adjust various parameters of the welding torch to allow welding despite a variable weld width. Parameters such as current and power can, for example, be adjusted.

[0020] Alternatively, the weld width can be determined by other elements of the welding machine, for example the clamping element.

[0021] According to an optional feature of the invention, the positioning member is configured to tilt the welding torch, in a plane common to at least one raised edge, by an angle between 0 and plus or minus 60°, depending on the distance determined by the detection device.

[0022] It should be noted that an angle of 0° means that the welding torch is perpendicular to the plane in which the main parts of the metal sheets lie. A negative angle indicates that the torch is inclined towards the welding machine, thus bringing at least part of the welding torch closer to the welding machine. A positive angle means that the torch is inclined away from the welding machine, thus moving at least part of the welding torch away from the welding machine.

[0023] The inclination of the welding torch thus allows it to adapt correctly to the varying height of the raised edges. Optionally, the positioning device can also be configured to perform translational movements of the welding torch in the plane of one of the raised edges.

[0024] According to an optional feature of the invention, the welding machine includes a control module controlling the positioning element according to the distance determined by the detection device.

[0025] In this case, the detection device, after determining the distance separating it from the free end, sends information relating to this distance to the control module.

[0026] According to an optional feature of the invention, the detection device is arranged, in the direction of travel, at the front of the welding torch. In this way, the information transmitted to the control module allows the latter to anticipate the height of the free end and thus the position that the welding torch must take to weld the free ends.

[0027] According to an optional feature of the invention, the welding element includes a support attached to the welding torch, said support having at least one stabilizer configured to facilitate movement of the welding torch.

[0028] The support can be attached to the welding torch while the stabilizer is in contact with the free end to be welded. In this way, the welding torch is stabilized, at least partially, by this stabilizer via the support, which facilitates the advancement and movement of the welding torch along the raised edges.

[0029] According to an optional feature of the invention, the support includes at least one oblong hole in which the stabilizer moves. Thanks to this design, the stabilizer adapts to a spacing between the support and the free end in order to stabilize the movement of the welding torch throughout the movement of the welding machine.

[0030] According to an optional feature of the invention, the stabilizer comprises a pin having a stud inserted into the oblong hole and a roller in contact with the free end of at least one of the raised edges. It should be understood that the stud mechanically holds the stabilizer in the oblong hole. The roller facilitates the advancement of the welding torch along the raised edges. The stabilizer thus ensures proper positioning of the welding torch during its movement.

[0031] According to an optional feature of the invention, the support comprises a first stabilizer and a second stabilizer arranged on either side of the welding torch.

[0032] It should be noted that the characteristics previously described for at least one stabilizer can be applied in the same way to the first stabilizer and the second stabilizer.

[0033] The presence of two stabilizers surrounding the welding torch facilitates adaptation to spacing and thus stabilizes the welding torch even more.

[0034] The invention also relates to a method for welding raised edges of metal sheets using a welding machine as previously mentioned. More particularly, according to the invention, a welding method comprises: - a first step during which, as the welding machine advances in the direction of travel, the detection device determines the distance separating it from the free end of at least one of the raised edges and delivers information relating to said distance to the control module, - a second stage during which the control module delivers, as the welding machine advances in the direction of travel, a signal to the positioning device in order to adapt the placement of the welding torch according to the information relating to said distance.

[0035] It should be noted that these two steps can be performed continuously during the advance of the welding machine. In this way, throughout the advance of the welding machine, said machine retrieves information enabling it to adapt to the height of the raised edges.

[0036] According to an optional feature of the invention, in the first step, the detection device determines a weld width of the raised edges, and in the second step, the control module adapts at least one parameter of the welding torch according to the weld width.

[0037] The weld width therefore corresponds to the resulting thickness of the stacked raised edges. This weld width can thus vary depending on the individual thickness of the raised edges, but also depending on the number of raised edges welded together.

[0038] By way of example, when welding a strake end, one may successively go from having to weld: - two raised edges of 0.7 mm with a 0.5 mm tab between them, which corresponds to a welding width of 1.9 mm, - two raised edges of 1.5 mm around two raised edges of 0.7 mm with a 0.5 mm tab between them, which corresponds to a welding width of 4.9 mm, - two edges raised by 1.5 mm, which corresponds to a welding width of 3 mm.

[0039] To adapt the welding torch to this variation in weld width, the control module can adjust various welding torch parameters. For example, in the case of a welding torch using laser scanning technology, the control module can modify the scanning parameters. For laser welding technologies, the control module 28 can also adjust parameters such as power, while for TIG or plasma technologies, the control module will adjust the intensity instead.

[0040] According to an optional feature of the invention, the welding process allows the welding machine to weld the raised edges together at a speed of between 20 and 100 cm / min. Comparatively, the speed of manual welding is of approximately 07 cm / min. Thus, as an example, in order to weld 3000 ends of strakes of a 174,000 m3 tank, a speed of 30 cm / min reduces the operating time by 270 hours, while at a speed of 100 cm / min, the welding machine reduces the operating time by 332 hours.

[0041] Other features, details and advantages of the invention will become clearer upon reading the following description by way of example, in conjunction with drawings in which:

[0042] [Fig-1] is a partial view of component parts of a membrane of a tank of transport and / or storage of liquid gas;

[0043] [Fig.2] is a side view of a welding machine for welding raised edges of at least two metal sheets;

[0044] [Fig.3] is a top view of the welding machine of [Fig.2];

[0045] [Fig.4] is a close-up and side view of a welding element of the machine welding described in figures 2 and 3.

[0046] It should first be noted that while the figures illustrate the invention in detail for its implementation, these figures can, of course, also serve to further define the invention, if necessary. It should also be noted that these figures only show examples of embodiments of the invention. Finally, the same reference numerals designate the same elements throughout all the figures.

[0047] Figure 1 is a view of component parts of a leak-proof membrane of a tank for the transport and / or storage of liquid gas, in particular liquefied natural gas. These parts constitute part of the tank wall, for example, one end of a tank strut, a strut being a metal sheet extending over several meters, thus forming a metal strip.

[0048] The part of the tank wall is here a set of metal sheets 1 forming one end of the tank strake. The set of metal sheets 1 comprises a first metal sheet 2, a second metal sheet 4, a third metal sheet 6 and a fourth metal sheet 8.

[0049] It should be noted that this set of metal sheets 1 is joined and sealed by the use of the welding machine according to the invention. This set of metal sheets 1 is described in more detail later in the description of [Fig. 1] in order to better understand the problem related to welding these metal sheets.

[0050] Each of these metal sheets comprises a main part 10 and at least one raised edge 12. The main parts 10 of each of the metal sheets extend in the same plane, while the raised edges 12 extend in intersecting planes, here perpendicular to that of the main parts. These raised edges 12 thus extend perpendicularly to the main parts over a height denoted H.

[0051] The first metal sheet 2 therefore comprises a main part 102 and a raised edge 122, the second metal sheet 4 comprises a main part 104 and a raised edge 124, the third metal sheet 6 comprises a main part 106 and a raised edge 126, and the fourth metal sheet 8 comprises a main part 108 and a raised edge 128.

[0052] Each of these raised edges 12 includes a free end 13, also called a free edge, which is welded to a free end 13 of a raised edge 12 of an adjacent metal sheet. This free end 13 is opposite a foot of the raised edge 12, the latter being the part that connects it to the main part 10.

[0053] The raised edge 122 of the first metal sheet 2 is thus welded to the raised edge 124 of the second metal sheet 4 via their free ends 13. The raised edge 126 of the third metal sheet 6 is welded to the raised edge 128 of the fourth metal sheet 8 via their free ends 13. In this way, the first metal sheet 2 is fixed by welding to the second metal sheet 4, and the third metal sheet 6 is fixed by welding to the fourth metal sheet 8.

[0054] To form the assembly of metal sheets 1, the first metal sheet 2 and the second metal sheet 4 must also be welded to the third metal sheet 6 and the fourth metal sheet 8. For this purpose, the assembly of metal sheets 1 includes a joining zone 14 in which the raised edge 126 of the third metal sheet 6 and the raised edge 128 of the fourth metal sheet 8, welded together at their free ends 13, are positioned between the raised edge 122 of the first metal sheet 2 and the raised edge 124 of the second metal sheet 4. Thus, at this joining zone 14, the weld creates a seal between four raised edges, and potentially an additional tab. Therefore, there is a weld width, denoted L, which varies along the raised edges 12.

[0055] In order for their free ends 13 to be welded together, the raised edge 122 of the first metal sheet 2 has the same shape as the raised edge 124 of the second metal sheet 4. More specifically, the raised edge 122 of the first metal sheet 2 and the raised edge 124 of the second metal sheet 4 each include a beveled area 16. Thus, at this beveled area 16, the height of the raised edge 122 of the first metal sheet 2 and the raised edge 124 of the second metal sheet 4 is less than the height of the rest of the raised edge 122 of the first metal sheet 2 and the raised edge 124 of the second metal sheet 4. Along this beveled area 16, the height H of the raised edges 122, 124 decreases.

[0056] The raised edge 126 of the third metal sheet 6 and the raised edge 128 of the fourth metal sheet 8 also have an identical shape, each comprising a fillet 18. At the level of this fillet 18, the height of the raised edge 126 of the third metal sheet 6 and of the raised edge 128 of the fourth metal sheet 8 is also less than that of the raised edge 126 of the third metal sheet 6 and of the raised edge 128 of the fourth metal sheet 8, measured next to the fillet 18.

[0057] This variation in the height of the raised edges 12 is due to the fact that all the metal sheets 1 are intended for one end of the tank's strake. Indeed, on this end of the strake, the fillet 18 allows the automatic weld of a conventional welding machine to be cut, while the lower edge 16 allows for a better transfer of stresses from one element to another. Because of this variation in the height H of the raised edges 12, machine welding is thus complex. The present invention, described in Figures 2, 3, and 4, solves this problem by providing a welding machine that adapts to the variation in this height H.

[0058] It should be noted that during the welding of the raised edges 12 together, a tab is typically placed between the two raised edges 12. In fact, one of the raised edges is welded to said tab and the other raised edge 12 is also welded to this tab. The tab is itself secured to an insulating mass forming part of the membrane tank.

[0059] Figure 2 is a side view of a welding machine 20 for welding raised edges of at least two metal sheets having a raised edge. More particularly, in this Figure 2, the welding machine 20 welds the raised edges 12 of each of the metal sheets in Figure 1, even when the height H varies. The welding machine according to the invention is particularly suited to welding two raised edges at the longitudinal end of two metal strakes or sheets.

[0060] The welding machine 20 comprises a frame 22 carrying a means for advancing the welding machine along the raised edges 12, which will be described with reference to [Fig. 3]. The advance means moves the welding machine 20 along the raised edges 12 in a direction of advance referenced SA.

[0061] In the case of welding the set of metal sheets 1 of [Fig.1], the direction of advancement SA is parallel to the raised edges 12 going from the third raised edge 126 and the fourth raised edge 128 towards the second raised edge 124 and the first raised edge 122.

[0062] It is then understood that, during its advance, the welding machine 20 must weld the fourth raised edge 128 and the third raised edge 126 together with a tab, even at the fillet 18. It must then weld the second raised edge 124 and the first raised edge 122 positioned on either side of the third raised edge 126 and the fourth raised edge 128, while simultaneously welding the third raised edge 126 to the fourth raised edge 128 at the joint zone 14. Finally, it must weld the second raised edge 124 with the first raised edge 122, even at the lowering zone 16.

[0063] For this purpose, the welding machine 20 according to the invention comprises a welding element 24 for welding the free ends 13 of the raised edges 12 together. This welding element 24 is designed to follow the profile of the raised edges 12 by adapting to the height H of the raised edge, in order to weld said free ends 13.

[0064] Fig. 3 is a top view of the welding machine 20 of Fig. 2. In this figure, the frame 22 is shown in dashed lines in order to allow observation of the internal operation of the welding machine 20.

[0065] In this figure, the welding machine 20 welds the free end 13 of the raised edges 126 of the third metal sheet 6 with the free end 13 of the raised edges 128 of the fourth metal sheet 8.

[0066] As previously stated, the frame 22 of the welding machine carries a feed means 222. This feed means 222 is here composed of a pair of feed rollers, although any other type of feed means 222 may be used. More specifically, one feed roller is positioned in contact with one of the raised edges 12, and another feed roller is positioned in contact with another of the raised edges 12.

[0067] The drive rollers then exert a rotational force on the raised edges 12, which has the effect of advancing the welding machine 20 in the direction of travel SA along the raised edges 12. In this embodiment, the center of the drive rollers is positioned on a line DI substantially perpendicular to the direction of travel. It should be noted that the term substantially perpendicular covers, by way of example, an angle between 87° and 90°.

[0068] A clamping member, referenced 224 on [Fig.3], is positioned in front of the welding element 24, in the direction of advancement SA, and in front of the advancement means 222. This clamping member 224 is, in this embodiment, composed of a first pair of clamping rollers.

[0069] The function of this first pair of clamping rollers is to clamp the raised edges 12 together. Their placement in front of the welding element 24, and more particularly of a welding torch 242 of the welding element, facilitates welding by bringing the free ends 13 of the raised edges 12 closer together. To achieve this, the first pair of clamping rollers is in contact with the raised edges 12 and applies a certain force that tends to bring the two raised edges 12 closer together. The clamping rollers of the first pair of clamping rollers have their center of rotation lying in a plane D2 substantially perpendicular to the direction of travel SA.

[0070] The welding machine 20 includes, in this embodiment, a clamping device 226 which is arranged behind, in the direction of travel SA, the welding element 24. This clamping device 226 is complementary to the clamping member 226 and it includes, similarly to the clamping member 224, a second pair of clamping rollers which is also in contact with the raised edges 12. The center of the clamping rollers of the second pair of clamping rollers lies in a plane D3 substantially perpendicular to the direction of travel SA.

[0071] It should be noted that the welding torch 242 is therefore spatially arranged between the advancement means 222 and the clamping member 224, and more particularly between the clamping member 224 and the clamping device 226.

[0072] Optionally, the welding machine 20 can also include a complementary advancement element with the advancement means 222. This advancement element is here composed of several pairs of wheels.

[0073] The drive mechanism comprises a first pair of wheels 228, a second pair of wheels 230, and a third pair of wheels 232, visible in [Fig. 2] and [Fig. 3]. Each of these wheels is arranged to be in contact with a principal portion 10 of the metal sheets. The role of the drive mechanism is to enable the welding machine 20 to move along these principal portions 10, in the direction of travel. The welding machine 20 thus rolls along the principal portions of the metal sheets, while the drive mechanism 222 applies the forces necessary to move the welding machine 20.

[0074] In this embodiment, the first pair of wheels 228 is arranged, in the direction of travel SA, in front of the welding element 24. The second pair of wheels 230 is arranged, in the direction of travel SA, behind the welding torch 242 and in front of the drive means 222, and the third pair of wheels 232 is arranged behind, in the direction of travel SA, the drive wheel 222.

[0075] In this embodiment, the chassis 22 is equipped with a control module 28. This control module 28 is in particular electrically connected to the welding element 24 in that it is the control module 28 which controls the operation and movements of the welding element 24.

[0076] It should be noted that the clamping member 224 can be equipped with sensors measuring the weld width L and delivering information on this width L to the control module 28. The latter can then adjust, for example, the intensity of the welding element in order to weld a greater or lesser width L, in particular at the level of the bonding zone 18.

[0077] Fig. 4 is a close-up and side view of the welding element 24 of the welding machine 20 described in Figures 2 and 3, when said welding machine 20 is at the level of the fillet 18 described in Figures 1 and 2.

[0078] The welding element 24 comprises, in addition to the welding torch 242, a support 244 and a detection device 246.

[0079] The welding torch 242 is used to weld the free ends 13 of the raised edges 12 together. The welding machine 20 therefore differs from prior art welding machines, in particular in that it welds the free ends 13 of the raised edges 12, whereas conventional welding machines generally weld the raised edges halfway up.

[0080] To properly weld the free ends 13 together, the welding torch 242 must be positioned, for example, at a distance of between 2 and 15 mm from the free ends 13. The welding torch 242 can use different technologies, for example TIG welding, plasma welding, laser scanning welding, or laser wire welding.

[0081] For example, for TIG welding, the welding torch is positioned at a distance of between 2 and 15 mm from the free ends 13, for an average intensity of the welding torch 242 of between 20 and 55 amperes.

[0082] By way of example, for plasma welding, the welding torch is positioned at a distance of between 2 and 15 mm from the free ends 13, for an average intensity of the welding torch 242 of between 30 and 95 amperes.

[0083] For example, for laser welding, the welding torch is positioned at a distance of between 2 and 5 mm from the free ends 13, for an average power of the welding torch 242 of between 500 and 1500 watts.

[0084] In this embodiment, the support 244 is fixed to the welding torch 242. It should be noted that this support 244 can be attached by any type of means ensuring a permanent attachment between the welding torch 242 and this support 244. In this particular case, the support 242 partially surrounds the welding torch 242. By way of example, the support 244 comprises two plates that enclose the welding torch 242.

[0085] The detection device 246 is here fixed to the support 244, at the front of the welding torch 242, in the direction of travel SA. This detection device 246 determines a distance D between itself and the free end 13 of the raised edges 12. This determination of the distance D is carried out, in particular, during the advancement of the welding machine 20 in the direction of travel SA. By way of example, the detection device is an infrared sensor, a laser detector, a light barrier, an ultrasonic sensor, a mechanical probe, and, in general, any device capable of determining a distance. The detection device 246 can also be designed to determine the weld width L.

[0086] It should be noted that the detection device 246 can be arranged on other elements of the welding machine 20. For example, it may be envisaged that the The detection device 246 is fixed to a U-shaped support piece, positioned upstream of the welding torch 242, and slides along the raised edges 12. In this way, the detection device is independent of the weld element, allowing it to remain at 90° to the plane in which the main parts 10 extend. This detection device can thus determine the distance D between itself and the free end 13 of the raised edges 12, but also determine a total thickness resulting from the stacking of raised edges 12 to be welded together, by determining the weld width L. As an example, a scan with a laser profilometer makes it possible to determine this distance D and this weld width L.

[0087] The welding element 24 also includes a positioning member 245 for the welding torch. This positioning member 245 allows the welding torch 242 to be positioned according to the distance D measured by the detection device 246. By way of example, in this embodiment, the positioning member 245 allows the welding torch 242 to tilt and / or move in translation, in a plane parallel to a raised edge 12.

[0088] The inclination of the welding torch 242 corresponds to an inclination in a plane common to at least one raised edge 12, at an angle varying between 0° and + / - 60°, depending on the distance measured by the detection device 246. When the angle is 0°, the welding torch 242 is essentially perpendicular to the plane in which the main parts 10 of the metal sheets extend. When the angle is negative, a welding nozzle 247 of the welding torch 242 is inclined so as to move away from the welding machine 20, as illustrated in [Fig. 4]. Conversely, when the angle is positive, the welding nozzle 247 of the welding torch 242 is inclined so as to move closer to the welding machine 20.

[0089] The positioning element 245 encompasses any means of moving the welding torch 242. This may include, for example, one or more electric motors, gears, hydraulic or pneumatic cylinders.

[0090] The positioning element 245 is controlled by the control module 28. Thus, during movement in the forward direction SA, the detection device 246 determines the distance D separating it from at least one of the free ends 13 of the raised edges 12. This distance D is transmitted to the control module 28, which processes it to determine the position of the welding torch 242 relative to the raised edges 12. The control module 28 then sends a signal to the positioning element 245, which tilts and / or translates the welding torch 242 according to its position relative to the raised edge. It is thus understood that the welding element 24 adapts to the height H of the raised edges 12.

[0091] It should be noted that the control module 28 can also modify other parameters of the welding torch 242 in order to adapt the machine to Welding 20 to the weld width L. For example, for a welding torch using laser scanning technology, the control module 28 can modify the scanning parameters, for example by acting on internal mirrors of the laser scanning technology's optical system. In addition, the control module 28 can also modify parameters such as the power for laser welding or the current for TIG or plasma welding.

[0092] In this embodiment, the support 244 comprises a first stabilizer 248 and a second stabilizer 249, which facilitate the movement of the welding element 24 on the free ends 13 of the raised edges 12. For this purpose, the support 244 includes a first oblong hole 250 and a second oblong hole 256, in which the first stabilizer 248 and the second stabilizer 249 move respectively. Such movement occurs in a plane parallel to a plane in which the raised edge 12 is inscribed.

[0093] More specifically, the first stabilizer 248 slides in the first oblong hole 250 by means of a first stud 252 located at one end of the first stabilizer 248. When the height H of the raised edges 12 varies, the first stud 252 slides in the first oblong hole 250 and then adapts to a spacing between the support 244 and the free ends 13 of the raised edges 12. Thus, since the support 244 is fixed to the welding torch 249, the first stabilizer 248 stabilizes the welding torch 242 during its movement.

[0094] The first stabilizer 248 here includes a roller 253 at the end opposite to that where the first pad 252 is located, allowing contact with the free ends 13 of the raised edges 12. This roller 253 facilitates the movement of the welding torch 242 along the free ends 13 in the direction of travel SA. The roller 253 may have a width at least equal to the weld width L illustrated in [Fig. 3].

[0095] The second stabilizer 249 is similar to the first stabilizer 248, comprising a second stud 257 cooperating with the second oblong hole 256 of the support 244 and a roller 258.

[0096] The first stabilizer 248 and the second stabilizer 249 are arranged on either side of the welding torch 242, in the plane in which the raised edge 12 is located, thus allowing the welding torch 242 to be correctly balanced by the two stabilizers 248, 249. These stabilizers 242, 249 are here purely mechanical, adapting to the height H by cooperation between the pads 252, 257 and the respective oblong holes 250, 256.

[0097] The invention also relates to a method of welding the raised edges 13 of the metal sheets presented in detail above.

[0098] This method includes a first step in which the welding machine 20 advances, in the direction of travel SA, along the raised edges 12 by means of the feed means 222, i.e., the pair of drive rollers in the previously described embodiment. During this advance, the clamping member 224, as well as the clamping device 226 in the embodiment shown in the preceding figures, clamp the raised edges 12 together. At the point where the raised edges 12 are clamped, the welding element 24, by means of the welding torch 242, welds the free ends 13 of the raised edges 12. During this advance, the detection device 246, positioned on the support 244 of the welding element 24, determines the distance D separating it from the free ends 13 of the raised edges 12. This information is transmitted to the control module 28.

[0099] During the first step, the detection device 246 can also determine the weld width L and transmit this information to the control module 28.

[0100] The method includes a second step in which the control module 28 sends a signal to the positioning member 245 so that the latter places the welding torch 242 at an appropriate distance determined by the information received by the control module 28. The positioning member 245 then adjusts the position of the welding torch 242 relative to the free ends 13 of the raised edges 12. More specifically, the control module 28 calculates and determines the position of the welding torch 242 as a function of the distance D measured by the detection device 246, and then adjusts its placement using the positioning member 245.

[0101] During this second step, the control module 28 can also adjust various parameters of the welding torch 242, such as the intensity or power, according to the information relating to the weld width L. This makes it possible to weld the free ends of the raised edges together, even when this weld width varies when the joint goes from two thicknesses, for two raised edges, to five thicknesses, when the joint includes four raised edges and a tongue.

[0102] It should be noted that these two steps are carried out continuously during the advancement of the welding machine 20, so that the control unit actively adapts the position of the welding torch 242 during welding.

[0103] This welding process thus makes it possible to weld the free ends 13 of the upturned edges 12 at a speed of between 20 and 100 cm / min. It is therefore clear that this process offers a distinct advantage over manual welding in terms of speed. For example, manual welding is carried out at approximately 7 cm / minute. For approximately 3,000 ends of the strakes of a 174,000 m³ tank, at 30 cm / minute, this represents a time saving of 270 hours, and at 100 cm / minute, it represents a time saving of 332 hours.

[0104] As just described, the present invention effectively achieves its objective by proposing a welding machine that welds the raised edges of metal sheets together and that adapts to the height of the raised edges by means of a detection device and a positioning element that adjusts the position of the machine's welding torch according to a distance separating the detection device from the raised edges.

[0105] The invention as just described cannot, however, be limited to the means and configurations exclusively described and illustrated, and also applies to all equivalent means or configurations and to any combination of such means or configurations.

Claims

Demands

1. A welding machine (20) for at least two metal sheets, each comprising a main portion (10) and at least one raised edge (12) extending substantially in a plane intersecting a plane in which the main portion (10) extends, the welding machine (20) comprising at least one frame (22) carrying a means for advancing the welding machine (20) on the metal sheets in a direction of advance (SA), said frame (22) carrying a clamping member (224) for clamping the raised edges (12) together, the clamping member (224) being positioned, in the direction of advance (SA), in front of the advancement member (222), the welding machine (20) comprising at least one welding element (24) including a welding torch (242) configured to weld together at least the raised edges (12), characterized in that the torch welding (242) is arranged, in the direction of travel (SA),between the clamping member (224) and the advancement means (222), said welding element (24) comprising a detection device (246) configured to determine a distance (D) separating said detection device (246) from a free end (13) of at least one of the raised edges (12), the welding machine (20) comprising a positioning member (245) of the welding torch configured to place the welding torch (242) at a distance from the free end (13) according to the distance (D) determined by the detection device (246).

2. Welding machine (20) according to claim 1, wherein the positioning member (245) is configured to tilt the welding torch (242), in a plane common to at least one raised edge (12), by an angle between 0 and plus or minus 60° depending on the distance (D) determined by the detection device (246).

3. Welding machine (20) according to any one of claims 1 or 2, comprising a control module (28) controlling the positioning member (245) as a function of the distance (D) determined by the detection device (246).

4. Welding machine (20) according to any one of claims 1 to 3, in which the detection device (246) is disposed, in the direction of travel (SA), in front of the welding torch (242).

5. Welding machine (20) according to any one of claims 1 to 4, wherein the welding element (24) comprises a support (244) integral with the welding torch (242), said support comprising at least one stabilizer (248) configured to facilitate movement of the welding torch (246).

6. Welding machine (20) according to claim 5, wherein the support (244) includes at least one oblong hole (250) in which the stabilizer (248) moves.

7. Welding machine (20) according to claim 6, wherein the stabilizer (248) comprises a spindle (251) provided with a stud (252) inserted in the oblong hole (250) and a roller (253) in contact with the free end (13) of at least one of the raised edges (12).

8. Welding machine (20) according to any one of claims 5 to 7, the support (244) comprises a first stabilizer (248) and a second stabilizer (249) arranged on either side of the welding torch (242).

9. A method for welding raised edges (12) of metal sheets using a welding machine (20) according to any one of claims 1 to 8 in combination with claim 3, comprising: - a first step in which, when the welding machine (20) advances in the direction of travel (SA), the detection device (246) determines the distance (D) separating it from the free end (13) of at least one of the raised edges (12) and delivers information relating to said distance (D) to the control module (28), - a second step in which the control module (28) delivers, when the welding machine (20) advances in the direction of travel (SA), a signal to the positioning element (245) in order to adapt the placement of the welding torch (242) according to the information relating to the distance (D).

10. A welding method according to claim 9, wherein: - during the first step, the detection device (246) determines a weld width (L) of the raised edges (12),

11. - during the second step, the control module (28) adapts at least one parameter of the welding torch (242) according to the width to be welded (L). Welding method according to any one of claims 9 or 10, wherein the welding machine (20) welds the raised edges (12) together at a speed of between 20 and 100 cm / min.