Welding machine with automatic stop function

Abstract

To provide a welding machine capable of automatically stop welding in a stop region selected on a welding object part.SOLUTION: The present invention relates to a welding machine (1) for welding at least two welding object parts (2), which is configured to be movable along the welding object parts (2). The welding machine (1) comprises: at least one pair of drive wheels intended to move the welding machine (1); and at least two welding wheels. The welding machine (1) comprises: a control unit (32) capable of controlling current passing through the welding wheels. The welding machine (1) comprises at least one stop device for stopping the welding machine (1) comprising at least one sensor (36) capable of detecting a point on the welding object part (2), The control unit (32) is configured to stop the welding of the welding object part (2) by means of the welding wheel at a predetermined distance from the point.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a welding machine provided with an electrode in the form of a welding wheel for welding welding target parts together.

Background Art

[0002] Current welding machines include a drive wheel, a welding wheel for welding welding target parts, and a drive member capable of rotating at least the drive wheel along the welding target parts. A current is supplied to the welding wheel by a current unit when the welding machine is moving to ensure welding of the welding target parts. Current welding machines are controlled by at least one operator, particularly to ensure that the welding machine stops at a desired position on the welding target parts.

Summary of the Invention

Problems to be Solved by the Invention

[0003] In order to speed up the welding of welding target parts, the drive wheel of the welding machine is rotated at a speed higher than that of the welding machine found in the prior art. Therefore, the welding speed of the welding target parts can be increased. However, in these welding machines, there is a problem that as the rotation speed of the drive wheel increases, it becomes difficult for the operator to control the welding machine. In particular, an increase in the rotation speed of the drive wheel reduces the stop tolerance, causes inaccuracy in the stop area where the welding machine stops with respect to the welding target parts, and the welds produced by the welding machine may become defective. Furthermore, an inaccurate welding machine stop area may pose a danger to the operator controlling the welding machine, particularly when the machine is arranged along the welding target parts located above the operator.

[0004] Therefore, an object of the present invention is to overcome the above problems by proposing a welding machine capable of automating at least the stop of welding in a selected stop area on a welding target part, in other words, a welding machine capable of stopping without operator intervention. [Means for solving the problem]

[0005] Accordingly, the present invention relates to a welding machine for welding at least two weldable parts, configured to be movable along a part to be welded, the welding machine comprising at least one pair of drive wheels extending in a longitudinal principal extending direction and intended to move the welding machine relative to the part to be welded, and at least two welding wheels capable of producing welds on the parts to be welded by rolling the welding wheels toward at least two parts to be welded, the welding machine comprising a control unit capable of controlling the current passing through the welding wheels, and the welding machine comprising at least one stop device for stopping the welding machine, the control unit being configured to stop welding of the part to be welded by the welding wheels at a predetermined distance from the point.

[0006] The welding machine according to the present invention can be used, for example, to weld together and / or to a fixed flange two raised edges of a sealing membrane that constitutes the wall of a tank for storing and / or transporting cryogenic products such as liquefied natural gas. For example, the welding machine may weld the raised edges of two adjacent parts, called a first weldable part and a second weldable part, to form a sealing membrane of the wall of a tank for storing and / or transporting cryogenic products. Alternatively, the welding machine may weld at least one of the raised edges to a fixed flange to form a third weldable part positioned between the two raised edges of the two adjacent parts. It should be noted that the weldable part can be either a raised edge or a fixed flange.

[0007] For this purpose, the welding machine is provided with at least a pair of drive wheels, which are driven by a drive member to ensure that the welding machine moves along the workpiece to be welded in the linear direction of welding, also called the forward direction of the welding machine. The drive member may be, for example, an electric, hydraulic, pneumatic, or mechanical drive member. Preferably, in the context of the present invention, the drive member is an electric motor.

[0008] The welding wheel enables the formation of a weld by contacting at least one of the parts to be welded, which may be a raised edge or a fixed flange. More specifically, according to a non-limiting example of the present invention, when welding a part to be welded, the movement of the welding machine relative to the part to be welded causes the welding wheel to rotate relative to the part to be welded, and current supplied by a power supply unit passes through the welding wheel, enabling the formation of a weld bead on the part to be welded.

[0009] A stopping device for a welding machine equipped with at least one sensor enables the automation of stopping the welding machine when the sensor detects a point on the part to be welded. In other words, when the sensor detects a point on the part to be welded, the welding machine, in particular the control unit, performs a procedure to gradually stop the welding machine so that at least the welding wheel of the welding machine stops at a predetermined distance from the point.

[0010] According to one feature of the present invention, the welding machine comprises at least one drive member capable of rotating a drive wheel, and the drive member is capable of driving the welding machine at a speed exceeding 4.5 m / min.

[0011] It should be noted that the advantage of such automation of stopping welding by a welding machine is that it allows the welding machine to be used at high speeds.

[0012] According to one feature of the present invention, the sensor is configured to detect at least one shape change of at least one part to be welded.

[0013] The phrase "a change in shape of at least one weldable part" means, for example, a recess formed in the material of at least one weldable part. This recess can take the form of, for example, a notch. Thus, in such a configuration of points, the sensor may be a mechanical sensor, a laser sensor, a Hall effect sensor, an inductive sensor, or an ultrasonic sensor.

[0014] According to one feature of the present invention, the sensor is configured to detect at least one thickness change of at least one part to be welded. This thickness change may take the form of a blind hole or a through hole.

[0015] In such a configuration of a point formed on at least one weldable part, the sensor may be an inductive sensor, a Hall effect sensor, a mechanical sensor, a laser sensor, or an ultrasonic sensor.

[0016] According to one feature of the present invention, the sensor is configured to receive a signal from a marker representing the position of a point.

[0017] In this case, the point may be virtual, in other words, not physically present on the part to be welded. According to this example, the marker may be placed at or at a non-zero distance from the point to enable the transmission of a signal received by the stop device's sensor to stop the welding machine, and to cause a change in the sensor's state upon reception of the signal. The marker is an indirect means of detecting the point by the sensor.

[0018] According to one feature of the present invention, the welding machine comprises at least two pairs of drive wheels, the welding wheels being positioned between the two pairs of drive wheels in the longitudinal direction of the welding machine.

[0019] According to one feature of the present invention, the sensor is located at a non-zero sensor distance from the welding wheel, and the sensor distance is considered in the longitudinal direction of the welding machine.

[0020] In particular, the front and rear ends of the welding machine are defined, and the terms front and rear are considered in relation to the forward direction of the welding machine along the part to be welded. Therefore, it will be understood that a sensor is placed at the front end of the welding machine to predict the detection of a point on the part to be welded before the welding wheel reaches that point while the welding machine is moving.

[0021] According to a non-limiting example of the present invention, the sensor distance between the sensor and the welding wheel is 150 mm to 300 mm, and the distance between the front end of the welding machine and the sensor is 0 mm to 150 mm.

[0022] According to one feature of the present invention, the welding machine includes at least one main body that defines a volume in which the welding wheel and at least one pair of drive wheels are at least partially disposed, and the sensor is disposed outside the volume defined by the main body of the welding machine.

[0023] In particular, it should be noted that the sensor is disposed outside the volume defined by the main body of the welding machine so as to be vertically disposed between the front end of the welding machine and a point during the movement of the welding machine along the welding target part before detection. Alternatively, the sensor may be supported by the outer surface of the front end of the welding machine. According to another alternative form, the sensor may be within the volume defined by the main body of the welding machine, especially when the sensor is a sensor laser.

[0024] A cooling system for cooling the welding wheel can be provided. This preferably consists of an internal circuit that circulates the cooling liquid as close as possible to the welding wheel, and this circuit further includes a container, a pump, and a cooling assembly supported by a trolley.

[0025] According to one feature of the present invention, the control unit is configured to reduce the intensity of the current starting from the detection of the point by the sensor.

[0026] According to one feature of the present invention, the control unit is configured to reduce the speed of the welding machine starting from the detection of the point by the sensor.

[0027] According to an alternative form of the present invention, the control unit is configured to stop the rotation of the drive wheel by the drive member of the welding machine when the sensor detects a point.

[0028] According to one feature of the present invention, the control unit is configured to synchronize the decrease in the intensity of the current with the decrease in the speed of the welding machine starting from the detection of a point by the sensor.

[0029] According to one feature of the present invention, the welding machine includes at least one man-machine interface arranged on a fixed trolley independent of the main body of the welding machine. Also, the power supply unit may be supported by the trolley.

[0030] According to one feature of the present invention, the signal transmitted or detected by the sensor forms an incident angle of 0 to 45 degrees with respect to the forward direction of the welding machine. The advantage of such a feature is that it enables the sensor to detect the point before the sensor of the welding machine reaches the point formed on at least one of the parts to be welded.

[0031] According to one feature of the present invention, the predetermined distance from the point, which is calculated between the point and a stop region different from the point, is 20 to 200 mm, and preferably, the distance is 50 to 100 mm.

[0032] In other words, the welding of the parts to be welded is stopped at a distance of 20 to 200 mm from the point. Therefore, the stop region defines the welding region of the region without welding.

[0033] The present invention also relates to a welding method for welding at least two parts to be welded by a welding machine according to any one of the above features. The welding method includes at least one first step in which a drive wheel is rotated so that the welding machine is moved along the part to be welded in the longitudinal direction in which the welding machine advances, at least one second step in which a welding wheel forms a welding bead along at least one part to be welded while having a current passing through them, at least one third step in which a sensor detects a point on at least one part to be welded, and at least one fourth step in which a control unit stops the welding of the part to be welded by the welding wheel at a predetermined distance from the point.

[0034] According to one feature of the welding method, during the fourth step, the drive member is configured to reduce the forward speed of the welding machine starting from the detection of a point, and the control unit is configured to reduce the current intensity starting from the detection of a point.

[0035] Furthermore, the reduction in the welding machine's forward speed and current intensity are synchronously controlled by the control unit. This allows the welding machine to produce a uniform weld bead even at the end of the weld, in other words, up to the welding machine stop area formed at a predetermined distance from the point.

[0036] According to one feature of the welding method, during the first and second steps, the drive member is configured to increase the forward speed of the welding machine, and the control unit is configured to increase the current intensity.

[0037] Furthermore, the increase in the welding machine's forward speed and current intensity are synchronously controlled by the control unit. This allows the welding machine to produce a uniform weld bead immediately after the start of welding on the part being welded.

[0038] According to one characteristic of the welding method, the moving speed of the welding machine upstream of the point in the forward direction is 4.5 m / min or more.

[0039] Further features, details, and advantages of the present invention will become more clearly apparent from the description provided below as an example, with reference to the drawings. [Brief explanation of the drawing]

[0040] [Figure 1] This is an overall perspective view of a tank for storing and / or transporting cryogenic products, including at least two weldable components that constitute the tank's sealing membrane. [Figure 2] This is a perspective view of a welding machine according to the present invention, which can weld the two parts shown in Figure 1. [Figure 3] This is an enlarged view of two weldable parts, at least one of which has a point created, according to a first example of the present invention. [Figure 4] This is an enlarged view of two weldable parts, at least one of which has a point created, according to a second example of the present invention. [Figure 5] This is an enlarged view of two weldable parts, at least one of which has a point created, according to a third example of the present invention. [Figure 6] Figure 2 is a top view of the welding machine, showing a sensor that detects a point created on one of the parts being welded. [Modes for carrying out the invention]

[0041] Firstly, while the drawings disclose the invention in detail for its implementation, it should be noted that these drawings naturally help to more clearly define the invention where applicable. It should also be noted that the drawings merely disclose embodiments of the invention. Finally, the same reference numerals indicate the same elements throughout the drawings.

[0042] Figure 2 shows a welding machine 1 configured to move along at least two weldable parts 2. More specifically, the weldable parts 2 constitute a sealing membrane 6 of the wall 8 of a tank 10 for storing and / or transporting cryogenic products, such as liquefied natural gas, as can be seen in Figure 1.

[0043] The welding machine 1 may, for example, be capable of welding the first raised edge 4a and the second raised edge 4b ​​of adjacent first weldable part 2a and second weldable part 2b, respectively. According to another example of the present invention, the welding machine may weld at least one of the raised edges 4a, 4b of one of the first weldable part 2a and / or the second weldable part 2b to a fixed flange 12 that forms a third weldable part 2c as shown in Figures 3 to 6, the fixed flange 12 being positioned between two adjacent raised edges 4. More specifically, the fixed flange 12 as shown in Figures 3 to 6 is fixed to the insulation material that forms part of the wall 8 of the tank 10 and is positioned between two adjacent raised edges 4. At least two of these welds on the welded parts 2a, 2b, and 2c form a weld bead 14 on at least one of the first raised edge 4a and / or the second raised edge 4b ​​extending along the weld axis S, as shown in Figures 3 to 5. The weld bead 14 formed between at least two welded parts 2 ensures a seal between the welded parts 2, and thus contributes to the sealing of the membrane 6 that constitutes the wall 8 of the tank 10 for storing and / or transporting cryogenic products.

[0044] In particular, the welding machine 1, as seen in Figures 2 and 6, has a substantially parallelepiped shape and comprises at least one body 42 extending in a main extension direction P parallel to the longitudinal direction L of the welding machine 1. The body 42 of the welding machine 1 comprises a front end 16 and a rear end 18 that face each other in the longitudinal direction L of the welding machine 1. It should also be noted that the concept of front and rear of the body 42 of the welding machine 1 refers to the forward direction A of the welding machine 1 along the welding axis S and the part to be welded 2 parallel to the longitudinal direction L of the welding machine 1. Furthermore, the body 42 of the welding machine 1 comprises an upper surface 20 and a lower surface (not shown) that face each other in the vertical direction V of the welding machine 1 perpendicular to its longitudinal direction L, and the lower surface is the surface of the body 42 of the welding machine 1 that faces the part to be welded 2.

[0045] The welding machine 1 according to the present invention, as shown in Figure 6, comprises at least one pair of drive wheels 24 intended to move the welding machine 1 relative to the part to be welded 2, and at least one drive member 26 capable of rotating the at least one pair of drive wheels 24.

[0046] More specifically, at least one pair of drive wheels 24 are positioned on the underside of the body 42 of the welding machine 1 so as to contact at least one of the parts 2 to be welded. Thus, the rotation of at least one pair of drive wheels 24 caused by the drive member 26 allows the pair of drive wheels 24 positioned in contact with the parts 2 to be welded to move the welding machine 1 along the parts 2 to be welded in a linear translational motion parallel to the forward direction A of the welding machine 1. More specifically, each wheel of the pair of drive wheels 24 is in contact with one of the raised edges 4 on one of the parts 2 to be welded. According to the illustrated example of the present invention, the welding machine 1 comprises a first pair of drive wheels 24a and a second pair of drive wheels 24b, respectively, positioned at the front end 16 and rear end 18 of the body 42 of the welding machine 1. Each of the drive wheels 24a and 24b of the pair of drive wheels 24a and 24b faces each other in the lateral direction T of the welding machine 1, which is perpendicular to the longitudinal direction L and the vertical direction V.

[0047] As described above, the welding machine 1 includes at least one drive member 26 that can rotate the drive wheel 24 and take the form of an electric, hydraulic, pneumatic, or mechanical drive member 26. Preferably, the drive member 26 according to the present invention is an electric motor. According to the present invention, at least one drive member 26 can rotate the drive wheel 24 such that the drive wheel moves the welding machine 1 along the part to be welded at a speed of more than 4.5 m / min.

[0048] The welding machine 1 according to the present invention comprises at least two welding wheels 28 that can weld parts 2 by rotating the welding wheels 28 relative to at least two parts 2 to be welded. Therefore, it should be noted that the welding wheels 28 can generate weld beads 14 along at least two parts 2 to be welded, as described above. Accordingly, the welding machine 1 comprises at least one first welding wheel 28a positioned in contact with the first raised edge 4a of the first part 2a to be welded, and a second welding wheel 28b positioned in contact with the second raised edge 4b ​​of the second part 2b to be welded. Furthermore, in the longitudinal direction L of the welding machine 1, the welding wheels 28 are positioned between the first pair of drive wheels 24a and the second pair of drive wheels 24b. The welding wheels 28 are positioned on the lower surface of the main body 42 of the welding machine 1 so as to be in contact with the parts 2 to be welded.

[0049] To perform the welding operation, the welding wheels 28 are intended to have a current passing through them during the operation of the welding machine 1, which is supplied by a power supply unit 30 shown in Figure 2, which in this case is supported by a trolley 46 of the welding machine 1, separate from the body 42 of the welding machine 1, which comprises the drive wheels 24 and the welding wheels 28, the trolley of which will be described in detail below in the detailed description. In addition, according to an example of the present invention not shown, the power supply unit may be housed in the body of the welding machine.

[0050] According to one example of the present invention, the welding wheel 28 can rotate freely relative to each of the drive wheels 24. Therefore, the welding wheel 28 is rotated by the welding wheel 28 directly contacting at least one of the parts to be welded 2 while the welding machine 1 is moving. The drive members 26 of the drive wheels 24 do not directly act on the rotation of the welding wheel 28. According to another example of the present invention, at least one drive member 26 is configured to rotate the welding wheel 28 along the parts to be welded 2. The welding machine 1 further comprises at least one control unit 32, which is housed in a trolley 46 and can control at least the current passing through the welding wheel 28.

[0051] According to the present invention, as shown in Figure 6, the welding machine 1 includes at least one stop device 34 for stopping the welding machine 1, which is equipped with at least one sensor 36 capable of detecting at least one point 38 on at least one raised edge 4 or fixed flange 12 of the part to be welded 2, in other words. For example, the point 38 is formed on at least one raised edge 4 on one of the parts to be welded 2 and / or on a visible portion of the fixed flange 12. The expression "visible portion of the fixed flange 12" means the portion of the fixed flange that extends vertically beyond at least one raised edge 4. The control unit 32 is configured to stop welding of the part to be welded 2 by the welding wheel 28 at a predetermined distance D from the point 38, and the sensor 36 changes state when it detects the point 38.

[0052] According to a first example of the present invention, which can be seen in Figure 3, a point 38 formed on at least one of the weldable parts 2 is a shape change of at least one of the weldable parts 2. More specifically, the shape change according to the example in Figure 3 is formed on the raised edges 4 of at least two weldable parts 2 and on the fixed flange 12 positioned between the raised edges 4. Thus, this shape change is characterized in this case by recesses of material formed on each of the raised edges 4 of at least two weldable parts 2 and on the fixed flange 12, such that the recesses of material are formed facing each other. Thus, in such a configuration of point 38, the sensor 36 of the stop device 34 may be a mechanical sensor, a Hall effect sensor, an induction sensor, a laser sensor, or an ultrasonic sensor.

[0053] Therefore, the mechanical sensor may rotate along one of the parts to be welded until it reaches a point formed by a recess in the material, triggering a switch that informs the stop device 34 of the position of the welding machine 1 along the part to be welded. If the sensor is a laser sensor or an ultrasonic sensor, these sensors normally detect the material that makes up one of the parts to be welded. When these sensors detect a point, which is a recess in the material representing a point, a change in the state of the sensor is triggered, informing the stop device 34 of the position of the welding machine 1 along the part to be welded.

[0054] According to a second example of the present invention, as can be seen in Figure 4, a point 38 formed on at least one of the welded parts 2 is a thickness change of at least one of the welded parts 2. According to an example of the present invention, point 38 is a thickness change of one of the raised edges 4 of at least one welded part 2 on which a sensor 36 is positioned opposite, and the thickness is considered along a straight line parallel to the lateral direction T of the welding machine 1. According to another example of the present invention, point 38 is a thickness change of a fixed flange 12, and the thickness is considered along a straight line parallel to the lateral direction T of the welding machine 1. This thickness change may be characterized, for example, by a blind hole or through hole formed in one of the welded parts 2. In such a configuration of point 38, the sensor 36 can take the form of an inductive sensor, a mechanical sensor, a Hall effect sensor or an ultrasonic sensor that enables direct detection of the thickness change of at least one of the welded parts 2. According to another example of the present invention, the sensor may be a laser sensor that enables detection of a change in distance between the transmission and reception of a laser at point 38 formed on at least one of the welded parts 2.

[0055] The induction sensor, in particular, enables the determination of the distance between the sensor and the material of at least one welded part 2, in which case the sensor reaching a point formed by a change in thickness generates a change in distance between the sensor and at least one welded part 2, and therefore causes a change in the state of the sensor.

[0056] Furthermore, it should be noted that, independently of the first and second embodiments of point 38, the point is formed on at least one of the parts to be welded 2 in a manner distinct from the weld bead 14 formed by the welding wheel 28. In other words, point 38 is offset perpendicularly from the weld bead 14. This feature makes it possible to limit the risk of unsound welds occurring at point 38, in which case the weld bead 14 is not formed over any change in shape or thickness in one of the parts to be welded 2.

[0057] According to a third example of the present invention, which can be seen in Figure 5, the sensor 36 is configured to receive a signal from a marker 40 representing the position of a point 38 on at least one part to be welded 2. It should be noted that in such a configuration, the marker 40 may be positioned to be spatially offset from the point 38. As in the above case, detection of the marker 40 by the sensor 36 changes the state of the sensor 36 and thus informs the stop device 34 of the position of the welding machine 1 relative to the point 38.

[0058] From the above, it will be understood that the sensor 36 according to the present invention can, in particular, transmit a signal to determine a change in the shape and / or thickness of at least one welded part 2 representing point 38, or in particular receive a signal from the marker 40, and the reception of the signal transmitted by the marker 40 represents point 38 and the position of the welding machine 1 relative to point 38.

[0059] As described above, the body 42 of the welding machine 1 defines a volume in which the welding wheels 28 and at least one pair of drive wheels 24 are at least partially arranged. More specifically, according to the illustrated example of the present invention, two welding wheels 28 and two pairs of drive wheels 24 are arranged within the volume defined by the body 42 of the welding machine 1.

[0060] Accordingly, according to the present invention, as can be seen in Figures 2 and 6, at least one sensor 36 is positioned outside the volume defined by the body 42 of the welding machine 1. More specifically, the sensor 36 is at a non-zero sensor distance F from the welding wheel 28, where the sensor distance F is considered in the longitudinal direction L of the welding machine 1. In particular, at least one sensor 36 is positioned at the front end 16 of the body 42 of the welding machine 1 such that it is upstream of the welding wheel 28 in the forward direction A of the welding machine 1. According to a non-limiting example of the present invention, at least one sensor 36 is positioned at a non-zero sensor distance F of 150 mm to 300 mm from the welding wheel 28. At least one sensor 36 is positioned at a distance of 0 mm to 150 mm from the front end 16 of the body 42 of the welding machine 1. Such placement of the sensor 36 relative to the welding wheel 28 makes it possible to predict the stopping of the welding machine 1 before the welding wheel 28 reaches point 38.

[0061] As described above, the control unit 32 is configured to stop the welding of the part to be welded 2 by the welding wheel 28 at a predetermined distance D from point 38, in other words, at a stop region 44 different from point 38. Preferably, the stopping of welding by the welding wheel 28 is effective in the stop region 44 located at a predetermined distance D of 20 mm to 200 mm from point 38. Preferably, the predetermined distance D is 50 to 100 mm from point 38. In other words, the control unit 32 is configured so that the welding wheel 28 forms a weld bead 14 up to the stop region 44 formed at a predetermined distance D from point 38. The control unit 32 also controls the drive member 26 so that the welding machine 1 stops when it reaches the stop region 44 located at a predetermined distance D from point 38.

[0062] For this purpose, the control unit 32 is configured to reduce the intensity of the current supplied to the welding wheel 28 by the power supply unit 30, starting from the detection of a point 38 by the sensor 36. In particular, it should be noted that the stop device 34 is configured to communicate with the control unit 32 so as to send a signal to the control unit 32 when its sensor 36 detects a point 38 formed on one of the parts to be welded 2.

[0063] Therefore, the control unit 32 reduces the intensity of the current supplied to the welding wheel 28, starting from the detection of point 38, until it reaches zero intensity when the welding machine 1, more specifically the welding wheel 28, is located in the stopping area 44 at a predetermined distance D from point 38. Similarly, the control unit 32 is configured to reduce the speed of the welding machine 1, starting from the detection of point 38 by at least one sensor 36. That is, the control unit 32 commands the drive member 26 to reduce the rotational speed of the drive wheel 24 from a speed faster than 4.5 m / min when the sensor 36 detects point 38 to a zero speed when the welding wheel 28 reaches the stopping area 44 at a predetermined distance D from point 38. Thus, according to the present invention, the control unit 32 is configured to synchronize the reduction in the intensity of the current supplied to the welding wheel 28 with the reduction in the speed of the welding machine 1, starting from the detection of point 38 by the sensor 36.

[0064] From the features of the welding machine 1 described above, it will be understood that the position of the stopping device 34 of the welding machine 1, in particular its sensor 36, makes it possible to autonomously, in other words, predict when the welding machine 1 will stop, without operator intervention. In other words, the welding machine 1 itself ensures that its moving speed and the intensity of the current supplied to the welding wheel 28 decrease in a predictable manner so that when the welding machine 1, in particular the welding wheel 28, reaches the stopping area 44 of the part to be welded, this speed and intensity have zero values.

[0065] According to an example of the present invention shown in Figure 6, at least one sensor 36 receives and / or transmits a signal such that the signal has an incident angle N of 0° to 45° with respect to the forward direction A of the welding machine 1. The signal generates a reading point on the part to be welded up to the detection of point 38, which corresponds to the moment when the control unit 32 begins to stop welding the part to be welded 2 by the welding wheel 28. Naturally, it will be understood that the signal transmitted and / or received by the sensor 36 is directed forward of the welding machine 1, in other words, directed away from the body 42 of the welding machine 1.

[0066] The advantage of such features is that the sensor 36 can improve the prediction of detecting a point 38 formed on one of the parts to be welded 2, and the sensor 36 can detect the point 38 before it reaches the point 38 while the welding machine 1 is in operation. This improves the prediction of stopping the welding machine 1 by the stopping device 34.

[0067] Alternatively, the sensor 36 receives a signal from the marker 40 that corresponds to the moment when the control unit 32 starts to stop welding the part 2 to be welded by the welding wheel 28.

[0068] As can be seen in Figure 2, the welding machine 1, apart from its main body 42, comprises at least a trolley 46 intended to support at least a power supply unit 30 for the welding wheel 28, at least one man-machine interface 48 enabling an operator to monitor the progress of welding of the part to be welded 2, and at least a control unit 32, and further comprises at least one cooling system 50 for cooling the welding wheel 28. The cooling system 50 for cooling the welding wheel 28 may consist of, for example, an internal circuit that circulates a coolant as close as possible to the welding wheel, and this circuit further comprises a container, a pump, and a cooling assembly supported by the trolley. Such a cooling system makes it possible to prevent the welding wheel 28 from overheating during the operation of the welding machine 1.

[0069] A welding method for welding at least two parts to be welded 2 using the welding machine 1 described above will be explained with reference to Figures 1 to 6.

[0070] The welding method includes at least one first step of rotating the drive wheel 24 by the drive member 26 under the control of the control unit 32 so as to move the welding machine 1 along the part to be welded 2 in the forward direction A of the welding machine 1 parallel to the longitudinal direction L. During this first step, the control unit 32 is configured to increase the forward speed of the welding machine 1 from zero speed to a speed exceeding 4.5 m / min. It should be noted that the speed of the welding machine 1 increases until a steady speed exceeding 4.5 m / min is reached. Furthermore, a moving speed exceeding 4.5 m / min corresponds to the speed of the welding machine 1 upstream of point 38 with respect to the forward direction A of the welding machine 1.

[0071] The method further includes a second step, following or simultaneously with the first step, in which a current passes through the welding wheel such that the welding wheel 28 forms a weld bead 14 along the parts to be welded 2, particularly along the raised edges 4 of at least two of the parts to be welded 2. In this second step, the control unit 32 is configured to increase the intensity of the current supplied to the welding wheel 28 by the power supply unit 30. This increase in intensity is carried out by the control unit 32 in synchronization with the increase in the moving speed of the welding machine 1. Therefore, it should be noted that the intensity of the current passing through the welding wheel 28 increases in proportion to the increase in the speed of the welding machine 1 in order to obtain a uniform weld bead 14 during the second step.

[0072] Following the second step, in the third step, the sensor 36 detects a point 38 on at least one part to be welded 2 by a change in the shape or thickness of one of these elements, or by receiving a signal transmitted by the marker 40 that represents the position of the point 38. Therefore, in the fourth step, the control unit 32 stops welding the part to be welded 2 by the welding wheel 28 at a predetermined distance D from the point 38. During the fourth step, the control unit 32 is configured to reduce the strength of the current supplied from the power supply unit 30 to the welding wheel 28, while controlling the decrease in the forward speed of the welding machine 1, starting from the detection of the point 38 by the drive member 26. Thus, the decrease in the speed of the welding machine 1 and the decrease in the strength of the welding current are synchronously achieved by the control unit 32.

[0073] The advantage of this feature is that it allows for a reduction in the rotational speed of the drive wheel 24 in proportion to the decrease in the intensity of the current passing through the welding wheel 28, so as to obtain a uniform weld bead 14 between point 38 and the stopping area 44.

[0074] Therefore, at the end of the fourth step, the welding machine 1 is in the stop area 44, its drive wheel 24 is stationary, in other words its rotational speed is 0, and no current is flowing through its welding wheel 28.

[0075] However, the present invention described herein is not limited to the means and configurations described and illustrated, but also applies to any equivalent means or configurations, and any combination thereof.

Claims

1. A welding machine (1) for welding at least two parts (2) to be welded, configured to be movable along the parts (2), the welding machine (1) extending in a main extension direction (P) of a longitudinal direction (L), comprising at least one pair of drive wheels (24) intended to move the welding machine (1) relative to the parts (2) to be welded, and at least two welding wheels (28) capable of producing welds of the parts (2) to be welded by rolling the welding wheels (28) relative to the at least two parts (2) to be welded, The welding machine (1) comprises a control unit (32) capable of controlling a current passing through the welding wheel (28), and the welding machine (1) comprises at least one stopping device (34) for stopping the welding machine (1), the stopping device (34) comprising at least one sensor (36) capable of detecting a point (38) on the parts to be welded (2), and the control unit (32) is configured to stop welding of the parts to be welded (2) by the welding wheel (28) at a predetermined distance (D) from the point (38).

2. 2. The welding machine (1) of claim 1, comprising at least one drive member (26) capable of rotating the drive wheel (24), the drive member (26) being capable of driving the welding machine (1) at a speed exceeding 4.5 m / min.

3. The welder (1) of claim 1, wherein the sensor (36) is configured to detect at least one change in shape of the at least one part (2) to be welded.

4. The welder (1) of claim 1, wherein the sensor (36) is configured to detect at least one thickness change of the at least one part (2) to be welded.

5. The welder (1) of claim 1, wherein the sensor (36) is configured to receive a signal from a marker (40) representing the location of the point (38).

6. 6. The welding machine (1) according to claim 1, comprising at least two pairs of drive wheels (24, 24a, 24b), and the welding wheel (28) is disposed between the two pairs of drive wheels (26) in the longitudinal direction (L) of the welding machine (1).

7. 6. The welding machine (1) of claim 1, wherein the sensor (36) is at a non-zero sensor distance (F) from the welding wheel (28), the sensor distance (F) being considered in the longitudinal direction (L) of the welding machine (1).

8. 6. The welding machine (1) of claim 1, further comprising at least one body (42) defining a volume in which the welding wheel (28) and the at least one pair of drive wheels (24) are at least partially disposed, and the sensor (36) is disposed outside the volume defined by the body (42) of the welding machine (1).

9. 6. The welding machine (1) according to any one of claims 1 to 5, wherein the control unit (32) is configured to reduce the intensity of the current starting from the detection of the point (38) by the sensor (36).

10. 6. The welding machine (1) according to any one of claims 1 to 5, wherein the control unit (32) is configured to reduce the speed of the welding machine (1) upon detection of the point (38) by the sensor (36).

11. A welding machine (1) as described in any one of claims 1 to 5, wherein the control unit (32) is configured to reduce the intensity of the current starting from the detection of the point (38) by the sensor (36), the control unit (32) is configured to reduce the speed of the welding machine (1) starting from the detection of the point (38) by the sensor (36), and the control unit (32) is configured to synchronize the reduction in the intensity of the current with the reduction in the speed of the welding machine (1) starting from the detection of the point (38) by the sensor (36).

12. 6. The welding machine (1) according to any one of claims 1 to 5, wherein the signal transmitted or detected by the sensor (36) forms an angle of incidence (N) of 0 to 45 degrees with respect to the forward direction (A) of the welding machine (1).

13. 6. The welding machine (1) according to claim 1, wherein a predetermined distance (D) from the point (38), calculated between the point (38) and a stop region (44) different from the point (38), is between 20 and 200 mm, and preferably, the distance (D) is between 50 and 100 mm.

14. 6. A welding method for welding at least two workpieces (2) using the welding machine (1) according to any one of claims 1 to 5, the welding method comprising: at least one first step in which the drive wheel (24) is rotated to move the welding machine (1) along the workpieces (2) in a longitudinal (L) direction in which the welding machine (1) advances (A); at least one second step in which, simultaneously with or after the first step, the welding wheels (28) have current passing therethrough to form a weld bead (14) along the at least one workpiece (2) to be welded; at least one third step in which the sensor (36) detects the point (38) on the at least one workpiece (2) to be welded; and at least one fourth step in which the control unit (32) stops the welding of the workpieces (2) by the welding wheel (28) at the predetermined distance (D) from the point (38).

15. 15. The welding method according to claim 14, wherein during the fourth step, the drive member (26) is configured to slow down the advancement speed of the welder (1) starting from the detection of the point (38) and the control unit (32) is configured to reduce the intensity of the current starting from the detection of the point (38).

16. 15. The welding method according to claim 14, wherein the speed of movement of the welding machine (1) upstream of the point (38) in the forward direction (A) is 4.5 m / min or more.

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