FR3127423A1 - Automatic stop welding machine. - Google Patents

Abstract

The invention relates to a welding machine (1) for at least two parts to be welded (2), configured to be movable along said parts to be welded (2), the welding machine (1) comprising at least one pair of drive rollers intended to set said welding machine (1) in motion, and at least two welding rollers, the welding machine (1) comprising a control unit (32) able to control a electric current flowing through the welding wheels, the welding machine (1) comprising at least one device for stopping the welding machine (1) comprising at least one sensor (36) capable of detecting a point on the part to be welded ( 2), the control unit (32) being configured to stop the welding of the parts to be welded (2) by the welding wheels at a determined distance from the point. Fig 2

Description

Automatic stop welding machine.

The present invention relates to welding devices comprising electrodes in the form of welding wheels, making it possible to weld together parts to be welded.

Current welding machines include driving wheels as well as welding wheels making it possible to operate the welding of the parts to be welded, as well as a drive member capable of rotating at least the driving wheels along parts to be welded. The welding wheels are supplied with electric current when moving the welding machine by means of an electric current unit, ensuring the welding of the parts to be welded. Current welding machines are controlled by at least one technician who ensures in particular the stopping of the welding machine at a desired location on the parts to be welded.

In order to increase the speed of welding of the parts to be welded, the drive wheels of the welding machines are driven in rotation at speeds higher than the speeds of the welding machines of the prior art. This makes it possible to increase the welding rate of the parts to be welded. However, a problem with these welding machines is that the increased rotational speed of the drive wheels makes it difficult for the technician to control the welding machine. In particular, the increase in the speed of rotation of the drive wheels decreases the stopping tolerance, then generating inaccuracies in the stopping zones of the welding machine with respect to the parts to be welded, so that the welds made by said welding machine may prove to be defective. Furthermore, the inaccuracy in the stopping zones of the welding machine can generate a danger for an operator controlling said welding machine, in particular when the latter is arranged along parts to be welded placed above the operator. .

The object of the present invention is therefore to overcome the aforementioned problem by proposing a welding machine capable of automating at least the stopping of its welding in a chosen stopping zone on the parts to be welded, that is to say a welding machine able to stop without the intervention of a technician.

The invention therefore relates to a machine for welding at least two parts to be welded, configured to be movable along said parts to be welded, the welding machine extending along a direction of main longitudinal elongation and comprising at least one pair of drive rollers intended to set said welding machine in motion relative to the parts to be welded, and at least two welding rollers able to weld the parts to be welded by rolling the welding rollers against the at least two parts to be welded, the welding machine comprising a control unit capable of controlling an electric current flowing through the welding wheels, the welding machine being characterized in that it comprises at least one device for stopping the welding machine comprising at at least one sensor capable of detecting a point on the part to be welded, the control unit being configured to stop the welding of the parts to be welded by the welding wheels at a determined distance from the point.

The welding machine according to the invention can be used for example to weld two raised edges together and/or with an anchoring wing of a watertight membrane constituting a wall of a tank for storing and/or transporting cryogenic products such as liquefied natural gas. For example, the welding machine can weld the raised edges of two adjacent parts called the first part to be welded and the second part to be welded, in order to form the sealed membrane of the wall of the cryogenic product storage and/or transport vessel. Alternatively, the welding machine can weld at least one of the raised edges with the anchoring wing, forming a third part to be welded, arranged between the two raised edges of the two adjacent parts. It is therefore understood that the part to be welded may be one of the raised edges or the anchoring wing.

To this end, the welding machine comprises at least the pair of drive wheels ensuring, by means of a drive member, the movement of the welding machine along the parts to be welded in a rectilinear welding direction, otherwise known as the direction of travel of the welding machine. The drive member may for example be an electric, hydraulic, pneumatic or even mechanical drive member. Preferably, the drive member within the scope of the invention is an electric motor.

Welding wheels allow the welding to be carried out, by contact with at least one of the parts to be welded, which can be at least one of the raised edges or the anchoring wing. More specifically, and according to a non-limiting example of the invention, during the implementation of the welding of the parts to be welded, the movement of the welding machine relative to the parts to be welded causes the rotation of the welding wheels against the parts to be welded and an electric current supplied by a power supply unit and passing through said welding wheels makes it possible to form a weld bead on said parts to be welded.

The device for stopping the welding machine comprising the at least one sensor makes it possible to automate the stopping of the welding machine, when said sensor detects the point on the part to be welded. In other words, once the sensor has detected the point on the part to be welded, the welding machine, and in particular the control unit, implements a procedure for progressive stopping of the welding machine, so that at less the welding wheels of the latter stop at a determined distance from the point.

According to one characteristic of the invention, the welding machine comprises at least one drive member capable of driving the drive wheels in rotation, the drive member being capable of driving the welding machine at a higher speed at 4.5 m/min.

We understand the advantage of such automation of the stopping of the welding by the welding machine in that it makes it possible to use said welding machine at a high speed.

According to one characteristic of the invention, the sensor is configured to detect at least one variation of a shape of at least one of the parts to be welded.

By variation of a shape of at least one of the parts to be welded is meant, for example a clearance formed in the material of said at least one part to be welded. This clearance can for example take the form of a notch. Thus, in such a configuration of the point, the sensor can be a mechanical sensor, a laser sensor, a Hall effect sensor, an inductive sensor or even an ultrasonic sensor.

According to one characteristic of the invention, the sensor is configured to detect at least one variation in a thickness of at least one of the parts to be welded. This variation in thickness can take the form of a blind or through hole.

In such a configuration of the point formed on at least one of the parts to be welded, the sensor can be an inductive sensor, a Hall effect sensor, a mechanical sensor, a laser sensor or else the ultrasonic sensor.

According to a characteristic of the invention, the sensor is configured to receive a signal from a beacon representing the position of the point.

It is understood that in such a case, the point can be virtual, that is to say not physically present on the parts to be welded. According to this example, the beacon can be arranged at the level of the point or at a non-zero distance from the point so as to allow the emission of a signal received by the sensor of the stopping device of the welding machine, causing the change status of said sensor upon receipt of said signal. It is understood that the beacon is a means of indirect detection of the point by the sensor.

According to a characteristic of the invention, the welding machine comprises at least two pairs of drive wheels, the welding wheels being arranged between the two pairs of drive wheels in the longitudinal direction of the welding machine.

According to a feature of the invention, the sensor is at a non-zero sensor distance from the welding wheels, the sensor distance being taken along the longitudinal direction of the welding machine.

In particular, a front end and a rear end of the welding machine are defined, the terms front/rear being to be considered in relation to the direction of advance of the welding machine along the parts to be welded. Thus, it is understood that the sensor is arranged at the level of the front end of the welding machine in order to anticipate the detection of the point on the part to be welded prior to the arrival of the welding wheels at the level of the point during the displacement of the welding machine.

According to non-limiting examples of the invention, the sensor distance between the sensor and the welding wheels is between 150 and 300mm and the distance between the front end of the welding machine and the sensor is between 0 and 150mm .

According to one characteristic of the invention, the welding machine comprises at least one body delimiting a volume in which the welding wheels and the at least one pair of drive wheels are arranged at least in part, the sensor being arranged at outside the volume delimited by the body of the welding machine.

It is understood in particular that the sensor is arranged outside the volume delimited by the body of the welding machine, so that it is, before detection, in a longitudinal direction between the front end of the welding machine and the point when moving the welding machine along the parts to be welded. As a variant, the sensor can be carried by an external face of the front end of the welding machine. According to another variant, the sensor can be included in the volume delimited by the body of the welding machine, in particular when said sensor is a laser sensor.

A cooling system for the welding wheels can be provided. It is preferably composed of an internal circuit circulating a cooling liquid as close as possible to the welding wheels, this circuit also comprises a tank, a pump and a cooling unit carried by the carriage.

According to one characteristic of the invention, the control unit is configured to reduce the intensity of the electric current from the detection of the point by the sensor.

According to a characteristic of the invention, the control unit is configured to reduce the speed of the welding machine from the detection of the point by the sensor.

According to a variant of the invention, the control unit is configured to stop the rotation of the drive wheels by the drive member of the welding machine when the point is detected by the sensor.

According to one characteristic of the invention, the control unit is configured to synchronize the reduction in the intensity of the electric current with the reduction in the speed of the welding machine from the detection of the point by the sensor.

According to one characteristic of the invention, the welding machine comprises at least one man/machine interface placed on a stationary carriage independent of the body of the welding machine. In addition, the power supply unit can be carried by the trolley.

According to one characteristic of the invention, a signal emitted or detected by the sensor forms an angle of incidence with respect to the direction of advance of the welding machine comprised between 0 degrees and 45 degrees. Advantage is taken of such a characteristic in that it enables the sensor to detect the point prior to the arrival of said sensor of the welding machine at the level of the point formed on at least one of the parts to be welded.

According to a characteristic of the invention, the determined distance from the point calculated between the point and a stop zone, different from the point is between 20-200mm, preferably the distance is between 50-100mm.

In other words, the welding of the parts to be welded is stopped between 20 and 200 mm from the point. The stop zone then delimits a zone of welding from a zone devoid of welding.

The invention also relates to a method of welding at least two parts to be welded by means of a welding machine according to any one of the preceding characteristics, the welding method comprising at least a first step during which the drive wheels are driven in rotation so as to move the welding machine along the parts to be welded in a longitudinal direction of advance of the welding machine, at least a second step, simultaneous or subsequent to the first step, during which the welding wheels are traversed by an electric current so as to form a weld bead along at least one of the parts to be welded, at least a third step during which the sensor detects the point on at least one of the parts to be welded and at least a fourth step during which the control unit stops the welding of the parts to be welded by the welding wheels at the determined distance from the spot.

According to a characteristic of the welding process, during the fourth step the drive member reduces the forward speed of the welding machine from the detection of the point and the control unit is configured to reduce the intensity electric current from point detection.

It will also be understood that the reduction in the forward speed of the welding machine and the reduction in the intensity of the electric current are controlled in a synchronized manner by the control unit. This allows the welding machine to produce a uniform weld bead even at the end of the weld, that is to say up to the stopping zone of the welding machine formed at the determined distance from the point

According to a characteristic of the welding process, during the first step and the second step, the drive member increases the forward speed of the welding machine and the control unit is configured to increase the intensity of the current electric.

It is further understood that the increase in the forward speed of the welding machine and the increase in the intensity of the electric current are controlled in a synchronized manner by the control unit. This allows the welding machine to produce a uniform weld bead from the start of the welding of the parts to be welded.

According to a characteristic of the welding process, the speed of movement of the welding machine upstream of the point in the direction of advance is greater than or equal to 4.5 m/min.

Other characteristics, details and advantages of the invention will emerge more clearly on reading the description given below by way of indication in relation to the drawings in which:

is a general perspective view of a tank for storing and/or transporting cryogenic products, comprising at least two parts to be welded constituting a sealed membrane of the tank;

is a perspective view of a welding machine according to the invention, capable of welding the two parts to be welded of the ;

is a close-up view of the two parts to be welded on at least one of which a point is materialized according to a first example of the invention;

is a close-up view of the two parts to be welded on at least one of which a point is materialized according to a second example of the invention;

is a close-up view of the two parts to be welded on at least one of which a point is materialized according to a third example of the invention;

is a top view of the welding machine of the showing a sensor detecting the materialized point on one of the parts to be welded.

It should first be noted that if the figures expose the invention in detail for its implementation, these figures can of course be used to better define the invention, if necessary. It should also be noted that these figures only show exemplary embodiments of the invention. Finally, the same references designate the same elements in all the figures.

There illustrates a welding machine 1 configured to move along at least two parts to be welded 2. More specifically, the parts to be welded 2 constitute a sealed membrane 6 of a wall 8 of a storage tank 10 and/or transport of cryogenic products, for example liquefied natural gas visible at the .

The welding machine 1 can for example make it possible to weld a first raised edge 4a and a second raised edge 4b respectively of a first part to be welded 2a and a second part to be welded 2b adjacent. According to another example of the invention, the welding machine can weld at least one of the raised edges 4a, 4b of one of the first part to be welded 2a and/or of the second part to be welded 2b, with a wing of anchor 12 forming a third piece to be welded 2c visible in FIGS. 3 to 6, said anchoring wing 12 being arranged between two raised edges 4 adjacent. More particularly, the anchoring wing 12, visible in Figures 3 to 6, is anchored to an insulator belonging to the wall 8 of the tank 10 and arranged between two raised edges 4 adjacent. Such welding of at least two of the parts to be welded 2a, 2b, 2c forms a weld bead 14, visible in FIGS. 3 to 5, on at least one of the first raised edge 4a and/or of the second raised edge 4b, s extending along a welding axis S. The weld bead 14 formed between the at least two parts to be welded 2 makes it possible, among other things, to ensure sealing between said parts to be welded 2, and thus contributes to the sealing of the membrane 6 constituting the wall 8 of the tank 10 storage and/or transport of cryogenic products.

The welding machine 1 particularly visible in Figures 2 and 6 comprises at least one body 42 which has a substantially parallelepipedic shape and which extends along a direction of main elongation P parallel to a longitudinal direction L of the welding machine 1. The body 42 of the welding machine 1 comprises in particular a front end 16 and a rear end 18, opposite to each other along the longitudinal direction L of the welding machine 1. It is further understood that the notion of front / rear of the body 42 of the welding machine 1 refers to a direction of advancement A of the welding machine 1 along the parts to be welded 2, parallel to the welding axis S and to the longitudinal direction L of said welding machine 1. Furthermore, the body 42 of the welding machine 1 comprises an upper face 20 and a lower face, not visible, opposite to each other in a vertical direction V of the welding machine 1, perpendicular to its longitudinal direction L, the lower face being the face of the body 42 of the welding machine 1 facing the parts to be welded 2.

The welding machine 1 according to the invention, visible at , comprises at least one pair of drive wheels 24 intended to set the welding machine 1 in motion relative to the parts to be welded 2, and at least one drive member 26, capable of rotating the at least one pair of drive wheels 24.

More precisely, the at least one pair of drive wheels 24 is arranged at the level of the lower face of the body 42 of the welding machine 1 so that it is in contact with at least one of the parts to be welded. 2. Thus, the rotation of at least one pair of drive wheels 24 operated by the drive member 26 allows said pair of drive wheels 24, disposed in contact with the parts to be welded 2, to generate the movement of the welding machine 1 along the parts to be welded 2 following a movement in rectilinear translation parallel to the direction of advance A of the welding machine 1. More precisely, each of the wheels of the pair of drive wheels 24 is in contact with one of the raised edges 4 of one of the parts to be welded 2. According to the example of the invention illustrated, the welding machine 1 comprises a first pair of drive wheels 24a and a second pair of drive wheels 24b disposed respectively at the front end 16 and at the rear end 18 of the body 42 of the welding machine 1. It is further understood that the drive wheels 24 of each of the pairs of drive wheels 24a, 24b are opposite each other in a transverse direction T of the welding machine 1, perpendicular to the longitudinal direction L and vertical V.

As mentioned previously, the welding machine 1 comprises at least one drive member 26 ensuring the rotation of the drive wheels 24 and which can take the form of an electric, hydraulic, pneumatic or still mechanical. Preferably, the drive member 26 according to the invention is an electric motor. According to the invention, the at least one drive member 26 is able to drive the drive wheels 24 in rotation so that the latter move the welding machine 1 at a speed greater than 4.5 m/min. , along the parts to be welded.

The welding machine 1 according to the invention comprises at least two welding wheels 28 capable of carrying out a welding of the parts to be welded 2 by rolling the welding wheels 28 against the at least two parts to be welded 2. It is therefore understood that the wheels welding 28 are suitable for making the weld bead 14 along the at least two parts to be welded 2 as mentioned above. Thus, the welding machine 1 comprises at least a first welding wheel 28a placed in contact with the first raised edge 4a of the first part to be welded 2a and a second welding wheel 28b placed in contact with the second raised edge 4b of the second part solder 2b. Furthermore, the welding wheels 28 are arranged between the first pair of drive wheels 24a and the second pair of drive wheels 24b along the longitudinal direction L of the welding machine 1. It is also understood that the welding wheels 28 are arranged at the level of the lower face of the body 42 of the welding machine 1 so that they are in contact with the parts to be welded 2.

In order to carry out a welding action, the welding wheels 28 are intended to be traversed by an electric current during the operation of the welding machine 1, the electric current being supplied by an electric power supply unit 30, visible at , and carried here by a carriage 46 of the welding machine 1, separate from the body 42 of the welding machine 1 comprising the drive wheels 24 and the welding wheels 28, said carriage being detailed later in the detailed description. Furthermore, according to a non-illustrated example of the invention, the power supply unit can be housed in the body of the welding machine.

According to an example of the invention, the welding wheels 28 are free in rotation with respect to each of the drive wheels 24. The welding wheels 28 are then driven in rotation during the displacement of the welding machine 1 by direct contact said welding wheels 28 against at least one of the parts to be welded 2. It is understood that the drive member 26 of the drive wheels 24 has no direct action on the rotation of the welding wheels 28. According to a another example of the invention, the at least one drive member 26 is configured to drive the welding wheels 28 in rotation along the parts to be welded 2. The welding machine 1 also comprises at least one control unit 32, here housed on the carriage 46, and able to control at least the electric current flowing through the welding wheels 28.

According to the invention and as visible in , the welding machine 1 comprises at least one stop device 34 of the welding machine 1 comprising at least one sensor 36 capable of detecting a point 38 on at least one of the parts to be welded 2, that is to say on at least one of the raised edges 4 or on the anchoring wing 12. For example, the point 38 is formed on at least one of the raised edges 4 of one of the parts to be welded 2 and/or on a visible part of the anchoring wing 12. By visible part of the anchoring wing 12 is meant a part of the latter which extends vertically beyond at least one of the raised edges 4. The steering unit 32 is configured to stop the welding of the parts to be welded 2 by the welding wheels 28 at a determined distance D from the point 38, the sensor 36 changing state when it detects the said point 38.

According to a first example of the invention visible in , the point 38 formed on at least one of the parts to be welded 2 is a variation of a shape of at least one of the parts to be welded 2. More precisely, the variation of shape according to the example of is formed on the raised edges 4 of at least two parts to be welded 2 and on the anchoring wing 12 arranged between the raised edges 4. This variation in shape is therefore characterized here by a release of material formed on each of the edges statements 4 of at least two parts to be welded 2 and on the anchoring wing 12, and in such a way that the clearances of material are formed opposite each other. Thus, in such a configuration of point 38, sensor 36 of stop device 34 can be a mechanical sensor, a Hall effect sensor, an inductive sensor, a laser sensor or even an ultrasonic sensor.

The mechanical sensor can then be a sensor rolling along one of the parts to be welded until it reaches the point, formed here by the release of material, causing the engagement of a switch informing the stop device 34 of the position of the welding machine 1 along the parts to be welded. If the sensor is a laser sensor or an ultrasonic sensor, these sensors normally detect the constituent material of one of the parts to be welded. When these sensors detect the point, and consequently the release of material, here representative of the point, a change of state of said sensors is triggered, informing the stop device 34 of the position of the welding machine 1 along the parts. welding.

According to a second example of the invention visible in , the point 38 formed on at least one of the parts to be welded 2 is a variation of a thickness of at least one of the parts to be welded 2. According to an example of the invention, the point 38 is a variation of the thickness one of the raised edges 4 of at least one of the parts to be welded 2 facing which the sensor 36 is arranged, the thickness being taken along a straight line parallel to the transverse direction T of the welding machine 1 According to another example of the invention, the point 38 is a thickness variation of the anchoring wing 12, the thickness being taken along a straight line parallel to the transverse direction T of the welding machine. 1. This thickness variation can be characterized for example by a blind or through hole, formed in one of the parts to be welded 2. In such a configuration of the point 38, the sensor 36 can take the form of an inductive sensor, d a mechanical sensor, a Hall effect sensor or even an ultrasonic sensor which make it possible to directly detect the variation in the thickness of at least one of the parts to be welded 2. According to another example of the invention , the sensor can be a laser sensor which makes it possible to detect a variation of a distance between the emission and the reception of the laser at the level of the point 38 formed on at least one of the parts to be welded 2.

The inductive sensor makes it possible in particular to determine a distance separating said sensor from a material of at least one of the parts to be welded 2, the arrival of the sensor at the level of the point formed here by a variation in thickness, generates a variation in the distance between the sensor and the at least one part to be welded 2, thus causing a change of state of said sensor.

It is also understood, independently of the first and second embodiment of point 38, that the latter is formed on at least one of the parts 2 to be welded in such a way that it is distinct from the weld bead 14 formed by the welding wheels 28. In other words, the point 38 is offset vertically from the weld bead 14. Such a characteristic makes it possible to limit the risks of an unreliable weld at the level of the point 38, the weld bead 14 then not being formed on a variation in shape or thickness of one of the parts to be welded 2.

According to a third example of the invention visible in , the sensor 36 is configured to receive a signal from a beacon 40 representative of the position of the point 38 on the at least one piece to be welded 2. It is then understood that in such a configuration, the beacon 40 can be arranged in such a way so as to be spatially offset from point 38. As in the previous cases, the detection of beacon 40 by sensor 36 modifies the state of said sensor 36, thus informing stop device 34 of the position of welding machine 1 in relation to point 38.

It is understood from the foregoing that the sensor 36 according to the invention can emit a signal in particular to determine a variation in shape and/or thickness of the at least one part to be welded 2 representative of the point 38, or can receive a signal in particular by the beacon 40, the reception of the signal emitted by the beacon 40 being representative of the point 38 and of the position of the welding machine 1 with respect to said point 38.

As mentioned above, the body 42 of the welding machine 1 delimits a volume in which are arranged at least in part the welding wheels 28 and the at least one pair of drive wheels 24. More particularly and according to the example of the invention illustrated, the two welding wheels 28 and the two pairs of drive wheels 24 are arranged in the volume delimited by the body 42 of the welding machine 1.

Thus, according to the invention and as visible in FIGS. 2 and 6, the at least one sensor 36 is arranged outside the volume delimited by the body 42 of the welding machine 1. More precisely, the sensor 36 is disposed at a non-zero sensor distance F from the welding wheels 28, the sensor distance F being taken along the longitudinal direction L of the welding machine 1. In particular, the at least one sensor 36 is disposed at the level of the front end 16 of the body 42 of the welding machine 1, so as to be upstream of the welding wheels 28 in the direction of advance A of the welding machine 1. According to examples of the invention non-limiting, the at least one sensor 36 is arranged at the non-zero sensor distance F from the welding wheels 28 of between 150 and 300 mm. The at least one sensor 36 is placed at a distance from the front end 16 of the body 42 of the welding machine 1 of between 0 and 150mm. Such an arrangement of the sensor 36 with respect to the welding wheels 28 makes it possible in particular to anticipate the stopping of the welding machine 1 before the arrival of the welding wheels 28 at the level of the point 38.

As previously described, the control unit 32 is configured to stop the welding of the parts to be welded 2 by the welding wheels 28 at the distance D determined from the point 38, that is to say in a zone d stopper 44 different from point 38. Preferably, the stopping of the welding by the welding wheels 28 is effective in the stop zone 44 arranged at the determined distance D between 20 and 200mm from the point 38. Preferably, the determined distance D is between 50 and 100 mm from point 38. In other words, the control unit 32 is configured so that the welding wheels 28 form the weld bead 14 up to the stop zone 44 formed at the determined distance D from point 38. It is further understood that the control unit 32 also controls the drive member 26 so that the welding machine 1 stops when it reaches the stop zone 44 arranged at the determined distance D from point 38.

To this end, the control unit 32 is configured to reduce the intensity of the current delivered by the power supply unit 30 to the welding wheels 28 from the detection of the point 38 by the sensor 36. It is understood in particular that the stop device 34 is configured to communicate with the driver unit 32 such that it sends a signal to the driver unit 32 when its sensor 36 detects the point 38 formed on one of the parts to be welded 2.

Thus, the control unit 32 reduces the intensity of the current delivered to the welding wheels 28, from the detection of the point 38 and in a decreasing manner until arriving at zero intensity when the welding machine 1 and more particularly the wheels 28 are in the stop zone 44 at the distance D determined from the point 38. Similarly, the control unit 32 is configured to reduce the speed of the welding machine 1 from the detection of the point 38 by at least one sensor 36. In other words, the control unit 32 controls the reduction of the speed of rotation of the drive wheels 24 to the drive member 26 in order to pass from one speed greater than 4.5 m/min on detection of point 38 by sensor 36 at zero speed when welding wheels 28 reach stop zone 44 at determined distance D from point 38. Thus, according to the invention, the control unit 32 is configured to synchronize the reduction in the intensity of the electric current delivered to the welding wheels 28 with the reduction in the speed of the welding machine 1 from the detection of the point 38 by the sensor 36.

It is understood from the characteristics of the welding machine 1 as they have just been described, that the stopping device 34 of the welding machine 1 and in particular the position of its sensor 36, makes it possible to anticipate the stopping of the welding machine 1 autonomously, that is to say without the intervention of a technician. In other words, the welding machine 1 itself ensures the reduction of its speed of movement and of its intensity of current delivered to the welding wheels 28 in advance so that the latter are of a zero value when the machine welding 1, and in particular the welding wheels 28, arrive in the stop zone 44 of the part to be welded.

According to an example of the invention visible at , the at least one sensor 36 receives and/or transmits a signal such that said signal forms an angle of incidence N with respect to the direction of advancement A of the welding machine 1, comprised between 0° and 45 °. The signal generates a reading point on the part to be welded and until detecting the point 38 which corresponds to the moment when the control unit 32 initiates the stopping of the welding of the parts to be welded 2 by the welding wheels 28. understands of course that the signal emitted and/or received by the sensor 36 is directed towards the front of the welding machine 1, that is to say opposite the body 42 of said welding machine 1.

Advantage is taken of such a characteristic in that it allows the sensor 36 to increase the anticipation of the detection of the point 38 formed on one of the parts to be welded 2, said sensor 36 being able to detect said point 38 before its arrival opposite said point 38 during the operation of the welding machine 1. This increases the anticipation of the stopping of the welding machine 1 by the stop device 34.

Alternatively, the sensor 36 receives a signal from the beacon 40 which corresponds to the moment from which the control unit 32 initiates the stopping of the welding of the parts to be welded 2 by the welding wheels 28.

As seen at , the welding machine 1 comprises at least the carriage 46 separate from its body 42 and intended to carry at least the power supply unit 30 of the welding wheels 28, at least one man/machine interface 48 allowing the technician to follow evolution of the welding of the parts to be welded 2, at least the control unit 32 and also comprises at least one cooling system 50 for the welding wheels 28. The cooling system 50 for the welding wheels 28 can for example be composed an internal circuit causing a coolant to circulate as close as possible to the welding wheels, this circuit further comprising a tank, a pump and a cooling unit carried by the carriage. Such a cooling system makes it possible in particular to avoid overheating of said welding wheels 28 during the operation of the welding machine 1.

A method of welding the at least two parts to be welded 2 by means of the welding machine 1 described previously will now be described in relation to FIGS. 1 to 6.

The welding process comprises at least a first step during which the drive wheels 24 are driven in rotation by the drive member 26 under the control of the control unit 32, so as to move the machine of welding 1 along the parts to be welded 2 along the direction of advance A of the welding machine 1 carried out parallel to the longitudinal direction L. During this first step, the control unit 32 is configured to increase the speed d progress of the welding machine 1 from zero speed to a speed greater than 4.5 m/min. It is then understood that the increase in the speed of the welding machine 1 is increasing until it reaches a level of speed greater than 4.5 m/min. It is also understood that the speed of movement greater than 4.5 m/min corresponds to a speed of the welding machine 1 upstream of point 38 in the direction of advance A of the welding machine 1.

The method also comprises a second step, subsequent to or simultaneous with the first step, during which the welding wheels 28 are traversed by an electric current so as to form the weld bead 14 along the parts to be welded 2, and in particular raised edges 4 of at least two of the parts to be welded 2. It is understood that during this second step, the control unit 32 is configured to increase the intensity of the current delivered in the welding wheels 28 by the power supply unit 30. This increase in intensity is carried out by the control unit 32 in a synchronized manner with the increase in the speed of movement of the welding machine 1. It is understood that this increases the intensity of the electric current flowing through the welding wheels 28 proportionally with the increase in the speed of the welding machine 1 so as to obtain a uniform weld bead 14 during the second step.

Following the second step, in a third step, the sensor 36 detects the point 38 on at least one of the parts to be welded 2, either through a variation in shape or thickness on one of these elements, or by receiving the signal emitted by the beacon 40 and representative of the position of the point 38. Thus, in a fourth step, the control unit 32 stops the welding of the parts to be welded 2 by the welding wheels 28 at the determined distance D from point 38. It is understood that during the fourth step, the control unit 32 is configured such that it controls the reduction in the forward speed of the welding machine 1 from the detection point 38, by means of the drive member 26, while reducing the intensity of the electric current supplied by the electric power supply unit 30 to the welding wheels 28. It is then understood that the reduction in the speed of the welding machine 1 and the reduction of the intensity of the welding current are carried out in a synchronized manner by the control unit 32.

Advantage is taken of such a characteristic in that it makes it possible to reduce the speed of rotation of the drive wheels 24 in proportion to the reduction in the intensity of the electric current passing through the welding wheels 28 so as to obtain a weld bead 14 uniform between point 38 and stop zone 44.

It is therefore understood that at the end of the fourth step, the welding machine 1 is in the stop zone 44 and has its drive wheels 24 in a static state, that is to say in a state where their speed of rotation is zero, and has its welding wheels 28 which are no longer traversed by the electric current.

The invention as it has just been 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 (16)

Welding machine (1) of at least two parts to be welded (2), configured to be movable along said parts to be welded (2), the welding machine (1) extending along a direction of main elongation ( P) longitudinal (L) and comprising at least one pair of drive rollers (24) intended to move said welding machine (1) relative to the parts to be welded (2), and at least two welding rollers ( 28) capable of welding the parts to be welded (2) by rolling the welding wheels (28) against the at least two parts to be welded (2), the welding machine (1) comprising a control unit (32) able to control an electric current flowing through the welding wheels (28), the welding machine (1) being characterized in that it comprises at least one device (34) for stopping the welding machine (1) comprising at at least one sensor (36) capable of detecting a point (38) on the part to be welded (2), the control unit (32) being configured to stop the welding of the parts to be welded (2) by the welding wheels ( 28) at a determined distance (D) from point (38). Welding machine (1) according to the preceding claim, comprising at least one drive member (26) able to drive the drive wheels (24) in rotation, the drive member (26) being capable of driving the welding machine (1) at a speed greater than 4.5 m/min. Welding machine (1) according to any one of the preceding claims, in which the sensor (36) is configured to detect at least one variation in a shape of at least one of the parts to be welded (2). Welding machine (1) according to any one of the preceding claims, in which the sensor (36) is configured to detect at least one variation in a thickness of at least one of the parts to be welded (2). Welding machine (1) according to any one of claims 1 or 2, in which the sensor (36) is configured to receive a signal from a beacon (40) representative of the position of the point (38). Welding machine (1) according to any one of the preceding claims, comprising at least two pairs of driving wheels (24, 24a, 24b), the welding wheels (28) being arranged between the two pairs of drive (26) in the longitudinal direction (L) of the welding machine (1). Welding machine (1) according to any one of the preceding claims, in which the sensor (36) is at a non-zero sensor distance (F) from the welding wheels (28), the sensor distance (F) being taken along the longitudinal direction (L) of the welding machine (1). Welding machine (1) according to any one of the preceding claims, comprising at least one body (42) delimiting a volume in which the welding wheels (28) and the at least one pair of drive (24), the sensor (36) being arranged outside the volume delimited by the body (42) of the welding machine (1). Welding machine (1) according to any one of the preceding claims, in which the control unit (32) is configured to reduce the intensity of the electric current from the detection of the point (38) by the sensor (36 ). Welding machine (1) according to any one of the preceding claims, in which the control unit (32) is configured to reduce the speed of the welding machine (1) from the detection of the point (38) by the sensor (36). Welding machine (1) according to Claims 9 and 10, in which the control unit (32) is configured to synchronize the reduction in the intensity of the electric current with the reduction in the speed of the welding machine (1) from the detection of the point (38) by the sensor (36). Welding machine (1) according to any one of the preceding claims, in which a signal emitted or detected by the sensor (36) forms an angle of incidence (N) with respect to a direction of advance (A) of the welding machine (1) between 0 degrees and 45 degrees. Welding machine (1) according to any one of the preceding claims, in which the distance (D) determined from the point (38) calculated between the point (38) and a stop zone (44) different from the point (38) is between 20-200mm, preferably the distance (D) is between 50-100mm. Method of welding at least two workpieces (2) to be welded by means of a welding machine (1) according to any one of the preceding claims, the welding method comprising at least a first step during which the rollers drive (24) are driven in rotation so as to move the welding machine (1) along the parts to be welded (2) in a direction of advance (A) longitudinal (L) of the welding machine ( 1), at least a second step, simultaneous or subsequent to the first step, during which the welding wheels (28) are traversed by an electric current so as to form a weld bead (14) along at least one of the parts to be welded (2), at least a third step during which the sensor (36) detects the point (38) on at least one of the parts to be welded (2) and at least a fourth step during from which the control unit (32) stops the welding of the parts to be welded (2) by the welding wheels (28) at the determined distance (D) from the point (38). Welding method according to the preceding claim, in which during the fourth step, the drive member (26) reduces the forward speed of the welding machine (1) from the detection of the point (38) and the driver unit (32) is configured to reduce the intensity of the electric current from the detection of the point (38). Welding method according to any one of Claims 14 to 15, in which the speed of movement of the welding machine (1) upstream of the point (38) in the direction of advance (A) is greater than or equal to 4 .5 m/min.