Welding device

Abstract

A welding device includes a moving assembly for at least one electrode through which an electric current for performing a welding process can be passed. The assembly includes at least one cylinder and at least one stem for rigidly supporting the electrode, the stem being at least partially housed within the cylinder and coaxially movable in alternating linear motion along the longitudinal axis (A) of the cylinder so as to press the at least one electrode against the parts to be welded with a corresponding welding force. The welding device also includes a device for measuring the welding force, the device including a plate and a plurality of deformation sensors, the plate being stably inserted between the stem and the at least one electrode, each with its face disposed perpendicular to the longitudinal axis (A), and the plurality of deformation sensors being housed in through slots in the plate and arranged along an imaginary circumference centered on the longitudinal axis (A).

Description

Technical Field

[0001] The present invention relates to a welding apparatus.

Background Art

[0002] As is known, the term "electric resistance welding" refers to a broad category of methods in which the materials to be welded are heated by their electrical resistance.

[0003] More precisely, in this technique, at least one electrode is pressed against the parts to be welded, and then an electric current is passed through the electrodes and the said parts. Due to the Joule effect, the current causes local heating at the contact points between the parts and the electrodes until the liquefaction of the relevant materials and subsequent welding.

[0004] Similarly, it is known that in order to ensure good welding, it is necessary to appropriately adjust and control three parameters: the current intensity, the welding time, and the force applied to the parts during welding.

Summary of the Invention

Problems to be Solved by the Invention

[0005] Regarding the first two parameters shown above, efficient devices are currently known that can control and adjust the desired values with sufficient reliability. However, so far, none of the various different solutions adopted to control the welding force have been completely satisfactory.

[0006] In practice, control may be performed using a gauge and a pressure regulating valve. This method applies "indirect" control in that it enables reading and controlling a pre-set pressure circuit value. By multiplying the pressure circuit value by the cross-sectional area of the cylinder pushing the electrode, the required force can be obtained. However, the gauge reads the pressure value at a point in the circuit somewhat removed from the pusher cylinder. Therefore, the sliding friction of the pusher cylinder and the influence of its negative weight, or forces generated during welding and operating "off-axis" (where the welding electrode and the cylinder are not coaxial), cannot be taken into account in the operation of the pusher cylinder.

[0007] Therefore, in practice, an electric resistance welding machine using a gauge and a pressure regulating valve cannot generate a force value corresponding to the desired value. The factors listed above vary unpredictably from welding cycle to welding cycle and, particularly when the reproducibility of the welding process constitutes an important factor, lead to vibrations and deviations that are usually unacceptable.

[0008] Some other electric resistance welding machines attempt to control the welding force using sensors that can measure deformations in the structure of the machine itself. Such deformations are caused by the forces generated during the welding stage. Due to disturbances and interferences caused by the high current during operation, these sensors are placed at a considerable distance from the welding point. Therefore, such electric resistance welding machines may have the same drawbacks as the previously described type. That is, there is a drawback in that the force components consumed by the friction between the various components of the movable stem of the cylinder cannot be properly taken into account. Therefore, the exact value of the force applied by the welding electrode to the material layer being welded cannot be known.

[0009] Both of the above approaches are further affected by inaccuracies. For example, there is the influence of the associated temperature (temperature changes the system yield by further changing the force at the electrode), or the influence of the hysteresis effect on the measuring components. The influence of the hysteresis effect occurs when transitioning from a higher adjustment value to a lower value, or vice versa.

[0010] Due to these reasons and the impossibility of obtaining clear information regarding the forces generated during welding, sometimes the operator has to stop production in order to check the actual forces applied to the electrodes, sandwich a force measuring device (e.g., a sample load cell) between the electrodes, and make the necessary adjustments.

[0011] However, considering that this check is usually performed without passing current through the electrodes, the measured force values and the new adjustments based on them do not correspond to the operating conditions that occur during welding. Furthermore, during welding, due to the flow of current between the electrodes, an electromagnetic force in the direction opposite to the applied force is generated, which can subtract the force from the electrode contact.

[0012] The object of the present invention is to solve the above problems and provide a welding device capable of performing an optimal measurement of the welding force, that is, the force with which the electrode presses against the part to be welded.

Means for Solving the Problems

[0013] Within the scope of this object, an object of the present invention is to provide a welding device capable of reading and accurately adjusting the welding force regardless of the position of the electrode with respect to the axis of the pusher cylinder.

[0014] Another object of the present invention is to provide a welding device capable of performing an optimal measurement of the welding force without being affected by distortion and other disturbing effects caused by the electromagnetic force generated during welding itself.

[0015] Another object of the present invention is to provide a welding device that guarantees a high reliability of operation.

[0016] Another object of the present invention is to provide a welding device that adopts a technical and structural architecture different from that of conventional devices.

[0017] Another object of the present invention is to provide a welding apparatus that can be easily implemented using elements and materials readily available in the market.

[0018] Another object of the present invention is to provide a welding apparatus that can be applied safely at low cost.

[0019] This objective, as well as these and other objectives that will become apparent hereinafter, are achieved by the welding apparatus according to claim 1.

[0020] Further features and advantages of the present invention will become more apparent from the following detailed description of the preferred but non-exclusive embodiments of the welding apparatus according to the present invention, which are shown by way of non-limiting example in the accompanying drawings. In the accompanying drawings, FIGS. 6 to 12 show the measuring apparatus of the present invention without a deformation sensor according to the first embodiment. FIGS. 13 to 17 show the measuring apparatus of the present invention according to the second embodiment.

Brief Description of the Drawings

[0021]

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DETAILED DESCRIPTION OF THE INVENTION

[0022] In particular, referring to the drawings, the welding apparatus according to the present invention is generally indicated by reference numeral 1. The welding apparatus 1 according to the present invention includes a moving assembly 2 for at least one electrode (not shown in the attached drawings, but an electrode known per se regardless of its shape). The electrode can pass a current for performing a welding process on two or more parts that are arranged along the moving track (alternating translation) of the electrode and are welded to each other.

[0023] More specifically, the assembly 2 comprises at least one cylinder 3 (typically pneumatic, hydraulic or electro - hydraulic) and at least one stem 4 which firmly (indirectly as will be described later) supports the electrodes. More specifically, the stem 4 is at least partially housed in the cylinder 3 and is coaxially movable in an alternating rectilinear motion along the longitudinal axis A of the cylinder 3. Thereby, the electrodes can be pressed against the parts to be welded with the corresponding welding force. According to a method known per se, during the stroke of withdrawing the stem 4 from the cylinder 3 (partially or completely), the electrodes supported by the stem 4 come into contact with the parts and the welding force is generated. When the welding is completed, the stem 4 can re - enter the cylinder 3 (as part of the alternating rectilinear motion) in order to facilitate the removal of the welded parts and the preparation of the apparatus 1 for another process.

[0024] More precisely, according to a method known per se, the apparatus 1 typically defines a support surface 5 on which parts to be welded (for example, a pair of metal plates) can be placed. The support surface 5 is effectively arranged along the stroke along which the electrodes can move (or at the end of the stroke), whereby the electrodes can press the parts against the surface 5 and a current can flow to perform the welding.

[0025] On the surface 5, a second electrode can act (from the opposite side), or in any case, the second electrode can be the part itself that enables the flow of the current.

[0026] In any case, since the techniques and methods so far are known per se, there is no need to further explain them.

[0027] It should also be noted that in a preferred application, the apparatus 1 is configured to perform electric resistance welding processes (of various known types). Thereby, the parts to be welded are heated by electrical resistance while the electrodes are pressing the parts against the surface 5 (or more generally, while the parts are clamped between the corresponding electrodes).

[0028] In any case, the use of the device 1 according to the invention provides the possibility of performing another type of welding process.

[0029] According to the invention, the device 1 comprises a welding force measuring device 6. More specifically, as will be explained in more detail below, the device 6 measures the value of the force with which the stem 4 and each electrode press against the parts to be welded during welding.

[0030] The device 6 includes a plate 7, which is stably inserted between the stem 4 and the electrode, and each of its surfaces 7a, 7b is arranged at right angles to the longitudinal axis A. As can be intuitively recognized, even from the attached figures, the surfaces 7a, 7b of the plate 7 are identified by the two larger dimensions of the plate 7 (the third dimension is the thickness or height of the plate 7 and is aligned or parallel with the longitudinal axis A).

[0031] The plate 7 is preferably made of a non-magnetic metal material and is substantially rectangular (as in the attached drawings), square, circular, etc.

[0032] Furthermore, the device 6 includes a plurality of strain sensors 8 (shown only in FIG. 13 for simplicity), and the plurality of strain sensors 8 are housed in through slots 9. The through slots 9 are provided in the plate 7 and are arranged along a virtual circumference B centered on the longitudinal axis A (the contour of which is shown in FIGS. 9, 15, and 17) (when viewed from above or below the plate 7).

[0033] The sensor 8 measures the deformation of the plate 7 caused by the generated welding force (alone) that is arranged in direct contact with the electrode or the element supporting the electrode (as will become clearer below) and / or, in any shape, in the vicinity of the weld point. Therefore, the optimal measured value of the welding force can be obtained from the reading obtained by the sensor 8 without interference or distortion that affects or changes the reading. Therefore, in this regard, the set goal is achieved.

[0034] Specifically, according to two particularly practical embodiments, the plate 7 has a number of slots 9 equal to four (as in the solution shown in FIGS. 6 to 12) or eight (as in the solution shown in FIGS. 13 to 17). In either case, these slots 9 have the same dimensions as each other and are regularly distributed along the virtual circumference B. The circumferential size of the slots 9 (i.e., the measurement along the virtual circumference B) is such that there is a small space (e.g., 5 to 10 millimeters) between the end of one slot 9 and the start of the next slot. In any case, the remaining sections of the plate 7 included between the end of a slot 9 and the start of the next slot can be conveniently calculated based on the type of material used, the maximum load of the cylinder 3, and more generally, the expected minimum and maximum amounts of deformation.

[0035] In any case, it should be noted that the scope of protection claimed herein includes plates 7 with any number of slots 9, these slots do not necessarily have to be identical to each other, and / or do not necessarily have to be regularly distributed around the virtual circumference B.

[0036] As a non-limiting example of the application of the present invention, in the preferred embodiment also shown in FIG. 13, each sensor 8 is an electrical resistance strain gauge and includes a deformable element firmly applied on a layered support 8a. And the support 8a is firmly applied to one of the two end walls 9a located opposite each other along the virtual circumference B of each slot 9.

[0037] As is known, the object to which the support 8a (plate 7) is applied deforms due to the stress it receives, and due to this deformation, the deformable element deforms. This causes a change in the electrical resistance that opposes the flow of current. By appropriately measuring this change, it is possible to find the value of the deformation and, thus, the value of the force applied to the plate 7.

[0038] In a preferred embodiment that enables obtaining a more accurate measurement value of the bonding force, referring further to FIG. 13, each slot 9 (regardless of their number) houses a pair of strain gauges (or other sensors 8). The pair of strain gauges is applied to each end wall 9a (or arranged at another point of the slot 9). Depending on specific requirements, two sensors 8 of the same slot 9 can be mounted at the same axial height (i.e., the height measured along the longitudinal axis A) or at different heights.

[0039] The presence of two or more sensors 8 of strain gauges or another type housed in the same slot 9 or different slots 9 allows the final result to be automatically corrected, and a result as an absolute value can be obtained regardless of the application position of the bonding force.

[0040] Usefully, each face 7a, 7b of the plate 7 has a receiving groove 10 for the electrical connection (such as a wire) of the sensor 8 between each pair of adjacent slots 9. Also, each groove 10 is effectively arranged along a virtual circumference B.

[0041] For simplicity, the electrical connections are not shown in the attached figures (in FIG. 13, the terminals connected to the sensor 8 are schematically shown), but they are known per se and can thus be easily intuited by those skilled in the art. The groove 10 (preferably having a semi-circular bottom, or other rounded bottom, but not limited thereto) effectively defines a recess for arranging the electrical connection between the sensors 8. This way, when the faces 7a, 7b contact the surrounding elements of the device 1, there is no risk that the electrical connection between the sensors 8 will be crushed or damaged (this will be described in more detail below. Also, as can be clearly seen by referring to FIG. 1 or FIG. 4).

[0042] In order to accurately ensure optimal protection of the sensor 8 (and its respective electrical connections) used for deformation and force measurement, advantageously, the slots 9 and the grooves 10 are closed by respective ones of a plurality of annular protective plugs 11, and the plurality of annular protective plugs 11 are applied to the corresponding faces 7a, 7b of the plate 7 and are arranged along the virtual circumference B.

[0043] The annular plugs 11 prevent dust, debris, and other types of impurities from entering the plate 7, and thus can protect the integrity and functionality of the components housed within the slots 9 and the grooves 10.

[0044] Advantageously, the welding device 1 comprises an electronic control and management unit, and the electronic control and management unit is configured for the operation of the moving assembly 2 and the adjustment of the strength of the welding force. This unit includes instructions for adjusting the strength of the welding force based on the data collected by the sensor 8, and the sensor 8 is controlled by the unit itself for this purpose.

[0045] The electronic unit can be of any type, for example, it can be an electronic controller mounted on the device 1. However, the possibility of using different types of electronic units (regardless of whether they are attached to the device 1) is not excluded. Thus, the electronic unit can be any reprogrammable hardware platform, or, in any form, can act on the strength of the welding force and / or the stroke of the stem 4.

[0046] More specifically, the electronic unit is configured to compare the value of the welding force actually occurring in a determined welding cycle (process) (typically having a duration of a few tenths of a second) with a preset force value. If a deviation occurs, immediate intervention can be carried out during that cycle right away, but more generally (considering that the duration of a single cycle is very short), detection of the deviation ensures that the unit automatically corrects that deviation in the next cycle. From a practical point of view, in order to set, control, and change the welding force, the electronic unit can act (via a proportional servo valve) on the circuit pressure of the circuit involved in the movement of the stem 4 and correct it so as to reach and maintain the desired load.

[0047] Advantageously, the measuring device 6 comprises a connection cable 12 for connecting the sensor 8 to a signal converter in order to transfer the data collected by the sensor 8 to the electronic control and management unit. Thus, in other words, during the application of the load generated by the assembly 2, the deformation of the sensor 8 is converted into an electrical signal and processed by the electronic unit. The electronic unit can return, for example, the applied load expressed in daN units.

[0048] The connection cable 12 is provided along the side of the plate 7 and is at least partially housed within a track 13 arranged in direct or indirect communication with the slot 9 (where the sensor 8 is housed).

[0049] Similar to the groove 10, the track 13 makes it possible to actually house the connection cable 12 in the plate 7. This enables the connection cable 12 not to protrude from the bulk of the plate 7 itself and thus to protect the connection cable 12.

[0050] To more securely protect the connection cable 12, the track 13 is preferably closed by an insertion member 14 (made of metal or another material). The insertion member 14 is applied to the corresponding side surface of the plate 7 and is provided with holes through which the connection cable 12 enters and exits (as shown in FIG. 7, for example).

[0051] Usefully, the plate 7 has a lateral pocket 15 arranged to communicate directly or indirectly with the slot 9. The lateral pocket 15 houses the electronic components associated with the sensors 8 and the external electrical connection terminals of these sensors 8.

[0052] For example, as shown in FIG. 17, the pocket 15 can communicate with one of the slots 9 via a first cylindrical hole 16 (thus, by the groove 10, the pocket 15 also communicates with the other slots 9).

[0053] In this way, all the sensors 8 can be connected to each other with those housed in the pocket 15. Further, a second cylindrical hole 17 connects the pocket 15 to the track 13, thereby completing the connection between the various components and enabling all to be effectively held within the size of the plate 7.

[0054] It should be noted that for the same purpose of protection as described above for the annular plug 11 and the insertion member 14, the pocket 15 can also be closed by a contour-forming plug 15a.

[0055] In a preferred embodiment that does not limit the application of the present invention in any case, the first surface 7a of the plate 7 is stably fixed to the free end of the stem 4, and the second surface 7b of the plate 7 on the opposite side of the first surface 7a is stably fixed to the electrode support block 18.

[0056] More specifically, the plate 7 is integrated with the stem 4 by means of a series of first screws 19 inserted into corresponding first holes 20 provided along the plate 7 (evenly arranged around the longitudinal axis A). The contact area between the stem 4 and the plate 7 effectively corresponds to the outer diameter of the stem 4 (except for the central hole 21 further provided for the exit of the electrical cable). In this way, the connection between the stem 4 and the plate 7 is formed by tightening the first screws 19 without causing deformation in the plate 7.

[0057] Similarly, referring further to a preferred but non-exclusive embodiment, on the side opposite to the contact with the stem 4, and thus along the second face 7b, a circular shallow recess 22 is provided which is coaxial with the longitudinal axis A and has a dimension wider than the diameter of the stem 4. In this way, the seating surface of the plate 7 on the support block 18 can correspond to the area outside the diameter of the stem 4, obtained by subtracting the surface of the shallow recess 22 from the entire second face 7b of the plate 7.

[0058] It should also be noted that in the portion of the plate 7 included (along the virtual circumference B) between the end of one slot 9 and the start of the next slot, there is an axial "continuity" (no empty space or cavity) between the stem 4 and the block 18. Preferably, these portions are arranged along the primary working direction and the secondary working direction.

[0059] The operation of the welding device according to the invention is as follows.

[0060] As shown, the support block 18 of the electrode (or the electrode in any case) is fixed to the stem 4, and the stem 4 can perform alternating linear motion along the longitudinal axis A. In this way, the device 1 acts as a press, and when the electrode reaches the limit position of maximum extraction from the cylinder 3 or moves in the direction of the limit position of maximum extraction, it is placed under pressure on two parts pre-arranged on the surface 5. Thereby, welding of these parts (by various techniques including, but not limited to, preferably electric resistance welding) can be performed.

[0061] The methods and elements involved in the implementation of welding are conventional in themselves. The feature of the present invention is, as shown, the adoption and its structure / configuration of the measuring device 6 inserted between the free end of the stem 4 and the electrode (between the stem 4 and the block 18).

[0062] The measuring device 6 comprises a plate 7 that defines an interior for housing the sensor 8 by means of a slot 9, and the sensor 8 is used to measure the deformation that occurs in the plate 7 when the stem 4 presses the electrode against the part to be welded and applies the required welding force.

[0063] Since the plate 7 is in direct contact with or disposed in the vicinity of the welding point (of the electrode or its support block 18), the deformation of the plate 7 read by the sensor 8 is the deformation due to the welding force applied to the part. The reading value is not affected by the interfering factors that affect the reading performed by a sensor located at a certain distance from the welding point in the conventional method. Even if there are factors such as the sliding friction of the stem 4, its negative weight effect, dissipation, and other reactions that may occur during welding, and those that cause their influence to be sensed at a location away from the welding point, the reading value of the sensor 8 can be kept truly accurate and precise without being affected at all.

[0064] Slot 9 provides shielding and protection to sensor 8 against disturbances, forces, or interferences caused by the (high-intensity) current passing through the electrode during welding, whereby sensor 8 is made less sensitive to such disturbances. Exactly for this reason, the present invention can place sensor 8 near the welding point and enable real-time reading of forces during process execution.

[0065] Thus, it can be seen that the device 1 according to the present invention can perform an optimal measurement of the welding force, that is, the force applied to the parts being welded during actual welding, and can eliminate the uncertainties of the process, thus fully achieving the set objectives.

[0066] Since plate 7 is in contact with the electrode and / or the corresponding block 18 and sensor 8 is arranged along the longitudinal axis A, the readings obtained by these sensors are truly accurate and precise even when the electrode is not aligned with the longitudinal axis A (which occurs in some applications). Therefore, device 1 can perform the reading and accurate adjustment of the welding force regardless of the position of the electrode relative to the longitudinal axis A of cylinder 3. This is a very practical and undoubtedly further advantage achieved by the present invention. It is related to one of the main problems associated with the use of load cells that are sometimes used in conventional devices to detect welding forces, namely the fact that in practice, such systems are sensitive to the position of the end point of the electrode relative to the position of the force sensor due to their design method.

[0067] Furthermore, since plate 7 is provided with groove 10, track 13, and pocket 15 (as well as cylindrical holes 16, 17), it can be seen that it is possible to accommodate, shield, and protect all the components necessary for operation and the functional connection of sensor 8 (by plug 11, 15a, and insertion member 14). This also enables the measurements performed by device 6 to have high reliability and accuracy (because they are not affected by distortion or interference in any part of the device).

[0068] For example, via an interface related to the electronic unit, the operator can program various parameters related to the execution of the welding cycle. For example, the value of the direct force applied to the electrode in the welding stage (in daN), the time in seconds or milliseconds to execute the step of approaching the upper electrode (supported by the stem 4), the current value required for the welding effect (in amperes), and the time in seconds or milliseconds to execute the welding.

[0069] It is emphasized again that the device 1 according to the present invention does not require information on the position of the electrode with respect to the longitudinal axis A. This is because it has already been found that this does not affect the reading of the measuring device 6.

[0070] Merely by way of example (and of course not limiting the application of the present invention), a possible welding cycle can have the following values. That is, the welding force is 500 daN, the approach time is 0.2 seconds, the current value is 40,000 A, and the welding time is 0.2 seconds.

[0071] Here, when the cycle is started in sequence, the following steps are executed. During the set approach time, the stem 4 supporting the upper electrode is lowered. By feeding back to the servo valve by the electronic unit, the pressure required for the cylinder 3 to apply the set welding force is determined. And when it is detected by the measuring device 6 that the force applied to the electrode corresponds to the desired value, welding is started by sending current to the electrode at the programmed time and intensity.

[0072] Therefore, the present invention can directly and independently control and manage each single step of each single welding cycle.

[0073] This represents another advantage of the present invention. In known solutions, often the operator has to set a time value that includes all cycle steps. This results in different welding effects for each cycle (for example, if the time used in the electrode approach step is short, the time for the next step of the cycle will be long, etc.). Therefore, significant production variations occur.

[0074] Finally, the deviation between the acquired reading value and the preset force value (for example, due to lack of alignment between the longitudinal axis A and the electrode, and / or due to the electromagnetic effect generated by welding) is automatically corrected and adjusted by the electronic unit in the next cycle.

[0075] The present invention conceived in this way is capable of numerous modifications and variations, all of which are included within the scope of the appended claims. Furthermore, all details can be replaced by other technically equivalent elements.

[0076] In the illustrated embodiments, the individual features shown in relation to specific examples can substantially be replaced by other different features existing in other embodiments.

[0077] In fact, the materials and dimensions used may be arbitrary according to requirements and the state of the art.

[0078] The disclosure of Italian patent application No. 102020000018202, to which the present application claims priority, is incorporated herein by reference.

[0079] If reference signs follow the technical features mentioned in the claims, these reference signs are included only for the purpose of enhancing the understanding of the claims, and thus such reference signs do not have a limiting effect on the interpretation of each element identified by such reference signs as an example.

Claims

1. A welding apparatus comprising a moving assembly (2) for at least one electrode through which a current for performing a welding process can pass, wherein the moving assembly (2) comprises at least one cylinder (3) and at least one stem (4) for firmly supporting the electrode, the stem (4) is at least partially received within the cylinder (3) and is coaxially movable along the longitudinal axis (A) of the cylinder (3) in an alternating linear motion so as to press at least one said electrode against a part to be welded with a corresponding welding force, comprising a device (6) for measuring the welding force, the device (6) having a plate (7) and a plurality of deformation sensors (8), the plate (7) is stably inserted between the stem (4) and at least one said electrode, and respective faces (7a, 7b) thereof are arranged at right angles to the longitudinal axis (A), the plurality of deformation sensors (8) are received within through slots (9) provided in the plate (7) and are arranged along a virtual circumference (B) centered on the longitudinal axis (A), characterized in that it is a welding apparatus.

2. The plate (7) has a number of slots (9) equal to four or eight, the slots (9) have the same dimensions as each other and are regularly distributed along the virtual circumference (B), characterized in that it is the welding apparatus according to Claim 1.

3. Each said deformation sensor (8) is a strain gauge including a deformable element firmly applied to a layered support (8a), the layered support (8a) is firmly applied to one of two end walls (9a) of each said slot (9) located opposite each other along the virtual circumference (B), characterized in that it is the welding apparatus according to Claim 1 or 2.

4. Each said slot (9) houses a pair of said strain gauges applied to respective said end walls (9a), characterized in that it is the welding apparatus according to Claim 3.

5. Each said face (7a, 7b) of the plate (7) has an accommodation groove (10) for electrical connection of the deformation sensor (8) between each pair of adjacent said slots (9), and the accommodation groove (10) is arranged along the virtual circumference (B), characterized in that it is the welding apparatus according to any one or two or more of Claims 1 to 4.

6. The slot (9) and the receiving groove (10) are closed by respective ones of a plurality of annular protection plugs (11), The plurality of annular protection plugs (11) are applied on the corresponding said surfaces (7a, 7b) of the plate (7) and arranged along the virtual circumference (B), The welding device according to claim 5, characterized in that.

7. Comprising an electronic control and management unit configured for the operation of the moving assembly (2) and the adjustment of the strength of the welding force, The electronic control and management unit includes instructions for adjusting the strength of the welding force based on data collected by the deformation sensor (8), The deformation sensor (8) is controlled by the electronic control and management unit, The welding device according to any one or more of claims 1 to 6, characterized in that.

8. The device (6) comprises a connection cable (12) for connecting the deformation sensor (8) to a signal converter in order to transfer data collected by the deformation sensor (8) to the electronic control and management unit, The connection cable (12) is, Provided along the side surface of the plate (7) and at least partially received in a track (13) arranged in direct or indirect communication with the slot (9), The welding device according to claim 7, characterized in that.

9. The plate (7) is, Provided with a side pocket (15) arranged in direct or indirect communication with the slot (9) and accommodating electronic components related to the deformation sensor (8) and external electrical connection terminals of the deformation sensor (8), The welding device according to any one or more of claims 1 to 8, characterized in that.

10. A first surface (7a) of the said surfaces (7a, 7b) of the plate (7) is stably fixed to the free end of the stem (4), A second surface (7b) of the said surfaces (7a, 7b) of the plate (7) on the opposite side of the first surface (7a) is stably fixed to at least one support block (18) of the electrode, The welding device according to any one or more of claims 1 to 9, characterized in that.

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