The present invention relates to a welding machine which is widely used in the field of head-tail welding of sheet-metal strips intended, for example, for making tubes.
Various technological processes are currently used for producing manufactured articles using a coil of metal material strip which is continuously worked in line as a starting material.
Basically, the coil is progressively unwound continuously and the strip is subjected to subsequent in-line processing. A typical example for such processes is represented by the production of longitudinally welded tubes, which takes place by progressively bending the strip around a longitudinal axis until the longitudinal edges of the strip are brought into contact, which edges are welded together to obtain a tube. Still in line, the tube is sectioned into portions of predetermined length according to known methods.
In order not to interrupt the continuity of production, a coil near depletion is replaced by welding the head end of a new coil at the tail end of the coil near depletion, with no need to stop the production line.
Welding machines are currently used to carry out this head-tail welding, which machines comprise a resting plane on which, by means of a locking means, the head end and tail end of the coils to be welded are positioned. The edges of the ends are approached one another and kept at a certain distance to allow the welding seam to penetrate the entire thickness of the strip. After positioning and locking the two ends to be welded, one or more welding torches perform the welding.
As is known, welding torches perform arc-type welding. In particular, as is known, a current generator creates an electric current between the strips to be welded and the welding torch and a grounding contact is introduced into the system to close the electric circuit between the welding torch itself and the strips.
Disadvantageously, known welding machines have drawbacks relating to the welding operations through several torches acting on the strips simultaneously.
In particular, in known welding machines, the grounding contacts relating to each torch are placed in proximity to each other, preferably, at one end of the locking means and interact operatively with the respective torches by means of grounding cables and clamps. In this situation, the grounding contacts interfere with each other, preventing the current generators from putting the grounding contacts themselves and the respective torches in operating relationship with each other for the correct calculation of the voltage and current that are necessary for the welding operations.
The technical task of the present invention is thus to provide a welding machine able to overcome the prior-art drawbacks which have emerged.
The object of the present invention is therefore that of providing a welding machine which allows a welding to be carried out without interference between the grounding contacts of the torches.
A further object of the present invention is therefore that of providing a welding machine in which each torch can be set with optimal welding parameters independently of the other torches so as to obtain a welding machine whose torches work simultaneously according to respective optimal conditions.
The stated technical task and specified objects are substantially achieved by a welding machine comprising the technical features disclosed in one or more of the appended claims. The dependent claims correspond to possible embodiments of the invention.
In particular, the stated technical task and specified objects are substantially achieved by a welding machine comprising a resting plane configured to support respectively a tail portion and a head portion of two metal sheets to be joined. The metal sheets are slidable along an advancement direction. The welding machine, subject-matter of the present invention, further comprises a sheet-metal pressing means configured to lock in a set position the head and tail portions on the resting plane and a plurality of welding torches configured to join respective edges of the tail and head portions and slidably movable along a transverse direction to the advancement direction. The welding machine is characterized in that it further comprises a plurality of grounding contacts that is each electrically associated with a respective welding torch and movable solidly constrained to the respective welding torch along the transverse direction.
Advantageously, the possibility of moving the grounding contacts together with the respective welding torch allows avoiding interferences between the grounding contacts, allowing the welding voltage and current to be optimally adjusted for each welding torch.
Further characteristics and advantages of the present invention will become more apparent from the indicative and thus non-limiting description of an embodiment of a welding machine.
Such a description will be set out below with reference to the appended drawings, which are provided solely for illustrative and therefore non-limiting purposes, in which:
With reference to the accompanying figures, 1 indicates a welding machine configured to allow the welding of a tail portion and a head portion of two metal sheets to be joined so as to substantially define a single metal sheet used for example in a line for making tubes.
In particular, as shown in
Preferably, the edges of the head portion and the edges of the tail portion extend along a transverse direction “B” to an advancement direction “A” of the metal sheets to be joined.
In the preferred embodiment, the aforesaid edges have the same length and the same thickness since the metal sheets have the same width and the same thickness.
In an alternative embodiment, the edges can have a length and/or thickness different from each other.
As shown in the accompanying figures, the welding machine 1 further comprises a sheet-metal pressing means 2 configured to lock in a set position the tail portion and the head portion on the resting plane “P”.
In the preferred embodiment, the sheet-metal pressing means 2 comprises respective pressers 2b movable along a direction that is perpendicular to the resting plane “P” between an active position and an inactive position.
In particular, in the active position, the pressers 2b lock the head portion and the tail portion of the metal sheets in contact with the resting plane “P”. In this position, in fact, the pressers 2b impart a compression on the head and tail portions so as to keep them in a flat configuration.
On the other hand, in the inactive position, the pressers 2b occupy a position that is distal from the metal sheets in such a way as to allow the latter, at the end of the welding operations, to advance along the advancement direction “A”.
Preferably, the pressers 2b are made in the form of horizontal crosspieces provided with a pressure surface facing downwards and located transversely to the advancement direction “A” of the metal sheets.
In the preferred embodiment, the welding machine 1 comprises a motor means, not shown, arranged to control the movement of the pressers 2b between the active and inactive positions.
In particular, the pressers 2b are movable, by means of the motor means, along respective vertical guides made, for example, in the form of vertical stems and positioned on the sides of the resting plane “P”.
The welding machine 1, subject-matter of the present invention, further comprises a plurality of welding torches 3 configured to join the respective edges of the tail and head portions of the metal sheets lying on the resting plane “P”. The welding torches 3 are slidably movable along a transverse direction “B” to the advancement direction “A” of the metal sheets so as to slide along the edges of the head portion and of the tail portion to carry out the welding.
Preferably, the welding torches 3 have an elongated shape extending along an extension direction “X” perpendicular to the resting plane “P”.
As shown in the accompanying figures, the welding machine 1 further comprises a plurality of grounding contacts 4 that is each electrically associated with a respective welding torch 3 and movable solidly constrained to the respective welding torch 3 along the transverse direction “B”.
Advantageously, the fact that each grounding contact 4 moves solidly constrained to the respective welding torch 3 avoids interferences and disturbances between the grounding contacts 4, increasing the overall efficiency of the welding machine 1.
Advantageously, the fact that each grounding contact 4 moves solidly constrained to the respective welding torch 3 allows each welding torch 3 to be set according to optimal operating parameters.
In the preferred embodiment, in order to move a grounding contact 4 solidly constrained to the respective welding torch 3, the welding machine 1 further comprises a guide 5 extending along the transverse direction “B” to the advancement direction “A” and a plurality of carriages 5a that is slidably movable on the guide 5 itself.
In greater detail, each carriage 5a supports a welding torch 3 and the respective grounding contact 4 so that the welding torch 3 and the grounding contact 4 themselves are simultaneously slidably movable to carry out the welding of the metal sheets underneath.
In other words, as shown in
Advantageously, the possibility of moving each welding torch 3 together with the respective grounding contact 4 allows, in use, keeping the mutual distance between the welding torch 3 and the grounding contact 4 itself fixed, considerably reducing the occurrence of interferences.
Preferably, each welding torch 3 and the respective grounding contact 4 are also movable towards and away from the resting plane “P” integrally, in particular, the welding torch 3 and the grounding contact 4 are mounted on the same lifting member 5b mounted in turn on a respective carriage 5a.
In use therefore, to carry out a head-tail welding between two metal sheets, the tail portion of a metal sheet and the head portion of a further metal sheet are arranged on the resting plane “P” and approached each other in such a way that the respective edges define a gap for the welding seam.
Preferably, the gap between the two metal sheets is underneath the guide 5 on which the support carriages 5a for the welding torches 3 and the respective grounding contacts 4 slide. In this situation, the sheet-metal pressing means 2 is moved slidably along the vertical guides so as to pass from the inactive position to the active position for locking the metal sheets.
Subsequently, each lifting member 5b moves the welding torches 3 and the respective grounding contacts 4 towards the edges to be joined.
In greater detail, as shown in
Once the welding torches 3 and the respective grounding contacts 4 have been brought close to the metal sheets, the carriages 5a are moved slidably along the guide 5 in such a way that each welding torch 3 and the respective grounding contact 4 are moved slidably along the transverse direction “B”. In particular, each welding torch 3 slides near the gap between the metal sheets while the respective grounding contacts 4 are in simultaneous sliding contact on the transverse bar 2a so as to close the electric circuit created with the respective welding torch 3 and activate the welding torch 3 itself to carry out the operations of joining the metal sheets.
In other words, as shown in
During the actuation of the welding torches 3, the carriages 5a move the welding torches 3 and the respective grounding contacts 4 slidably so that while a welding torch 3 is progressively creating a welding seam in the gap between the metal sheets, the respective grounding contact 4 slides on the transverse bar 2a moving together with the welding torch 3 itself.
Advantageously, the possibility of moving each welding torch 3 together with the relative grounding contact 4 separately from the others prevents the occurrence of sudden variations in voltage and current which might lead to damages to the welding itself.
With reference now to
In particular, the plate 4a is configured to abut, and subsequently slide, on the transverse bar 2a when the lifting members 5b move closer to the welding torches 3 and the grounding contacts 4 to the metal sheets to be joined.
Preferably, the movable plate 4a is made of copper.
Even more preferably, the movable plate 4a has a seat or a cavity 4a′ configured to receive an end portion 3a of the respective welding torch 3.
Advantageously, this conformation of the movable plate 4a allows considerably reducing the distance between the welding torch 3 and the movable plate 4a itself such that the probability of interferences occurring during the joining operations of the metal sheets is further reduced.
In the embodiment shown in the accompanying figures, the plate 4a is supported by a respective grounding arm 6.
Preferably, the grounding arm 6 is parallel to the extension direction “X” of the respective welding torch 3 and even more preferably, the grounding arm 6 extends perpendicularly to the resting plane “P”.
As shown in
In particular, the plate 4a is supported restingly on a shoulder that is preferably below the grounding arm 6.
Preferably, the grounding arm 6 comprises an inner shaft 6a defining below the shoulder and an outer hollow shaft 6b slidably mounted on the inner shaft 6a.
The outer shaft 6b also has anchoring means 8 for anchoring to a movement structure 9 of the grounding arm 6.
In the embodiment shown in the accompanying figures, the movement structure 9 is made in the form of a plate connected to the carriage 5a and configured to support both a welding torch 3 and the grounding arm 6 supporting the relative plate 4a. In this embodiment, therefore, the welding torch 3 is anchored to the movement structure 9 as well as the respective grounding contact 4 which is engaged with the grounding arm 6, in turn fixed to the movement structure 9 by means of the anchoring means 8.
In a further embodiment, not shown, the grounding arm 6 is anchored directly to the welding torch 3 by means of the anchoring means 8.
In the preferred embodiment, shown in
In use, therefore, when each welding torch 3 approaches the edges of the metal sheets to be joined, the lifting member 5b moves the welding torch 3 and the respective plate 4a engaged with the grounding arm 6 towards the metal sheets. In this situation, during the approach to the metal sheets, the plate 4a intercepts the transverse bar 2a of the sheet-metal pressing means 2 and abuts therewith while the respective welding torch 3 slides inside the seat 4a′ of the plate 4a and continues its motion of approach to the edges of the metal sheets to bring its end portion 3a to a position close to the edges themselves.
In this situation, while the welding torch 3 is moving towards the metal sheets and the plate 4a is in abutment with the transverse bar 2a, the hollow outer shaft 6b slides on the inner shaft 6a until it intercepts the elastic element 7.
The elastic element 7 is therefore compressed depending on how much the welding torch 3 moves in its motion of approach towards the metal sheets beyond the abutment level of the plate 4a against the transverse bar 2a.
If, for example, the welding torch 3 falls far below the level at which the plate 4a rests on the transverse bar 2a, the elastic element 7 is compressed a lot by the hollow outer shaft 6b which thus exerts a high pressure on the plate 4a. On the contrary, if the welding torch 3 ends its approach to the metal sheets slightly below the level defined by the plate 4a resting on the transverse bar 2a, the elastic element 7 undergoes less compression by the outer hollow shaft 6b sliding on the inner shaft 6a and therefore, the crushing pressure exerted on the plate 4a is lower.
In the preferred embodiment shown in
Preferably, the adjusting means 10 is made in the form of bolts fitted on the grounding arm 6.
Advantageously, the presence of the adjusting means 10 allows the welding machine 1 to be adapted to any type and size of the metal sheets to be treated.
In fact, by adjusting the upper limit position of the hollow outer shaft 6b with respect to the inner shaft 6a, it is possible to adjust the pressure exerted by the plate 4a on the transverse bar 2a depending on how much the respective welding torch 3 needs to approach the metal sheets to be joined.
Once each welding torch 3 reaches the position near the edges of the head and tail portions of the metal sheets and the respective movable plate 4a abuts with the transverse bar 2a, the carriages 5 are moved along the guide 5. In this situation, the movable plates 4a are slidably moved in contact with the transverse bar 2a and the relative welding torches 3 are slidably moved along the edges of the head and tail portions to be joined to carry out the welding.
The present invention achieves the proposed objects, eliminating the drawbacks that have emerged from the known art.
In particular, the integral movement of the welding torches 3 with the respective grounding contacts 4 allows a correct setting of the voltage and current suitable for welding for each welding torch 3 without interferences between the welding torches 3 themselves.
The integral movement of the welding torches 3 with the respective grounding contacts 4 allows a joint between the head portion and the tail portion of two metal sheets to be made by means of more than two welding torches 3, considerably speeding up the cycle times.
The integral movement of the welding torches 3 with the respective grounding contacts 4 avoids interferences between the grounding contacts 4 of the various welding torches 3 so as to obtain an optimal welding seam.
Number | Date | Country | Kind |
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102021000006080 | Mar 2021 | IT | national |