Welding machine

Abstract

A welding machine, preferably of the flash-butt welding type, designed to facilitate the maintenance of the clamping devices (3, 4, 6, 7), such as clamps, of the two longitudinal metal products to be welded. Advantageously, a first structure (2) provided with first clamping devices (3, 4) and a second structure (5) provided with second clamping devices (6, 7) are supported in a first portion (10) of a carriage (1) delimited by a first beam (9) and a second beam (8) of the carriage (1) parallel to the feeding direction (X), while at least one transformer (36) is fixed to the carriage (1) and supported in a second portion (11) of the carriage (1) arranged laterally outside the first portion (10).

Description

Field of the Invention

[0001] The present invention relates to a welding machine, preferably of the flash butt welding type, for longitudinal metal products such as billets, bars or blooms, suitable for welding the heads and tails of two consecutive longitudinal products to each other along a roller table generally arranged upstream of a rolling mill. Background Art

[0002] In rolling mills, especially endless type rolling mills, metal products coming from casting machines or external storage are welded together and then rolled seamlessly.

[0003] The metal products to be welded are typically semi-finished cast products such as, for example, billets, bars or blooms.

[0004] Welding is performed by joining the tail of one product to the head of the next product.

[0005] Welding is achieved with the help of an electric arc generated by a power source connected to the products to be welded. This technique is called flash welding.

[0006] During the welding process, the product must be effectively held in place. For this purpose, a clamping device is provided, which is used to hold the product in place during welding and usually also acts as a conductor for the welding current.

[0007] This clamping device generally includes elements that come into direct contact with the products to be welded, specifically clamps. As welding progresses, the clamps holding the head and tail of the products to be welded are brought together by hydraulic cylinders known as upsetting cylinders. This operation is necessary to connect the ends to be welded, eliminate any inclusions and air bubbles, compensate for material losses in the form of burrs caused by melting, and ensure effective adhesion between the two welded parts (this forms the joint known as the weld joint).

[0008] A known type of flash butt welding machine generally comprises two structures, each provided with a pair of clamps, these structures being substantially parallel to one another and inclined at an angle of approximately 45° relative to a plane defined by a carriage supporting the machine. This inclination allows the contact force of the clamps with the product to be applied evenly on the sides of the product, thus allowing optimal holding and centering of the product.

[0009] Unfortunately, the transformer, which is provided with conductors connected to the two structures to supply current to the tail and head of the two products to be welded, is located above the inclined upper surface of the two structures, which makes access to the internal components of the machine and, therefore, maintenance difficult. Even disassembling and removing heavy parts from the machine becomes a difficult operation that must be performed manually by the operator entering the machine under difficult conditions.

[0010] Therefore, there is a need to address at least the above-mentioned disadvantages by creating a welding machine that can provide easy maintenance and can be operated with auxiliary equipment (such as cranes and bridge cranes) to remove heavy objects. SUMMARY OF THE INVENTION

[0012] One of the purposes of the present invention is to create a welding machine, preferably of the flash butt welding type, which allows easy access to the internal parts of the fixture holding structure, allows quick maintenance and cleaning, and allows the possibility of operating with common auxiliary equipment (such as cranes and bridge cranes) to remove heavy parts.

[0013] Another object of the present invention is to create a welding machine that is simple from a structural point of view and that still allows to perform the movements required by known welding machines.

[0014] Yet another object of the present invention is to create a welding machine that improves operator safety.

[0015] The present invention achieves at least one of the above and other objects evident in view of the present description by means of a welding machine, preferably of the flash butt welding type, for welding together the tail of a first longitudinal metal product and the head of a second longitudinal metal product along the feed direction X of said longitudinal metal products, the machine comprising a carriage suitable for sliding along the feed direction X, said carriage supporting:

[0016] - a first structure connected to the bracket;

[0017] - a first clamping device, which is arranged on the first structure to clamp the tail of the first metal product or the head of the second metal product;

[0018] a second structure which slides parallel to the feed direction relative to both the first structure and the carriage;

[0019] - a second clamping device, which is arranged on the second structure to clamp the head of the second metal product or the tail of the first metal product;

[0020] - at least one transformer provided with conductors connected to the first clamping means and the second clamping means, respectively, to supply current to the tail portion and the head portion;

[0021] Therein, the first and second structures are supported in a first section of the carrier, which is delimited by first and second beams of the carrier, the first and second beams being parallel to the feed direction X, while at least one transformer is fixed to the carrier and thereby supported in a second section of the carrier, which is arranged laterally outside the first section.

[0022] Advantageously, the transformer is integrally fixed to the bracket and is not located above the two structures, facilitating access to and maintenance of the machine's internal components from above. Disassembling and removing heavy parts and components from the machine also becomes an extremely simple operation that can be performed using common auxiliary equipment, such as cranes and overhead cranes. Advantageously, machine components requiring maintenance are accessible and can be lifted from above.

[0023] Preferably, the conductors connecting the transformer to the first and second clamping devices, respectively, pass underneath the first and second structures, respectively, so that the space between the first and second clamping devices is freely accessible from below in the absence of longitudinal metal products to be welded.

[0024] Further advantages are represented by a variant in which the second structure can slide parallel to the feed direction and relative to both the first structure and the carriage on two beams that are part of the carriage itself and delimit said first section of the carriage, or the second structure can slide on two further beams different from those of the carriage, which are part of a lifting system suitable for lifting the first and second structures together relative to the carriage by means of a rotation through a predetermined angle along a plane transverse to said feed direction.

[0025] In addition, the configuration of the welding machine according to the present invention allows the production of a drainage floor below the welding machine, the distance between the drainage floor and the product passing line can be less than 1.5 meters, preferably less than 1 meter. This means that a foundation is laid for realizing a production line with lower costs.

[0026] Further features and advantages of the present invention will become more apparent from the detailed description of a preferred but non-exclusive embodiment.

[0027] The dependent claims describe particular embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The invention is described with reference to the accompanying drawings, provided by way of non-limiting example, in which:

[0030] Figure 1 is a perspective view of a first embodiment of a welding machine according to the present invention;

[0031] Figure 2 yes Figure 1 A top view of the machine in FIG;

[0032] Figure 2a yes Figure 1 A top view of a variation of the machine in FIG.

[0033] Figure 3 yes Figure 1 Bottom view of the machine;

[0034] Figure 4 It is along Figure 2 A cross-sectional view of the machine taken along plane AA;

[0035] Figure 5 It is along Figure 2 A cross-sectional view of the machine taken through plane BB;

[0036] Figure 6 yes Figure 1 A first side view of the machine in FIG.

[0037] Figure 7 is a perspective view of a second embodiment of a welding machine according to the present invention;

[0038] Figure 8 is a top view of another variant of the welding machine according to the present invention;

[0039] Figure 9 yes Figure 8 A perspective bottom view of the other variant of the invention.

[0040] The same reference numerals and letters in the drawings indicate the same elements or components.

[0041] Description of Exemplary Embodiments of the Invention

[0042] Some examples of the flash butt welding type welding machine according to the present invention are explained with reference to the accompanying drawings.

[0043] In all embodiments of the invention, a welding machine suitable for welding the tail of a first longitudinal metal product to the head of a second longitudinal metal product along a feed direction X of said longitudinal metal products comprises a carriage 1 suitable for sliding on at least two sliding guides 20, 30 along said feed direction X over a roller table (not shown) on which the longitudinal metal product, such as a blank, a billet or a bar, advances.

[0044] Bracket 1 supports:

[0045] - a first structure 2 connected to the bracket 1;

[0046] - first clamping devices 3, 4, which are arranged on the first structure 2 and are used to clamp the tail of the first metal product or the head of the second metal product;

[0047] - a second structure 5 which slides parallel to the feed direction X relative to both the first structure 2 and the carriage 1 ;

[0048] - second clamping devices 6, 7, which are arranged on the second structure 5 and are used to clamp the head of the second metal product or the tail of the first metal product;

[0049] - at least one transformer 36 provided with conductors 37, 38, 39, 40 connected respectively to the first clamping means 3, 4 and to the second clamping means 6, 7, to supply electric current to the tail and to the head.

[0050] exist Figures 1-6 In the first embodiment shown, the first structure 2 defines a longitudinal axis Z ( ) inclined at an acute angle (preferably between 30° and 70°, for example 45°) relative to the horizontal plane. Figure 1 The second structure 5 defines a line parallel to the longitudinal axis Z ( Figure 1 )' of its own longitudinal axis Z', the second structure 5 is arranged substantially parallel to the first structure 2 and is spaced apart from the first structure 2 along the feed direction X of the product to be welded.

[0051] In a variant (not shown), instead, the first structure 2 and the second structure 5 , which are substantially parallel to each other, define respective longitudinal axes arranged substantially horizontally.

[0052] At least one infeed guide and at least one outfeed guide are optionally provided for feeding metal products to and from the welding machine, each guide being constrained to a respective structure 2 , 5 along the feed axis X. Alternatively, the guides may be part of the carriage 1 .

[0053] Preferably, the first clamping devices 3, 4 and the second clamping devices 6, 7 can be respectively provided on the first structure 2 and the second structure 5 by means of corresponding moving systems 41, 42; 43, 44 ( Figure 2 and Figure 3 ) is adjusted in position. For example, such a movement system comprises a hydraulic cylinder or a jack, or an electric actuator or a mechanical moving device (such as a cam or an eccentric device).

[0054] In particular, the first clamping means 3, 4 of the first structure 2 comprises a respective upper clamp 3 and a respective lower clamp 4. Each clamp 3, 4 can be moved by a respective movement system 41, 42 ( Figure 2 and Figure 3 ) moves along the Z axis.

[0055] The second clamping means 6, 7 of the second structure 5 comprises a corresponding upper clamp 6 and a corresponding lower clamp 7. In addition, each clamp 6, 7 can be moved by a corresponding moving system 43, 44 ( Figure 2 and Figure 3 ) moves along the Z' axis.

[0056] The movement and therefore adjustability of all the clamps of the clamping device advantageously eliminates the need to have to tilt or rotate the two structures 2, 5 slightly to prevent the metal product (eg blank) from sliding on the lower clamp, which is fixed in prior art machines.

[0057] Advantageously, the first and second structures 2, 5 are supported and possibly also contained in a first section 10 of the carriage 1, which is delimited by first and second beams 9, 8 of the carriage, which are parallel to each other and to the feed direction X, while at least one transformer 36 is fixed to the carriage 1 and is completely supported and possibly also completely contained in a second section 11 of the carriage 1, which is arranged laterally outside the first section 10. The transformer 36 can be a single transformer. Alternatively, a group of transformers can be provided, which together supply power to the clamps 3, 4, 6, 7 via conductors 37, 38, 39, 40.

[0058] Alternatively, in a variant of this first embodiment (not shown), two or more transformers are provided, fixed to the bracket 1 and fully supported and possibly also fully contained in the second section 11 .

[0059] In a first embodiment of the invention, the second section 11 of the carriage 1 can be defined by the second beam 8 and the third beam 17 of the carriage 1, the third beam 17 preferably being parallel to the second beam 8. The first beam 9 and the third beam 17 are the perimeter beams of the carriage 1, while the second beam 8 is the intermediate beam. At least two further perimeter beams are provided transversely (preferably perpendicularly) to the beams 9, 8, 17 so as to define the perimeter of the carriage 1 together with the beams 9 and 17.

[0060] The carriage 1 is preferably arranged on two sliding guides 20, 30 fixed directly or by means of a frame to the floor below the welding machine, said sliding guides being parallel to each other and to the axis X. Figure 2 In a variant of , the first beam 9 and the second beam 8 of the carriage 1 are positioned at the respective sliding guides 20, 30. In this case, the first section 10 of the carriage 1 is located at and above the area delimited by the sliding guides 20, 30. Alternatively, in Figure 2aIn a variant of , the second beam 8 is positioned at the sliding guide 30 and the third beam 17 is positioned at the sliding guide 20. In this case, the second section 11 of the carriage 1 is located at and above the area bounded by the sliding guides 20, 30.

[0061] Alternatively, the beams 9 , 8 or the beams 8 , 17 can also be offset relative to the sliding guides 20 , 30 .

[0062] Optionally, conductors 37, 38 and conductors 39, 40 connecting the transformer 36 to the first clamping devices 3, 4 and the second clamping devices 6, 7, respectively, pass under the first structure 2 and the second structure 5, respectively, so that the space between the first clamping devices 3, 4 and the space between the second clamping devices 6, 7 are freely accessible from below in the absence of longitudinal metal products to be welded.

[0063] Preferably, if Figure 2 、 Figure 3 and Figure 5 、 Figure 6 As better shown in FIG, the upper conductors 37, 39 exiting the transformer 36 can advance parallel to each other by passing a small extension under the first structure 2 and the second structure 5, respectively, until they reach the vicinity of the respective upper clamps 3 and 6. Preferably, the current flow pattern is such that the circuit is closed between the upper clamps 3 and 6 of the two structures.

[0064] like Figure 3 、 Figure 5 and Figure 6 As best shown in FIG, lower conductors 38, 40 exiting transformer 36 can advance parallel to each other for a first run beneath first and second structures 2, 5, respectively. Before reaching upper clamps 3, 6, lower conductors 38, 40 can deviate by moving away from each other for a second run, then advance parallel to each other for a third run, and again approach each other near the feet of first and second structures 2, 5, via a fourth run. The fifth and final run of conductors 38, 40 ultimately reaches the vicinity of respective lower clamps 4 and 7. Preferably, the current flow pattern is such that the circuit is closed between lower clamps 4 and 7 of the two structures. Therefore, the runs of lower conductors 38, 40 are configured so as to be fully accessible from below the area encompassing clamps 3, 4 and 6, 7.

[0065] Advantageously, since the transformer 36 is not arranged above the structures 2 and 5, the space between the first clamping devices 3, 4 and the space between the second clamping devices 6, 7 are freely accessible from above and below in the absence of longitudinal metal products to be welded.

[0066] In a variant (not shown) in which two or more transformers (e.g., only two transformers arranged one above the other) are included in the second section 11 of the carrier 1, the first upper and lower conductors exit the respective transformers and reach the clamps 3 and 4, respectively, of the first structure 2, while the second upper and second lower conductors exit the respective transformers and reach the clamps 6 and 7, respectively, of the second structure 5. Again, in this case, the current flow pattern is such that two circuits are closed, respectively, between the upper clamps 3 and 6, and between the lower clamps 4 and 7.

[0067] However, in all variants, the conductors may be arranged in configurations different from those described above while maintaining the space between the first clamping devices 3, 4 and the space between the second clamping devices 6, 7 freely accessible from below in the absence of longitudinal metal products to be welded.

[0068] Preferably, the first structure 2 and the second structure 5 , in addition to being arranged substantially parallel to each other, are also arranged transversely to (preferably orthogonally to) the first beam 9 and the second beam 8 .

[0069] In particular, Figure 1-Figure 7 In the first variant shown, the first beam 9 and the second beam 8 have a respective first portion, which is close to the first structure 2 and to which the first structure 2 is integrally fixed, and a respective second portion, which is remote from the first structure 2 and to which the second structure 5 is slidingly connected.

[0070] In a variant of the present invention, the second portion of the first beam 9 is inserted into the first through hole 21 of the second structure 5 ( Figure 1 and Figure 5 ), the first through hole 21 is internally provided with a first roller or pad 12 for the second structure 5 to slide on the first beam 9; and the second portion of the second beam 8 is inserted into the second through hole 22 of the second structure 5 ( Figure 5 ), the second through hole 22 is internally provided with a second roller or pad 13 for the second structure 5 to slide on the second beam 8.

[0071] Preferably, the second portion of the first beam 9 and the first through hole 21 both have a quadrilateral cross section, and the first through hole 21 is only provided on two mutually opposite inner sides ( Figure 5 ) are provided with first rollers or pads 12 (preferably above and below the first beam 9). Optionally, a pair of first rollers 12 ( Figure 4 ). In addition, the second portion of the second beam 8 and the second through hole 22 may have a quadrilateral cross section, and the second through hole 22 is provided with at least one second roller or pad 13 on at least three inner sides thereof. In particular, Figure 5In a variant of the present invention, four rollers or pads 13 are provided, one on each inner side of the through-hole 22. Alternatively, in a variant (not shown), only three rollers or pads 13 are provided, one upper roller being located on the upper inner side of the through-hole 22, and therefore above the beam 8, while the other two rollers are located to the sides of the beam 8. Thus, there are no lower rollers or pads, the presence of which would result in a better alignment.

[0072] In a particular variant, the first rollers 12 are idle, housed in corresponding seats obtained in the second structure 5 and projecting into the first through-holes 21 to come into contact with the mutually opposite surfaces of the first beam 9; and the second rollers 13 are also idle, housed in corresponding seats obtained in the second structure 5 and projecting into the second through-holes 22 to come into contact with the corresponding lateral surfaces of the second beam 8.

[0073] Instead of the quadrilateral cross-sections of the beams 9 , 8 and the corresponding through-holes 21 , 22 , the second portion of the first beam 9 and the first through-hole 21 both have circular cross-sections, and the first through-hole 21 is provided with a first pad 12 ; and the second portion of the second beam 8 and the second through-hole 22 both have circular cross-sections, and the second through-hole 22 is provided with a second pad 13 .

[0074] Furthermore, the sliding of the second structure 5 on the beams 9 and 8 can alternatively be achieved by reversing the configuration of the rollers or pads between the two through-holes 21, 22. Thus, the first through-hole 21 of the second structure 5 can be internally provided with at least three rollers or pads 13 for the second structure 5 to slide on the first beam 9; and the second through-hole 22 of the second structure 5 can be internally provided with second rollers or pads 12 only on two inner sides opposite to each other for the second structure 5 to slide on the second beam 8.

[0075] If it is necessary or desired to slightly move the two structures 2, 5 to prevent the metal product (e.g. blank) from slipping on the lower clamp, Figure 8 and Figure 9 The second variant shown in FIG provides that the first and second structures 2, 5 are supported in the first section 10 of the carriage 1 not by means of beams 8 and 9 of the carriage itself, but by means of a lifting system adapted to lift the first and second structures 2, 5 together relative to the carriage 1 by means of a rotation along a plane transverse to the feed direction X. This rotation may lie within a range of 1° to 25°, for example 1° to 15°. This lifting system thus makes it possible to move the structures 2, 5 relative to the product to be welded.

[0076] The lifting system, preferably a linkage type lifting system, comprises:

[0077] a first axis of rotation 19 parallel to and close to the first beam 9 of the carriage and constrained to the carriage so as to rotate about its axis, for example being pivotally connected at its ends to a peripheral beam of the carriage transverse to the feed direction X;

[0078] a second axis of rotation 18 parallel to and close to the second beam 8 of the carriage and constrained to the carriage so as to rotate about its axis, for example being pivotally connected at its ends to said transverse peripheral beam;

[0079] a further first beam 29 , distinct from the bracket, placed parallel to, close to and possibly above the first axis of rotation 19 and the first beam 9 ;

[0080] a second additional beam 28 , distinct from the bracket, placed parallel to, close to and possibly above the second axis of rotation 18 and the second beam 8 ;

[0081] at least one first lever 45 connecting directly or indirectly the first axis of rotation 19 to said further first beam 29 ;

[0082] at least one second lever 46 directly or indirectly connecting the second axis of rotation 18 to said further second beam 28 ;

[0083] Preferably, at least one connecting rod or tie rod 48 connecting the first rotation axis 19 and the second rotation axis 18 .

[0084] In a variant, the longitudinal axis of the first rotational axis 19 and the longitudinal axis of the second rotational axis 18 are parallel and arranged in a first horizontal plane. The longitudinal axis of the first additional beam 29 and the longitudinal axis of the second additional beam 28 are also parallel and arranged in a second horizontal plane above the first horizontal plane. The relative position between each rotational axis 18, 19 and the corresponding additional beam 28, 29 is such that the levers 45, 46 are always tilted at an acute, non-zero angle relative to the vertical.

[0085] Preferably, the following is provided ( Figure 8 ):

[0086] two first levers 45 , each of which is fixed at its first end to a respective end of the first rotation axis 19 and is connected at its second end directly or indirectly to a respective end of the further first beam 29 ;

[0087] two second levers 46 , each second lever 46 being fixed at its first end to a respective end of the second rotation axis 18 and connected at its second end directly or indirectly to a respective end of the further second beam 28 .

[0088] Further first beams 29 and further second beams 28 support both the first structure 2 and the second structure 5 , the first structure 2 and the second structure 5 being arranged substantially parallel to each other and transversely, preferably orthogonally, to the further first beams 29 and the further second beams 28 .

[0089] At least one actuator 47 is provided, which is adapted to rotate the first rotation axis 19 and / or the second rotation axis 18 by a predetermined angle so that the first structure 2 and the second structure 5 can be lifted together relative to the bracket 1 .

[0090] Preferably, Figure 8-Figure 9 In a variant, only one actuator 47 is provided, for example fixed to the beam 8 of the carriage 1 , which acts on a further lever 49 of the second axis of rotation 18 .

[0091] From the hold position ( Figure 9 ), actuator 47 pushes lever 49 downward, causing rotation shaft 18 to rotate about its own axis by a predetermined angle and transmitting the upward rotation to further beam 28 via lever 46. Because further beam 28 and further beam 29 together laterally support structures 2 and 5, the upward rotation is also transmitted to further beam 29, and thus rotation shaft 19 also rotates about its axis accordingly. Preferably, connecting rod or tie rod 48 can synchronize the rotation of the two rotation shafts 18 and 19, thereby facilitating lifting through the rotation of further beams 28 and 29.

[0092] In particular, the further first beam 29 and the further second beam 28 have a respective first portion close to the first structure 2 and to which the first structure 2 is integrally fixed, and a respective second portion remote from the first structure 2 and to which the second structure 5 is slidably connected.

[0093] In a variant of the invention, the second portion of the additional first beam 29 is inserted into the first through-hole 21 of the second structure 5, which first through-hole 21 is internally provided with a first roller or pad for the second structure 5 to slide on the additional first beam 29; and the second portion of the additional second beam 28 is inserted into the second through-hole 22 of the second structure 5, which second through-hole 22 is internally provided with a second roller or pad for the second structure 5 to slide on the additional second beam 28.

[0094] Preferably, the second portion of the further first beam 29 and the first through hole 21 both have a quadrilateral cross section, and the first through hole 21 is provided with first rollers or pads (in a manner similar to Figure 5 Optionally, a pair of first rollers are provided on each of the two inner sides (in a manner similar to Figure 4Likewise, the second portion of the further second beam 28 and the second through hole 22 may have a quadrilateral cross section, and the second through hole 22 may be provided with at least one second roller or pad on at least three inner sides thereof. In particular, in a variant (in a manner similar to Figure 5 In a manner similar to that described above, four second rollers or pads are provided, one on each inner side of the through-hole 22. In another variant, only three second rollers or pads are provided instead, one upper roller being located on the upper inner side of the through-hole 22, therefore above the beam 28, and two further rollers being located to the sides of the beam 28. Thus, there are no lower rollers or pads, the presence of which would result in a better alignment.

[0095] In a particular variant, the first rollers are idle, housed in corresponding seats obtained in the second structure 5 and projecting into the first through-holes 21 to come into contact with the mutually opposite surfaces of the further first beam 29; and the second rollers 13 are also idle, housed in corresponding seats in the second structure 5 and projecting into the second through-holes 22 to come into contact with the corresponding side surfaces of the further second beam 28.

[0096] Instead of the quadrilateral cross-sections of the further beams 29 , 28 and the corresponding through-holes 21 , 22 , the second portion of the further first beam 29 and the first through-hole 21 both have circular cross-sections, and the first through-hole 21 is provided with a first pad; whereas the second portion of the further second beam 28 and the second through-hole 22 both have circular cross-sections, and the second through-hole 22 is provided with a second pad.

[0097] Furthermore, the sliding of the second structure 5 on the additional beam 29 and the additional beam 28 can alternatively be achieved by reversing the configuration of the rollers or pads between the two through-holes 21 and 22. Thus, the first through-hole 21 of the second structure 5 can be internally provided with at least three second rollers or pads for the second structure 5 to slide on the additional first beam 29; and the second through-hole 22 of the second structure 5 can be internally provided with first rollers or pads only on two inner sides opposite to each other for the second structure 5 to slide on the additional second beam 28.

[0098] A further advantage of the present invention may be to provide the carriage 1 with at least one motor 31 connected to a gear 32 adapted to engage a rack 33 ( Figure 6 ).

[0099] In the welding machine of the invention, adjustment means 23, 24 may be provided for moving the second structure 5 towards or away from the first structure 2 along said feed direction X. The approach is performed in particular when welding two products by flash butt welding.

[0100] Optionally, the adjusting device is an upsetting cylinder 23, 24, preferably two in number.

[0101] The upsetting cylinders 23 , 24 are pivotally connected at their first end to the first structure 2 and at their second end to the second structure 5 by means of respective pins.

[0102] exist Figure 5 In the variant shown, the first upsetting cylinder 23 is arranged below and behind the first and second structures 2, 5. In contrast, the second upsetting cylinder 24 is arranged substantially at the foot of the first and second structures 2, 5. Preferably, the two upsetting cylinders 23, 24 are arranged along the same substantially horizontal plane.

[0103] The second embodiment of the welding machine of the present invention is Figure 7 As shown. The description provided above for the first embodiment also applies to the second embodiment. The difference between the second embodiment and the first embodiment is that the second embodiment provides:

[0104] a first transformer 36 fixed to the carriage 1 and fully supported and possibly also fully contained in the second sector 11 of the carriage 1 , arranged laterally outside the first sector 10 defined by the first beam 9 and the second beam 8 ;

[0105] and a second transformer 36 ′ fixed to the carriage 1 and supported in, and possibly also contained in, a third sector 11 ′ of the carriage 1 , arranged laterally outside the first sector 10 opposite the second sector 11 .

[0106] A first section 10 of the carriage 1 is defined by a first beam 9 and a second beam 8 of the carriage 1 which are parallel to the feed direction X.

[0107] The second section 11 of the carriage 1 is defined by said second beam 8 and a third beam 17 of the carriage 1 , the third beam 7 preferably being parallel to the second beam 8 .

[0108] The third section 11 ′ of the carriage 1 is defined by said first beam 9 and a fourth beam 7 ′, the fourth beam 7 ′ preferably being parallel to the first beam 9 .

[0109] The fourth beam 7 ′ and the third beam 17 are peripheral beams of the carriage 1 , whereas the first beam 9 and the second beam 8 are intermediate beams of the carriage.

[0110] At least two further perimeter beams are provided transversely (preferably perpendicularly) to the beams 7 ′, 9 , 8 , 17 to define, together with the beams 7 ′, 17 , the perimeter of the carriage 1 .

[0111] In this second embodiment, the upper conductor 37 and the lower conductor 39 exit the first transformer 36 and reach the upper clamp 3 and the upper clamp 6 of the structure 2 and the structure 5, respectively; while the upper conductor 40 and the lower conductor 38 exit the second transformer 36' and reach the lower clamp 4 and the lower clamp 7 of the structure 2 and the structure 5, respectively. In this case as well, the current flow pattern is such that two circuits are closed between the upper clamp 3 and the upper clamp 6 and between the lower clamp 4 and the lower clamp 7, respectively.

[0112] A third embodiment of the welding machine of the present invention (not shown) differs from the aforementioned second embodiment in that the third embodiment provides:

[0113] - the first structure 2 defines a longitudinal axis Z inclined at an acute angle relative to the horizontal, preferably between 30° and 70°, for example 45°;

[0114] - and the second structure 5 defines its longitudinal axis Z' which is oblique relative to the longitudinal axis Z and inclined relative to the aforementioned horizontal plane at an obtuse angle preferably comprised between 120° and 160°, for example 135°.

[0115] The second structure 5 is arranged substantially parallel to the first structure 2 and is spaced apart from the first structure 2 along the feeding direction X of the products to be welded.

Claims

1. A welding machine for welding a tail portion of a first longitudinal metal product to a head portion of a second longitudinal metal product along a feed direction (X) of the first and second longitudinal metal products, the machine comprising a carriage (1) adapted to slide along the feed direction (X), the carriage (1) supporting: - a first structure (2) connected to said bracket (1); - first clamping means (3, 4) arranged on the first structure (2) to clamp the tail of the first longitudinal metal product or the head of the second longitudinal metal product; - a second structure (5) suitable for sliding relative to both the first structure (2) and the carriage (1) parallel to the feeding direction; - second clamping means (6, 7) provided on the second structure (5) for clamping the head of the second longitudinal metal product or the tail of the first longitudinal metal product; - at least one transformer (36) provided with conductors (37, 38, 39, 40) connected to the first clamping means (3, 4) and the second clamping means (6, 7), respectively, to supply current to the tail and the head; in, The first structure (2) and the second structure (5) are supported in a first section (10) of the bracket (1), the first section (10) being delimited by a first beam (9) and a second beam (8) of the bracket (1), the first beam (9) and the second beam (8) being parallel to the supply direction (X), while the at least one transformer (36) is fixed to the bracket (1) and supported in a second section (11) of the bracket (1), the second section (11) being arranged laterally outside the first section (10).

2. The machine according to claim 1, wherein The machine is a welding machine of the flash welding type.

3. A machine according to claim 1 or 2, wherein only one transformer (36) or two or more transformers are provided which are completely supported in the second section (11) of the bracket (1); or wherein at least two transformers are provided, a first transformer (36) of the two transformers being fixed to the bracket (1) and supported in the second section (11) of the bracket (1), and a second transformer (36') of the two transformers being fixed to the bracket (1) and supported in a third section (11') of the bracket (1), the third section (11') being arranged laterally outside the first section (10) on a side opposite to the second section (11).

4. Machine according to claim 1, wherein said second sector (11) is delimited by said second beam (8) and a third beam of said carriage (1).

5. The machine according to claim 4, wherein The third beam is parallel to the feed direction (X).

6. A machine according to claim 4 or 5, wherein In the case where only one transformer (36) or two transformers are fully supported in the second section (11), the first beam (9) and the third beam are peripheral beams of the bracket (1), while the second beam (8) is an intermediate beam; or wherein, in the case where the first transformer (36) is supported in the second section (11) and the second transformer (36') is supported in the third section (11') of the bracket (1), the third section (11') is delimited by the first beam (9) and the fourth beam (7'), the third section (11') being arranged laterally outside the first section (10) on the side opposite to the second section (11), the fourth beam (7') and the third beam are peripheral beams of the bracket (1), while the first beam (9) and the second beam (8) are intermediate beams of the bracket.

7. Machine according to any of claims 1 to 6, wherein said conductors (37, 38, 39, 40) connect said at least one transformer (36) to said first clamping means (3, 4) and to said second clamping means (6, 7), respectively, said conductors (37, 38, 39, 40) passing under said first structure (2) and under said second structure (5), respectively, such that the space between said first clamping means (3, 4) and the space between said second clamping means (6, 7) are freely accessible from below in the absence of longitudinal metal products to be welded.

8. The machine according to any one of claims 1 to 7, wherein: In the absence of longitudinal metal products to be welded, the space between the first clamping devices (3, 4) and the space between the second clamping devices (6, 7) are freely accessible both from above and from below.

9. The machine according to claim 1, wherein the first structure (2) and the second structure (5) are arranged substantially parallel to each other and transverse to the first beam (9) and the second beam (8).

10. The machine according to claim 9, wherein The first structure (2) and the second structure (5) are arranged orthogonally to the first beam (9) and the second beam (8).

11. A machine according to claim 9 or 10, wherein the first structure (2) and the second structure (5) define respective longitudinal axes (Z, Z') inclined at an acute angle between 30° and 70° relative to a horizontal plane; or wherein the first structure (2) and the second structure (5) define respective longitudinal axes arranged substantially horizontally.

12. The machine according to any one of claims 1 and 9-11, wherein The first structure (2) and the second structure (5) are supported in the first section (10) of the carriage (1) by means of a lifting system, which is suitable for lifting the first structure (2) and the second structure (5) together relative to the carriage (1) by means of rotation along a plane transverse to the feed direction (X).

13. The machine of claim 12, wherein the lifting system is of the linkage type.

14. The machine according to claim 13, wherein The lifting system comprises: - a first rotation axis (19) parallel to and close to the first beam (9) of the carriage and constrained to the carriage to rotate about the axis of the first rotation axis (19); - a second rotation axis (18) parallel to and close to the second beam (8) of the carriage and constrained to the carriage to rotate about the axis of the second rotation axis (18); - a further first beam (29), different from the bracket, parallel to, close to and above the first rotation axis (19) and the first beam (9); - a second additional beam (28), distinct from the bracket, parallel to, adjacent to, and above the second rotation axis (18) and the second beam (8); wherein the further first beam (29) and the further second beam (28) support both the first structure (2) and the second structure (5), the first structure (2) and the second structure (5) being arranged substantially parallel to each other and transverse to the further first beam (29) and the further second beam (28); wherein the first rotation axis (19) is directly or indirectly connected to the further first beam (29) by means of at least one first lever (45); wherein the second rotation axis (18) is connected directly or indirectly to the further second beam (28) by means of at least one second lever (46); And at least one actuator (47) is provided, which is suitable for rotating the first rotation axis (19) and / or the second rotation axis (18) by a predetermined angle so that the first structure (2) and the second structure (5) can be lifted together relative to the bracket (1).

15. The machine according to claim 14, wherein The first structure (2) and the second structure (5) are arranged orthogonally to the further first beam (29) and the further second beam (28).

16. Machine according to claim 14 or 15, wherein the further first beam (29) and the further second beam (28) have a respective first portion and a respective second portion, wherein the first portion is close to the first structure (2) and the first structure (2) is integrally fixed to the first portion, and the second portion is remote from the first structure (2) and the second structure (5) is slidingly connected to the second portion.

17. The machine according to any one of claims 1 and 9-11, wherein The first structure (2) and the second structure (5) are supported in the first section (10) of the bracket (1) by means of the first beam (9) and the second beam (8) of the bracket (1), the first beam (9) and the second beam (8) having a corresponding first portion and a corresponding second portion, the first portion being close to the first structure (2) and the first structure (2) being integrally fixed to the first portion, and the second portion being remote from the first structure (2) and the second structure (5) being slidably connected to the second portion.

18. The machine according to claim 17, wherein The first structure (2) and the second structure (5) are directly supported in the first section (10) of the bracket (1) by means of the first beam (9) and the second beam (8) of the bracket (1).

19. The machine of claim 16, wherein: The second portion of the additional first beam (29) or the second portion of the first beam (9) is inserted into a first through hole (21) of the second structure (5), the first through hole (21) being internally provided with a first roller or pad (12) for the second structure (5) to slide on the additional first beam (29) or the first beam (9); and wherein the second portion of the additional second beam (28) or the second portion of the second beam (8) is inserted into a second through hole (22) of the second structure (5), the second through hole (22) being internally provided with a second roller or pad (13) for the second structure (5) to slide on the additional second beam (28) or the second beam (8).

20. The machine of claim 19, wherein: The second portion of the further first beam (29) or the second portion of the first beam (9) and the first through hole (21) both have a quadrilateral cross section, and the first through hole (21) is provided with the first roller or pad (12) only on two opposite inner sides; and the second portion of the further second beam (28) or the second portion of the second beam (8) and the second through hole (22) both have a quadrilateral cross section, and the second through hole (22) is provided with at least a second roller or pad (13) on at least three of its inner sides; Or wherein the second portion of the further first beam (29) or the second portion of the first beam (9) and the first through hole (21) both have a circular cross-section, and the first through hole (21) is provided with the first roller or pad (12); and wherein the second portion of the further second beam (28) or the second portion of the second beam (8) and the second through hole (22) both have a circular cross-section, and the second through hole (22) is provided with the second roller or pad (13).

21. The machine of claim 20, wherein: A pair of first rollers is provided on each of the two opposing inner sides.

22. A machine according to claim 20 or 21, wherein The first roller or pad (12) is idle, housed in a corresponding seat obtained in the second structure (5), and projects into the first through hole (21) to contact mutually opposite surfaces of the further first beam (29) or the first beam (9); and wherein the second roller or pad (13) is idle, housed in a corresponding seat obtained in the second structure (5), and projects into the second through hole (22) to contact corresponding side surfaces of the further second beam (28) or the second beam (8).

23. A machine according to any one of claims 1 to 22, wherein the carriage (1) is suitable for sliding on at least two sliding guides (20, 30) along the feeding direction (X), and is provided with at least one motor (31), the motor (31) being connected to a gear (32), the gear (32) being engaged with a rack (33) provided on at least one of the sliding guides (20, 30).

24. Machine according to any one of claims 1 to 23, wherein adjustment means (23, 24) are provided for moving the second structure (5) towards or away from the first structure (2) in the feeding direction (X).

25. A machine according to any one of claims 1 to 24, wherein the first clamping device (3, 4) and the second clamping device (6, 7) can be adjusted in position by means of corresponding movement systems (41, 42; 43, 44) respectively provided on the first structure (2) and the second structure (5).

26. Machine according to any one of claims 1 to 25, wherein all parts of the machine to be maintained are accessible and can be lifted from above.

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