Plant and process for the production of reinforcement bars for window / door frame profiled elements

Abstract

The plant (1) comprises: holding means (2) adapted to hold at least a first bar and a second bar (4) made of at least one metallic material and extending along relevant longitudinal directions, each provided at its respective ends with a first ending surface (5) and with a second ending surface (6); cutting means (8) adapted to cut the first bar to obtain at least one reinforcement bar which can be inserted within a relevant window / door frame profiled element and a relevant residual bar (9) provided with the second ending surface (6); retaining means (11) adapted to retain the residual bar (9) and the second bar (4) aligned with each other, with the second ending surface (6) of the residual bar (9) facing the first ending surface (5) of the second bar (4); resistance welding means (14) adapted to butt weld the residual bar (9) and the second bar (4) and comprising a pair of electrode assemblies (15), each adapted to contact one respective of either the second bar (4) or the residual bar (9) at the relevant ending surfaces (5, 6) to determine a flow of current; wherein at least one of the electrode assemblies (15) comprises a notched surface (18) provided with one or more sharp projections (19) and adapted to contact the respective bar (4, 9).

Description

[0001] PLANT AND PROCESS FOR THE PRODUCTION OF REINFORCEMENT BARS FOR WINDOW / DOOR FRAME PROFILED ELEMENTS

[0002] Technical Field

[0003] The present invention relates to a plant and a process for the production of reinforcement bars for window / door frame profiled elements.

[0004] Background Art

[0005] In the window / door frame sector, it is common practice to use bars to reinforce plastic window / door frame profiled elements. The reinforcement bars are generally made of metallic material, such as steel or other alloys, and are fitted into the internal cavity of the profiled elements in order to give the final window / door frame greater strength and robustness. The reinforcement bars also serve as supports for the additional mechanical parts necessary for the operation of the window / door frame, such as hinges, handles, locking systems, etc.

[0006] The known production processes and related plants involve cutting metallic bars depending on the length of the profiled element to be reinforced in order to obtain the corresponding reinforcement bar. In particular, metallic bars can be obtained, e.g., by extruding molten metallic material or by bending sheet metal.

[0007] The metallic bars are generally long, for example 6-6.5 meters, and can be cut several times to obtain as many reinforcement bars.

[0008] The reinforcement bars can be inserted directly into the relevant profiled element at the end of each cutting operation, or stored together and installed at a later stage.

[0009] Bar cutting operations inevitably result in the formation of residual end portions that are too short to be used as reinforcement bars.

[0010] These residual bars are therefore discarded and a new metallic bar is cut.

[0011] After machining the first bar, the remaining residual bar must therefore be removed from the production line to make room for a second bar.

[0012] This operation not only interrupts production operations and consequently lengthens the relevant timeline, but also results in the formation of a large amount of waste products, which has significant consequences on the production costs of the reinforcement bars.

[0013] The discarded residual bars are in fact sent for disposal, reducing the amount of material that can actually be used. Furthermore, this drawback requires the purchase of an excess number of metallic bars in order to ensure the production of the required number of reinforcement bars.

[0014] For these reasons, methods are known that involve the recovery of the residual bar by joining the residual bar itself to a subsequent bar to obtain a recovered bar, which is then subjected to cutting operations.

[0015] Document WO2023126746A1 describes a method for recovering residual bars through a resistance butt welding operation of the residual bar to a second bar, carried out by means of the flow of an electric current through the ending surfaces of the bars themselves facing each other. However, this known method is susceptible to improvement.

[0016] In fact, the inevitable exposure of the bars to oxygen in the air leads to the formation of oxide on their surfaces, which is generally less conductive than the corresponding pure metal and does not allow effective flow of current as would be the case with pure metal. Therefore, the method described in WO2023126746A1, although rapid and effective in preventing the formation of excessive weld bead, requires the use of a significantly high electrical current in order to ensure effective welding even of oxidized bars.

[0017] Description of the Invention

[0018] The main aim of the present invention is to devise a plant and a process for the production of reinforcement bars for window / door frame profiled elements that allow ensuring effective joining of the bars and avoiding excessive expenditure of resources.

[0019] A further object of the present invention is to devise a plant and a process for the production of reinforcement bars for window / door frame profiled elements that allow the production and management costs of the production plant to be reduced.

[0020] Yet another object of the present invention is to devise a plant for the production of reinforcement bars for window / door frame profiled elements that is compact and simple to manufacture and use.

[0021] Another object of the present invention is to devise a plant and a process for the production of reinforcement bars for window / door frame profiled elements that allow the aforementioned drawbacks of the prior art to be overcome within the scope of a simple, rational, easy and effective to use as well as affordable solution.

[0022] The aforementioned objects are achieved by the present plant for the production of reinforcement bars for window / door frame profiled elements having the characteristics of claim 1.

[0023] The aforementioned objects are further achieved by the present process for the production of reinforcement bars for window / door frame profiled elements having the characteristics of claim 12.

[0024] Brief Description of the Drawings

[0025] Other characteristics and advantages of the present invention will become more apparent from the description of a preferred, but not exclusive, embodiment of a plant and a process for the production of reinforcement bars for window / door frame profiled elements, illustrated by way of an indicative, yet non-limiting example in the attached drawings, in which:

[0026] Figure 1 is an axonometric view of a plant according to the invention;

[0027] Figure 2 is an axonometric view of a machine provided with the welding means according to the invention; Figures 3-4 are detailed views of the electrode assemblies according to the invention;

[0028] Figure 5 is a schematic representation of the electrode in contact with the metallic bar;

[0029] Figures 6-7 are further detailed views of the electrode assemblies according to the invention. Embodiments of the Invention

[0030] With particular reference to these figures, reference numeral 1 globally denotes a plant for the production of reinforcement bars for window / door frame profiled elements.

[0031] The plant 1 comprises holding means 2 adapted to hold at least a first bar and a second bar 4 made of at least one metallic material.

[0032] The bars are elongated bodies made, e.g., of iron, steel, or other alloys and can be obtained, e.g., by extruding such molten metallic material or by bending metallic sheets.

[0033] In the embodiment shown in the figures, the bars are hollow and have a rectangular crosssection. It cannot, however, be ruled out that the bars may have a different cross-section, e.g., “U”-shaped, “L”-shaped or be of the plate-shaped type. It cannot also be ruled out that the bars may be solid, i.e. , not hollow.

[0034] The bars extend along their relevant longitudinal directions and each is provided with a first ending surface 5 and with a second ending surface 6 substantially perpendicular to the relevant longitudinal direction.

[0035] Specifically, the holding means 2 comprise a holding surface 7 adapted to receive and support the bars arranged substantially side by side and parallel to each other.

[0036] Adequately, the holding means 2 are adapted to hold a plurality of bars; however, for the sake of simplicity, the following disclosure will refer exclusively to a first bar and a second bar 4.

[0037] The plant 1 also comprises cutting means 8 adapted to cut the first bar to obtain at least one reinforcement bar that can be inserted within a relevant window / door frame profiled element and a relevant residual bar 9 provided with the second ending surface 6.

[0038] Depending on the length of the reinforcement bars to be obtained, the first bar can be cut several times to obtain as many reinforcement bars.

[0039] The residual bar 9 corresponds to the end stretch of the first bar, resulting from the cutting operations, which is too short to be used as a reinforcement bar.

[0040] The cutting means 8 comprise a cutting device 10 adapted to cut the bar along a cutting plane transverse to the relevant longitudinal direction.

[0041] In the embodiment shown in the figures, the cutting plane is substantially perpendicular to the longitudinal direction. It cannot, however, be ruled out that the cutting plane may be inclined with respect to the longitudinal direction.

[0042] Still with reference to the embodiment shown in the figures, the cutting device 10 comprises a blade tool. It cannot, however, be ruled out that the cutting device 10 may be of a different type. The plant 1 also comprises retaining means 11 partly defining a substantially horizontal line of work 12 and adapted to retain the residual bar 9 and the second bar 4 aligned with each other on the line of work 12, with the second ending surface 6 of the residual bar 9 facing the first ending surface 5 of the second bar 4.

[0043] In the context of this disclosure, the term “line of work” refers to the set of surfaces on which the bars are placed during the production of the reinforcement bars. In detail, according to the embodiment shown in the figures, the line of work 12 is substantially horizontal and straight.

[0044] The retaining means 11 comprise a pair of retaining assemblies 13, each adapted to retain a respective bar of either the second bar 4 or the residual bar 9.

[0045] The retaining means 11 will be described in greater detail later in this disclosure.

[0046] The plant also comprises resistance welding means 14 adapted to butt weld the residual bar 9 and the second bar 4 by means of the flow of current through the ending surfaces 5, 6 facing each other to obtain a welded bar.

[0047] In this disclosure, the term “butt weld” refers to a type of welding carried out by juxtaposing the ending surfaces 5, 6 of the second bar 4 and of the residual bar 9.

[0048] As is well known to technicians in the field, resistance butt welding is an autogenous pressure welding method wherein the metallic material is heated by electrical resistance, allowing metallic materials to be joined without the use of filler material.

[0049] Filler materials are materials that are heated until they melt and are transferred to the area to be welded. Once solidified, the filler materials serve as a bridge between the welded parts. However, the filler material is not always the same as the metallic parts to be welded and may have different physical and mechanical properties. In addition, welding times using filler materials are generally very long

[0050] Resistance welding allows for the continuity of the reinforcement bar material to be achieved in a very short time, thus making the joint area sufficiently strong and robust and avoiding possible differences in physical-mechanical behavior caused by the use of filler materials.

[0051] The welded bar is therefore formed by the residual bar 9 and by the second bar 4 joined together in a welding area and undergoes a new cut to produce new reinforcement bars. Any new residual bar 9 is in turn welded to a subsequent bar.

[0052] In accordance with the embodiment shown in the figures, the holding means 2, the retaining means 11, the welding means 14 and the cutting means 8 are arranged in succession to define the line of work 12.

[0053] Specifically, the retaining means 11 and the welding means 14 are mounted on board the same machine, indicated in the drawings with reference numeral 3.

[0054] However, it should be noted that the components of this plant 1 can be mounted on respective machines located within the same production plant or even in separate plants. In this case, the cutting and welding operations can also be carried out at different times and not necessarily during the same production cycle. In other words, it cannot be ruled out that the cutting means 8 and the welding means 14 may be mounted on board separate machines, not necessarily located in succession with each other, with one machine provided with the cutting means 8 and one machine provided with the welding means 14.

[0055] The plant 1 also usefully comprises positioning means 16 adapted to position each of the bars with respect to the cutting means 8 and to the welding means 14.

[0056] The positioning means 16 are adapted to move each of the bars along a direction of forward movement D along which the line of work 12 extends.

[0057] More specifically, the positioning means 16 determine the forward movement of the first bar with respect to the cutting means 8 by a distance corresponding to the length of the reinforcement bar to be produced.

[0058] The positioning means 16 comprise at least one pusher body 17 adapted to abut against the second ending surface 6 of the first bar.

[0059] The pusher body 17 can be moved, in a known manner, sliding along the direction of forward movement D to push the first bar from the operating station towards the cutting station.

[0060] The positioning means 16 then determine the forward movement of the second bar 4 with respect to the welding means 14 to align it with the residual bar 9 and to allow it to be retained by the retaining means 11.

[0061] The welding means 14 comprise a pair of electrode assemblies 15, each adapted to contact a respective one of either the second bar 4 or the residual bar 9 at their relevant ending surfaces 5, 6 to determine the flow of current.

[0062] Specifically, one of the electrode assemblies 15 is applicable to the residual bar 9 while the other of the electrode assemblies 15 is applicable to the second bar 4.

[0063] The welding means 14 also comprise a transformer assembly, not shown in detail in the figures, adapted to modulate the electrical voltage coming from the electrical power source.

[0064] According to the invention, at least one of the electrode assemblies 15 comprises a notched surface 18 provided with one or more sharp projections 19 and adapted to contact the respective bar 4, 9.

[0065] The notched surface 18 allows the electrode assembly 15 to overcome any layer L of metal oxide that may be present on the bars 4, 9 and allows effective conduction of the electric current. As a result, even in the presence of a layer L of metal oxide completely covering the bar 4, 9, the welding means 14 are still able to ensure effective welding, thus concentrating the flow of current and electrical power where it is actually needed, i.e., between the ending surfaces 5, 6, thus avoiding unnecessary waste of electrical energy.

[0066] Advantageously, the notched surface 18 comprises a plurality of sharp projections 19, which allow for a large contact surface and optimal transfer of electrical current from the electrode assembly 15 to the bar 4, 9.

[0067] In accordance with the embodiment shown in the figures, each of the sharp projections 19 extends along a substantially straight direction of development.

[0068] In practice, each sharp projection 19 has a surface intended to come into contact with the bar 4, 9, which is substantially linear and straight.

[0069] The sharp projections 19 are also substantially parallel to each other.

[0070] It cannot, however, be ruled out that the sharp projections 19 may have a different shape. For example, each sharp projection 1 may have a surface intended to come into contact with the bar 4, 9 that is substantially point-like. This solution can be achieved by means of conical or pyramidal projections.

[0071] According to a preferred embodiment, the distance S between the base of the sharp projections 19 and the respective ridge is of between 0.01 and 3 mm, preferably of between 1 mm and 2 mm and even better of between 1.4 mm and 1.6 mm.

[0072] In actual facts, the sharp projections 19 are cantilevered from an ideal base plane B of the notched surface 18 by a value equal to the distance S (Figure 5).

[0073] Usefully, each of the electrode assemblies 15 comprises at least one electrode 20 defining the notched surface 18 and movable along at least one direction of work W between a home position, wherein they are moved away from the respective bars 4, 9, and a position of work, wherein they are brought closer to the respective bars 4, 9, with the notched surface 18 in contact with a face of the respective bar 4, 9, and result in the flow of current.

[0074] The electrode 20 consists of a body made of electrically conductive material and responsible for the actual flow of current. The electrode 20 is connected to the transformer assembly and to the source of electrical energy by means of at least one connecting member 21, also made of electrically conductive material.

[0075] The connecting member 21 is also of the flexible type in order to facilitate the movement of the electrode itself between the home position and the position of work. For example, the connecting member 21 is of the copper braid type.

[0076] The electrode 20 is moved to the position of work when it is necessary to weld the bars 4, 9.

[0077] For this purpose, the electrode assembly 15 comprises a movement system comprising a guiding unit 22 running parallel to the direction of work W and supporting the electrode 20 by sliding and a motorized actuator 23 adapted to move the electrode 20 on the guiding unit 22.

[0078] In accordance with the preferred embodiment, each of the electrode assemblies 15 comprises a pair of electrodes 20, each defining a respective notched surface 18 and adapted to contact a respective face of the respective bar 4, 9, and movable between the home position and the position of work along directions of work W transverse to each other.

[0079] The use of two electrodes 20 allows the surface area adapted to contact the bar 4, 9 to be increased in order to optimize the flow of current.

[0080] Furthermore, the use of two electrodes 20 allows ensuring constant contact with the bars 4, 9, even if the shape of the bars 4, 9 is such that one of the faces is inclined or otherwise difficult to reach by one electrode 20, as the other electrode 20 can still be relied upon.

[0081] Specifically, one of the electrodes 20 can be moved along a substantially horizontal direction of work W, with the respective notched surface 18 arranged substantially vertically, and is adapted to contact a substantially vertical face of the bar 4, 9. The other electrode 20, on the other hand, can be moved along a substantially vertical direction of work W, with the respective notched surface 18 arranged substantially horizontally, and is adapted to contact a substantially horizontal face of the bar 4, 9.

[0082] Advantageously, at least one of the electrode assemblies 15 is associated with one of the retaining assemblies 13.

[0083] The retaining assemblies 13 are configured to retain the bars 4, 9 during the flow of current in order to prevent accidental displacement of the same and consequent welding errors.

[0084] In detail, each of the retaining assemblies 13 comprises at least one abutment plane 24 and at least one clamping body 25 adapted to retain a respective bar 4, 9 against the abutment plane 24. The clamping body 25 is movable along a direction substantially perpendicular to the abutment plane 24 and is configured to abut against a face of the respective bar 4, 9 and to press the latter against the abutment plane 24.

[0085] In accordance with the embodiment shown in the figures, the retaining assemblies 13 comprise a pair of clamping bodies 25.

[0086] Specifically, each of the retaining assemblies 13 comprises a substantially horizontal abutment plane 24, which defines part of the line of work 12, and a substantially vertical abutment plane 24.

[0087] The clamping bodies 25 are movable along directions substantially orthogonal to each other and are configured to abut against respective faces of the bar 4, 9, substantially orthogonal to each other, and to press the bar itself against the respective abutment planes 24.

[0088] Advantageously, at least one of the electrodes 20 coincides with one of the clamping bodies 25. In other words, the flow of current is carried out through a body which, besides having the function of transferring the electric current, also has the function of holding the bar 4, 9 in place. In this way, the machine 3 is simple in construction and operation, has fewer moving parts, and allows for faster operating times. Not least, this solution ensures that the bars 4, 9 are effectively held in place before applying the current, thus preventing accidental displacement during welding. Furthermore, as mentioned above, this expedient allows the layer L of metal oxide that may be present on the bars 4, 9 to be penetrated and the electric current to be conducted effectively, avoiding the need to clean the most oxidized bars beforehand. Embodiments wherein the electrode 20 and the clamping body 25 are made of separate bodies cannot however be ruled out.

[0089] Furthermore, each of the sharp projections 19 develops along a direction of development which is transverse to the line of work 12. In actual facts, the sharp projections 19 are arranged transversely to the longitudinal development of the bars 4, 9. This prevents the bars 4, 9 from moving with respect to the line of work 12 along directions parallel to their longitudinal development, i.e., to the line of work itself.

[0090] Preferably, each of the sharp projections 19 develops along a direction of development which is substantially orthogonal to the line of work 12.

[0091] Advantageously, each of the electrodes 20 coincides with one of the clamping bodies 25. In other words, both electrodes 20 also have a retaining function.

[0092] As a result of the retaining of the bars 4, 9 and of the application of the electrodes 20, the bars 4, 9 are moved close to each other to carry out the welding.

[0093] For this purpose, the welding means 14 comprise a displacement system adapted to mutually move the retaining assemblies 13 between an away position, wherein the ending surfaces 5, 6 are spaced apart from each other, and a close position, wherein the ending surfaces 5, 6 are joined and pressed together.

[0094] Specifically, the retaining assemblies 13 are both movable with respect to a substantially vertical reference plane P.

[0095] The bars 4, 9 are arranged on the retaining means 11 on opposite sides with respect to the reference plane P and the ending surfaces 5, 6 are arranged parallel thereto.

[0096] The displacement system comprises at least one guiding body 26 extending parallel to the direction of forward movement D and supporting the abutment plane 24 of a respective retaining assembly 13 by sliding.

[0097] The displacement system also comprises an actuator, not shown in detail in the figures, adapted to move the retaining assembly 13 on the guiding body 26.

[0098] The actuator allows the position of the retaining assemblies 13 to be adjusted during the joining of the bars 4, 9 as well as the pressure applied hereto during subsequent compression to be adjusted.

[0099] Specifically, the bars 4, 9 are moved close to each other to join the ending surfaces 5, 6, thus causing an electric arc to form.

[0100] As is well known, an electric arc is an electrical discharge that is generated between two metallic parts that are close together and connected to an electrical circuit.

[0101] As the ending surfaces 5 and 6 move close to each other, the electrical circuit tends to close and open repeatedly due to the inevitable mechanical rebounds that are generated. This causes the formation of electric arcs which, in this specific case, are accompanied by high voltages combined with high currents.

[0102] The electric arc is accompanied by the flow of current between the ending surfaces 5, 6, which causes a strong development of heat due to the Joule effect and allows very high temperatures (3,000°C - 4,000°C) to be reached, leading to the softening and possibly melting of the metallic material in a very short time.

[0103] More specifically, the electric arc causes the formation of plasma, which generates heat.

[0104] Advantageously, the current has an intensity of between 1 KA and 20 KA. Preferably, the current has an intensity of between 3 KA and 10 KA.

[0105] This makes it possible to generate a large amount of energy and optimize the welding process, thus speeding up the operating times.

[0106] This phenomenon leads to the softening of the metallic material of the bars 4, 9, which are then compressed together using the displacement system to intimately join the softened metal.

[0107] Subsequently, the cooling of this molten metal generates the welding area that holds the bars 4, 9 together.

[0108] Advantageously, the plant 1 also comprises removal means 28 configured to remove part of the metallic material from at least one of the ending surfaces 5, 6.

[0109] The removal means 28 have the function of removing any metal oxide present on the ending surfaces 5, 6 and of further optimizing the flow of electric current and the formation of the electric arc. In this sense, the removal means 28 contribute to reducing the energy expenditure required for welding the bars 4, 9.

[0110] Preferably, the removal means 28 and the welding means 14 are mounted on board the same machine 3, so that welding can be carried out immediately after the removal of the metallic material. It cannot, however, be ruled out that the removal means 28 and the welding means 14 are mounted on board of separate machines and not necessarily placed in succession with each other and / or in the same production plant.

[0111] Advantageously, the removal means 28 are placed between the two retaining assemblies 13.

[0112] The removal means 28 are configured to remove the metallic material both on the residual bar 9 and on the second bar 4.

[0113] Advantageously, the removal means 28 are configured to remove the metallic material simultaneously on both ending surfaces 5, 6.

[0114] The removal means 28 comprise a milling tool 29 that can be moved along the reference plane P. The milling tool 29 develops longitudinally along an axis of development and can rotate around itself around the axis of development.

[0115] The milling tool 29 develops longitudinally in the reference plane P.

[0116] In other words, the milling tool 29 is of the elongated type and its axis of development lies in the reference plane P. In detail, the milling tool 29 is of the end mill type.

[0117] The milling tool 29 can be moved along at least one substantially vertical direction of milling F. The milling tool 29 is arranged transversely with respect to the direction of milling F.

[0118] The direction of milling F is also coplanar with the axis of development. In other words, the direction of milling F also lies in the reference plane P.

[0119] In other words, the milling tool 29 is moved upward or downward and its axis of development is arranged not vertically. During this movement, the milling tool 29 is placed in contact with the ending surface 5, 6 to determine the removal of the metallic material.

[0120] In accordance with a preferred embodiment, the phase of milling is also carried out under dry conditions.

[0121] The removal means 28 comprise a movement assembly 30 adapted to move the milling tool 29 and comprising: a guide that develops parallel to the direction of milling F and supports the milling tool 29 by sliding; an actuator adapted to move the milling tool 29 on the guide.

[0122] Furthermore, the milling tool 29 is usefully inclined with respect to a horizontal plane by a predefined angle of work.

[0123] Specifically, with reference to the preferred embodiment wherein the bars 4, 9 are hollow and have a rectangular cross- section, the use of a milling tool 29 inclined with respect to a horizontal plane allows facilitating the movement thereof along the direction of milling F and optimizing the machining of the bars themselves. In fact, when moving along the direction of milling F, the inclined milling tool 29 abuts against the bar 4, 9 not at a flat face thereof, but at an edge, which offers less resistance to milling. This not only simplifies the milling operation, but also prevents possible deformation of the bar.

[0124] Usefully, the angle is of between 5° and 45°. Preferably, the angle is of between 10° and 35°, and even more preferably it is 20°.

[0125] Furthermore, the removal means 28 usefully comprise an intake assembly 31 adapted to suck up the metallic residues generated by the removal of the metallic material.

[0126] The intake assembly 31, in addition to preventing the dispersion of dust and metallic chips in the workplace, with a consequent risk to the safety of the plant, also prevents them from settling on the ending surfaces 5, 6, affecting the subsequent welding.

[0127] The intake assembly 31 comprises an intake motor 32 and a conveyor body 33 arranged to partly surround the milling tool 29 and connected to the intake motor 32.

[0128] Specifically, the intake motor 32 generates a vacuum inside the conveyor body 33, which allows the metallic residues generated during removal to be sucked up.

[0129] Usefully, the conveyor body 33 comprises at least two inlet openings for the metallic residues, arranged facing respective retaining assemblies 13.

[0130] In accordance with the embodiment shown in the figures, the openings comprise a first opening arranged on top of the milling tool 29 and a second opening arranged below the milling tool 29. In detail, the opening is arranged on top of or below the milling tool 29 depending on the way of rotation of the latter and, consequently, on the direction imparted to the metallic residues during removal.

[0131] According to a further aspect, the present invention also refers to a process for the production of reinforcement bars for window / door frame profiled elements.

[0132] This process can be implemented using the plant 1 described above.

[0133] The process first involves a phase of supplying at least one first bar and at least one second bar 4 made of at least one metallic material.

[0134] The process comprises a phase of cutting the first bar to obtain at least one reinforcement bar which can be inserted within a relevant window / door frame profiled element and a residual bar 9 provided with the second ending surface 6.

[0135] Specifically, the process comprises repeating the cutting phase of the first bar depending on the length of the desired reinforcement bars.

[0136] In this regard, it should be noted that the cutting phase is carried out by moving the bar along a direction of forward movement D, substantially parallel to the longitudinal direction depending on the length of the desired reinforcement bars, so as to position the bar itself where the cutting device 10 is located.

[0137] The process then involves a phase of positioning the second bar 4 aligned with the residual bar 9 with respect to their respective longitudinal directions

[0138] The phase of positioning is then carried out by the movement of the second bar 4 along the direction of forward movement D so as to align it with the residual bar 9.

[0139] The process also comprises a phase of retaining the bars 4, 9 with the first ending surface 5 of the second bar 4 facing the second ending surface 6 of the residual bar 9.

[0140] In detail, the phase of retaining comprises a step of clamping the second bar 4 and the residual bar 9.

[0141] The process then comprises a phase of welding the second bar 4 to the residual bar 9 carried out by means of a flow of current through the ending surfaces 5, 6 facing each other to obtain a welded bar.

[0142] In detail, the phase of welding comprises a step of application of electrode assemblies 15 to the second bar 4 and to the residual bar 9 at the relevant ending surfaces 5, 6 to determine the flow of current.

[0143] According to the invention, the step of application is carried out by placing the notched surface 18 in contact with the respective bar 4, 9. Specifically, the step of application is carried out by partly penetrating the notched surface 18 through the metal oxide coating the surface of the bar 4, 9. The sharp projections 19 thus come into contact with the pure metal of the bar 4, 9 and allow effective transfer of the electric current. Advantageously, the step of application coincides with the step of clamping.

[0144] In other words, the application of the electrode assemblies 15 also determines the clamping of the bars 4, 9.

[0145] Advantageously, the process then comprises the repetition of the phases of cutting, positioning, and welding for the welded bar.

[0146] The welded bar is then subjected to the phase of cutting again to produce new reinforcement bars, and any new residual bar 9 is welded again to a subsequent bar.

[0147] The phase of welding also comprises a step of joining the ending surfaces 5, 6 together to form an electric arc.

[0148] In particular, the step of joining is carried out by bringing the second bar 4 and the residual bar 9 close to each other.

[0149] Usefully, the step of joining is carried out in such a way as to soften the metallic material.

[0150] The step of joining is carried out for a time of between 0.1” and 20”, preferably of between 1” and 5”, and even more preferably of between 1.5” and 2”.

[0151] In particular, the step of joining is carried out in such a way as to lead to the formation of a sufficient amount of softened metallic material to give the welding area adequate strength but which, however, does not result in the creation of an excessively protruding weld bead.

[0152] This phase of resistance welding allows minimizing the formation of a weld bead that protrudes outward.

[0153] Traditional welding processes, especially those involving the use of a filler material, such as e.g. coated electrode welding, can result in the formation of an abundant weld bead protruding from the welding area.

[0154] In this specific case, the presence of a protruding weld bead could jeopardize the insertion of the reinforcement bar into the relevant window / door frame profiled element. The reinforcement bars are generally provided with a section that fits to size into the cavity defined by the window / door frame profiled element and a protruding weld bead would prevent the insertion thereof.

[0155] Therefore, when traditional welding processes are used, the reinforcement bar would have to undergo further machining to remove part of this weld bead.

[0156] The present process allows therefore further fixing this technical problem and avoiding subsequent machining of the reinforcement bars, thereby further reducing production times.

[0157] More specifically, the step of joining is carried out in such a way that the thickness of the protruding weld bead is less than a predefined minimum value.

[0158] The minimum value is determined based on the dimensions of the internal cavity of the window / door frame profiled element and the dimensions of the reinforcement bar section. It follows that, for example, while in some cases a protruding 2 mm thick weld bead may still allow the reinforcement bar to be inserted into the relevant window / door frame profiled element, in other cases even a protruding 0.5 mm thick weld bead may j eopardize this operation.

[0159] Finally, the phase of welding comprises a step of mutual compression of the ending surfaces 5, 6. During this phase, the softened metallic material of the ending surfaces 5, 6 joins intimately and, as a result of cooling, forms the welding area.

[0160] In particular, during the step of compression, the electrode assemblies 15 are moved away from the second bar 4 and from the residual bar 9, thus interrupting the flow of current and allowing the metallic material to cool down.

[0161] Usefully, the step of compression is carried out for a time of between 0.1” and 10”, preferably of between 0.5” and 3”.

[0162] At the same time, the step of compression is carried out at a pressure of between 1 MPa and 15 MPa.

[0163] As a result of the phase of welding, the second bar 4 and the residual bar 9 are joined together through a substantially continuous, resistant weld area and provided with a small weld bead. Usefully, prior to the phase of welding, the process also comprises a phase of cleaning at least one of the ending surfaces 5, 6 carried out by removing metallic material.

[0164] The phase of cleaning allows the ending surfaces 5, 6 to be evened out and leveled, making them substantially smooth and flat and allowing the effective mutual contact surface and the strength of the joining area to be increased.

[0165] In addition, the phase of cleaning allows any impurities that could affect the subsequent phase of welding, such as portions of oxidized metallic material, to be removed.

[0166] The phase of cleaning therefore makes the subsequent phase of welding more effective, ensures a strong bond between the bars 4, 9 and reduces energy consumption.

[0167] The phase of cleaning is carried out by the movement of the milling tool 29 along at least the direction of milling F.

[0168] Specifically, the milling tool 29 is moved upward or downward and, during this movement, the milling tool 29 is placed in contact with the ending surface 5, 6 to remove the metallic material. Advantageously, the phase of cleaning is carried out simultaneously on both bars 4, 9. In detail, when moving along the direction of milling F, the milling tool 29 is placed in contact on one side with the residual bar 9 and on the other side with the second bar 4.

[0169] More specifically, to carry out the phase of cleaning, the bars 4, 9 are brought close to each other at a mutual distance less than the diameter of the milling tool 29 which, when moving along the direction of milling F, comes into contact with both ending surfaces 5, 6, smoothing them.

[0170] In accordance with the preferred embodiment, the phase of cleaning is carried out after the phase of positioning and before the phase of welding, i.e., after the first bar has been cut. It cannot, however, be ruled out that the phase of cleaning may be carried out before the phase of cutting, i.e., on the starting bars.

[0171] It has in practice been ascertained that the described invention achieves the intended objects and, in particular, the fact should be emphasized that the process and plant for the production of reinforcement bars for window / door frame profiled elements ensure effective j oining of the bars and avoid excessive waste of resources.

[0172] Furthermore, this process and plant make it possible to reduce the production and management costs of the production plant.

Claims

CLAIMS1) Plant (1) for the production of reinforcement bars for window / door frame profiled elements, comprising: holding means (2) adapted to hold at least a first bar and a second bar (4) made of at least one metallic material and extending along relevant longitudinal directions, each provided at its respective ends with a first ending surface (5) and with a second ending surface (6) substantially perpendicular to said relevant longitudinal direction; cutting means (8) adapted to cut said first bar to obtain at least one reinforcement bar which can be inserted within a relevant window / door frame profiled element and a relevant residual bar (9) provided with said second ending surface (6); retaining means (11) partly defining a substantially horizontal line of work (12) and adapted to retain said residual bar (9) and said second bar (4) aligned with each other on said line of work (12), with said second ending surface (6) of said residual bar (9) facing the first ending surface (5) of said second bar (4); resistance welding means (14) adapted to butt weld said residual bar (9) and said second bar (4) by means of the flow of current through said ending surfaces (5, 6) facing each other to obtain a welded bar, wherein said welding means (14) comprise a pair of electrode assemblies (15), each adapted to contact one respective of either said second bar (4) or said residual bar (9) at the relevant ending surfaces (5, 6) to determine said flow of current; characterized by the fact that at least one of said electrode assemblies (15) comprises a notched surface (18) provided with one or more sharp projections (19) and adapted to contact the respective bar (4, 9).2) Plant (1) according to claim 1, characterized by the fact that said sharp projections (19) develop along a direction transverse to said line of work (12).3) Plant (1) according to one or more of the preceding claims, characterized by the fact that said sharp projections (19) develop along a substantially orthogonal direction to said line of work (12).4) Plant (1) according to one or more of the preceding claims, characterized by the fact that the distance (S) between the base of said sharp projections (19) and the respective ridge is of between 0.01 and 3 mm.5) Plant (1) according to one or more of the preceding claims, characterized by the fact that each of said electrode assemblies (15) comprises at least one electrode (20) defining said notched surface (18) and movable along at least one direction of work (W) between a home position, wherein they are moved away from said respective bars (4, 9), and a position of work, wherein they are brought closer to said respective bars (4, 9) and said notched surface (18) is in contact with a face of the respective bar (4, 9) and result in the flow of current.6) Plant (1) according to one or more of the preceding claims, characterized by the fact that said electrode assembly (15) comprises a movement system comprising a guiding unit (22) running parallel to said direction of work (W) and supporting said electrode (20) by sliding and a motorized actuator (23) adapted to move said electrode (20) on said guiding unit (22).7) Plant (1) according to one or more of the preceding claims, characterized by the fact that each of said electrode assemblies (15) comprises a pair of electrodes (20), each defining a respective notched surface (18) and adapted to contact a respective face of the respective bar (4, 9) and movable between the home position and the position of work along directions of work (W) transverse to each other.8) Plant (1) according to one or more of the preceding claims, characterized by the fact that said retaining means (11) comprise a pair of retaining assemblies (13), each adapted to retain one respective of either said second bar (4) or said residual bar (9), at least one of said electrode assemblies (15) being associated with one of said retaining assemblies (13).9) Plant (1) according to one or more of the preceding claims, characterized by the fact that each of said retaining assemblies (13) comprises at least one abutment plane (24) and at least one clamping body (25) adapted to retain the respective bar (4, 9) against said abutment plane (24), said electrode (20) coinciding with said clamping body (25).10) Plant (1) according to one or more of the preceding claims, characterized by the fact that said retaining assemblies (13) comprise a pair of clamping bodies (25), each of said electrodes (20) coinciding with one of said clamping bodies (25).11) Plant (1) according to one or more of the preceding claims, characterized by the fact that it comprises removal means (28) configured to remove part of the metallic material from at least one of said ending surfaces (5, 6).12) Process for the production of reinforcement bars for window / door frame profiled elements, comprising the following phases: supplying at least one first bar and at least one second bar (4) made of at least one metallic material and extending along relevant longitudinal directions, each provided at its respective ends with a first ending surface (5) and with a second ending surface (6) substantially perpendicular to said relevant longitudinal direction; cutting said first bar to obtain at least one reinforcement bar which can be inserted within a relevant window / door frame profiled element and a residual bar (9) provided with said second ending surface (6); positioning said second bar (4) aligned with said residual bar (9) with respect to said longitudinal directions; retaining said bars (4, 9) with the first ending surface (5) of said second bar (4) facing the second ending surface (6) of said residual bar (9);resistance butt welding said second bar (4) and said residual bar (9) carried out by means of the flow of current through said ending surfaces (5, 6) facing each other to obtain a welded bar, wherein said phase of welding comprises a step of application of electrode assemblies (15) to said second bar (4) and to said residual bar (9) at the relevant ending surfaces (5, 6) to determine said flow of current; characterized by the fact that at least one of said electrode assemblies (15) comprises a notched surface (18) provided with one or more sharp projections and by the fact that said step of application is carried out by contacting said notched surface (18) with the respective bar (4, 9).13) Process according to claim 12, characterized by the fact that said phase of retaining comprises a step of clamping said second bar (4) and said residual bar (9), said step of application coinciding with said step of clamping.

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