Patent Description:
The welding apparatus in which the supporting device according to the invention can be mounted is particularly suitable for joining profiled bars made of polyvinyl chloride (PVC), but may also be used for joining together profiled bars made of polymeric material different from PVC, or from composite material, or provided with reinforcing elements made of metallic material. In general, the above-mentioned welding apparatus can be used for joining together profiled bars which can be welded to each other by applying heat and pressure.

Examples of known welding apparatuses are disclosed in <CIT> and <CIT>.

<CIT> discloses a welding apparatus according to the preamble of claim <NUM> which serves for joining profiled bars made of polymeric material, giving rise to a good quality joint between the profiled bars.

For this purpose, the apparatus disclosed in <CIT> comprises a pair of supporting devices or counterblocks for supporting respective ends of two profiles to be welded. Each supporting device comprises a supporting element to which a containment element is fixed, in such a way that the containment element is floating along a direction parallel to a longitudinal axis of the corresponding profiled bar. The containment elements prevent the material which forms the profiled bars, which is heated and softened during welding, from flowing towards the outside of the profiled bars. This prevents the formation of a welding seam visible from the outside of the profiled bars at the zone where the profiled bars are welded.

Each containment element is also provided with a protuberance, which projects towards the longitudinal axis of the corresponding profiled bar for being housed in a seat made close to an end section of the corresponding profiled bar. Owing to the interaction between the protuberances of two containing elements facing each other, a recess is formed at the joint between the profiled bars which may have, for example, a V-shaped geometry. This recess, similar to that which is usually present in the joints between adjacent bars of door and window frames made of wood, gives the joint between the profiled bars an aesthetically pleasing appearance.

With the same supporting device, it is possible to weld together different types of profiled bars, having dimensional and geometrical features not too different from each other. More specifically, in order to pass from welding profiled bars of a certain type to welding profiled bars of a new type, which have dimensional and geometrical features not too different from those of the previous type, it is possible to use the same supporting elements, but it is necessary to replace the containment elements, on each of which the protuberance is obtained. Each containment element is indeed suitable for profiled bars having clearly determined dimensional and geometrical features and cannot be used effectively for welding profiled bars which have different dimensional or geometrical features, even just slightly, from those of the profiled bars for which it was designed.

If supporting devices of the type disclosed in <CIT> are used, replacement of a containment element in a supporting device already mounted on the welding apparatus is a relatively long and delicate operation, which must be performed whilst the welding apparatus is stationary and therefore requires a relatively long machine stop and a consequent loss of productivity.

Moreover, in order to mount the new containment element with the sufficient precision it is necessary to posses a particular skill in carrying out fine adjustment operations, which not all operators possess.

Similar drawbacks occur when a worn or broken containment element must be replaced with a new containment element of the same type.

An object of the invention is to improve the supporting devices for supporting profiled bars on a welding apparatus, suitable for joining adjacent profiled bars by welding.

A further object is to provide a supporting device comprising a supporting element which supports a containment element for containing the softened material during welding, wherein the containment element can be replaced quickly, without requiring extended machine stops.

Another object is to provide a supporting device comprising a supporting element which supports a containment element for containing the softened material during welding, wherein the containment element can be replaced simply, even by non-expert operators.

According to the invention, there is provided a supporting device for supporting a profiled bar during a welding operation, comprising a lower supporting element and an upper supporting element movable relative to each other between a clamping position, in which a profiled bar can be locked between the lower supporting element and the upper supporting element, and a disengagement position, in which the profiled bar can be disengaged from the lower supporting element and from the upper supporting element, wherein at least one supporting element selected from the upper supporting element and the lower supporting element comprises: a containment element for containing the softened material of the profiled bar during welding, the containment element having a deflecting protuberance which projects towards a longitudinal axis of the profiled bar for diverting the softened material towards the inside of the profiled bar;
characterized in that said at least one supporting element selected from between the upper supporting element and the lower supporting element further comprises:.

Owing to the invention, it is possible to replace a containment element of a supporting device in a particularly quick and easy manner. For this purpose, it is sufficient to mount on the base component the intermediate component to which the containment element has been previously fixed.

The position of the containment element may be adjusted by acting on the adjustment means before fixing the intermediate component to the base component. In this way, the adjustment operations can be performed outside the welding apparatus and the assembly formed by the containment element and the intermediate component can be fixed to the base component, already installed on the welding apparatus, after the adjustment operations have already been performed. The assembly formed by the containment element and the intermediate component on the welding apparatus may thus be fixed with just a few simple operations, which even an unskilled operator is able to perform.

This makes it possible to replace a containment element with very limited downtimes of the welding apparatus.

The invention can be better understood and implemented with reference to the accompanying drawings which illustrate a non-limiting example embodiment of it and in which:.

<FIG> shows a welding head <NUM> for joining together a profiled bar <NUM> and a further profiled bar <NUM> by welding. The profiled bar <NUM> and the further profiled bar <NUM> are intended, in particular, to form a door or window frame, after having been joined to other two profiled bars, not shown.

The profiled bar <NUM> and the further profiled bar <NUM> may be made of polymeric material, particularly polyvinyl chloride (PVC). However, it is also possible to use the welding head <NUM> for welding profiled bars made of polymeric materials different from PVC, or composite materials, or having an outer structure made of PVC or another polymeric material and an internal metal reinforcement, for example made of aluminium.

Each profiled bar <NUM>, <NUM> has a first face <NUM> and a second face <NUM>, opposite the first face <NUM>. Between the first face <NUM> and the second face <NUM> two side faces <NUM> are interposed, which are opposite one another. While the first face <NUM> and the second face <NUM> are intended to remain visible after installation of the door or window in a building, the side faces <NUM> are not visible after installation.

The first face <NUM>, the second face <NUM> and the side faces <NUM> may have various shapes, not necessarily flat.

Each profiled bar <NUM>, <NUM> extends along a corresponding longitudinal axis Z. Both the profiled bar <NUM> and the further profiled bar <NUM> are hollow inside.

The welding head <NUM> is configured to join the profiled bar <NUM> to the further profiled bar <NUM> in such a way that the longitudinal axes Z of the profiled bar <NUM> and of the further profiled bar <NUM> are arranged transversally, in particular perpendicularly, relative to each other. The profiled bar <NUM> and the further profiled bar <NUM> are therefore joined together to form an angle which, in the example shown, is equal to <NUM>°.

More in detail, the welding head <NUM> is configured to join the profiled bar <NUM> to the further profiled bar <NUM> along a joining perimeter affecting all the faces of the profiled bar <NUM> and of the further profiled bar <NUM>. In other words, the welding head <NUM> is configured to form, at the interface between the profiled bar <NUM> and the further profiled bar <NUM>, a welding bead which extends in a joining zone between the first faces <NUM>, in a joining zone between the second faces <NUM> and a joining zone between the side faces <NUM> of the profiled bar <NUM> and of the further profiled bar <NUM>.

The joining zone between the side faces <NUM> does not remain visible after installation of the door or window obtained from the profiled bars <NUM>, <NUM>. The presence of a welding bead in this joining zone does not therefore normally create particular difficulties.

As described in more detail below, the welding head <NUM> makes it possible to minimise, or even prevent, the welding bead from being visible, in particular on the first faces <NUM> and on the second faces <NUM> of the profiled bars <NUM>, <NUM>. The welding head <NUM> may be included in a welding machine comprising four welding heads, each of which is similar to the welding head <NUM> shown in <FIG>. In this case, the welding machine allows a door or window frame to be rapidly formed, since each welding head is arranged for joining, by welding, two adjacent profiled bars, so that the four corners of the frame are formed simultaneously.

Alternatively, the welding head <NUM> may form part of a welding machine comprising a single welding head <NUM>, or comprising two welding heads <NUM>. The welding head <NUM> comprises a base <NUM> and a casing <NUM> positioned above the base <NUM>. The base <NUM> is arranged for restingly receiving the profiled bars to be welded, using supporting devices which will be described below in detail. The casing <NUM> houses some mechanical devices and some electronic parts which allow the profiled bars to be welded.

Above the base <NUM> a supporting device <NUM> is positioned, the supporting device <NUM> being arranged for supporting an end portion <NUM> of the profiled bar <NUM>. A further supporting device <NUM> is also positioned above the base <NUM>, the further supporting device <NUM> being arranged for supporting a further end portion <NUM> of the further profiled bar <NUM>.

The supporting device <NUM> and the further supporting device <NUM> are also called "counterblocks".

The supporting device <NUM> and the further supporting device <NUM> are intended to be fixed to the base <NUM> by fixing means which may be, for example, of the magnetic type.

Each supporting device <NUM>, <NUM> comprises a lower supporting element <NUM>, suitable for supporting an end portion <NUM>, <NUM> of the corresponding profiled bar <NUM>, <NUM>.

In particular, each supporting element <NUM>, which may be, for example, L-shaped, is delimited by a supporting surface <NUM>, suitable for supporting a face, particularly the second face <NUM>, of a profiled bar <NUM>, <NUM>. The supporting surface <NUM> may be a flat surface, intended to be arranged horizontally during operation of the welding head <NUM>.

Each supporting element <NUM> is also delimited by a resting surface <NUM>, against which a side face <NUM> of a profiled bar <NUM>, <NUM> can rest. The resting surface <NUM>, which may be flat or also have other geometries, is arranged vertically during operation of the welding head <NUM>.

Each supporting device <NUM>, <NUM> further comprises an upper supporting element <NUM> for locking a profiled bar <NUM>, <NUM> on a supporting device <NUM>, <NUM>. The upper supporting element <NUM> is movable relative to the lower supporting element <NUM> by movement means, not shown, in a direction of movement which, in the example shown, is vertical. The upper supporting element <NUM> is in particular movable between a disengagement position, in which a profiled bar <NUM>, <NUM> can be moved freely between the lower supporting element <NUM> and the upper supporting element <NUM>, and a clamping position, in which the upper supporting element <NUM> locks the profiled bar <NUM>, <NUM> against the lower supporting element <NUM>, so as to prevent movements of the profiled bar <NUM>, <NUM> relative to the corresponding supporting device <NUM>, <NUM>.

The upper supporting element <NUM> is suitable for engaging with the first face <NUM> of a profiled bar <NUM>, <NUM>. In particular, the upper supporting element <NUM> is delimited by a locking surface <NUM>, which, in the example shown, is arranged horizontally, suitable for abutting against the first face <NUM>.

The supporting device <NUM> and the further supporting device <NUM> are movable relative to each other so as to move towards each other, or alternatively move away from each other, the end portion <NUM> and the further end portion <NUM>. This is made possible by driving means and by further driving means included in the welding head <NUM>. The driving means and the further driving means act respectively on the supporting device <NUM> and on the further supporting device <NUM>, after they have been positioned on the base <NUM>, in order to move them away from each other or towards each other.

During operation of the welding head <NUM>, the longitudinal axis Z of the profiled bar <NUM> is arranged transversally, in particular perpendicularly, to the longitudinal axis Z of the further profiled bar <NUM>.

The welding head <NUM> allows the profiled bar <NUM> to be joined to the further profiled bar <NUM> at respective end sections <NUM>, each of which is (in the example shown) arranged on a plane tilted by <NUM>° relative to the longitudinal axis Z of the profiled bar <NUM> or of the further profiled bar <NUM>.

The welding head <NUM> comprises an abutment element <NUM>, shaped in particular like a plate, which can be inserted between the end sections <NUM> of the profiled bar <NUM> and of the further profiled bar <NUM> during a positioning step for positioning the profiled bar <NUM> and the further profiled bar <NUM> on the welding head <NUM>. In particular, the abutment element <NUM> can be inserted between the end sections <NUM> before locking the profiled bar <NUM> and the further profiled bar <NUM> respectively in the supporting device <NUM> and in the further supporting device <NUM>.

The welding head <NUM> further comprises a heating device which includes a heating element <NUM>, shaped for example like a plate, suitable for being interposed between the end sections <NUM> of the profiled bar <NUM> and of the further profiled bar <NUM>, so as to heat the material which forms the profiled bar <NUM> and the further profiled bar <NUM>, at the end sections <NUM>. The profiled bars <NUM>, <NUM> are thus locally softened.

Pushing means are furhter for pushing the profiled bar <NUM> against the further profiled bar <NUM>, in such a way as to apply a pressure which allows the profiled bar <NUM> to be joined to the further profiled bar <NUM> at the respective end sections <NUM> on which the material which forms the profiled bars <NUM>, <NUM> has been previously softened.

The pushing means may comprise the driving means and the further driving means, not illustrated, which move the supporting device <NUM> and the further supporting device <NUM> relative to each other.

The abutment element <NUM> and the heating element <NUM> are movable so as to be able to be inserted between the end sections <NUM> of the profiled bars <NUM>, <NUM>, or alternatively moved away from the end sections <NUM>.

Each supporting device <NUM>, <NUM> further comprises a pair of containment elements for locally containing the softened material of the profiled bars <NUM>, <NUM> close to the respective end sections <NUM>, thereby preventing undesired escape of the material after the end sections <NUM> have interacted with the heating element <NUM>.

In particular, for each supporting device <NUM>, <NUM> two containment elements <NUM> may be provided, associated respectively with the lower supporting element <NUM> and with the upper supporting element <NUM>. The containment element <NUM> associated with the upper supporting element <NUM> is arranged for containing the softened material in a joining zone between the profiled bar <NUM> and the further profiled bar <NUM> on the first face <NUM>. The containment element <NUM> associated with the lower supporting element <NUM> is, on the other hand, arranged for containing the softened material in a joining zone between the profiled bar <NUM> and the further profiled bar <NUM> on the second face <NUM>.

<FIG> shows the supporting device <NUM> in which the lower supporting element <NUM> is shown in an exploded view, whilst the upper supporting element <NUM> is shown in an assembled configuration.

The further supporting device <NUM> may have a structure identical to that of the supporting device <NUM>.

Each supporting element <NUM>, <NUM> comprises a base component <NUM>, which is mounted in a floating manner on the corresponding supporting device <NUM>, <NUM> so as to be movable in a direction parallel to the longitudinal axis Z of the profiled bar <NUM> or of the further profiled bar <NUM>.

To ensure that each base component <NUM> is mounted in a floating manner on the support device <NUM>, <NUM>, each base component <NUM> is associated with an elastic element <NUM>, such as, for example, a spring, visible in <FIG>, which pushes the corresponding base component <NUM> parallel to the longitudinal axis Z of the profiled bar <NUM> or of the further profiled bar <NUM>. In particular, each elastic element <NUM> of the supporting device <NUM> pushes the corresponding base component <NUM> towards the further supporting device <NUM>, that is to say, it keeps the base component <NUM> in an extended position.

Each base component <NUM> may be moved, that is to say, retracted, towards a central zone of the profiled bar <NUM>, by applying to each base component <NUM> a force sufficient to overcome the resistance of the corresponding elastic element <NUM>.

Each supporting element <NUM>, <NUM> further comprises a containment element <NUM> for locally containing the softened material of the profiled bars <NUM>, <NUM> close to the respective end sections <NUM>, thereby preventing unwanted escape of that material after the end sections <NUM> have interacted with the heating element <NUM>.

In particular, for each supporting device <NUM>, <NUM> there may be two containing elements <NUM>, which respectively form part of the lower supporting element <NUM> and the upper supporting element <NUM>.

Each upper containment element <NUM> has a protuberance <NUM> which projects towards the longitudinal axis Z of the corresponding profiled bar <NUM>, <NUM>.

Each protuberance <NUM> is suitable for being received in a seat <NUM>, shown in <FIG>, formed close to the end section <NUM> of the profiled bar <NUM> or to the further profiled bar <NUM>.

The seat <NUM> is made by removing material, for example by milling, from the first face <NUM> or from the second face <NUM> of the profiled bar <NUM> or of the further profiled bar <NUM>.

Each containment element <NUM> is delimited by an abutment face <NUM> suitable for abutting against a corresponding abutment face <NUM> of the further supporting device <NUM> which supports the further profiled bar <NUM>. The protuberance <NUM> is arranged in a position adjacent to the contact face <NUM>.

The abutment face <NUM> defines a welding plane P, shown in <FIG>, on which the profiled bar <NUM> is intended to be welded to the further profiled bar <NUM>.

In the example shown, in which the profiled bar <NUM> and the profiled bar <NUM> are intended to be joined to each other to form an angle of <NUM>°, the welding plane P is inclined by <NUM>° relative to the longitudinal axis Z of the profiled bar <NUM> and of the further profiled bar <NUM>.

Each supporting element <NUM>, <NUM> further comprises an intermediate component <NUM> suitable for being interposed between the containment element <NUM> and the base component <NUM>.

More specifically, the containment element <NUM> can be fixed in a removable manner to the intermediate component <NUM>, for example by means of a pair of fixing screws <NUM>. Each fixing screw <NUM> passes through a through hole <NUM> made in the containment element <NUM> and engages in a threaded hole <NUM> made in the intermediate component <NUM>. In this way, the containment element <NUM> can be fixed to the intermediate component <NUM> before the latter is mounted on the welding apparatus.

The number of fixing screws <NUM> may be selected as desired.

The intermediate component <NUM> is in turn connectable in a removable manner to the base component <NUM>.

For this purpose, in the example illustrated, there is provided a connecting screw <NUM> which passes through a through hole <NUM> made in the intermediate component <NUM> and engages in a threaded hole <NUM> made in the base component <NUM>.

An access hole <NUM> may be formed on the containment element <NUM> for accessing the connecting screw <NUM> even when the containment element <NUM> is already fixed to the intermediate component <NUM>.

Owing to the access hole <NUM>, it is possible to fix the intermediate component <NUM> to the base component <NUM>, or remove the intermediate component <NUM> from the base component <NUM>, without having to remove the containment element <NUM> from the intermediate component <NUM>.

Adjusting means are further provided for adjusting the position of the containment element <NUM> relative to the intermediate component <NUM>.

The adjustment means can in particular be configured to adjust the position of the containment element <NUM> relative to the intermediate component <NUM> along two different adjustment directions parallel to the welding plane P.

The adjustment directions are in particular a vertical direction Z1 and a horizontal direction X1 parallel to the welding plane P.

The adjusting means comprise first adjusting means for adjusting the position of the containment element <NUM> relative to the intermediate component <NUM> along the vertical direction Z1 and second adjusting means for adjusting the position of the containment element <NUM> relative to the intermediate component <NUM> along the horizontal direction X1.

More specifically, the adjustment means may comprise at least one adjustment protrusion <NUM> which projects from the intermediate component <NUM> and is received with clearance in a slot <NUM> of the containment element <NUM>. In the example shown two or three adjustment protrusions <NUM> are provided for each intermediate component <NUM>.

Each adjustment protrusion <NUM> has the shape of a prism with a rectangular base, with rounded corners.

As shown in <FIG>, each adjustment protrusion <NUM> is delimited by a first face <NUM>, which in the example shown is a substantially horizontal flat face, that is to say, perpendicular to the vertical direction Z1. Each adjustment protrusion <NUM> is also delimited by a second face <NUM>, which, in the example illustrated, is a substantially vertical flat face, that is to say, perpendicular to the horizontal direction X1.

The first adjustment means may comprise at least a first threaded adjustment element <NUM>, more specifically a threaded grub screw, which is screwed into a hole <NUM>' in the intermediate component <NUM> and has one end in contact with the first face <NUM> of the adjustment protrusion <NUM>. The first threaded adjustment element <NUM> extends along a direction parallel to the vertical direction Z1.

By screwing or unscrewing the first threaded adjustment element <NUM> relative to the intermediate component <NUM>, the position of the end of the first adjusting element <NUM> is varied along the vertical direction Z1, that is to say, in the corresponding hole <NUM>'. In this way, it is possible to vary the position of the adjustment protrusion <NUM> inside the corresponding slot <NUM>, along the vertical direction Z1. Consequently, it is possible to vary the position of the containment element <NUM> relative to the intermediate component <NUM> along the vertical direction Z1.

The second adjustment means may comprise at least a second threaded adjustment element <NUM>, more specifically a threaded grub screw, which is screwed into a hole <NUM>' made in the intermediate component <NUM> and has one end in contact with the second face <NUM> of the adjustment protrusion <NUM>. The second threaded adjustment element <NUM> extends along a direction parallel to the horizontal direction X1, like the corresponding hole <NUM>'. By acting on the second threaded adjustment element <NUM>, it is possible to vary the position of the adjustment protrusion <NUM> inside the corresponding slot <NUM>, along the horizontal direction X1. Consequently, it is possible to vary the position of the containment element <NUM> relative to the intermediate component <NUM> along the horizontal direction X1.

In the example shown, for each intermediate component <NUM> two or three first threaded adjustment elements <NUM> and a single second threaded adjustment element <NUM> are provided. More specifically, both the first threaded adjustment element <NUM> and the second threaded adjustment element <NUM> act on one of the adjustment protrusions <NUM>. Only a corresponding first threaded adjustment element <NUM> acts, on the other hand, on another, or other two, adjustment protrusions <NUM>.

Locking elements <NUM> are provided for locking the first threaded adjustment element <NUM> or the second threaded adjustment element <NUM> after the containment element <NUM> has been correctly positioned relative to the intermediate component <NUM>. The locking elements <NUM> may comprise respective threaded grub screws which extend inside respective holes <NUM>' perpendicularly to the first threaded adjustment element <NUM> and/or to the second threaded adjustment element <NUM> and lock the first threaded adjustment element <NUM> or the second threaded adjustment element <NUM> by coming into contact with the threaded adjustment elements.

In the example shown, the containment element <NUM> is mounted on the base component <NUM>, outside the welding apparatus, by positioning the adjustment projections <NUM> inside the corresponding slots <NUM>. The position of the containment element <NUM> relative to the base component <NUM> is then adjusted by acting on the first threaded adjustment elements <NUM> and on the second threaded adjustment element <NUM>.

In particular, by means of the second threaded adjustment element <NUM> it is possible to correctly position the containment element <NUM> along the horizontal direction X1, whilst by means of the first threaded adjustment elements <NUM> it is possible to correctly position the containing element <NUM> along the vertical direction Z1.

The first threaded adjustment elements <NUM> may be positioned differently from each other, for example in such a way that one of the first threaded adjustment elements <NUM> penetrates more in the containment element <NUM> compared with another first threaded adjustment element <NUM>. In this way, it is possible to vary the inclination of the containment element <NUM> relative to the intermediate component <NUM> about a horizontal axis.

Once the containment element <NUM> has been correctly positioned relative to the intermediate component <NUM>, it is possible to lock the first threaded adjustment elements <NUM> and the second threaded adjustment element <NUM> owing to the locking elements <NUM>. Moreover, the containment element <NUM> is fixed to the intermediate component <NUM> by the fixing screws <NUM>.

The assembly formed by the containment element <NUM> and by the intermediate component <NUM>, already correctly positioned relative to each other, may now be fixed to the base component <NUM> owing to the connecting screw <NUM>.

Reference means are further provided for mounting the intermediate component <NUM> in a predetermined position on the base component <NUM>.

The reference means may comprise a pair of pins <NUM> fixed relative to the intermediate component <NUM>, suitable for engaging in corresponding holes <NUM> of the base component <NUM>.

Owing to the pins <NUM> and the holes <NUM>, the assembly formed by the containment element <NUM> and by the intermediate component <NUM> may be mounted in a repeatable manner on the base component <NUM>.

From the foregoing, it is evident that the containment element <NUM> can be replaced quickly and easily when necessary. For this purpose, it is sufficient to fix the assembly formed by the containment element <NUM> and by the intermediate component <NUM> to the base component <NUM> by means of the connecting screw <NUM>, after having correctly positioned the above-mentioned assembly on the base component <NUM> owing to the reference means.

The adjustment operations on the containment element <NUM> can be performed outside the welding apparatus, mounting the containment element <NUM> on the intermediate component <NUM>, in such a way as to prevent extended machine stoppages.

The operation of the welding head <NUM> is described below, with reference to <FIG>. These drawings are schematic cross-sections each of which is taken along the vertical planes which contain the longitudinal axes Z of the profiled bar <NUM> and of the profiled bar <NUM>, respectively. The cross-section planes have then each been rotated by <NUM>° away from each other, so as to obtain a cross-section lying on the plane of the sheet.

The profiled bar <NUM> and the further profiled bar <NUM> are prepared beforehand, by cutting them to the desired length and forming end sections <NUM> according to the desired shape. In the example of <FIG>, the profiled bars <NUM>, <NUM> are cut at <NUM>° relative to the corresponding longitudinal axis Z, so as to form end sections <NUM> each of which lies in a plane at an angle of <NUM>° to the longitudinal axis Z of the respective profiled bar <NUM>, <NUM>.

After cutting, the seats <NUM> are made on the first face <NUM> and on the second face <NUM> of each profiled bar <NUM>, <NUM>.

As described in more detail below, the seats <NUM> have the function of receiving the material of the welding bead which will be formed in a joining zone between the profiled bars <NUM>, <NUM> respectively on the first faces <NUM> and on the second faces <NUM>.

The seats <NUM> are formed upstream of the welding head <NUM>, in particular upstream of the welding apparatus in which the welding head <NUM> is included. This avoids complicating the structure of the welding head <NUM> and/or the welding apparatus, which does not need to comprise complicated material removal devices, nor devices for removing chippings.

The profiled bar <NUM> and the further profiled bar <NUM> are then positioned on the welding head <NUM>. In particular, as shown in <FIG>, the profiled bar <NUM> is rested on the lower supporting element <NUM> of the supporting device <NUM>, whilst the further profiled bar <NUM> is rested on the lower supporting element <NUM> of the further supporting device <NUM>.

Both the upper supporting element <NUM> of the supporting device <NUM> and the upper supporting element <NUM> of the further supporting device <NUM> are still in the disengagement position, that is to say, in the position in which the profiled bars <NUM>, <NUM> are free to move relative to the upper supporting element <NUM> and to the lower supporting element <NUM> of the corresponding supporting device <NUM>, <NUM>.

The abutment element <NUM> guarantees the correct positioning of the profiled bars <NUM>, <NUM>, between which it is interposed. For that purpose, the end sections <NUM> of the bar <NUM> and of the further profiled bar <NUM> are brought to abut against the contact element <NUM>, on opposite sides of the latter.

A positioning step is thus carried out in which the profiled bars <NUM>, <NUM> are positioned in a repetitive manner on the welding head <NUM>, by arranging them in a predetermined position relative to the abutment element <NUM>, with which the end sections <NUM> are in contact.

As a result of contact between the end sections <NUM> and the abutment element <NUM>, the containment elements <NUM> (whose ends are normally in a more advanced position than the end sections <NUM>) are moved backwards along the profiled bar <NUM> or the further bar <NUM>. This occurs because the abutment element <NUM> exerts a sufficient force on the containment elements <NUM> to overcome the force of the elastic elements <NUM>.

For this reason, towards the end of the positioning step, as shown in <FIG>, the containment elements <NUM> are in contact with the abutment element <NUM>. The corresponding protuberances <NUM> are housed in the seats <NUM>.

At this point, the upper supporting element <NUM> of the supporting device <NUM> is moved in the direction D1 shown in <FIG> and displaced towards the lower supporting element <NUM> of the supporting device <NUM>, until reaching the clamping position, in which the end portion <NUM> of the profiled bar <NUM> is locked on the supporting device <NUM>.

Similarly, the further profiled bar <NUM> is locked between the lower supporting element <NUM> and the upper supporting element <NUM> of the further supporting device <NUM>, by moving the upper supporting element <NUM> in the direction D2 until reaching the clamping position.

The supporting device <NUM> and the further supporting device <NUM> are now moved away from each other to move them to the position of <FIG>. In this way, the end sections <NUM> of the profiled bar <NUM> and of the further profiled bar <NUM> disengage from the abutment element <NUM>, which can thus be moved away from the profiled bars <NUM>, <NUM> and repositioned in the casing <NUM>.

It should be noted that, after the abutment element <NUM> has moved away from the profiled bars <NUM>, <NUM>, the elastic element <NUM> associated with each containment element <NUM> pushes the corresponding containment element <NUM> beyond the end section <NUM> of the respective profiled bar <NUM>, <NUM>.

Summing up, the step described above with reference to <FIG> can be defined as a step of locking the profiled bars <NUM>, <NUM> on the corresponding supporting device <NUM>, <NUM>, moving away the profiled bars <NUM>, <NUM> from each other and removing the abutment element <NUM>.

Subsequently, as shown in <FIG>, the heating element <NUM> is moved outside the casing <NUM> and inserted between the profiled bar <NUM> and the further profiled bar <NUM>.

The driving means associated with the supporting device <NUM> move the profiled bar <NUM> for bringing the end section <NUM> of the profiled bar <NUM> into contact with the heating element <NUM>. Similarly, the further driving means associated with the further supporting device <NUM> bring the end section <NUM> of the further profiled bar <NUM> into contact with the heating element <NUM>.

During this step, the heating element <NUM> is heated to a predetermined temperature, so as to transfer heat to the end sections <NUM> of the profiled bar <NUM> and of the further bar <NUM> with which it is in contact. The material which forms the bar <NUM> and the further profiled bar <NUM> is therefore brought to a relatively high temperature and consequently softened close to the end sections <NUM>. As the material forming the profiled bar <NUM> and the further profiled bar <NUM> is softened close to the end sections <NUM>, the driving means acting on the supporting device <NUM> further push the profiled bar <NUM> towards the heating element <NUM>, moving the profiled bar <NUM> with a controlled speed. The profiled bar <NUM> is consequently further moved close to the heating element <NUM>, in such a way as to soften a stretch of profiled bar <NUM> having a predetermined length, measured starting from the original end section <NUM>.

Similarly, the further driving means associated with the further supporting device <NUM> push the further profiled bar <NUM> towards the heating element <NUM>, by moving the further profiled bar <NUM> with a controlled speed. A stretch of the further profiled bar <NUM> having a predetermined length, measured starting from the corresponding original end section <NUM>, is thus softened.

The step described above may be defined as a step of softening the material which forms the profiled bar <NUM> and the further profiled bar <NUM> close to the end sections <NUM>.

During the softening step, the containing elements <NUM> are pushed in contact with the heating element <NUM>. The containment elements <NUM> prevent the softened material from flowing above the first face <NUM> and below the second face <NUM>.

The protuberances <NUM> are housed in the seats <NUM> of the profiled bar <NUM> and in the further profiled bar <NUM>.

The protuberances <NUM> move the softened material towards the inside of the profiled bars <NUM>, <NUM>, that is to say, towards the longitudinal axis Z of the profiled bar <NUM> and of the further profiled bar <NUM>. In other words, the protuberances <NUM> act as deflectors which divert the softened material, moving it away from the first face <NUM> and from the second face <NUM> and moving it towards the inside of the profiled bars <NUM>, <NUM>, which are hollow inside.

After the softening step, that is to say, after a stretch of predetermined length of the profiled bar <NUM> and of the further profiled bar <NUM> has been softened, the supporting device <NUM> and the further supporting device <NUM> move away from the heating element <NUM>. Consequently, the profiled bars <NUM>, <NUM> detach from the heating element <NUM>, which may now be withdrawn inside the casing <NUM>. Subsequently, the supporting device <NUM> and the further supporting device <NUM>, owing to the corresponding driving means and further driving means, push the profiled bar <NUM> and the further profiled bar <NUM> against each other, as shown in <FIG>. The end sections <NUM> of the profiled bar <NUM> and of the further profiled bar <NUM> are thus brought into contact with each other.

After the end sections <NUM> of the profiled bar <NUM> and of the further profiled bar <NUM> have been brought into contact with each other, the profiled bar <NUM> and the further profiled bar <NUM> are further moved towards each other. In that way, a pressure is applied on the profiled bar <NUM> and on the further profiled bar <NUM> such as to weld the profiled bar <NUM> to the further profiled bar <NUM>. The welding is performed by joining of portions of softened material close to the end sections <NUM>.

During this step, which may be defined as a welding step, the containment elements <NUM> are pushed into contact with each other and are arranged in a position of mutual contact.

The protuberances <NUM> are adjacent to each other and together form a penetrating portion <NUM> which penetrates into the portions of softened material already in contact with each other.

The containment elements <NUM> thus allow the softened material of the profiled bar <NUM> and the further profiled bar <NUM> to be contained. In this way, respective welding beads <NUM> extending inside the profiled bars <NUM>, <NUM> are generated in the joining zones between the first faces <NUM> and the second faces <NUM>. The welding beads <NUM> are shaped by the protuberances <NUM>, as described in more detail below.

After the profiled bar <NUM> and the further profiled bar <NUM> have been pushed against each other for a desired time, the welding step ends. The product obtained by joining the profiled bar <NUM> and the further profiled bar <NUM> can now be removed from the welding head <NUM>.

In this way, a joint <NUM> shown schematically in <FIG> is obtained between the profiled bar <NUM> and the further profiled bar <NUM>. It should be noted that in the joining zone between the first faces <NUM> and the second faces <NUM> a recess <NUM> is defined having a cross-section in the shape of a "V", that is to say, a shape matching the shape of the penetrating portion <NUM>. The welding bead <NUM> is not visible from the outside in the joining zone.

In the joining zones between the side faces <NUM>, on the other hand, lateral welding beads <NUM> are present, one of which is shown in <FIG>. The lateral welding beads <NUM> are intended to be covered after installation of the door or window frame, for example by a wall or by glass, and their presence is not therefore problematic.

The recesses <NUM> may also have different shapes from that shown in <FIG>. In fact, the shape of the recesses <NUM> depends on the shape of the protuberances <NUM>, so that modifying the shape of the protuberances <NUM> also changes the geometry of the recess <NUM>.

Claim 1:
A supporting device for supporting a profiled bar (<NUM>, <NUM>) during a welding operation, comprising a lower supporting element (<NUM>) and an upper supporting element (<NUM>) movable relative to each other between a clamping position, in which a profiled bar (<NUM>, <NUM>) can be locked between the lower supporting element (<NUM>) and the upper supporting element (<NUM>), and a disengagement position, in which the profiled bar (<NUM>, <NUM>) can be disengaged from the lower supporting element (<NUM>) and from the upper supporting element (<NUM>), wherein at least one supporting element selected from between the upper supporting element (<NUM>) and the lower supporting element (<NUM>) comprises:
- a containment element (<NUM>) for containing the softened material of the profiled bar (<NUM>, <NUM>) during welding, the containment element (<NUM>) having a deflecting protuberance (<NUM>) which projects towards a longitudinal axis (Z) of the profiled bar (<NUM>, <NUM>) for diverting the softened material towards the inside of the profiled bar (<NUM>, <NUM>);
characterized in that said at least one supporting element selected from between the upper supporting element (<NUM>) and the lower supporting element (<NUM>) further comprises:
- a base component (<NUM>), movable along a direction parallel to the longitudinal axis (Z) of the profiled bar (<NUM>, <NUM>);
- an intermediate component (<NUM>) to which the containment element (<NUM>) can be fixed, the intermediate component (<NUM>) being removably connectable to the base component (<NUM>),
- adjusting means for adjusting the position of the containment element (<NUM>) relative to the intermediate component (<NUM>).