The present invention relates to a fixing system for cement building constructions, in particular on a fixing system of the type that can be pre-assembled to concrete items.

The present invention further relates to a process for making said fixing system.

Fixing systems are known, which can be pre-assembled to concrete items.

These fixing systems typically comprise profiles or channels that have C-shaped cross-sections.

Such fixing profiles are usually made of steel or aluminium and comprise, on their back - i.e. the opposite surface to the C-shaped opening - a plurality of integral or dummy tie-rods forming the part anchoring the profiles themselves to the concrete.

The C-shaped fixing profile and the respective anchoring part are put into the formworks, as well as the reinforcement rods.

In particular, the tie rods of the fixing profile will be near the steel bars forming the reinforcement of the concrete structures before the concrete is cast.

The open part of the C-shaped fixing profile remains adherent to the formwork so that, after the concrete item has been produced, the C-shaped cavity is accessible for carrying out and completing the fixing; such completion also requires one or more connectors be inserted in the C-shaped sections of the profile .

Such connectors, which are known in themselves, can comprise a screw with a shaped head or a fixing plate into which a threaded pin is screwed.

The head of the screw enters the C and turns by 90° for carrying out the fixing.

The plate is pre-inserted into the C-shaped channel and houses the threaded bar for carrying out the fixing.

Other concrete structural elements - such as for example pillars, beams or prefabricated slabs- or steel structural elements - such as for example anchorages of ventilated façades or more simply glass doors, shelves and brackets of channels and other cable trays or various water or gas pipes are usually fixed to the threaded pins of the connectors and the screws -.

The threaded end of the screw and the threaded pin of the plate are fundamental fixing elements projecting from the concrete item.

A fixing system provided with a C-shaped profile is known, for example, from document EP 0 758 039 A1 filed in the name of Halfen.

Initially and for a long time the C-shaped fixing profiles were manufactured through hot drawing.

In fact such a process was deemed necessary for obtaining the desired shear and tensile strength, reinforcing the proximal edges to the C-shaped opening and increasing the mass of steel placed in adherence to the application point of the load.

However, it was later discovered that the fixing profiles could be successfully made by cold deformation obtaining tensile and shear strength at least comparable with those of the fixing profiles obtained by hot deformation.

The author of the present invention considers that anchoring profiles can be made through cold deformation obtaining mechanical resistance - at least tensile and shear resistance - even greater than that of hot deformed profiles.

Nevertheless the author of the present invention observed that it would be desirable to be able to produce fixing profiles obtained prevalently, or even exclusively, through cold deformation, and having a resistance to longitudinal sliding loads having a substantially similar value to the transverse tensile and shear load resistance - i.e. perpendicular to the profile itself.

An object of the present invention is therefore providing a fixing profile having an improved resistance to longitudinal sliding loads in comparison with known fixing profiles and which can be obtained through a less expensive and energy consuming process than the known ones.

In a first aspect of the present invention, such object is achieved with a fixing system for building constructions having the features according to claim 1.

In a second aspect of the present invention, such object is achieved with a process having the features according to claim 9.

The dependent claims are directed to further features of the invention.

The advantages attainable with the present invention shall become more readily apparent to the person skilled in the art by the following detailed description of some particular, non-limiting embodiments, described with reference to the following schematic figures.

• Figure 1 shows an exploded perspective view of a fixing system according to a first particular embodiment of the present invention;
• Figure 2 shows a perspective view of a section of the fixing profile of the fixing system of Figure 1;
• Figure 2A shows a perspective view of a portion of the toothing of the profile of Figure 2;
• Figure 2B shows a partially sectioned view according to the section plane A-A, of a portion of the toothing of Figure 2A coupled with the toothing of Figure 3;
• Figure 3 shows a perspective view of a connector of the fixing system of Figure 1;
• Figure 4 shows a perspective view of an instant of a production process in which, through a forming roller, the toothings of the profile of Figures 2, 2A, 6-9 can be made, according to a particular embodiment of the invention;
• Figure 4A shows a detailed view of the toothing of the forming roller of Figure 4, according to an observation direction parallel to the axis of rotation of the roller itself;
• Figure 4B shows a detailed view of the toothing of a forming roller according to a particular and alternative embodiment, according to an observation direction parallel to the axis of rotation of the roller itself;
• Figure 5 shows a pair of bending rollers that can be used to bend a strip of sheet metal and form the profile of Figures 2, 2A, 6-9 observed according to a parallel direction to the axes of rotation of the rollers themselves;
• Figure 6 shows a cross section of the fixing profile of
• Figure 2;
• Figure 6A shows an enlarged detail of the view of Figure 6;
• Figure 7 shows a cross section of a fixing profile of a fixing system according to a second particular embodiment of the present invention;
• Figure 8 shows a cross section of a fixing profile, having substantially omega shaped cross sections, of a fixing system according to a third particular embodiment of the present invention;
• Figure 9 shows a cross section of a fixing profile of a fixing system according to a fourth particular embodiment of the present invention;
• Figure 10 shows a perspective view of an anchor head screw that can be used as a connector in a fixing system according to the embodiments of the previous Figures;
• Figure 11 shows an exploded perspective view of a fixing system according to a fifth particular embodiment of the present invention.

In the present description:

• tensile strain on a fixing profile 10 means strain in a parallel direction to an anchoring nail 16 and/or to the pins 30 that are fixed to a respective connector 24, 24';
• shear strain means strain that pushes or pulls a connector 24, 24' in a substantially perpendicular direction both to the longitudinal direction of the profile 10 and in the direction of the tensile strain, i.e. strain orthogonal to the tensile strain acting both transversally to the profile 10 and in the direction of the profile 10;
• sliding strain means strain that tends to cause a connector 24 slide along a respective fixing profile 10, i.e. strain in which the load has the same direction as the profile 10.

By way of example, referring to Figure 1 a longitudinal sliding-, tensile- and shear strain, is parallel to the axis X, Z and Y respectively.

Figures 1, 2, 2A, 2B, 3, 4, 4A, 5, 6, 10 relate to a fixing system for fixing for example to concrete in building constructions according to a first particular embodiment that can be used for example for fixing another prefabricated concrete element to a concrete element - such as for example a pillar panel, or a glass-aluminium façade to the concrete slab of the building or even the guides of the lift to the concrete wall of the compartment in which the lift operates or even for example a pillar, beam, wall or slab.

Such fixing system, indicated with the overall reference 2, comprises at least one fixing profile 10, 10', 10", 10''' obtained by cold bending of a band, strip or other metal sheet so as to confer substantially C-shaped cross sections thereto.

A fixing profile 10, 10', 10", 10''' according to the invention can also have substantially omega shaped cross sections; such cross sections can however be considered, in the present description, to be a particular type of C-shaped sections.

The sheet metal from which the profile 10, 10', 10", 10''' is obtained preferably has a thickness comprised between 1-10 millimetres or between 2-5 millimetres and preferably 2-4 or 3 or 8 mm.

The sheet from which the profile 10, 10', 10", 10''' is obtained can be made for example of steel.

The fixing profile 10 forms an external back 14, 14', 14" and two side flaps 13, 13', 13" which extend perpendicularly or however transversally to the external back 14, 14', 14" (Figures 2, 6-9).

The side flaps 13, 13', 13" end in a respective engagement edge 15, 15', 15".

As for example, in Figures 2, 6-9, the external back 14, 14', 14", the side flaps 13, 13', 13" and the engagement edges 15, 15', 15" can form substantially flat faces.

The external back 14, 14', 14", the side flaps 13, 13', 13" and the engagement edges 15, 15', 15" define and delimit within them an internal channel 12.

The profile 10, 10', 10", 10''' is obtained by substantially cold deforming a band or strip of metal material that forms two major faces FM1, FM2.

In the present description hot and cold deformating a metal indicate processings in which the metal is plastically deformed respectively above and below the recrystallization temperature of the metal itself.

From the external surface of the external back 14 a plurality of anchoring nails 16 can extend, configured as anchoring elements of the fixing profile, i.e. to be fixed onto a first structural component, typically a concrete item.

Each anchoring nail 16 is preferably provided with a fixing end 18 which preferably forms a head, a cylindrical leg 20 with a constant section, preferably circular, and a connecting portion 22 with the external back 14 of the fixing profile 10.

Preferably, the fixing system comprises one or more connectors 24, 24' described in more detail below and configured to be inserted into the internal channel 12 of the fixing profile 10 or however to be engaged with the first toothing(s) 17 of a related fixing profile 10, 10', 10" 10'''.

The connectors 24 can advantageously have the shape of a generally and substantially flat plate (Figure 1, 3), with an overall square, rectangular (Figure 1, 3), polygonal shape, more or less oblong and a more or less rounded profile.

In combination or alternatively to such expedient, the fixing system can comprise one or more screws whose heads -which may for example be hammer or anchor heads (Figure 10) - are inserted into the internal channel 12 of the fixing profile 10.

The connectors 24 can be provided already inserted into profiles 10 by the installer of the profiles, or the purchaser of the profiles 10 can inserts the connectors 24 or the screws into the profiles themselves before having cemented or installed them.

Said fixing system can possibly further comprise a counter-plate 58 -which can have for example the shape of an L-shaped bracket; the aforementioned threaded pin 30, a nut or another female screw 62 and possibly a washer 60 (Figure 11).

According to an aspect of the invention, in the fixing profile 10, 10', 10", 10''' at least one from among the two major faces FM1, FM2 at or near at least one of the two engagement edges 15 forms at least a first toothing 17.

Advantageously, at least one from among the two major faces FM1, FM2 at or near both engagement edges 15 forms at least one toothing 17.

Preferably, each first toothing 17 extends at least along half of the overall length of the profile 10, more preferably along at least three quarters of such length, even more preferably along at least 0.9 times such length and even more preferably along the entire total length of the profile 10.

The internal channel 12, the external back 14, the at least two engagement edges 15 and each toothing 17 extend parallel or more generally longitudinally to the fixing profile 10.

Alternatively or in combination with what has been described up to now, each toothing 17 extends parallel or more generally longitudinally to the engagement edge on which it is obtained.

Still according to an aspect of the invention, the at least one toothing 17 -and more preferably each toothing 17- is obtained by plastic deformation.

Advantageously each first toothing 17 and/or second toothing 41, described in more detail below, is obtained by moulding, rolling, bending or more generally plastic deformation, cold.

Advantageously, the at least one toothing 17 is of the straight tooth type 170, in the sense that each tooth extends in a direction substantially perpendicular to the line -or however to the row- formed by the various teeth 170 of the toothing (Figure 2A, 2B).

In other embodiments not shown, however, the at least one toothing 17 can also be of the angled tooth type.

Advantageously both toothings 17 are obtained on a portion of one of the two major faces FM1, FM2 turned towards the inside of the profile 10 (Figure 2, 2A, 4, 6, 7, 11).

Furthermore, this makes it even more convenient to arrange the first toothings 17 and possibly the connector 24, 24' inside the profile 10, where they are more protected from splashes of liquid concrete that could otherwise filter between the toothings 41 and 17 reducing the adherence and resistance to longitudinal sliding.

Alternatively, as shown for example in Figure 8, 9 both toothings 17 are obtained on a portion of one of the two major faces FM1, FM2 turned towards the outside of the profile 10".

Preferably the teeth 170 of each toothing 17 have substantially trapezium shaped cross sections (Figure 2A) i.e. severed tip or triangular shaped.

Advantageously, the cross sections of the teeth 170 of each toothing 17 have a minimum height HD comprised between 0.8-4.0 millimetres, and more preferably comprised between 1-3 millimetres and for example equal to 1.5 millimetres, where such height HD means the difference in level between the top and the deepest point of the same cross section of the tooth in question (Fig.2A).

Advantageously, the cross sections of the teeth 170 of each toothing 17 form an angle at the vertex α [alpha] preferably comprised between 85°-135° and, for example, equal to 90°.

Preferably, the teeth 170 of the toothing 17 have a length WD comprised between 2-10 millimetres and more preferably between 3-6 millimetres (Figure 2A).

Such dimensions, shapes and, in general, constructional features of the teeth of the toothings 17 enable or, however, make easier teeth themselves be produced through plastic cold forming .

Advantageously, as will be described in more detail below, the toothings 17 are made through a first step in which semi-processed teeth are made - belonging to the corresponding semi-processed toothings - through cold deformation; in this step, the top of each tooth may be flat, rounded or even form, for example, a substantially sharp or pointed crest; still in this first step two adjacent semi-processed teeth are separated by a preferably V-shaped notch.

Preferably, the teeth of the toothings 17 assume their final shape already -and only- with this first cold deformation step.

With the subsequent bending process, which is preferably a dynamic process in which the metal sheet crosses a suitable series of forming rolls, the toothings 17 are generally subject to the stretching of the surface of the metal sheet.

The technique adopted can partly modify the shape of the hollow zone comprised between two adjacent teeth.

The toothing thus obtained has a shape repetitiveness consisting of flat, rounded or cusp shapes in the upper part of the tooth and the lower W-shaped part can acquire in the plan view a trapezoidal shape suitable for housing the teeth 410 of the toothings 41 of the connector 24.

Each toothing 41 preferably comprises a row of teeth 410; each of such rows is preferably arranged at a respective engagement surface 38 or 40, and is preferably parallel or longitudinal to such respective engagement surface 38 or 40.

The pitch and the dimensions of the teeth previously indicated enable a more uniform displacement of the material so that the toothed profile is regular both in the finished product and during processing.

The invention shows that the subsequent passages through the rollers do not compromise the quality of the toothing obtained, which remains sufficiently deep.

The toothing obtained from the process described enables the fixing to increase the sliding load performance increasing from 2 to 5 times the sliding load of the anchorage with respect to the load obtained without the toothings 17.

The toothing enables the sliding load resistance to be made greater than or equal to the tensile load resistance.

Each connector 24 advantageously has a cross sectional shape and size that conform, for example substantially complementary, to the internal shape of the internal channel 12 of the related fixing profile 10.

Each connector 24 advantageously has a length L, measured in the longitudinal direction of the fixing profile 10, greater than the width W1, measured in the cross sectional direction of the fixing profile 10, of the connector 24 itself (Figure 3).

Advantageously, the length L of the connector 24 is greater than or equal to 1.15 times its width W1, and even more preferably greater than or equal to 1.6 or 2 times the width W1.

Advantageously, the length L of the connector 24 is greater than or equal to 24 millimetres, more preferably greater than or equal to 40 or 40 millimetres.

Significant lengths L increase the resistance of the fixing system, enabling it to reach high resistance values and fulfil the needs expressed in the structural calculations by European legislation, even if threaded bars 30 produced by third parties, which are not made by the same manufacturer as the profile 10, are screwed thereto, and connectors 24, with steels commonly found in the world.

Advantageously, the connector 24 is arranged in the profile 10 when the assembly is offered to the buyers by the fixing manufacturer, preferably enabling the connector 24 to move along the profile 10 for adjusting the anchorage before locking it and fixing it definitively.

The profile 10 and connectors 24 preferably form a single supply kit able to offer known and certified performance levels.

Previously the anchorage comprised two distinct parts, the profile 10 and one or more bolts of the type shown in Figure 10; it was recommended to the user to use them correctly without combining profiles 10 and bolts coming from different manufacturers.

The previous teachings enable, in addition to what is known up to now, the sliding, or longitudinal shear, load resistance to be increased, as a third performance of the anchorage after the transverse shear and tensile resistance.

The anchorage with sliding performance is obtained with the simple use of common threaded bars 30 to be combined with the threaded hole 26 of the connector 24.

Advantageously, such threaded bars 30 have a standard thread MA, which can be easily found all over the world.

Such threaded bars 30 can be easily coupled with the connectors 24 which can be advantageously and cheaply produced by the same manufacturer as of the profiles 10 making the first toothings 17 and the second toothings 41 with the most appropriate coupling tolerances so as to increase the mechanical resistance of their coupling as much as possible.

Furthermore, the plate connectors 24 can be easily coupled with threaded pins 30 having various lengths, which can be very easily found in most countries and also in relatively remote places.

As, for example, in the embodiment of Figures 1, 2, 6, 8 the engagement edges 15 can be advantageously inclined towards the external back 14 of the profile 10, i.e. bent towards the inside of the profile 10, with an angle of inclination β, β' [beta, beta first] preferably comprised between 40°-90°, more preferably between 50°-75°, even more preferably between 60°-70° and for example equal to about 68°.

Advantageously, the angle of inclination β, β' is substantially acute.

An acute angle β, β' and for example comprised between 40°-90° makes the fixing system 2 much more resistant to axial tractions on the pins 30.

The engagement edges 15 join the respective side flaps 13, 13' forming bends whose internal surfaces have average radii of curvature RC preferably comprised between 0.5 and 5 millimetres, and more preferably between 1 and 3 millimetres (Figure 6A).

The two side flaps 13, 13' are inclined with respect to the external back 14, 14' by an angle γ, γ' [gamma, gamma first] preferably comprised between 45°-130°, more preferably between 85°-100° and even more preferably between 87°-92°.

Angles γ, γ' proximal to 90°, and for example comprised between 75°-105°, between 80°-100° or between 87°-92° increase the tensile resistance of the fixing system making it particularly suitable for making anchorages buried in concrete elements; such angles make the anchoring of the profile 10 to the concrete particularly effective and firm, possibly making the anchorages 16 superfluous.

As, for example, in Figure 6, 8 the angle γ [gamma] may be comprised between 85°-100° or about between 87°-92° .

As, for example, in Figure 7, 9 the angle β' [beta, beta first] can be comprised for example between 90°-120° and the angle γ' [gamma first] can be comprised, for example, between 65-75° degrees.

Accordingly, each connector 24 is preferably provided with a pair of inclined engagement surfaces 38 and 40 which can be engaged in shape coupling with the respective engagement edges 15 of the fixing profile 10, 10'.

Furthermore, advantageously on each engagement surface 38, 40 a second toothing 41 is provided configured for being engaged with the toothing 17 of the corresponding engagement edge 15 (Figure 3).

As will be set out in detail below, the teeth of the first toothings 17 of the engagement edges 15 actually can have strongly variable cross sections, which can be seen in Fig 2B, ideally moving along the direction of the width of the tooth itself, and have a substantially overall wedge shape, as shown for example in Figures 2A, 2B.

The second toothings 41 and/or the first toothings 17 can be zinc-coated, for example hot zinc-coated, without this compromising the correct operation and mechanical resistance.

For coupling with the possible wedge shape of the teeth of the toothings 17, the teeth 410 of the toothings 41 are smaller than the teeth of the toothings 17 so as to be able to enter sufficiently into the compartments between the teeth of the toothings 17, as shown for example in Figure 2B, where the profiles of the cross sections of the teeth 410 of the toothings 41 are shown with dashed and dotted lines.

The teeth 410 of the toothings 41 can have cross sections with substantially constant sizes and shapes, ideally moving along the width direction of the tooth itself.

The contact between the two inclined surfaces 38 and 40 of the connector 24 and the two corresponding engagement edges 15 of the fixing profile 10 allow the loads be stably transferred from the connector 24 to the internal channel 12, passing from such open upper edge to the external back 14, and from such external edge 14 to the anchoring nails 16 that enable the definitive transfer of the loads to the concrete.

The engagement between the toothings 17 and 41 notably increases the resistance of the fixing system to longitudinal sliding loads. For example, it was possible to obtain a profile 10 whose sliding resistance passed from 600 kg for smooth surfaces 15 to 2,300 kg for toothed surfaces 17.

The profile 10 according to the mentioned claims was designed to have a tensile load resistance of 1,700 kg.

Each connector 24 is also preferably provided, at the respective inclined surfaces 38 and 40, with a pair of rounded edges 42 and 44 configured for not generating indentations in the internal channel 12 in the assembled configuration of the fixing system.

The internal channel 12 advantageously has an overall height H, measured between the external back 14 and the open edge, which is smaller than the width W2, measured in the transverse direction of the fixing profile 10, of the internal channel 12 itself.

This latter feature enables the fixing profile 10 to occupy a reduced space within the concrete, thanks to the low depth of the internal channel 12, allowing for example the profile 10 to be positioned above the reinforcing bars/rebars.

A penetration -or embedding- by a greater depth H of the fixing profile 10 in the concrete can increase the fixing performance and therefore the load applicable to the fixing, but constrains the positioning of the reinforcement cages, imposing possible changes to the design and complex steps for preparing the reinforcements.

The mechanical effects on the fixing system between the engagement edges 15, the toothings 17 of the channel and the inclined surfaces 38, 40 and the toothings 41 of the connector 24 enable lower punctual strain with respect to the anchoring bolts of the system itself, contributing to greater performance levels with less local stress and a greater distribution of high loads with respect to the loads supported - or applied - by the anchoring bolts 24'.

In this way, the use of calculation coefficients in use in the design legislative standards give the fixing system higher levels of safety, an aspect which cannot be neglected in light of the applications of the fixing in the fixing sector for building constructions.

Each connector 24 can be provided with a connection portion 26, having for example the shape of a circular, square, polygonal hole, slit or other opening or female seat, preferably provided with a standard thread MA or other standard mechanism.

The adoption of a "standard" connection characterises the anchoring system simplifying the compatibility of the present invention with accessories that can be easily found throughout the world such as, for example, a simple threaded bar 30 preferably provided with a standard or unified thread, preferably MA.

On the other hand, the state of the art of anchoring systems with anti-sliding features exclusively provided for the use of bolts with a head designed like the channel 12, such as, for example, the anchor head screw 24' shown in Figure 10.

Now, anchor head screws are not commonly used and may be difficult to find, especially in certain regions of the world and in case of urgency, causing building site delays.

During the mounting of the connection system and prior to being tightened, each connector 24 can slide in and along the internal channel 12 of the respective fixing profile 10.

During the mounting in the site, the connector 24 can change position until the moment of tightening the bolt or other pin 30 with the other fixing components.

The threaded pin 30 can possibly be provided with a hexagonal end 31 -for example male hexagonal - which enables it to be screwed with electric screwdrivers.

Using the threaded pin 30 with electric screwdrivers 26 fixing the pin 30 in the hole 26 of the connector 24 is extremely quick and safe.

The hexagonal head 31 may be male or female - in the latter case internal to the threaded bar 30.

In embodiments not shown, the hexagonal end can be replaced with male or female coupling heads provided for coupling with corresponding screwing tools, and have for example a Torx shape (R).

This enables the fixing system to assume an adjustable position along the channel 12.

The connector 24 enables the load to be applied to the fixing profile 10 at any point along its length and independently from the position of the anchored nails 16 placed on the external back 14 of the fixing profile 10 itself.

According to an aspect of the present invention, the fixing profile 10 previously described can be produced through the following process:

• S.1) preparing a metal sheet LM which forms two major faces FM1, FM2 facing in two directions in the space substantially opposite each other;
• S.2) making on at least one of such major faces at least one toothing 17 extending in a predetermined working direction DL, by plastic cold forming;
• S.3) bending, again by cold deformation, the semifinished product obtained by step S.2 in order to obtain the fixing profile 10 so that the latter has substantially C-shaped cross sections and forms the aforesaid internal channel 12, external back 14 and so that the at least two engagement edges 15, the at least one toothing 17 is located at or near to a respective engagement edge 15, and so that the inner channel 12, the outer back 14, the at least two engagement edges 15 and the at least one toothing 17 extend longitudinally with respect to the fixing profile 10.

In step S.1 the metal sheet LM is preferably a metal band or strip, preferably flat.

The predetermined processing direction DL in step S.2 may be for example the direction in which the metal sheet is caused to advance during a rolling step or in a continuous bending machine.

A continuous bending machine in the present description means a machine comprising a plurality of work stations that simultaneously perform respective processes on the band, strip or other metal sheet while it advances along the machine itself.

Preferably in step S.2), at least two toothings 17 parallel or at least longitudinal to one another are created on at least one of such major faces, through plastic cold forming and both toothings 17 extend in the predetermined processing direction.

Preferably, in step S.2) each toothing 17 is arranged at or near to a respective edge of the metal sheet and is preferably arranged substantially parallel or longitudinal to such edge, which preferably forms one of the engagement edges 15 of the finished 10 profile.

In step S.2 the toothing or toothings 17 can be made through an appropriate die 50 provided with a forming toothing 52 in turn comprising a plurality of forming teeth 520 (Figure 4, 4A).

The die 50 is or advantageously comprises a forming roller configured for forming -for example by moulding or pressing 17- the finished profile 10 rolling or roto-translating on the starting band, strip or other metal sheet LM (Figure 4, 4A).

Advantageously the forming toothing or toothings 52 extend at or in proximity to the bases - or other ends - of the forming roller 50 (Figure 4).

In that case the forming toothings 52 are separated by an appropriate distance from one another (Figure 4).

Advantageously, at least part of the forming teeth 52, and more preferably all, have triangular shaped (Figure 4A) or severed tip shaped (Figure 4B) cross sections, so as to be able to produce toothings, described in more detail, having teeth whose cross sections are also substantially triangular or trapezoidal.

Teeth of such shapes form semi-processed toothings 17" whose teeth may possibly be later deformed by bending rollers 54, 56 reducing the total movements of the metal -and therefore the internal tensions- and without excessively changing the overall shape of the teeth during the deformation.

In other embodiments not shown, at least part of the forming teeth 520, and more preferably all of them, have substantially trapezium or cusp shaped cross sections.

Preferably, the cross sections of the forming teeth 520 have a minimum height HDF comprised between 1 and 10 millimetres or between 1 and 5 millimetres or between 1 and 3 millimetres, and more preferably comprised between 1.5-2.5 millimetres and for example about equal to 2.3 millimetres, where such height HDF means the difference in level between the top and the deepest point of a same cross section of the tooth in question (Figure 4A).

Preferably, the cross sections of at least part of the forming teeth 520, and more preferably all of them, form an angle at the vertex α [alpha] preferably comprised between 30°-110° or between 40°-90°, and for example equal to 60° (Figure 4A).

Preferably, step S.2 is performed prior to step S.3.

A possible particular example used in the aforementioned fixing system is now described.

The fixing profile 10, in which one or more connectors 24 or 24' have been previously inserted, can be for example embedded in a concrete cast leaving the internal channel 12 and the connectors 24 or 24' facing the external environment.

Once the concrete has solidified, one or more of the threaded pins 30 can be threaded into the respective threaded holes 26 or other connecting portions 26 of the various connectors.

The threaded pins 30 may possibly be glued into the respective female seats 26 of the connectors 24 increasing cohesion and preventing any detachment.

Possibly counterplates 58 and washers 60 can be inserted onto the threaded pins 30 and respective nuts 62 can be screwed so as to clamp the counterplates in a pack against the profile 10.

The counterplates 58 can have the shape of brackets to which other concrete or metal components or components of electrical or electronic appliances can in turn be fixed.

The counterplates 58 can possibly be previously buried in other concrete elements to be assembled to the first.

A possible particular embodiment of a process for producing the fixing profile 10 is now described.

A metal band slides in a continuous bending machine -not shown- in the predetermined direction DL.

In a first work station, the band is crushed and engraved by the roller 50 which rolls on the metal band LM rotating onto itself about an axis AR1 preferably perpendicular to the predetermined sliding direction DL.

Through cold deformation the two forming toothings 52 of the roller 50 form along the band LM two semi-processed toothings 17", which extend parallel -or more generally can extend longitudinally- to one another (Figure 4).

Possibly the teeth of such semi-processed toothings 17" can in part project above the remaining surface of the metal band LM.

Subsequently, one or more bending stations, at least one of which may be provided with a pair of bending rollers 54, 56 of the type shown in Figure 5, bend the metal band so as to form the fixing profile 10, in particular forming the internal channel 12, the external back 14 and the two engagement edges 15.

One or more pairs of bending rollers preferably comprise a first 54 and a second roller 56 which both form two truncated cone-shaped or however tapered end stretches (Figure 5).

Such rollers preferably rotate on themselves about axes of rotation AR2, AR3 parallel to one another.

Preferably, the shapes of the sides of the rollers are substantially complementary to one another (Figure 5).

For that purpose, preferably in the first 54 and in the second roller 56, the diameter of such ends is respectively increasing and decreasing ideally moving along the axis AR2, AR3 and towards the outside of the roller itself.

There may be three or more of such bending stations and for example a number comprised between 3-25, 5-20, 5-14 stations.

In a known way, the metal band LM is pressed passing into the middle of each pair of bending rollers 54, 56; in particular when pulling the metal sheet and making it advance in the various bending stations, each pair of bending rollers 54, 56 possibly deforms the semi-processed toothings, possibly giving the teeth more of a wedge shape, without compromising the ability of the toothings 41 of the connectors 24 to be coupled.

Preferably the predetermined working direction DL coincides with the longitudinal direction in which the finished profile 10, 10', 10", 10''' extends.

As partly already described, the toothings 17 enable the sliding resistance of the fixing systems of the type in question to be notably increased.

This enabled the author of the present invention to obtain the results previously disclosed.

The cold deformation of the toothings 17 hardens and toughens the metal, increasing the mechanical resistance of the toothings 17 themselves in general; at the same time, it enables the necessary processes for producing the profiles 10, 10', 10", 10''' to be uniformed, enabling them to be obtained mainly if not exclusively through cold deformations and increasing the efficiency and productivity of the production process and in particular reducing energy consumptions, in particular if compared with the energy consumptions of drawing processes or more generally hot forming processes, making the production process eco-sustainable.

Most of the processes for producing fixing profiles 10, 10', 10", 10''' can be performed by the same bending machine, preferably of the continuous type.

As already mentioned, the toothings 17 performed on the fixing profile through cold moulding -or more generally deformation- are more resistant to toothings that have been hot moulded or made for example by the removal of shavings, contributing to increasing the mechanical resistance of the profile 10, 10', 10", 10''' not only to sliding but also to shear and tensile strain.

The embodiments previously described are subject to different modifications and variations without departing from the scope of protection of the present invention.

For example, the threaded pins or even not threaded 30 can also be obtained as single parts from the respective connectors 24'.

Every reference in this description to "an embodiment", "an example of embodiment" means that a particular feature or structure described in relation to such embodiment is comprised in at least one embodiment of the invention and in particular in a particular variant of the invention as defined in a main claim.

The fact that such expressions appear in various steps of the description does not imply that they necessarily only refer to the same embodiment.

Furthermore, when a feature, element or structure is described in relation to a particular embodiment, it is observed that it falls within the skills of the average person skilled in the art to apply such feature, element or structure to other embodiments.

Numerical references that only differ in terms of different superscripts 21', 21", 21^III unless specified otherwise indicate different variants of an element with the same name.

Moreover, all details may be replaced with other technically equivalent elements.

For example, the materials used, and the dimensions, may be any according to the technical requirements.

It is to be understood that an expression of the type "A comprises B, C, D" or "A is formed by B, C, D" also comprises and describes the special case in which "A is comprised of B, C, D".

The expression "A comprises an element B" unless specified otherwise can be interpreted as "A comprises one or more elements B".

References to a "first, second, third, ... n-th entity" have the sole aim of distinguishing them from one another but the indication of the n-th entity does not necessarily imply the existence of the first, second ... (n-1)th entity.

The examples and lists of possible variations of this application are to be considered as non-exhaustive lists.