WO2013064187A1

WO2013064187A1 - System for forming composite laminates

Info

Publication number: WO2013064187A1
Application number: PCT/EP2011/069330
Authority: WO
Inventors: Jordi Brufau Redondo; Antoni SOLÀ LORENTE
Original assignee: Applus Servicios Tecnológicos S.L
Priority date: 2011-11-03
Filing date: 2011-11-03
Publication date: 2013-05-10
Also published as: US9789673B2; ES2647763T3; WO2013064309A1; US20140290866A1

Abstract

The present invention relates to a system for shaping laminar composites, comprising a base (1) with at least one longitudinal mandrel element (2) comprising a shape to be given to a composite laminate (3) arranged on the mandrel element (2) for obtaining a formed composite laminate (3'), and at least one roll-forming pressure device (4) assembled in a support carriage (5) such that it is capable of placing the roll- forming pressure device (4) in at least one position in which it rolls over the composite laminate (3) pressing it against the mandrel element (2) for forming it and obtaining the formed laminate (3'), the roll-forming pressure device (4) comprising a rolling hollow cover (4a) made of elastically flexible material with a tread (4b), and the rolling hollow cover (4a) being susceptible to containing a fill fluid at a fill pressure which allows the tread (4b) to elastically adapt to the shape of the mandrel element (2) and exert a chosen pressure on the composite laminate (3).

Description

SYSTEM FOR FORMING COMPOSITE LAMINATES

Technical Field of the Invention

The present invention is comprised in the technical field of systems for forming pre-impregnated composite laminates, particularly in the field of systems for the continuous production of sections of these laminates.

Background of the Invention

The parts obtained from composite laminates, such as, for example, those formed by sheets of carbon fibers or glass fibers pre-impregnated with resin (prepregs), are widely used in industry, for example as components in the aeronautical industry such as stringers, stiff eners and structural reinforcements. These components are distinguished by their light weight and high mechanical resistance (specific resistance).

One of the existing technologies for the continuous formation of composite laminates is based on a system of rollers and mandrel (roll-forming), originally conceived for manufacturing metal sections. Metal rollers press the composite against the surface of the mandrel debulking the composite and giving it the shape of the mandrel. The part obtained is then cured in an autoclave.

United States patent US-7249943-B2 describes an apparatus for forming stiffeners and other elements of reinforcement of composites, comprising a base having in its upper part a longitudinal mandrel with the shape to be given to the laminate arranged thereon, as well as one or several rollers assembled in one or several supports, such that the rollers roll over the composite pressing it against the mandrel for forming it and obtaining the composite part with the desired geometry and ready to be cured. The rolling surface of the rollers has a configuration complementary to the cross-section of the mandrel. Although this apparatus allows manufacturing straight structural sections with changes in thickness and bends, it is not capable of manufacturing more complex geometries, such as for example geometries with changes in plane for overcoming obstacles (joggles), twisted geometries, etc. Furthermore, even for obtaining simple geometric shapes, such as for example components with an omega-shaped cross-section, it is necessary to have several rollers, all provided with their respective pressure adjustment systems, which complicates and makes the structure of such systems more expensive and jeopardizes the quality of the part obtained due to the occurrence of wrinkles when the rollers act on the composite. Additionally, when working with solid rollers with more or less rigid surfaces, the pressure they exert on the pre-impregnated composite laminate produces in some areas, depending on the geometry of the mandrel, a displacement of the resin causing its thickness to be reduced in certain parts of the material, which leads to the material and the corresponding parts formed therefrom after curing losing part of their resistance characteristics, as well as dimensional tolerances and rigidity, which is particularly detrimental in applications of the parts in fields which require particularly reliable qualities, such as the aeronautical industry for example. Another effect that is produced in the laminates formed by means of roll-forming is the spring back phenomenon, which consists of the tendency to recover the initial geometry of the laminate once it has been formed by the forming rollers.

Description of the Invention

The object of the present invention is to overcome the drawbacks of the state of the art described above by means of a system for forming composite laminates, for example pre-impregnated carbon or glass fiber laminates, comprising a base with at least one mandrel element arranged longitudinally in its upper part, the mandrel element having the shape to be given to the composite laminate, which is arranged on the mandrel element for obtaining the formed laminate, and at least one roll-forming pressure device assembled in a support device such that it is capable of placing the roll-forming pressure device, for example in the form of a roller or roll, in at least one position in which it rolls over the composite laminate, pressing it against the mandrel element for forming it and obtaining the formed laminate, characterized in that

the roll-forming pressure device comprises a roll-forming hollow cover made of elastically flexible material with a tread which is preferably smooth;

the roll-forming hollow cover is susceptible to containing at least one fill fluid, such as air, or an inert gas, at a fill pressure which allows the tread to elastically adapt to the shape of the mandrel element and exert a controlled pressure in a broader, adaptable and controlled pressure area, on the composite laminate.

The most important contribution of the present invention is the versatility and adaptability of the rolling pressure device which can be used as a single forming element adaptable to many different geometries and jigs, and to the bends, joggles and changes in thickness which the component to be formed has. The chamber of each rolling pressure device can exert on the laminates a uniform pressure force without in turn imposing a uniform geometry.

The roll-forming pressure device is preferably assembled in a vertical adjustment mechanism for regulating the height and the pressure exerted by the roll- forming pressure device on the composite laminate, the vertical adjustment mechanism being assembled in the support device. According to the invention, the support device can be, for example, a support carriage longitudinally movable with respect to the mandrel element. Alternatively, the support device can be stationary in which case the mandrel element is longitudinally movable with respect to the support device.

The roll-forming pressure device is assembled in the support device such that when it rolls over the composite laminate, it presses it against the mandrel element such that the plies forming it are debulked and adapt to the surface of the upper face of the mandrel element, thus progressively adopting the shape of the mandrel element and the formed laminate thus being formed. Due to the flexibility of the roll-forming hollow cover, the pressure of the tread on the composite laminate arranged on the mandrel element adapt the plies of the composite laminate to the contour of the mandrel element, such that as the roll-forming pressure device gradually rolls over the composite laminate in the longitudinal direction, successive parts of the laminate are trapped between the smooth surface of the tread and the mandrel element. Therefore, the composite laminate is debulked and formed with the final desired geometry upon the passage of the roll-forming pressure device. The nature of the roll-forming hollow cover allows it to adapt to surfaces of composite laminates arranged on mandrel elements with shapes that lack symmetry on their sides, which allows forming formed laminates with sides having different configurations, which represents a substantial advantage of the present invention compared to technology with more or less rigid solid rollers used in conventional roll-forming systems. On the other hand, the roll- forming hollow cover has a higher adaptation capacity than classic roller systems do, absorbing the changes in the geometry of the mandrel element (for example joggles or asymmetries) to a greater extent, and exerting the pressure in a more progressive uniform manner and on a more extensive contact surface which, on one hand, reduces the number of wrinkles and the magnitude thereof and, on the other hand, prevents displacements of the resin, the desired distribution of the resin in the formed laminates thus being maintained to a greater extent, which in turn allows obtaining higher quality formed laminates in terms of, for example, their resistance, rigidity and dimensional tolerances.

Another added effect of the present invention to be highlighted with respect to the classic metal or elastomeric roller system is the securing effect which the roll- forming hollow cover exerts in its rolling as the result of a larger contact surface on the composite laminate, which aids in immobilizing the laminate, preventing its displacement to a greater extent with respect to the axis of symmetry in the roll-forming process as well as the subsequent occurrence of wrinkles. For example, in forming an omega-type stringer, since the tread can exert a pressure front acting simultaneously on the head (upper part), on the flanks and on the feet (side flanges) of the composite laminate, such that with one or several pneumatic chambers rolling from the initial part of the laminate towards the end part, the composite laminate is progressively formed, expelling the air from the central part towards the sides and from top to bottom, which contributes to reducing wrinkles in the formed laminate, a high quality formed and debulked laminate thus being obtained. Likewise, the flexibility and adaptability of the roll-forming hollow cover aids in reducing internal stresses in the composite laminate.

In one embodiment of the invention, the system further comprises at least one pair of side rolling pressure devices assembled on transversely opposite sides of the support device by means of respective transverse rotation shafts with respect to the mandrel element, such that they roll and exert pressure respectively on respective flanks defined between the upper part and respective side parts of the formed laminate due to the action of the roll-forming hollow cover of the roll-forming pressure device before this pair of side rolling pressure devices. Preferably, at least one of the side rolling pressure devices comprises an elastically flexible side rolling hollow cover, provided with a tread and filled with at least one fill fluid, which allows its tread to elastically adapt to the corresponding flank of the mandrel element and exert a predetermined pressure on the flank of the formed laminate. The rotation shaft of at least one of the side rolling devices can be inclined with respect to the mandrel element for the purpose of acting more efficiently on the turning radii of the geometry.

For marking longitudinal radii which join the changes in plane of the section to be formed in the formed laminate, the system can be provided with at least one pair of solid marking rollers assembled on transversely opposite sides of the support device by means of respective transverse and inclined rotation shafts with respect to the mandrel element such that they roll and exert pressure in the bent areas of the formed laminate. At least one of the marking rollers can be made of an elastomeric material.

The system can also comprise at least one pair of solid smoothing rollers assembled on transversely opposite sides of the support device by means of respective transverse and coplanar rotation shafts with respect to the mandrel element such that they roll and exert pressure in respective side parts of the formed laminate. At least one of the smoothing rollers can be made of an elastomeric material.

In one embodiment of the invention in which the support device is stationary and the mandrel element is longitudinally movable with respect to the support device, the system comprises an initial train of rollers comprising a initial upper roll-forming pressure device and an initial lower rigid roller, and a final train of rollers comprising a final upper roll-forming pressure device and a final lower rigid roller. The roll-forming pressure devices have the features previously described in this description and can be assembled in a support device which can be like the one previously described. The mandrel element is connected to drive means for passing the composite laminate between the upper roll-forming pressure devices and the lower rigid rollers., One or more intermediate rollers such as those previously described in the present specification for example can be arranged between the initial and final trains of rollers, and it also preferably comprises one or more lower rigid intermediate rollers on which the mandrel element is supported. It can also comprise one or more intermediate upper roll-forming pressure devices.

According to this embodiment, the mandrel element can comprise a longitudinal upper part with an initial sector and a final sector, the initial sector being shorter than the final sector such that due to the action of the roll-forming pressure devices in the composite laminate a longitudinal head is progressively formed in the composite laminate. The mandrel element can further comprise a lower face with longitudinal guiding means, for example a longitudinal track, in which the lower rigid rollers are guided.

Alternatively, the lower rigid rollers can be provided with respective circumferential grooves located between side contact surfaces, in which case the mandrel element is a guide element in the form of a flat bar with a guided lower part in the circumferential grooves and an upper part projecting from the circumferential grooves. The final sector of the upper part of the guide element projects further from the circumferential groove of the final rigid roller than the initial sector of the upper part of the guide element projects from the circumferential groove of the initial rigid roller, such that when the roll-forming hollow covers roll over the composite laminate arranged on the upper part of the guide element and the side surfaces of the rigid rollers, the upper part of the guide element is susceptible to forming a longitudinal head of progressively increasing height in the composite laminate. In order to achieve this increase in the height of the head of the composite laminate, the guide element can have a height that progressively increases from its initial sector towards its final sector, and/or the circumferential groove in the initial rigid roller can be deeper than the groove in the final rigid roller. In this last case, the guide element can have a uniform height from its initial sector towards its final sector. Also in this case, one or more trains of intermediate rollers can be provided, in which preferably the lower rigid rollers also have circumferential grooves located between side contact surfaces in which the lower part of the guide element is guided.

The system for forming composite laminates according to the present invention can further comprise at least one consolidation system, comprising at least one extensible cover and extending means for depositing the extensible cover on at least one part of the formed laminate for consolidating the formed laminate arranged on the mandrel element, the consolidation system comprising a thermal treatment system with a thermal blanket as an extensible cover and/or a vacuum bag debulking system with a laminar strip as an extensible cover, or a combined consolidation system with an extensible multifunction cover integrating the thermal bag and the laminar strip.

The extending means can be assembled in a support structure for progressively depositing the extensible cover at least on the formed laminate. The extensible cover is preferably made of a flexible material that can be wound on a winding device forming part of the extending means, such that the extensible cover is deposited on the laminate after unwinding it from the winding device.

For depositing the extensible cover as it is unwound from the winding device on the formed laminate, the extending means can comprise at least one extending and positioning roller assembled in the carriage. In one embodiment, the extending means comprise a first extending and positioning roller assembled transversely in the carriage such that it is capable of receiving the extensible cover and guiding it above the upper face of the formed composite laminate, as well as a second extending and positioning roller assembled transversely in the support structure such that it is capable of depositing the extensible cover on the formed laminate after its passage over the first roller. Preferably, the winding device is assembled in the support structure, and the support structure forms part of the support device.

According to the invention, several consolidation systems can be provided, such as for example a vacuum bag debulking system and a thermal treatment system, which can have the function of heating and/or cooling the formed composite laminate, and which can each comprise respective different consecutive extending means for depositing the extensible cover or, in the event that the extensible cover is a multifunction cover integrating the thermal blanket and the vacuum bag, common extending means for depositing the multifunction cover.

In processes for the continuous, roll-forming type formation of components such as stringers, once the component is formed it tends to suffer the spring-back effect, i.e., once the forming rollers have formed the composite laminate, the formed laminate can tend to partially recover the initial geometry. To prevent this effect, after the process for forming composite laminates a vacuum bag can be used consisting of a closed volume, established by means of a film or membrane covering the composite laminate, which is deposited on a preferably smooth surface and closed within the closed volume. The leak-tightness of the vacuum bag is formed by means of sealing elements in the perimeter of the vacuum bag. Furthermore, depending on the type of film or membrane used, aeration fabrics may be necessary for being able to extract the air in the entire closed volume. The vacuum is formed by connecting a circuit coming from a vacuum system, for example a vacuum pump, to the closed volume of the vacuum bag by means of at least one valve specific for such applications.

In the vacuum bag debulking system which, according to the present invention, can be used to prevent the spring-back effect, the extensible cover can be formed by a vacuum bag formed by an extensible laminar strip in the form of a film or membrane hermetically sealable on its sides at the base of the mandrel element, such that when it is connected to the vacuum circuit, it forms a bag which acts on the formed laminate, keeping it pressed against the mandrel element, debulking it and preventing the laminate from recovering part of the initial geometry after being formed by the forming rollers (spring-back effect).

For placing and positioning the extensible laminar strip progressively on at least the formed laminate, the debulking system can comprise, as extending means, placing means assembled in a supporting carriage structure movable along the mandrel element. These placing means can comprise a winding device on which the extensible laminar strip is wound and from which it is unwound as the supporting carriage structure moves forward along the mandrel element. As the extensible laminar strip is gradually unwound from the winding device onto the formed laminate, the placing means can comprise at least one placing roller assembled in the supporting carriage structure above the mandrel element.

In one embodiment, the placing means comprise a first placing roller assembled transversely in the supporting carriage structure such that it is capable of receiving the extensible laminar strip and guiding it above the upper face of the composite laminate or of the formed laminate, as well as a second placing roller assembled transversely in the supporting carriage structure such that it is capable of depositing the extensible laminar strip, after its passage over the first placing roller, on the debulked laminate. The winding device is preferably assembled in the supporting carriage structure, and the supporting carriage structure forms part of the support device.

The extensible laminar strip can be placed on the composite laminate before its passage over or the roll-forming pressure device or devices, in which case at least one of the pneumatic chambers of the roll-forming pressure devices can also serve to press the pneumatic strip on the contour of the formed laminate. Complementarily, or in the event that the placing means are arranged for placing the extensible laminar strip after the passage of the roll-forming pressure device or devices, the vacuum bag debulking system can comprise a roll-placing and sealing pressure device, comprising an elastic roll-placing hollow cover with a tread and filled with at least one fill fluid at a fill pressure which allows the tread to elastically adapt to the contour of the formed laminate, and is sized such that it is susceptible to pressing the sides of the extensible laminar strip against the side parts of the base of the mandrel element for enabling the hermetic sealing of the laminar strip and, therefore, the generation of the vacuum bag. The air inlet routes which would cancel the vacuum effect generated inside the closed volume by the vacuum bag as the supporting carriage gradually moves forward are thus substantially prevented.

Depending on the geometry of the composite laminate, the film or membrane making up the laminar strip which allows forming the vacuum bag can incorporate auxiliary elements necessary for generating the vacuum, such as for example an absorption or aeration fabric. This film or membrane, with its possible auxiliary elements, is unwound from the winding device and extended on the exposed face of the composite laminate such that as the result of its flexibility, it adapts substantially to the surface and contour of the formed laminate located on the mandrel element. For sealing the free sides and the end of the laminar strip forming the vacuum bag on the base of the mandrel element, leak-tightness forming elements, among others, can be provided such that the air inlet routes in the area in which the vacuum is generated are substantially prevented. For sealing the sides of the vacuum bag in the case of complex geometries of the formed laminate, the mandrel element can comprise longitudinal notches at its base which, by means of a rolling dispensing system assembled in the supporting carriage structure, allow housing therein respective gaskets assuring the side leak-tightness of the membrane as it is gradually extended as the supporting carriage structure gradually moves forward, closing and sealing the volume of the vacuum bag in which the composite laminate and/or the formed laminate is confined and where the vacuum is applied.

The vacuum is formed from the start and as the closed volume increases behind the rolling pressure device in the longitudinal direction of the mandrel element and in the same forward movement direction of the support carriage due to the pressure exerted by the rolling hollow cover of the roll-forming pressure device and/or of the roll-placing pressure device. Therefore, when the support carriage with the rolling pressure device moves, the vacuum keeps the formed laminate pressed against the mandrel element consolidating the desired geometry as the formed laminate gradually cools or, where appropriate, as will be explained below in the present description, is cured. In the retained area of the laminar strip there is at least one vacuum valve installed where the circuit from the vacuum pump will be connected.

According to this embodiment, when the support device moves forward and the pressure roller gradually forms the composite laminate, the bag the free end of which is retained in the rear part of the base of the mandrel element, is gradually unwound from the winding device and, passing through at least one placing roller and then through the roll-forming pressure device with the rolling hollow cover, it is progressively deposited on the composite laminate. When the debulking process has ended, this system is moved backwards rewinding the membrane and, where appropriate, the side leak-tight gaskets, leaving the formed laminate free.

In another embodiment of the system, and depending on the complexity of the final geometry of the component, the placing means for placing the extensible laminar element of the vacuum bag and the leak-tight gasket dispensing system, when needed, can be placed in front of the forming carriage, such that the roll-forming pressure device or devices perform at the same time the forming, the placement and the sealing of the extensible laminar strip for forming the vacuum bag.

In roll-forming type processes for the continuous formation of composite parts, cooling of the component is usually essential for consolidating the formed composite part and stopping the curing process started in the heating applied to the laminate prior to and during the forming process, and also for storing the formed component in a cold chamber for subsequent curing. Existing technologies are based on cooling the mandrel element by means of pressurized air systems on the exposed face of the composite laminate or by means of a cooling circuit integrated in the mandrel element.

For performing a cooling thermal treatment, the present invention can be provided with a thermal consolidation system, such as for example a cooling system for the consolidation of the geometry of the formed laminate, in which the extensible cover is a cooling thermal blanket. This system reduces the process time since it continuously follows the forming process and has a high thermal energy transfer capacity since it is in direct contact with the exposed face of the formed laminate. Furthermore, it minimizes thermal inertia because it substantially reproduces the geometry of the formed laminate and, accordingly, the cooling which is achieved is more homogenous, minimizing the internal stresses of the formed laminate.

The cooling thermal blanket according to the present invention can comprise a lower face substantially capable of adapting to the contour of the formed laminate arranged on the mandrel element and an upper face, and it can be connectable to a circuit of a cooling heat exchange fluid, such as a liquid such as, for example, water, for which the cooling thermal blanket comprises at least one fluid inlet and at least one fluid outlet connectable to the circuit coming from a cooling device, and at least one internal chamber located inside the thermal blanket connected to the circuit coming from the cooling device through the fluid inlet and the fluid outlet of the thermal blanket.

For positioning the thermal blanket progressively on the formed laminate, the thermal treatment system can comprise, as extending means, positioning means assembled in a support carriage structure movable along the mandrel element. These positioning means can comprise a winding device on which the thermal blanket is wound and from which the thermal blanket is unwound as the support carriage structure moves forward along the mandrel element. For depositing the thermal blanket as it is unwound from the winding device on the formed laminate, the positioning means can comprise at least one positioning roller assembled in the support carriage structure above the mandrel element. In one embodiment, the positioning means comprise a first positioning roller assembled transversely in the support carriage structure such that it is capable of receiving the thermal blanket and guiding it above the upper face of the formed laminate, as well as a second positioning roller assembled transversely in the support carriage structure such that it is capable of depositing the thermal blanket, after its passage over the first positioning roller, on the debulked laminate. Preferably, the winding device is assembled in the support carriage structure, and the support carriage structure forms part of the support device.

Although the thermal blanket has a natural geometry reproducing the exposed surface of the composite laminate such that it substantially adapts to the contour of the formed laminate which is on the mandrel element as the result of its flexibility, preferably it is also is capable of acquiring a substantially flat geometry as it is wound on the winding device assembled in the support carriage structure.

In one embodiment of the invention, the cooling thermal blanket comprises a plurality of tubes extending between its upper and lower faces and they can be connected to the fluid inlet by means of at least one inlet manifold and a the fluid outlet by means of at least one outlet manifold. In this embodiment, the inlet and the outlet of this circuit of tubes inside the thermal blanket are preferably located at the fixed end of the cooling thermal blanket, such that the fluid flows through the tubes inside the thermal blanket from the fixed end where the fluid inlet is located to the opposite end to again return to the fixed end, such that suitable cooling takes place. Thermocouples are additionally placed inside the thermal blanket for the control and regulation of the temperature of the thermal blanket. Their connectors are likewise located at the fixed end of the thermal blanket. The distribution of the tubes inside the thermal blanket and the path of the cooling fluid are configured such that it compensates for the thermal inertia of the mandrel element and a more homogenous and efficient cooling of the laminate is thus achieved.

Alternatively, the same thermal blanket can also be used as a heating blanket for curing the formed laminate. To that end, the thermal blanket can be provided with at least one thermistor extending longitudinally through the inside of the thermal blanket and fed by the corresponding electrical circuit, or a heating fluid can be circulated through the inside of the thermal blanket. In this last case, the fluid inlet and the fluid outlet are connected to a heat exchange circuit comprising a heating device. The blanket is made of a flexible material capable of withstanding a temperature greater than the curing temperature of the formed laminate, at which either the fluid coming from the heat exchanger or the resistors are heated, for curing the resin. The heating fluid can be, for example, a special liquid for such applications such as an oil. The distribution of the tubes or resistors and the direction of the flow or the temperature of the resistors are configured the same way as in the cooling blanket for compensating for the thermal inertia of the mandrel element.

Both in the case of the cooling blanket and of the heating blanket, for increasing the thermal energy transfer capacity the system can be provided with at least one conduit for a heat exchange fluid extending internally through the mandrel element and it can be connectable to the circuit where the fluid coming from the circuit coming from the cooling device or the heating device circulates.

The thermal blanket can be positioned on the composite laminate directly after the passage of the roll-forming pressure device or devices. Alternatively, in the event that the system for forming composite laminates according to the present invention also comprises the vacuum bag debulking system described above, the thermal blanket can be positioned on the extensible laminar strip which is placed on the formed laminate.

When the composite laminate has been formed and the thermal blanket arranged, a cooling liquid, for example cold water, can be circulated through the conduits inside the mandrel element and through the conduits of the thermal blanket for the purpose of cooling and therefore consolidating the formed laminate. Once the formed laminate is consolidated, in such application the formed laminate consolidated by cooling is removed from the mandrel element and it is cold stored pending use in a co-curing process in an autoclave.

Alternatively, in the application of curing the formed laminate in the mandrel element itself, it is not necessary to cool the formed laminate for consolidating its geometry since by extending the thermal blanket on the composite part eventually debulked in the vacuum bag, this time with the circulation of a heating liquid or by means of an electric resistor integrated in the thermal blanket, curing is obtained keeping the component in vacuum conditions and at the curing temperature for the necessary time, finally obtaining a consolidated and cured part with the geometry reproducing the mandrel element. Therefore, this embodiment of the system according to the present invention can dispense with curing in the autoclave which allows on one hand saving the step of transferring the formed composite part to the autoclave and dispensing with the autoclave as such, and, on the other hand, a more homogenous curing is obtained because, since the thermal blanket adapts to the contour of the formed laminate, a better and more homogenous application of the heat for curing takes place.

Depending on the complexity of the geometry of the final component, the thermal blanket and the vacuum bag can be integrated in a windable multifunction cover which can be deposited in the composite laminate by extending and positioning means such as those described above. Such multifunction cover can comprise a first flexible longitudinal part forming the thermal blanket and a second part attached to the first part which can extend around and forms the vacuum membrane or film which can incorporate the leak-tight gasket form for assuring the side sealing at the base of the mandrel element, forming a single multifunction cover extensible from a winding device operating similarly to the winding device described above in reference to the thermal bag.

The fill fluid of the rolling hollow cover or covers can be a gaseous fluid such as for example air, liquid, viscous or viscoelastic, and combinations of such fluids for filling the rolling hollow cover can also be used. In a preferred embodiment, the fill fluid is a gas, such as for example air, in which case the rolling hollow cover can be a pneumatic chamber. The weight, thermal stability and viscosity of the fill fluid or fluids can be used as an element which aids in adapting the laminate to the geometry of the mandrel element, which is particularly useful in hot-forming processes. When the system is provided with several rolling hollow covers, they can contain the same or different fill fluids.

Brief Description of the Drawings

Aspects and embodiments of the invention are described below based on schematic drawings in which

Figure 1 is a front-side perspective view of a first embodiment of the forming system according to a the present invention;

Figure 2 is a simplified side elevational view of the forming system shown in Figure 1 ;

Figure 3 is a simplified upper plan view of the forming system shown in Figure

1 ;

Figure 4 is a section view of the system along line A-A seen in Figure 2;

Figure 5 is a section view of the system along line B-B seen in Figure 2;

Figure 6 is a front perspective view of an embodiment of a mandrel element on which a shaped laminar material is overlain;

Figure 7 is a simplified view of an embodiment of a circuit of a heat exchange fluid for the system according to the invention

Figure 8 is a simplified side elevational view of a second embodiment of the forming system according to the present invention;

Figure 9 is an upper plan view of the forming system shown in Figure 8;

Figure 10 is a section view along line C-C seen in Figure 9;

Figure 1 1 is a front perspective view of an embodiment of a multifunction cover integrating the thermal blanket and vacuum bag functions;

Figure 12 is a simplified side elevational view of a third embodiment of the present invention;

Figure 13 is a front-side perspective view of the debulking and forming elements present in said third embodiment;

Figure 14 is a side elevational view corresponding to Figure 13;

Figure 15 is a rear-side perspective view corresponding to Figure 13;

Figure 16 is a partial upper plan view based on Figure 13;

Figure 17 is a rear-side perspective view of the system for positioning the thermal blanket present in the embodiment of Figure 12;

Figure 18 is a rear-side perspective view of the system for placing the laminar strip and the system for positioning the thermal blanket present in the embodiment of

Figure 12;

Figure 19 is a cross-section view along line E-E shown in Figure 12;

Figure 20 is a cross-section view along line D-D shown in Figure 12;

Figure 21 is a view of detail I marked in Figure 12;

Figure 22 is a rear-side perspective view based on Figure 21 ;

Figure 23 is a simplified side elevational view of a fourth embodiment of the system of the present invention;

Figure 24 is a cross-section view along line F-F shown in Figure 23;

Figure 25 is a cross-section view along line G-G shown in Figure 23;

Figure 26 is a simplified side elevational view of a fourth embodiment of the system of the present invention;

Figure 27 is a cross-section view along line F-F shown in Figure 26;

Figure 28 is a cross-section view along line G-G shown in Figure 26.

These drawings show reference numbers identifying the following elements:

1 base

2 longitudinal mandrel

2a upper part of the mandrel

2b conduit for heat exchange fluid in the mandrel

2c longitudinal track

2d lower part of the mandrel

3 preimpregnated composite laminate

3a upper face of the laminate

3' formed laminate

3a' upper face of the formed laminate

4 roll-forming pressure device

4a roll-forming hollow cover

4b tread

4c rim

4d rotation shaft

5 forming carriage

5a, 5b vertical support section

5a', 5b' lower vertical support section

5c, 5d horizontal attachment section

5c', 5d' lower horizontal attachment section

5e, 5f longitudinal extension

6a, 6b lug

7 support carriage structure

7a, 7b side partition

7c transverse attachment bar

7d, 7e vertical support section

8 thermal blanket

8a upper face 8b lower face

8c longitudinal tubes

8d fluid inlet

8e fluid outlet

8f inlet manifold

8g outlet manifold

9a first positioning roller

9b second positioning roller

10 circuit of a heat exchange fluid

10a cooling device

10b heating device

10c fluid pump

10d feed conduit

10e outlet conduit

10f control valve

10g valve of the cooling circuit

10h valve of the heating circuit

1 1 winding device

12 support wheel

13 lower guiding wheel

14 supporting carriage structure

14a, 14b side partition

14c, 14d vertical support section

15 winding device

16 laminar strip of vacuum bag

17a first placing roller

17b second placing roller

18 multifunction cover

18a first part of the multifunction cover

18b second part of the multifunction cover

19 electric resistors

20 side rolling pressure device

20a side rolling hollow cover

21 securing rolling pressure device

21 a securing rolling hollow cover

22 roller made of an elastomeric material for marking radii 23 smoothing roller made of an elastomeric material

24 roll-placing pressure device

24a roll-placing hollow cover

25 fixing system

26 lower rigid roller

26a perimetric flange

26b rotation shaft

26c circumferential groove

26d side contact surface

Embodiments of the Invention

According to the embodiment shown in Figures 1 to 5, the system for forming composite laminates comprises a base -1 - with a longitudinal mandrel element in the form of a longitudinal mandrel -2- having an omega-shaped cross-section to be given to a laminar composite -3- which can be, for example, a preheated prepeg laminate which is arranged on the mandrel -2- for obtaining a formed laminate -3'-. Likewise, the system comprises a support device in the form of a forming carriage -5- in which is assembled a roll-forming pressure device in the form of forming pressure roller -4- comprising a roll-forming hollow cover in the form of an inflatable forming pneumatic chamber -4a-, with a tread -4b- having a smooth surface and is elastically adaptable to the shape of the mandrel -2-. The forming pneumatic chamber -4a- is susceptible to containing at least one fill fluid at a fill pressure which allows the tread -4b- to elastically adapt to the shape of the mandrel -2- and exert a chosen pressure on the composite laminate -3-. Several conduits -2b- through which a heat exchange fluid can circulate extend through the inside of the base -1 - and the mandrel -2-. As shown in Figure 6, the mandrel -2- can have a complex shape which allows obtaining formed composite parts, for example having an omega-shaped cross-section with a variable geometry extending in variables planes, or having other sections.

In the embodiment shown in Figures 1 to 5, the forming carriage -5- is a carriage longitudinally movable with respect to the mandrel -2-, comprising a support carriage structure -7-. The forming pressure roller -4- rotates on a transverse shaft coupled by its respective ends in respective lugs -6a, 6b- which in turn are assembled in respective vertical support sections -5a, 5b-, the lower end parts of which are provided with respective lower guiding wheels -13- arranged such that they are susceptible to rolling on the lower face of the base -1 -. The height at which the lugs -6a, 6b- are assembled in the vertical sections -5a, 5b- is adjustable, such that the lugs -6a, 6b- and the vertical sections -5a, 5b- form a vertical adjustment mechanism -5a, 5b; 6a, 6b- which allows adjusting the vertical position of the forming pressure roller -4- and, therefore, contributing to regulating the pressure exerted by the forming pressure roller -4- on the composite laminate -3-.

The support carriage structure -7- comprises respective side partitions -7a, 7b-, also provided in their lower parts with lower guiding wheels -13- arranged such that they are susceptible to rolling on the lower face of the base -1 -. The forming carriage -5- and its support carriage structure -7- are supported and can roll on the base -1 - on one hand by means of the forming pressure roller -4- and, on the other hand, by means of the support wheels -12- which roll over the sides of the upper face of the base -1 , whereas they are guided in the lower portion at the base by means of the guiding wheels -13-.

The side partitions -7a, 7b- of the support carriage structure -7- are attached to one another by means of a transverse bar -7c-. At the end part, opposite the forming pressure roller -4-, the support carriage structure -7- is provided with respective vertical support sections -7d, 7e- between the upper parts of which a winding device -1 1 - is arranged assembled in a transverse rotation shaft and in which is wound a thermal blanket -8- in the form of a windable flexible strip. Between the partitions -7a, 7b-, there are furthermore arranged a first positioning roller -9a- assembled transversely in the support carriage structure -7- such that it is capable of receiving the thermal blanket -8- and guiding it positioned above the upper face -3a- of the formed laminate -3'-, and a second positioning roller -9b- assembled transversely in the support carriage structure -7- such that it is capable of depositing the thermal blanket -8-, after its passage over the first roller -9a-, on the formed laminate -3'-. The support carriage structure -7- is attached to the forming carriage -5- by means of respective horizontal attachment sections -5c, 5d- connecting the support sections -5a, 5b- with the respective upper parts of the side partitions -7a, 7b- of the support carriage structure -Ί-.

The thermal blanket -8- is made of a flexible material and comprises an upper face -8a- and a lower face -8b- and is susceptible to adapting to the contour of the formed laminate -3'- arranged on the mandrel -2- and comprises therein a plurality of also flexible, longitudinal tubes -8c- extending between its upper face -8a- and lower face -8b-. As can be seen in Figure 7, these longitudinal tubes -8c- are connected, for example, by means of respective manifolds -8f, 8g- forming part of the thermal blanket -8-, respectively, to a fluid inlet -8d- and a fluid outlet -8e-, such that a heat exchange liquid can flow through said tubes -8c-.

The thermal blanket -8- forms part, together with the conduits -2b- extending axially through the inside of the base -1 - and of the mandrel -2-, of a thermal treatment system such as the one shown in Figure 7, where it can be seen that the thermal blanket -8- comprises a fluid inlet -8d- and a fluid outlet -8e- which are connected respectively to an inlet manifold -8f- and to an outlet manifold -8g- in turn connected to the longitudinal tubes -8c-. In the embodiment shown in Figure 7, the fluid inlet -8d- of the thermal blanket -8- is connected through a feed conduit -10d- to a fluid pump -8c- which in turn is susceptible to suctioning a cooling fluid cooled by a cooling device -10a- or a heating fluid heated by a heating device -10b-, and pumping it to the fluid inlet -8d- of the thermal blanket -8-. On the other hand, once the cooling fluid or, where appropriate, the heating fluid, has passed through the longitudinal tubes -8c-, it is collected by the outlet manifolds -8g-, passes through the fluid outlet -8e- and flows through the outlet conduit -10e- from which, depending on whether it is a cooling or heating fluid, it is directed by the action of the control valve -1 Of- to the cooling device -10a- or to the heating device -10b-. Valves -10g- and -1 Oh- respectively interconnected in the circuit travelled by the cooling fluid and in the circuit travelled by the heating fluid are provided to direct the respective fluids.

The embodiment of the system illustrated in Figures 1 to 5 operates as follows for obtaining a formed laminate from the composite laminate -3-.

Once the composite laminate -3- is arranged on of the mandrel -2-, the forming carriage -5- and its support carriage structure -7- are moved by the action of a motor (not shown in the drawings) such that the pressure roller -4- rolls in the direction of the arrows shown in Figures 1 to 3 for obtaining the formed laminate -3'- from the composite laminate -3- previously heated to a suitable temperature for assuring ductility for forming purposes and, in the event that the composite laminate -3- is a prepeg laminate, for activating the corresponding resin.

Given that the forming pressure roller -4- is assembled in the forming carriage

-5- such that it presses the composite laminate 3- against the mandrel -2-, the composite laminate -3- is debulked and bent, thus progressively adopting the shape of the mandrel -2- and thereby becoming a formed laminate -3'-. The flexibility of the forming pneumatic chamber -4a- and the pressure of the tread -4a- on the composite laminate -3- located on the mandrel -2- makes the composite laminate -3- adapt to the contour of the mandrel -2- such that as the forming roller -4- rolls in the longitudinal direction on the laminate -3-, successive parts of the laminate -3- are trapped between the smooth surface of the tread -4b- and the mandrel -2- and the composite laminate -3- is thus formed upon the passage of the forming pressure roller -4-.

Since the tread -4b- of the forming roller exerts its pressure first on the upper face -3a- of the laminar composite -3- and from there progressively on the sides and then on the side flaps of the composite laminate -3- and thus progressively from the front part of the composite laminate -3- backwards, a form is progressively produced with the expulsion of air from the part central towards the sides and from top to bottom in the laminate -3-, which contributes to the displacement and to the reduction of wrinkles in the formed laminate -3'-, a high quality formed laminate -3'- thus being obtained.

As the carriage -5, 7- gradually moves forward, the thermal blanket -8- the free end of which is retained in the rear part of the base -1 -, is gradually unwound from the winding device -1 1 - and, passing through the first positioning roller -9a- and then through the second positioning roller -9b-, it is progressively deposited on the formed composite part -3'-. The presence of the second positioning roller -9b- is optional.

For consolidating the formed laminate -3'-, a cooling liquid, for example cold water, is circulated through the conduits -2c- inside the base -1 - and the mandrel -2- and through the longitudinal tubes -8c- of the thermal blanket -8- for the purpose of cooling and therefore consolidating the formed laminate -3'-. Once the formed laminate

-3'- is consolidated the cooling liquid flow is cut off and the forming carriage -5- is retracted and the winding device -1 1 - is operated for removing the thermal blanket -8- and winding it again.

Alternatively to the consolidation of the formed laminate -3'-, a heating liquid, for example oil, can be circulated through the longitudinal tubes -8c- and the conduits -2b- for heating the formed laminate to its curing temperature, such as for example up to 180⁵C in the cases of parts obtained from prepregs, for obtaining a cured part.

In the embodiment shown in Figures 8 to 10, the system comprises all the elements described above in reference to Figures 1 to 17, and furthermore a vacuum bag debulking sub-system. As can be seen, the forming carriage -5- comprises a supporting carriage structure -14- with respective side partitions -14a, 14b-, also provided with support wheels -12- and lower guiding wheels -13-. The supporting carriage structure -14- is provided with respective vertical support sections -14c, 14d- between the upper parts of which a winding device -15- is arranged assembled on a transverse rotation shaft and on which a windable laminar strip -16- is wound. Between the partitions -14a, 14b- there are furthermore arranged a first placing roller -17a- assembled transversely in the supporting carriage structure -14- such that it is capable of receiving the laminar strip 16- and guiding it positioned above the upper face -3a- of the composite laminate -3-, and, optionally, a second placing roller -17b- assembled transversely in the supporting carriage structure -14- such that it is capable of depositing the laminar strip -16- after its passage over the first placing roller -17a- on the composite laminate -3-. The supporting carriage structure -14- is attached to the forming carriage -5- by means of respective longitudinal extensions -5d, 5e- of the horizontal attachment sections -5c, 5d- connecting the support sections -5a, 5b- with the respective upper parts of the respective side partitions -7a, 7b; 14a, 14b- of the structures -7, 14-.

The laminar strip -16- is a film or membrane serving to create a vacuum in the composite laminate -3- and it can incorporate auxiliary elements necessary for creating the vacuum, such as for example an absorption or aeration fabric. The laminar strip -16- with its possible auxiliary elements is unwound from the winding device -15- and extended above the upper face -3a- of the composite laminate -3- such that as the result of its flexibility, it substantially adapts to the surface and contour of the composite laminate -3- placed on the mandrel -2-. Seen in the movement direction of the forming carriage 5- in the embodiment of the system shown in Figures 8 to 10, the supporting carriage structure -14- with the winding device -15- is arranged in front of the roll- forming pressure device -4- such that the latter acts on the extended laminar strip -16- such that since the roll-forming pressure device -4- has a high capacity of adapting to the exposed surface -3a- of the composite laminate -3- due to its pneumatic chamber -4a- seals the longitudinal edges of the laminar strip -16- against the base -1 -, a vacuum bag thus being formed around the composite laminate -3-. By means of sealing the free sides of the laminar strip at the base the air inlet routes which would cancel the vacuum effect generated inside the closed volume by the vacuum bag as the forming carriage -5- gradually moves forward are substantially prevented.

The free sides of the laminar strip arranged on the mandrel are likewise sealed by means of, among others, leak-tightness forming elements (not shown in the drawings), such that the air inlet routes in that area are substantially prevented when the vacuum is created. For sealing the sides of the laminar strip -16- and for thus being able to form the vacuum bag in the case of complex component geometries, the mandrel can comprise longitudinal notches which, by means of a rolling dispensing system (not shown in the drawings) assembled in the forming carriage -5- or in the supporting carriage structure -14-, allows housing therein a gasket assuring the side leak-tightness of the membrane as it is gradually extendeds as the carriage -5- gradually moves forward, closing and sealing the sides of the laminar strip -16- and thus creating the volume of the vacuum bag in which the material is confined and where the vacuum is applied.

The vacuum is formed from the start and as the closed volume of the vacuum bag increases behind the pneumatic chamber -4a- in the longitudinal direction of the mandrel -2- and in the same forward movement direction of the forming carriage -5- due to the pressure exerted by the roll-forming pressure device -4-. The vacuum keeps the formed laminate -3'- pressed against the mandrel -2- consolidating the geometry of the formed laminate -3'- as it gradually cools. In the retained area of the laminar strip at least one vacuum valve (not shown in the drawings) is installed where a pneumatic circuit coming from a vacuum pump will be connected (not shown in the drawings).

Figure 1 1 shows an embodiment of a multifunction cover -18- integrating the thermal blanket -8- and the vacuum laminar strip -16- in a single windable multifunction element. Such multifunction cover comprises a flexible longitudinal upper part -18a- forming the thermal blanket -8- attached to a lower part -18b- in the form of a flexible film or membrane which serves to form the vacuum bag, the multifunction cover -18- being unwindable from a winding device similar to the winding device -8- herein described in reference to the thermal bag. The upper part -18a- houses electric heating resistors -19-. The lower part 18b- is wider than the upper part -18a- assuring optimal side sealing at the base -1 - where the mandrel -2- is located.

Figures 12 to 22 show a third embodiment of a system for obtaining formed laminates according to the present invention.

According to this third embodiment, the system comprises a roll-forming pressure device in the form of a forming roller -4- comprising a roll-forming hollow cover -4a- with a tread similar to the roll-forming device -4- described above in the present description in reference to the first two embodiments of the invention.

Respective side rolling pressure devices -20- comprising respective pneumatic chambers -20a- are arranged behind the forming roller -4-. The pneumatic chambers -20a- rotate on respective transverse shafts inclined with respect to the mandrel -2- and they are arranged such that upon rolling, they exert pressure on the flanks of the formed laminate -3'- obtained by the action of the forming roller and therefore debulk and form them. The pneumatic chambers -20a- are elastically deformable and filled with at least one fill fluid at a fill pressure which allows their treads to adapt elastically to the area of the respective flanks of the mandrel -2- and to thus exert a predetermined pressure on the flanks of the formed laminate -3'-.

Respective elastomeric rollers for marking radii -22- rotating in transverse shafts and inclined with respect to the mandrel -2- are provided after the side rolling pressure devices -20- and are intended for marking the radii in the flanks of the formed laminate -3'-. Behind the elastomeric rollers for marking -22- there are respective smoothing elastomeric rollers -23- rotating in transverse shafts and coplanar to the mandrel -2- and arranged such that are they susceptible to marking and smoothing the side parts of the formed laminate -3'-.

A securing rolling pressure device -21 - is provided between the elastomeric rollers for marking -22- and the smoothing elastomeric rollers -23-, comprising a securing rolling hollow cover -21 a- rotating in a transverse shaft and coplanar with respect to the mandrel -2- and rolling over the upper part -2a- of the mandrel -2. The securing rolling pressure device -21 - serves for securing the formed laminate -3'- during the action of the elastomeric rollers -21 , 23-. The securing rolling hollow cover -21 a- of the securing rolling pressure device -21 - is also elastically deformable and is filled with at least one fill fluid at a fill pressure which allows its tread to elastically adapt to the upper part -2a- of the mandrel -2- and to thus exert a chosen pressure on the upper face -3a'- such that the formed laminate -3'- is firmly and uniformly immobilized when the elastomeric rollers -22, 23- act.

There is a winding device -15- behind the forming elastomeric rollers -23- on which there is wound a laminar strip -16- that is progressively placed on the formed laminate -3'- by the action of the placing roller -17a-, behind which there is arranged a roll-placing pressure device -24- comprising an elastic roll-placing hollow cover -24a- filled with at least one fill fluid at a fill pressure which allows its tread to elastically adapt to the contour of the formed laminate -3'-, and it is sized such that it is susceptible to pressing the sides of the laminar strip -16- against the side parts of the mandrel -2- so that the vacuum bag intended for preventing the spring-back effect in the formed laminate -3'- can be formed similarly to that described above in reference to Figures 8-10.

After the roll-placing pressure device -24- there is arranged a winding device -1 1 - carrying the thermal blanket -8- which is placed on the formed laminate -3'- by means of the positioning roller -9a-. The functions of the thermal blanket -8- are the same as those previously described in this description in reference to the first and second embodiment of the system according to the present invention. The thermal fluid supplied through the feed conduit -10d- enters through the inlet manifold -8f- into the longitudinal tubes -8c- and leaves it through the outlet manifolds -8g- which are in turn connected to the outlet conduit -1 Oe- (Figures 17, 19, 21 , 22).

The roll-forming pressure device -4-, the side rolling pressure devices -20-, the elastomeric rollers -21 , 23- of the securing rolling pressure device -22-, the winding device -15- of the laminar strip -16-, the placing roller -17a-, the roll-placing pressure device -24-, the winding device -1 1 - and the positioning roller -9a- are assembled in a forming carriage -5- with their carriage structures -7, 14- having a configuration similar to the forming carriage -5- and to the support structures -7, 14- which have previously been described in the present description and which are moved longitudinally by the mandrel -2- in their forward movement in the direction of the arrows shown in Figures 12-18.

As can be seen in Figures 17-19, 21 and 22, in the third embodiment of the system the end free parts of the laminar strip -16- and of the thermal blanket -8- are trapped by their side edges between respective securing plates -25- and the side surfaces of the mandrel -2.

Figures 23 to 25 show a fourth embodiment in which the support device -5- is stationary and the mandrel element -2- is longitudinally movable with respect to the support device -5-, and in which the system comprises an initial train of rollers -A-, two trains of intermediate rollers -B, C- and a final train of rollers -D-.

Each train of rollers comprises an upper roll-forming pressure device in the form of a forming pressure roller -4- and a lower rigid roller -26-. The roll-forming pressure device -4- comprises a roll-forming hollow cover -4a- such as that previously described in the present description assembled in a rim -4c- rotating on a rotation shaft

-4d-, whereas the lower rigid roller -26- comprises a perimetric flange -26a- and rotates on a rotation shaft -26b-. The rotation shafts -4d, 26b- are coupled respectively between a pair of upper vertical support sections -5a, 5b- and a pair of lower vertical support sections -5a', 5b'- and are adjustable in height for contributing to regulating the pressure exerted by the forming pressure roller -4- on the composite laminate -3-. The vertical support sections -5a, 5b- of the forming pressure rollers -4- are connected to one another by respective upper horizontal attachment sections -5c, 5d-, whereas the lower vertical support sections -5a', 5b'- of the lower rigid rollers -26- are connected to one another by respective lower horizontal attachment sections -5c', 5d'-.

The mandrel element -2- is connected to drive means [not shown in the drawings] for passing the composite laminate -3- deposited on the mandrel element -2- between the treads -4b- of the upper forming pressure rollers -4- and the lower rigid rollers -26, 26'-. The mandrel element -2- comprises a longitudinal upper part -2a- with an initial sector [left side of Figure 23] and a final sector [right side of Figure 23], the initial sector being shorter than the final sector. Therefore, due to the increasing height of the upper part -2a- of the mandrel element -2- due to the action of the forming pressure rollers -4- an upper part -3a- of the composite laminate -3- is gradually formed that increases in height until reaching the desired shape of the upper face -3a'- of the formed laminate -3-. On its lower face, the mandrel element -2- is provided with longitudinal guiding means in the form of a longitudinal track -2c- in which the perimetric flanges -26a- of the lower rigid rollers -26- are guided. Figures 26 to 28 show a fourth embodiment in which the support device -5- is also stationary and the mandrel element -2- is also longitudinally movable with respect to the support device -5-, and in which the system also comprises an initial train of rollers -A-, two trains of intermediate rollers -B, C- and a final train of rollers -D-.

Each train of rollers comprises an upper roll-forming pressure device in the form of a forming pressure roller -4- and a lower rigid roller -26-. The roll-forming pressure device -4- comprises a roll-forming hollow cover -4a- such as that previously described in the present description assembled in a rim -4c- rotating on a rotation shaft -4d-, whereas the lower rigid roller -26- comprises a circumferential groove -26c- demarcated between respective side contact surfaces -26d- and rotates on a rotation shaft -26b-. The depth of the circumferential grooves -26c- in the lower rigid rollers -26- progressively decreases from the initial train of rollers -A- towards the final train of rollers -D- such that the depth of the groove -26c- of the lower rigid roller -26- of the initial train of rollers -A- is greater than that of the groove -26c- of the lower rigid roller -26- of the first train of intermediate rollers -B-, the depth of the groove -26c- of the lower rigid roller -26- of the first train of intermediate rollers -B- in turn is smaller than that of the groove -26c- of the lower rigid roller -26- of the second train of intermediate rollers -C-, and the depth of the groove -26c- of the lower rigid roller -26- of the second train of intermediate rollers -C- is in turn less than that of the groove -26c- of the lower rigid roller -26- of the final train of rollers -D-.

The rotation shafts -4d, 26b- are coupled respectively between a pair of upper vertical support sections -5a, 5b- and a pair of lower vertical support sections -5a', 5b'- and are adjustable in height for contributing to regulating the pressure exerted by the forming pressure roller -4- on the composite laminate -3-. The vertical support sections -5a, 5b- of the forming pressure rollers -4- are connected to one another by respective upper horizontal attachment sections -5c, 5d-, whereas the lower vertical support sections -5a', 5b'- of the lower rigid rollers -26- are connected to one another by respective lower horizontal attachment sections -5c', 5d'-.

In the fifth embodiment shown in Figures 26 to 28, the mandrel element is a guide element in the form of a flat bar -2- having uniform height with a lower part -2d- guided in the circumferential grooves -26c- of the lower rigid rollers -26- and an upper part -2a- projecting from the circumferential grooves -26c. The mandrel element -2- is connected to drive means [not shown in the drawings] for passing the composite laminate -3- deposited on the mandrel element -2- between the treads -4b- of the upper forming pressure rollers -4- and the lower rigid rollers -26, 26'-.

Due to the decrease in the depth of the grooves -26c- of the respective lower rigid rollers -26-, the upper part -2a- of the guide element -2- projects increasingly more from the circumferential grooves -26c- of the respective lower rigid rollers -26- such that when the roll-forming hollow covers -4- roll over the composite laminate -3- arranged on the guide element -2- and the side surfaces -26d- of the respective rigid rollers -26-, the upper part -2a- of the guide element -2- increasingly penetrates the composite laminate -3- such that a longitudinal head of progressively increasing height projecting from the upper face of the composite laminate -3- is formed.

Claims

1 . - System for forming composite laminates, comprising a base (1 ) with at least one longitudinal mandrel element (2) in its upper face, comprising a shape to be given to a composite laminate (3) which is arranged on the mandrel element (2) for obtaining a formed laminate (3'); and at least one roll-forming pressure device (4) assembled in a support device (5) and susceptible to being placed in at least one position in which it rolls over the composite laminate (3) pressing the composite laminate (3) against the mandrel element (2) for forming it and obtaining the formed laminate (3'); characterized in that

the roll-forming pressure device (4) comprises a roll-forming hollow cover (4a) made of elastically flexible material with a tread (4b);

the rolling hollow cover (4a) is susceptible to containing at least one fill fluid at a fill pressure which allows the tread (4b) to elastically adapt to at least part of the mandrel element (2) and exert controlled pressure on the composite laminate (3).

2. - System according to claim 1 , characterized in that the tread (4b) comprises a smooth rolling surface.

3. - System according to claim 1 or 2, characterized in that the fill fluid is selected from gaseous fluids, liquid fluids, viscous fluids, viscoelastic fluids and combinations thereof.

4. - System according to claim 3, characterized in that the fill fluid is at least one gas, and the roll-forming hollow cover (4a) is a pneumatic chamber.

5. - System according to any one of claims 1 to 4, characterized in that the roll- forming pressure device (4) is assembled in a vertical adjustment mechanism (5a, 5b; 6a, 6b) for regulating the pressure exerted by the roll-forming pressure device (4) on the composite laminate (3), the vertical adjustment mechanism (5a, 5b; 6a, 6b) being assembled in the support device (5).

6. - System according to any one of claims 1 to 5, characterized in that it comprises at least one pair of side rolling pressure devices (20) assembled on transversely opposite sides of the support device (5) by means of respective transverse rotation shafts with respect to the mandrel element (2), such that they roll and exert pressure respectively on respective flanks defined between the upper part (3a) and respective side parts of the laminate (3') formed by the roll-forming pressure device (4) before the pair of side pressure devices (20).

7.- System according to claim 6, characterized in that at least one of the side rolling pressure devices (20) comprises an elastically deformable side rolling hollow cover (20a) provided with a tread and filled with at least one fill fluid, which allows its tread to elastically adapt to the corresponding flank of the mandrel element (2) and exert a predetermined pressure on the flank of the formed laminate (3').

8. - System according to claim 6 or 7, characterized in that the rotation shaft of at least one of the side rolling devices (20) is inclined with respect to the mandrel element (2).

9. - System according to claim 7 or 8, characterized in that the fill fluid of the side rolling hollow cover (20a) is selected from gaseous fluids, liquid fluids, viscous fluids, viscoelastic fluids and combinations thereof.

10.- System according to claim 9, characterized in that the fill fluid of the side rolling hollow cover (20a) is at least one gas, and the rolling hollow cover (4a) is a pneumatic chamber.

1 1 . - System according to any one of claims 1 to 10, characterized in that it comprises at least one pair of solid marking rollers (22) assembled on transversely opposite sides of the support device (5) by means of respective transverse and inclined rotation shafts with respect to the mandrel element (2) such that they roll and exert pressure in respective bent areas of the formed laminate (3') for marking longitudinal radii which join changes in plane of the part to be formed.

12. - System according to claim 1 1 , characterized in that at least one of the marking rollers (22) is a roller made of an elastomeric material.

13. - System according to any one of claims 1 to 12, characterized in that it comprises at least one pair of solid smoothing rollers (22) assembled on transversely opposite sides of the support device (5) by means of respective transverse and coplanar rotation shafts with respect to the mandrel element (2) such that they roll and exert pressure in respective side parts of the formed laminate (3').

14. - System according to claim 13, characterized in that at least one of the smoothing rollers (23) is a roller made of an elastomeric material.

15. - System according to any one of claims 1 to 14, characterized in that it comprises at least one consolidation system comprising at least one extensible cover (8, 16, 18) and extending means for depositing the extensible cover on at least one part of the formed laminate (3'), for consolidating the formed laminate (3') arranged in the mandrel element (2), the consolidation system being selected from a thermal treatment system in which the extensible cover is a thermal bag (8), a vacuum bag debulking system in which the extensible cover is a laminar strip (16), and a combined consolidation system in which the extensible cover is a multifunction cover (18) integrating the thermal bag (8) and the laminar strip (16).

16. - System according to claim 15, characterized in that the extending means are assembled in a support structure (7, 14), for progressively depositing the extensible cover at least on the formed laminate (3').

17. - System according to claim 16, characterized in that the extending means comprise a winding device (1 1 , 15), and the extensible cover (8, 16) can be unwound from the winding device (1 1 , 15).

18. System according to claim 17, characterized in that the extending means comprise at least one extending roller (9a, 9b; 17a, 17b) assembled in the support structure (7, 14) above the mandrel element (2) for extending the extensible cover (8, 15) as it is unwound from the winding device (1 1 , 15) and depositing it on at least the formed laminate (3').

19. - System according to claim 18, characterized in that the extending means comprise

a first extending roller (9a, 17a) assembled transversely in the support structure (7, 14) such that it is capable of receiving the extensible cover (8, 16) and guiding it above the upper face (3a, 3a') of the laminate of the composite laminate (3) or of the formed laminate (3'); and

a second extending roller (9b) assembled transversely in the support structure (7, 14) such that it is capable of depositing the extensible cover (8, 16) after its passage over the first roller (9a, 17a) at least on the formed laminate (3').

20. - System according to claim 17, 18 or 19, characterized in that the winding device (1 1 , 15) is assembled in the support structure (7, 14).

21 . - System according to any one of claims 16 to 20, characterized in that the support structure (7, 14) forms part of the support device (5).

22.- System according to any one of claims 15 to 21 , characterized in that the extensible cover is a thermal blanket comprising a lower face (8b) substantially capable of adapting to the contour of the formed laminate (3') arranged on the mandrel element (2) and an upper face (8b).

23.- System according to claim 22, characterized in that the thermal blanket (8) is connectable to a circuit of a heat exchange fluid (10) and comprises at least one fluid inlet (8d) and at least one fluid outlet (8e), connectable to the circuit of the heat exchange fluid (10), and at least one internal chamber located inside it, connected to the circuit of the heat exchange fluid (10) through the fluid inlet (8d) and the fluid outlet (8e).

24.- System according to claim 23, characterized in that the thermal blanket (8) comprises a plurality of longitudinal tubes (8c) extending between its upper face (8a) and its lower face (8b), and in that the longitudinal tubes (8c) are connected to the circuit of the heat exchange fluid (10).

25. - System according to claim 23 or 24, characterized in that the thermal blanket (8) is susceptible to containing a liquid heat exchange fluid.

26. - System according to claim 25, characterized in that the fluid inlet (8d) and fluid outlet (8e) of the thermal blanket (8) are connectable to a cooling device (10a).

27. - System according to claim 25 or 26, characterized in that the fluid inlet (8d) and fluid outlet (8e) of the thermal blanket (8) are connectable to a heating device (10b).

28. - System according to claim 27, characterized in that the liquid heat exchange fluid is a heatable oil.

29. - System according to claim 22, characterized in that the thermal blanket (8) comprises at least one thermistor (19) extending longitudinally through the inside of the thermal blanket (8).

30. - System according to any one of claims 27 to 29, characterized in that the thermal blanket (8) is made of a material capable of withstanding at least temperature greater than the curing temperature of the formed laminate (3').

31 . - System according to any one of claims 19 to 30, characterized in that the laminar strip (16) of the vacuum debulking system is hermetically sealable on its sides at the base (1 ) of the mandrel element (2).

32. - System according to claim 31 , characterized in that it comprises a roll- placing pressure device (24) comprising an elastic roll-placing hollow cover (24a) with a tread and filled with at least one fill fluid at a fill pressure which allows the tread to elastically adapt to the contour of the formed laminate (3'), and is sized such that it is susceptible to pressing the sides of the laminar strip (16) against the side parts of the base (1 ) of the mandrel element (2) for assuring the hermetic sealing of the laminar strip (16).

33. - System according to claim 32, characterized in that the fill fluid of the roll- placing hollow cover (24a) is selected from gaseous fluids, liquid fluids, viscous fluids, viscoelastic fluids and combinations thereof.

34. - System according to claim 33, characterized in that the fill fluid of the roll- placing hollow cover (24a) is at least one gas, and the rolling hollow cover (4a) is a pneumatic chamber.

35. - System according to any one of claims 15 to 34, characterized in that the multifunction cover (18) of the combined consolidation system comprises a first longitudinal part (18a) with a thermal blanket (8) function attached to a second longitudinal part (18b) with a laminar strip (16) function hermetically sealable on its sides at the base (1 ) of the mandrel element (1 ).

36. - System according to claim 35, characterized in that the second part (18b) of the multifunction cover is wider than its first part (18b) for assuring its side sealing at the base (1 ) of the mandrel element (2).

37. - System according to any one of the preceding claims, characterized in that it comprises at least one conduit (2b) for a heat exchange fluid extending longitudinally through the inside of the mandrel element (2).

38. - System according to any one of the preceding claims, characterized in that the support device (5) is a forming carriage longitudinally movable with respect to the mandrel element (2) and in that the mandrel element (2) is stationary.

39. - System according to any one of claims 1 to 37, characterized in that the support device (5) is stationary, and in that the mandrel element (2) is longitudinally movable with respect to the support device (5).

40.- System according to claim 39, characterized in that

it comprises a plurality of trains of rollers (A, B, C, D) including an initial train of rollers (A) and a final train of rollers (D);

each train of rollers (A, B, C, D) comprises an upper roll-forming pressure device (4) and a final lower rigid roller (26);

the mandrel element (2) is connected to drive means for passing the composite laminate (3) between the upper roll-forming pressure devices (4, 4') and the lower rigid rollers (26, 26').

41 . - System according to claim 40, characterized in that the mandrel element (2) comprises a longitudinal upper part (2a) with an initial sector and a final sector, the initial sector being shorter than the final sector.

42. - System according to claim 40 or 41 , characterized in that the mandrel element (2) comprises a lower part (2d) with longitudinal guiding means (2c) in which the lower rigid rollers (26) are guided.

43. - System according to claim 42, characterized in that the longitudinal guiding means (2c) comprise a longitudinal track.

44. - System according to claim 40, characterized in that

the lower rigid rollers (26) comprise respective circumferential grooves (26c) located between side contact surfaces (26d);

the mandrel element (2) is a guide element in the form of flat bar with a guided lower part (2d) in the circumferential grooves (26c) and an upper part (2a) projecting from the circumferential grooves (26c); the upper part (2a) of the guide element (2) comprises an initial sector and a final sector;

the guide element (2) projects further from the circumferential groove (26c) of the lower rigid roller of the final train of rollers (D) than from the circumferential groove of the lower rigid roller (26) of the final train of rollers, such that when the roll-forming hollow covers (4) roll over the composite laminate (3) arranged on the guide element (2) and the side contact surfaces (26d) of the lower rigid rollers (26), the upper part (2a) of the guide element (2) is susceptible to forming a longitudinal head of progressively increasing height in the upper face (2a) of the composite laminate (3).

45. - System according to claim 44, characterized in that the guide element (2) has a height that progressively increases from its initial sector towards its final sector.

46. - System according to claim 44, characterized in that the circumferential grooves (26c) have respective depths decreasing from the rigid roller (26) of the initial train of rollers (A) to the final train of rollers (D).

47. - System according to claim 45, characterized in that the guide element (2) has a uniform height from its initial sector towards its final sector.