WO2010069923A1

WO2010069923A1 - Aircraft central pedestal

Info

Publication number: WO2010069923A1
Application number: PCT/EP2009/067086
Authority: WO
Inventors: Stéphane TRENTO
Original assignee: St-Aero
Priority date: 2008-12-15
Filing date: 2009-12-14
Publication date: 2010-06-24
Also published as: FR2939766B1; FR2939766A1

Abstract

The invention relates to a central pedestal for a flight deck of an aircraft, to which to attach aircraft instrumentation and control members, which comprises a three-dimensional shell (8) made of composite material containing inorganic or organic fibres held in a polymer matrix, attached by an underside (11) to a flight deck floor structure, open on an opposite top side (12) and having substantially solid peripheral walls (13, 14) extending between the underside (11) and the top side (12). It also comprises an electrically conductive frame (9) to which to attach the various components, and which is assembled with the shell (8) at the top side (12) thereof. The shell is also formed as a one-piece component. It is associated with a trim strip (10) around its upper peripheral edge (21).

Description

CENTRAL PYLONE OF AIRCRAFT

The present invention is in the field of the development of aircraft cockpits. It relates to a central pylon for such a cockpit, a method of manufacturing such a central pylon, and an aircraft that is equipped. The invention will be more precisely described in the present description with reference to a preferred field of application of the invention which is an aircraft flight deck. It applies similarly to any other type of aircraft in which there is conventionally a central pylon, or in which it may be useful to install such a pylon. Aircraft cockpits, in particular aircraft, particularly large ones, are frequently equipped in a conventional manner with a central console, commonly called central pylon, which is arranged between the seats intended for the two pilots and which supports flight control and flight control systems and devices, eg engine control devices, airbrakes, flaps, navigation systems, cabin telephones, various instruments and equipment, etc .; These organs are connected to the aircraft systems by wiring arranged inside the pylon. The central pylon is fixed to the ground of the cockpit, supported by a front face against the main console or dashboard of the aircraft, itself placed in front of the cockpit seats, in front of the cockpit in the direction of normal movement of the aircraft in flight.

Currently, the central pylon of an aircraft cockpit is formed of a perforated metal structure which consists of an assembly of bolted parts and / or riveted to each other. These metal parts are usually machined in thick plates, or formed by cutting and folding for those made of thin sheets. A casing is assembled on this metal structure fixed in the cockpit, so as to cover the lateral peripheral faces and the face rear, located opposite the main console, to protect the elements arranged in its interior and ensure a better aesthetic pylon. This envelope is formed of elements that may be metallic, or made of thermoformed plastic and / or non-structural composite, and which are assembled to each other. The control and control members are in turn fixed on a metal frame disposed in the upper face of the pylon, so as to be accessible to the pilots of the aircraft.

Such central pylons are long, and therefore expensive to manufacture, due in particular to the large number of parts that compose them and the various operations, including machining and assembly, to be performed for their manufacture. In addition, in order to meet a constant requirement in the field of aircraft which is the optimization of the mass of the elements that compose them, the metal parts forming the structure are preferably machined in thick plates of a light alloy, and therefore also prove to be costly, both in the rate of material removed which frequently reaches 95%, and in the price of the material itself. For similar reasons, the casing also has a high cost. The assembly of all these elements is long to implement, and it requires extensive assembly tools. The present invention aims to overcome the drawbacks of the existing central pylons for cockpits of aircraft, including those mentioned above, by proposing a central pylon that is quick to manufacture, at limited cost, and easy and quick to install in the aircraft. The invention also aims to ensure that this central pylon has a reduced mass, at the same time as a good aesthetic appearance, and a structural resistance adapted to the stresses to which it is likely to be subjected during its use in flight.

According to the invention, a central pylon for the cockpit of an aircraft, for fixing control and control members of the aircraft, comprises a three-dimensional hull made of composite material comprising mineral or organic fibers held in a matrix. polymer, which fixed by a lower wall on a floor structure of the cockpit, which is open at an opposite upper face, and which has peripheral walls, between the bottom wall and the upper face, which are substantially solid. The hull is associated with an electrically conductive frame for fixing the control and control elements of the aircraft, which is assembled at its upper face.

Preferably, the attachment frame of the control and control members of the aircraft is metallic. It may also be formed of any other material, for example a composite material based on fibers embedded in a polymer resin, the metallization of the equipment then being carried out by conventional means in themselves, for example by a conductive fitting connected to a metallization interface.

The shell according to the invention has structural parts whose shapes develop in the three directions of a reference axis system. This shell thus itself carries out both the presentation of the control and control members in a two-dimensional plane substantially defined by its open upper face, and the up-height of these organs with respect to the floor of the aircraft, as well as than their support at this height. According to an advantageous characteristic of the invention, the three-dimensional shell is a one-piece piece.

The pylon according to the invention thus consists mainly of a metal frame and a three-dimensional shell which forms both the working structure of the pylon, capable of withstanding in particular the weight of the various control and control organs and equipment that the pylon must support, by presenting them in a position in which they are easily accessible to a user seated on a pilot's seat of the aircraft, and the exterior of the pylon ensuring the protection of equipment inside the pylon and an aesthetic appearance satisfactory of the latter. The working structure and the outer cladding of the tower are thus quite advantageously formed in one and the same room. The fact that the shell is formed of composite material also advantageously makes it possible, by virtue of the intrinsic properties of such materials, to obtain the advantageous characteristics necessary for its use as a carrier element of an aircraft central pylon, in terms of mechanical strength on the one hand, and beautiful aesthetic appearance on the other.

For the mounting of the pylon in the cockpit, the hull is positioned in the conventional manner for the metal structures of the prior art, that is to say with a front peripheral face directed towards a main console occupying all the before the cockpit, in front of the pilots' seats. The cables needed for the power supply and the connections of the various control and control elements carried by the pylon come most generally from this zone, as well as from the cockpit floor. In order to ensure the passage of these cables towards the inside of the pylon to connect them to the control and control members carried by the upper frame, the shell according to the invention advantageously comprises an opening on at least one peripheral wall, preferably on the front peripheral wall disposed towards the main control console disposed at the front of the cockpit relative to the normal direction of movement of the aircraft. The other peripheral walls, that is to say the side walls and the rear wall, which are those that are exposed to the view in the cockpit, are substantially full, so that they hide the cables and equipment to inside the pylon and ensure an aesthetic appearance of the pylon.

By substantially solid, it is meant in the present description that the peripheral walls have little or no openings, and that they thereby provide the properties required for an outer cladding of the aircraft's central pylon, that is to say to say the protection and concealment of the equipment in its interior. The peripheral walls are thus provided with the minimum of openings necessary to ensure proper operation of the equipment contained in the pylon, that is to say an opening for the passage of the required cables, advantageously in the front part the least visible from the pylon because of its positioning in the cockpit, and if necessary reduced openings on the side walls, preferably at a lower edge of the latter, so as to ensure adequate ventilation of the volume inside the pylon to prevent overheating which is harmful to the proper functioning of the equipment. These openings may, if necessary, be used for ventilation of the cockpit.

The three-dimensional shell receives on its upper face an electrically conductive upper frame configured to allow the attachment of the various control and control members. This frame is preferably made of light alloy, preferably aluminum alloy, so that it advantageously combines mechanical strength, good electrical conductivity and lightness.

It is particularly formed by machining, so as to ensure the control of the accuracy necessary to mount the equipment that is attached to it. The central pylon according to the invention offers many advantages over the pylons of the prior art. It is easy to manufacture, since formed only two main parts which are themselves formed of a single block (or two blocks possibly for the metal frame, for reasons of material flow). The assembly time is also reduced for the same reasons, as well as the tools required for this assembly. The gain is also measured at the level of transport and storage prior to installation in the aircraft, as only two parts are to be managed.

Thanks to the properties of the materials chosen for its constitution, the pylon according to the invention has a reduced mass, which proves quite advantageous in the aeronautical field.

According to an advantageous characteristic of the invention, the three-dimensional shell according to the invention is formed of monolithic composite material and / or sandwich, preferably with a honeycomb structure.

A composite material is defined throughout the present description in a conventional manner, that is to say as constituted by the assembly of several different elementary materials or components bonded together, more particularly mechanically resistant fibers distributed in a polymer organic resin matrix. The term "resin" here defines a polymer compound, which may be of the thermoplastic or thermosetting type, which plays the role of a structural adhesive in which the fibers are dispersed in a more or less organized manner. The composite material thus formed has mechanical properties of its own, quite advantageous in terms of mechanical strength and lightness.

The shell according to the invention is preferably made by molding, from pre-impregnated resin fibers deposited in successive folds in the mold, and then subjected to baking. It preferably comprises both monolithic parts, that is to say forming a monoblock of which it is impossible to separate the constituents, and sandwich parts, preferably with honeycomb structure, that is to say having a solid alveolar layer between two monolithic composite sheets to which it is structurally bonded, in particular by gluing. The sandwich parts are characterized in particular by a high mechanical strength for a relatively small mass, so that it is quite advantageous according to the invention to integrate such parts in the shell, so as to give it great strength. at the same time as a reduced mass.

In preferred embodiments of the invention, the shell is formed of honeycomb sandwich composite material in planar areas thereof, so that it advantageously has high rigidity at these areas. It is preferably formed of monolithic composite material in rugged areas, also called shaped areas, these rugged areas being defined in opposition to the flat areas and being naturally self-stiffened. The monolithic composite material may optionally, depending on the zones, be reinforced by ribs or profiles. Localized reinforcements may also be made, as needed, in the form of additional pleats, material change, etc. In general, the choice of the material, the thickness and the orientation of the folds for each zone of the hull are determined according to the mechanical and geometrical constraints defined for the pylon by the specifications, so as to ensure the latter a structural strength sufficient to allow it to withstand the forces exerted on him both by the weight of the equipment that it is intended to support, by the various forces of acceleration, deceleration, vibration, etc., suffered in flight.

According to an advantageous characteristic of the invention, the bottom wall of the hull is preferably in the form of a dropped edge delimiting a central opening in the bottom of the hull, for the passage of cables from the floor of the aircraft . This fallen edge is advantageously formed in one piece with the rest of the shell, and it advantageously allows the latter to be given a transverse rigidity allowing it to be fixed to the floor of the aircraft without the forces associated with this binding being resumed on its walls. peripheral devices.

In preferred embodiments of the invention, an inner receiving flange of the frame is formed at an upper peripheral edge of the shell. This internal flange is preferably formed by machining the shell after its manufacture. It preferably occupies substantially the entire periphery of the hull. It receives sleepers externally delimiting the electrically conductive frame. In preferred embodiments of the invention, the frame is assembled to the shell by gluing.

The various openings necessary for the proper functioning of the equipment fixed in the pylon may be formed during the manufacturing process by molding, or machined in the walls of the finished shell.

Orifices are preferably drilled in the bottom wall of the shell to allow attachment to the ground wall of the cockpit. According to an advantageous characteristic of the invention, the hull is associated at the level of this lower wall with metal inserts, preferably glued to the hull, for its attachment to the floor of the cockpit. These inserts make it possible to manage the contact pressures of the fasteners on the composite parts. At the attachment points, the thickness of the shell is further preferably progressively increased, so as to manage the stress concentrations in these parts.

In preferred embodiments of the invention, the pylon comprises a trim strip of an upper peripheral edge of the shell, preferably formed of composite material or thermoplastic and attached to this shell. Such a headband advantageously rises the aesthetic appearance of the pylon, while protecting the edges of the walls of the hull and the fastening zone in the hull. In addition, this part being particularly exposed and can be damaged in the cockpit, it remains advantageously removable.

The shell according to the invention is advantageously both light, rigid and resistant to the forces that can be exerted on it in operation.

The central pylon according to the invention advantageously consists of a reduced number of parts, which simplifies the management of parts inventory, and its assembly time inside the aircraft is greatly reduced compared to the pylons of the prior art. As an illustration, the manufacturing and assembly cycle in the aircraft is approximately ten weeks, compared with twenty weeks for the towers of the prior art.

The invention also relates to an aircraft whose cockpit is equipped with a central pylon according to the invention, wherein the three-dimensional hull is attached to a floor of the cockpit by its lower wall.

According to a method of manufacturing a central pylon according to the invention, the manufacture of the shell is implemented in an outer mold. This mold is advantageously formed of several separable parts, so as to facilitate the demolding of the part. Such a form of implementation proves particularly particularly advantageous from an economic point of view. Indeed, it is possible by means of the same mold to manufacture shells three-dimensional unchanged external rib, but of varying thickness according to the needs and the mechanical stresses to which the shell will respond in operation, the differences in thicknesses from one part to another then being obtained by variations in the number of folds and / or structure of the material in the selected areas. Such a manufacturing method thus allows an evolution in the choice of materials, the number of plies, the orientation of the fibers, depending on the mechanical stresses fixed for the part, without impacting the tooling.

In addition, this gives a shell whose outer surface is directly satisfactory in terms of surface condition, roughness, shape tolerance, and to which it is necessary to apply only a finishing treatment, especially paint before use.

This mold is preferably made of a material of thermal expansion coefficient close to that of the material constituting the shell, preferably of steel, whose thermal expansion coefficient is equal to 12 × 10 ^-6 K ^-1 .

The invention will now be more specifically described in the context of preferred embodiments, which are in no way limiting, shown in Figures 1 to 8, in which: - Figure 1 shows in exploded view the various constituent elements of an example of a central pylon of the prior art; Figure 2 shows in perspective view the pylon of Figure 1 in which the different elements are assembled to each other; Figure 3 illustrates in perspective view the main three-dimensional shell of a central pylon according to the invention; FIG. 4 represents an upper metal frame of a central pylon according to the invention; FIG. 5 shows an upper covering strip of a central pylon according to the invention; FIG. 6 illustrates in perspective view a central pylon according to the invention in which are assembled the shell of Figure 3, the frame of Figure 4 and the strip of Figure 5; Figure 7 shows schematically, in section along a transverse plane, a mounting zone of the frame on the shell of the tower of Figure 6; and Figure 8 schematically illustrates, in section along a transverse plane, an attachment zone of the hull of the tower of Figure 6 on a floor of an aircraft flight deck.

The following description will be used in the context of a two-pilot airplane cockpit pylon, a general case of civil or military transport aircraft. This preferred field of application is however not restrictive of the invention.

A central pylon for flight cockpit, as proposed by the prior art, is shown in Figures 1 and 2, respectively exploded and assembled configuration. This pylon consists mainly of a metal structure 1, on which are fixed control organs and flight control of the aircraft, and a casing 2 designed to partially surround the metal structure so as to protect the equipment in its interior and to give a better aesthetic appearance to the pylon. The metal structure 1 is formed of a multitude of metal parts 3, 4, which are formed by machining, for the pieces cut in the mass 3, or by cutting and folding for the parts made in sheet metal 4. These different parts are assembled to each other by bolting and / or riveting. They are generally made of a light alloy, so as to form an overall hull mass as low as possible.

The casing 2 is also formed of several distinct elements 5, which may be made of thermoformed plastic or non-structural composite material.

As can be seen in FIG. 1, in order to obtain the tower shown in FIG. 2, it is according to the prior art necessary to manufacture and to assemble a large number of pieces. These manufacturing and assembly operations take a long time to implement, and they require significant specific tooling. This entails high manufacturing and assembly costs, and all the more so since the materials which are chosen for the manufacture of a pylon whose properties, and in particular the mass, are suitable for the aeronautical field, present in themselves - even a high cost.

The pylon of the prior art as shown in Figure 2 is fixed by screwing, through lower legs 6 of the structure 1, on a floor of the cockpit. The control and control members are fixed to them on the upper metal bars 7 of the structure

1.

The central pylon according to the present invention overcomes the drawbacks of existing prior art pylons, especially those mentioned above. Like the towers of the prior art, it is intended to be placed in the cockpit of the aircraft between the pilots' seats, so as to present the latter with different control and flight control elements and control systems. the device. The tower is disposed in this cockpit supported on a ground surface thereof by a wall that will be described throughout this description of the lower wall, with reference to its normal mounting position in an aircraft. The control and control members are fixed at an opposite upper face of the pylon, so as to be easily accessible to pilots from the pilot seats. Between this upper face and this lower wall, the pylon has peripheral walls, a so-called front wall disposed opposite a main control console located at the front of the cockpit, the front being here defined relative in the direction of normal movement of the aircraft, a so-called rear opposite wall, located on the inside of the cockpit, and side walls. The pylon according to the invention, as represented by way of example in FIGS. 3 to 8, comprises three main elements: a hull three-dimensional 8 which is monobloc, an electrically conductive frame 9, preferably metal, and an upper trim strip 10.

The three-dimensional shell 8 is intended to be fixed to a floor wall of the cockpit, and to support the metal frame 9 on which are fixed the control and flight control devices and conventional systems themselves. It can take any desired form. In the preferred embodiment of the invention shown in the figures, and more particularly in FIG. 3, it has substantially the shape of a rectangular parallelepiped, which nevertheless has different slanted and curved sections. This form of the shell is however not at all restrictive of the invention, and the shell can take any desired shape.

The hull 8 is here defined in the same way as the pylon as a whole, with reference to its normal positioning for use in a conventional aircraft cockpit. It comprises a lower wall 11, located on the ground of the cockpit, which is in the form of a dropped edge, extending towards the center of the hull substantially perpendicular to the peripheral walls that it comprises, occupying substantially the entire periphery of the hull and delimiting in its interior an opening 32 formed in the bottom of the hull for the passage of cables from the floor of the aircraft and to connect with the control and control members of the aircraft of the pylon.

The shell 8 is open at its opposite upper face 12. This opening may occupy the entire upper surface of the shell, as in the embodiment shown in the figure, or only part of this surface.

The shell 8 also has a rear peripheral wall 13 and lateral peripheral walls 14, which are substantially solid. Here it is meant by substantially solid that these peripheral walls have little or no openings. In preferred embodiments of the invention, they may be drilled in specific areas, preferably located in the lower part of the walls, orifices 16 providing ventilation of the internal volume of the hull inside which control and flight control equipment is available.

On a peripheral wall before 17, disposed in the cockpit to a main console, called dashboard, located at the front of the aircraft, the hull 8 has an opening 18 which allows to lighten the hull without impairing its overall rigidity, and which allows the passage of power cables of equipment and control and control organs, and their connection to the various associated devices.

The shell 8 is formed of composite material, consisting of mechanically strong fibers distributed in a polymer organic resin matrix acting as a structural adhesive.

The shell is preferably made by the implementation of an outer mold, inside which are deposited successive layers of resin pre-impregnated fibers in the not fully crosslinked state. The invention does not exclude that the shell 8 is made by any other conventional method in itself for the manufacture of parts made of composite material, for example by the technique known as RTM (for English Resin Transfer Molding), that known under the name of RTM Light, or that of the infusion of resin. The fibers used according to the invention may be of the organic or inorganic type, such as in particular aramid fibers, carbon fibers, glass fibers, or a mixture of these fibers. These fibers may be arranged in fabrics of different weights and weavings, for example in taffeta, twill, satin, etc., used alone or in combination, or in nonwovens, in which the fibers are all oriented in the same direction.

Any conventional resin in itself can be used within the scope of the invention, with preference for thermosetting resins, for example epoxy resins, phenolic resins or a mixture of both. The shell 8 may be formed of monolithic or sandwich composite material, preferably having a honeycomb structure core. In advantageous embodiments of the invention, it comprises both monolithic parts and sandwich parts, the latter offering in particular the advantage of high mechanical rigidity for a low mass. Particularly preferred in the context of the invention a monolithic material for shaped areas, and a sandwich material for flat areas.

For sandwich portions, the core is for example made of a foam or, preferably, a honeycomb, including but not limited to paper or aluminum. This core is between two monolithic composite material panels.

For example, for the manufacture of the shell 8, it is preferred to use a so-called female outer mold, that is to say having a mainly concave molding surface. This mold may for example consist of several separate parts, to facilitate the demolding operations of the hull. It may in particular be formed of steel, aluminum, or monolithic composite material based on glass fibers or carbon.

The shell 8 is preferably manufactured in the following manner.

In a schematic manner, after the conventional operations of preparing the tools and cutting the various constituent elements (fabrics, cores, adhesive films), it is proceeded to the draping of the outer skin of the shell.

Layers of fibers not pre-impregnated with non-fully cross-linked resin are draped over the molding surface and then covered with a cover which is sealed on its edges with the mold. A partial evacuation is performed between the mold and the sheet, so as to ensure the pressure of the layers against each other under the effect of atmospheric pressure.

The assembly is subjected to a cooking operation in an autoclave or in an oven, while maintaining the pressure on the layers, so as to ensure the crosslinking and the hardening of the resin. The firing temperature is chosen according to the polymerization temperature of the resin, according to calculations within the reach of the skilled person. The operation is carried out for example at 120 ^° C. and 4 bars.

It is then proceeded to the placement of the core in the areas concerned, and then the draping of the inner skin and the polymerization, in a manner similar to that described above, for example at 120 ^° C. and 1.5 ^° C. bar. After demolding, the hull 8 thus obtained, in the form of a single piece, is subjected to various finishing treatments, including deburring, machining, primer and paint.

The various openings in its walls are in particular made by machining at the different faces of the shell. According to the invention, it can however also be provided that all or part of these openings are formed during the same process of manufacturing by molding.

The pylon according to the invention also comprises a metal frame 9, shown in Figure 4, which is formed by machining, preferably in a block, or optionally in two blocks assembled to one another. This frame is advantageously made of light alloy, especially aluminum alloy. It comprises, inside peripheral crosspieces 19 which delimit it, a trellis formed of metal bars 20. These bars are intended to receive the control and control elements, in particular the joysticks, the instrumentations, and the various other equipment to be fixed on the pylon.

The realization of this frame by integral machining makes it possible to guarantee a precision of the dimensions necessary for the correct mounting of the control and control elements to be fixed on the pylon.

The frame 9 is in substantially rectangular plane. Its shape and its sectional area are substantially equivalent to that of the opening of the upper face 12 of the shell 8. Here is understood by substantially equivalent that the frame has the same shape as the opening, to manufacturing inaccuracies, and a surface in section slightly greater than that of the opening, so as to completely cover the latter, while projecting over at least two of its opposite edges so as to be able to be deposited in abutment on an upper peripheral edge 21 of the shell defining this upper opening.

In order to accurately receive the frame 9 at its upper face 12, the shell 8 is machined on an upper peripheral edge 21, so as to form an inner peripheral rim 22 around the opening, as shown in section in the figure 7. The frame 9 rests by its external cross members 19 on this rim 22. For this purpose, in preferred embodiments of the invention, the cross members 9 comprise at their lower end a perpendicular return 23, which increases the stability of support frame 9 on the flange 22 and allows a precise and fast assembly without additional tools. The frame 9 is fixed on the flange 22, in particular by gluing.

In this figure 7 clearly appear the different constituent parts of the shell 8, namely a rugged monolithic portion 29, shown in continuous stripes in the figure, and a flat sandwich portion 30, the honeycomb core is shown in broken lines. According to the particular configuration of the hull, these parts of different constitutions are distributed according to the stiffness requirements specific to each zone of the hull and manufacturing constraints related to its shape, according to calculations within the reach of the skilled person . The tower according to the invention may finally optionally comprise an upper trim strip 10, which is shown in Figure 5. This strip is preferably formed of composite material or thermoplastic. It has substantially the shape of the upper part of the rear peripheral walls 13 and side 14 of the shell 8, while being slightly wider. It is fixed on the shell so as to cover these upper edges externally and thus to protect the edges of the walls and the fastening zone of the metal frame 9 on the shell and the lateral faces of the crosspieces 19 of the latter, as illustrated in FIG. 6. The strip 10 is preferably fixed on the shell 8 by reversible fixing means, so as to be dismountable and replaced independently of the rest of the pylon, for example by positive fastening means such as screws, or by a fastening system of the type with loops and hooks. It thus remains advantageously removable.

The manufacturing operations of the various constituent elements of the invention are easy and quick to perform. The assembly operations of these elements with each other are also quick to implement, and they do not require significant specific tooling. The cost of manufacturing and assembling the pylon according to the invention is therefore advantageously reduced, in particular much less than that of the prior art. For the storage of parts and the management of spare parts, the limited number of separate parts involved in the constitution of the pylon is particularly interesting in terms of gains in time and money.

In Figure 6 there is shown the pylon according to the invention fully assembled. In practice, it is preferred to assemble the shell 8 and the metal frame 9 at the factory, prior to assembly and fixing in the cockpit of the aircraft. The strip 10 is in turn preferably, but not limited to, mounted on the pylon once it has been fixed to the ground structure of the cockpit and that the various equipment has been installed in its interior, a part to avoid any risk of damage to the band during transport and installation in the aircraft, and secondly to facilitate the mounting of equipment inside the pylon.

The hull 8 plays in the pylon the role of both working structure between the metal frame 9 and the ground wall of the aircraft on which it is fixed, for the recovery of the forces exerted by the weight of the equipment attached to the frame 9 and the different efforts that are applied to them, and dressing the pylon on its peripheral faces. It thus ensures the protection of the rear faces of the equipment fixed on the frame 9. It advantageously has a good aesthetic appearance in itself, without it being necessary to associate it with additional elements, besides, if necessary, the headband. covering 10 for its upper part receiving the frame 9.

Due to the properties of the materials that constitute it, the hull 8 is advantageously light. Depending on the size of the pylon, its mass may be up to about 40% less than the mass of metal structure pylons of the prior art.

The hull is made without the need for removal of a large mass by machining and is therefore particularly economical in terms of material consumed.

In addition, still thanks to the advantageous properties of the composite materials in terms of mechanical strength, and particularly for the sandwich portions, the shell 8 has a good mechanical strength, similar to that of the structures of the towers of the prior art. This is all the more advantageous as this hull is highly stressed during its use in the aircraft, firstly by the weight of the equipment attached to the frame 9 that it supports, of the order of several tens of kg, in particular 40 to 50 kg, but also on the other hand by the forces undergone during the altitude acceleration of the aircraft, by the associated vibration forces and by the stresses in the event of an accident, typically associated with a deceleration which can rise up to 9g in the direction of the axis of the aircraft.

For fixing the hull to a ground wall 24 of the cockpit, orifices are drilled at different positions in the lower wall 11 of the hull 8. The preferred locations for these orifices are the corners of the hull 8, so that to present the best resistance to efforts. For example, at each orifice, metal inserts 26 are fixed to the wall 11, in particular by gluing, so as to partially fit into the orifice and to protrude peripherally on the faces of the wall, respectively on its lower face 25 and its upper face 27, as shown in Figure 8. The shell 8 is assembled to the floor wall 24 by a conventional fastening system itself, providing a solid attachment, for example by bolting 28. This fixation is preferably carried out also through elements 31 of the lower primary substructure of the floor of the aircraft.

Depending on the particular configurations and constraints to which may be subject to the pylon according to the invention, the shell 8 may further comprise reinforcements, for example carbon, at these areas most stressed and attachment points.

It is also conceivable in the context of the invention that it is metallized on certain parts, or that it includes metal ramps in its interior to connect the equipment contained in the pylon to the ground.

The above description clearly illustrates that by its different characteristics and advantages, the present invention achieves the objectives it has set for itself. In particular, it provides an aircraft cockpit central pylon that is easy and quick to manufacture, at a moderate cost, and has good strength properties along with reduced mass and aesthetic appeal. outside.

Claims

1. Central pylon for cockpit of an aircraft, for fixing control and control members of said aircraft, characterized in that it comprises a three-dimensional shell (8) of composite material comprising mineral or organic fibers maintained in a polymer matrix, being secured by a bottom wall (11) to a floor structure (24) of said cockpit, open at an opposite upper face (12), and having peripheral walls (13, 14) substantially solid between said bottom wall (11) and said upper face (12), and an electrically conductive frame (9) for fixing said members, assembled to said shell at said upper face (12).

Central pylon according to claim 1, characterized in that the shell (8) is in one piece.

3. Central pylon according to claim 1 or 2, characterized in that the frame (9) is made of aluminum alloy.

4. Central pylon according to any one of claims 1 to 3, characterized in that the shell (8) is formed of monolithic composite material in uneven areas and sandwich composite honeycomb structure in planar areas.

Central pylon according to any one of claims 1 to 4, characterized in that an inner flange (22) for receiving said frame (9) is formed at an upper peripheral edge (21) of the shell ( 8).

6. Central pylon according to any one of claims 1 to 5, characterized in that the frame (9) is assembled to the shell (8) by gluing.

Central pylon according to any one of claims 1 to 6, characterized in that the bottom wall (11) of the shell (8) is the shape of a fallen edge defining a central opening (32).

8. central pylon according to any one of claims 1 to 7, characterized in that the shell (8) is associated at said lower wall (11) with metal inserts (26), preferably glued to said shell ( 8) for attachment to said floor structure (24).

9. central pylon according to any one of claims 1 to 8, characterized in that the shell (8) has on at least one peripheral wall an opening (18) for the passage of cables connected to said control and control members, preferably on a front peripheral wall (17) disposed towards a main steering console disposed in front of said cockpit.

10. Central pylon according to any one of claims 1 to 9, characterized in that it comprises a strip (10) for covering an upper peripheral edge (21) of the shell (8), preferably formed composite material, and assembled to said shell (8) by gluing.

Aircraft whose cockpit is equipped with a central pylon according to any one of claims 1 to 10, wherein said hull (8) is attached to a floor structure (24) of said flight deck by said bottom wall (11).

12. A method of manufacturing a central pylon according to any one of claims 1 to 10, characterized in that the manufacture of the three-dimensional shell (8) is implemented in an outer mold.

13. The method of claim 12, characterized in that the mold is made of steel.