FR2834496A1 - Caravan trailer has aerodynamic body made from monocoque floor and walls of conical sections made from reinforced composition material - Google Patents

Abstract

A caravan body is made from joined sections of truncated conical shape making a self-supporting structure when assembled. The walls of the caravan are made from a sandwich material with a lightweight core of expanded or extruded foam and inner and outer skins. The floor is of a reinforced thermo-setting composition material with a honeycomb core. A caravan body is made from joined sections of truncated conical shape making a self-supporting structure when assembled. The walls of the caravan are made from a sandwich material with a lightweight core of expanded or extruded foam and inner and outer skins. The floor is of a reinforced thermo-setting composition material with a honeycomb core. The forward end sections of the body have vertical axes and lines perpendicular to their surfaces converging towards the caravan's center of gravity. The sides are made from sections of larger truncated cones of similar configuration, and the floor is a monoshell with no lengthwise members.

Description

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Recreational vehicles called CARAVANS mainly have two functions:
1. a road function for site changes
2. a function of housing and protecting its occupants.

évoluent avec la technologie mais, les deux fonctions ont tantôt pris le pas l'une sur l'autre à cause de critères commerciaux et d'utilisation. Both are the subject of standards, construction and use recommendations which

evolve with technology but, the two functions have sometimes taken precedence over each other because of commercial and use criteria.

Also in the 1920s, caravans hitched to low-power vehicles had a parallelepiped shape for reasons of volume and habitability. Thirty years later, because the tractors are more powerful, the aerodynamics, essentially in profile, are emerging and the shapes are rounded to promote speed and reduced consumption, a little to the detriment of habitability. In the 70s and 80s, the golden age of development, they became more cubic and less easy to tow, without the primary need to be part of the normal flow of traffic. It is undoubtedly one of the causes of their decline in front of the rise of another type of vehicle, come from the United States and adapted to a faster tourism, capable in the mind of the user of exploiting the highway, at high speed.

été les matériaux de la première génération, remplacés par la tôle d'aluminium pour le parement extérieur, le bois et le contreplaqué préservant alors un isolant afin d'agrémenter l'habitation. Depuis les vingt dernières années, l'exploitation, par collage, des matériaux identiques donne exclusivement des formes planes qui engendrent des volumes

parallélépipédiques, peu propices à l'aérodynamique. At the same time, construction followed an evolution of materials: wood, plywood have

were the first generation materials, replaced by aluminum sheet for exterior cladding, wood and plywood while preserving insulation to enhance the home. For the past twenty years, the exploitation, by gluing, of identical materials gives exclusively flat shapes which generate volumes

rectangular, little conducive to aerodynamics.

The object of the present invention described below defines the criteria of shapes and materials making it possible to reconcile the implementation, aerodynamics and habitability, light and insulating materials associated with a process reducing the manufacturing costs by a reduction of specific manufacturing tools.

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The volume generated must have aerodynamics: - frontal, along the longitudinal axis to reduce the power required for traction - transverse to guarantee better stability in lateral wind and eliminate the effect of torque, gyration around the center of gravity of the vehicle
Knowing that the force of penetration into the air meets the equation F = and that the aerodynamic power is expressed by an attempt (fig. 1) to reduce the latter by reduction of k (frontal shape) and reduction of the surface front S (master torque) (1), (2)
According to the present invention (fig. 2), in order to guarantee the conditions of stability of the caravan subjected to aerodynamic effects, the front will be constituted for an upper part of the body by the assembly of trunks of cones (3), ( 4) -developable, regulated surfaces- of substantially vertical axis of revolution, whose trunk sectors (3), (4) are tangent to each other, and whose normal (8), (9), (10) the trunk passes into the immediate area of location of the center of gravity G of the vehicle. The aerodynamic forces directed along this normal (fig. 2) then create additional stability support and will be more favorable if the normal (8), (9), (10) at the walls of the trunks of cones are located between the ball of coupling and center of gravity G. In the present invention, for the same reasons, it is possible to retain a shape in portion of spheres, but this will not be easy to use, as is the truncated cone . The frontal surfaces selected are preferably surfaces in the trunk of cones, developable and adjusted.

The central, front part of the bodywork will be based for the same reasons on the juxtaposition of cylinders with substantially vertical axes.

The lower part (7), front of the body will be based on the juxtaposition of the trunks of cones.

The whole being the envelope, by developable surfaces regulated by a volume which can be likened to portions of tangent spheres. ' The gradual transition from frontal aerodynamics to lateral aerodynamics results in the exploitation of trunks of cones (3), (4), (5), (6) whose normals (8), (9), ( 10) at the wall always converge towards the center of gravity, except for the frankly transverse aerodynamics where the walls (25) straighten out by the use of the trunk of cones of vertical axes, of very small angle angle and very large base radius.

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relief, incluant dans son épaisseur les organes de suspension, de tringlerie, de stabilisation, de canalisations propres à l'usage. Finally, the base (24), the floor, will be substantially free and free of

relief, including in its thickness the organs of suspension, linkage, stabilization, pipes suitable for use.

 The present invention involves the use of composite materials in order to create the living conditions of a living cell (fig. 5). The outer skin (11) mechanically protects against attacks of all kinds and will be followed, internally, by an insulator (12) and another inner skin (13) which will play more a role of decoration and ambiance.

 The flat walls used so far make use of an assembly of aluminum sheet (outer skin), of a plywood with decorative surface for the interior, the two being separated by an insulator of the polystyrene foam type bonded to each skin and reinforced by a frame of wooden battens (pine or poplar) necessary to fix the furniture.

 The object of the present invention is to produce composite sandwich panels from inner skins (13) and light outer skins (11) of the same nature and which can advantageously be manufactured by a pigmented resin, then a polyester resin reinforced by fabrics. glass (mat or roving). These components can be replaced, at higher cost, with an epoxy resin and aramid or carbon fabrics. These skins are, depending on the nature of the composite, calculated in thickness to withstand the constraints imposed by the specifications, the bodywork being necessarily self-supporting. The interest of the same type of skin (11), (13) streamlines manufacturing, lowers costs and provides balanced panels essential to avoid distortion to temperature variations. The separation of the skins is obtained by a core (12), preferably made of expanded or extruded foam, allowing a chemical bond (bonding) skin-foam-skin. The foam (12) will be rigid, preferably made of polyurethane or polyvinyl chloride to accept bonding with polyester resin, or a polyurethane adhesive.

The implementation of the present invention then justifies the option of regulated developable forms. After having placed the gel coat, resin and reinforcement (11) in the female mold, the foam (12), which comes in a plate, will first be cut to size and striated along the axes of the adjusted surface (3), (4 ), (5), (6) in order to be able to press without difficulty by bending on the skin (11); the coating of glue is done at the time of removal. The inner skin (12) will then be produced immediately by spraying with resin and cut fiber. It is then advisable to deposit on the assembly a demolding felt and a sealing film to mold the assembly, under vacuum, during the polymerization.

Another characterization of the product can be done by injection of foam between the two walls formed beforehand and put in place in conformers capable of accepting the thrust of the foam. This solution, much more expensive, more uncertain for

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la définition de la qualité de la mousse, reste possible p2834496rmes surtout non développables.

the definition of the quality of the foam, remains possible p2834496rmes especially not developable.

The base, floor (24), will be for the present invention-in order to ensure lightness- devoid of side members, but, taking into account the rigidity of the "monocoque" construction, the foam of the bodywork will be advantageously replaced (fig. 5) by a honeycomb (15) whose thickness and dimensioning are also calculated according to the specifications.

The floor receives before laminating (14) the installation of the inserts, wood or metal of the attachments of the ancillary components, the reservations for the vents, passage of pipes, conductors, and housing of the gas tanks.

According to the present invention, the assembly of the different parts will advantageously be done by two half-shells (fig. 7), the upper part (16) of which covers the laminate floor at the same time as the lower half-shell part (17); the assembly being done by gluing on the thickness of the sandwich. This solution is by far the most advantageous because it allows the two half-shells of the interior components-kitchen, chests and furniture-to be equipped with specific functions (water, gas, electricity, refrigeration, heating) in an open volume for the base and to work the upper half shell, turned over (therefore open) for the installation of the bays, pavilion cupboards etc ..., then to carry out the assembly at the last moment.

A variant of the present invention (fig. 8) consists in making the volume by juxtaposing sections of which the central part (20), (21), (22) can be modular in length, thus taking advantage of the use of the same front end-ends (18) and rear end (19) - for several body lengths. This variant combines the advantage of aerodynamic composite ends with the composite central section (preferably) or traditional, by panels with an outer skin of aluminum.

Claims (12)

1. light, mobile, rigid caravan, the shape of which is obtained by trunks of juxtaposed cones (3), (4), (5), (6) or intersecting to present an aerodynamic solid, envelope of a truncated ovoid at the back, characterized in that:. the upper front shape is composed of regulated surfaces (3), (4), (5), (6), developable, frustoconical, of substantially vertical axes and whose normals (8), (9), (10) to the wall converges in the immediate vicinity of the gravity frame G of the vehicle, the lateral shape (25) is composed of large trunks of cones connected to the front shape by other trunks of cones whose normal to the walls converge towards the center of gravity G of the vehicle, * the floor (24) without relief acts as a platform devoid of side members to constitute with the walls a monocoque assembly, 'after assembly of the components the assembly forms a self-supporting bodywork.  2. caravan according to claim 1, characterized in that the walls are of reinforced composite material of the light-core sandwich type (12) separating the outer skin (11) from the inner skin (13).  3. caravan according to claims 1 & 2, characterized in that the walls are constituted by an outer skin (11) of reinforced thermosetting composite material. <Desc / Clms Page number 6>  4. caravan according to claims 1 & 2, characterized in that the core (12) of the sandwich is insulating in the form of expanded foam or extruded by panels.  5. caravan according to claims 1,2, 4, characterized in that the core panel (12) is striated along the axis of the adjusted surfaces (3), (4), (5), (6) to closely fit the shapes by bending.  6. caravan according to claims 1 to 5, characterized in that the striated core is glued under vacuum to the outer skin (11).  7. caravan according to claims 1 to 6, characterized in that the inner skin (13) is obtained by a reinforced thermosetting composite, sprayed and polymerized during evacuation.  8. caravan according to claim 1, which is characterized by a floor made of thermosetting composite reinforced with honeycomb core (15).  9. caravan according to claims 1 and 2, characterized in that the floor has fixing inserts and various reserves related to the self-supporting function.  10. caravan according to claims 1 to 9, characterized in that the components are assembled to form the assembly by two half shells (fig. 7), one upper (16), the other lower (17 ), linked by a reinforced thermosetting composite.  11. caravan according to claims 8 and 9, characterized in that the floor (24) is integrated by a thermosetting composite reinforced with the lower half-shell (17).  12. Light dwelling caravan, characterized in that its constituent elements (fig. 8) are assembled from several longitudinal sections (20), (21), (22), the central section (20), ( 21), (22), which may be of traditional constitution, accepts front (18) and rear (19) elements made like those of the caravan according to claims 1 to 9.