The present invention relates to a deployable device comprising elements connected to a support by articulations situated in a plane and the axes of which form, within this plane, a convex polygon. This device is capable of moving from a folded-up position in which the said elements form a first angle with the said plane, to a deployed position in which the elements form a smaller angle with the said plane and together constitute a substantially continuous surface.
The object of the invention is to provide a device forming a continuous surface, of large dimensions, capable of resisting, without modification, compressive forces resulting from a flow of aerodynamic or other origin, in a deployed position, and capable of being folded-up and stored within a space of reduced diameter.
A device of this type finds its application, in particular, in the aerospace field, on planetary reentry bodies where all the measuring instruments must be stored at launch in a reduced space (for example the nose cone of the launcher rocket) and, when it penetrates into the atmosphere, offer a continuous aerodynamic surface so as not only to decelerate this reentry but also to constitute a screen to the rise in temperature to which the said instruments in contact with the atmosphere will be exposed.
The application of a device according to the invention in such a field must enable probes to be produced which have large dimensions in the deployed state but occupy a restricted space during launch.
Deployable devices of the type mentioned at the beginning are known with the same operating principle as an umbrella, moving from a folded-up closed position to a deployed open position, the opening or closing operation being performed by action on ribs articulated about an axis in order to form, at their base, a supporting polygon and between which can be tensioned pieces of an initially approximately circular fabric panel formed into a dome by the curvature of the ribs.
This type of device can be combined with those of U.S. Pat. Nos. 3,228,634 and 4,896,847.
Other types of deployable devices are also known in the packaging industry in which, for ease of storage, folding and shaping systems are employed which make it possible, for example, to obtain a cardboard container from a flat element.
However, when deployed, umbrellas do not provide a surface of stable shape when they are subjected to an intense aerodynamic flow. Known cardboard packages for their part are not known for interacting with a drive device capable of holding them in place against an aerodynamic flow.