Abstract: A flexible spherical bearing, comprising two end pieces connected by a stack of interconnected alternate layers of a flexible material, such as elastomer, and of a strong material, such as metallic material and at least one cavity filled with an incompressible fluid and extending between the two end pieces without the interposition of elastomer. Such a bearing is used for connecting a helicopter rotor blade to the rotor hub of this helicopter.

Abstract: The connection is of the Cardan type comprising a rigid intermediate structure, a first modular assembly of flexible connection elements placed between the intermediate structure and the first rigid body to allow relative rotation of the structure and of the first rigid body about a first axis x--x, and a second modular assembly of flexible connection elements placed between the intermediate structure and the second rigid body to allow the relative rotation of the structure and of the second rigid body about a second axis. The first and second assemblies comprise flexible bearings and abutments fabricated, at least partly, from a resilient material.This device is particularly suitable for anchoring a floating platform to the sea bed.

Abstract: The invention relates to a combustion chamber of a ramjet and booster rocket, which comprises an inner envelope provided with upstream lateral ports for the inlet of air and a downstream nozzle for ejecting the combustion gases, to allow functioning of the rocket at cruising speed; an outer envelope, concentric to the inner envelope and closed, with the exclusion of a single rear port for the ejection of the gases, to allow functioning of the rocket at launching speed; and separating means for separating from the combustion chamber at least a part of the outer envelope, at the end of the launching phase, in order to ensure the clearance of the upstream lateral ports of the inner envelope.

Abstract: An axial electromagnetic bearing for supporting the end of a shaft rotating a high speed of the type comprising an armature in the form of a disc attached to the shaft and a fixed annular armature disposed facing the disc armature a short distance from the former so as to define a small axial air gap therebetween, the said fixed armature comprising excitation windings and a ferromagnetic core, the bearing being characterized in that radial grooves are provided in the peripheral portion of the disc and situated facing the annular fixed armature.The arrangement causes a reduction in the effect of Eddy currents without detracting from the mechanicl strength of the bearing.

Abstract: The present invention relates to a process for the preparation of asymmetric dimethylhydrazine by a reaction capable of producing, as impurity, formaldehyde dimethylhydrazone, wherein said reaction is effected in the presence of hydrazine.

Abstract: An igniter for a combustible powder block comprises a non combustible receptacle with an ignition initiator arranged at one end of the receptacle and a charge in the receptacle for thrusting on to the combustible parts of the block to produce ignition, the charge including a pyrotechnic ejection compound, a pyrotechnic ignition compound and reactive divided metals, the charge having decreasing activity successively from the end of the receptacle carrying the initiative.

Abstract: The reinforcement for a reinforced three dimensional structure comprises four bundles of rectilinear elements with the elements of each bundle arranged in the form of spaced parallel sheets with the sheets of two of the bundles parallel to one another and alternately disposed, the sheets of the other two bundles being similarly arranged but inclined to the sheets of the first mentioned bundles.

Abstract: Tail unit for a missile comprising at least one system of two pairs of curved blades, whereof one of the longitudinal edges is fixed to the periphery of a cylindrical body, whereby the blades of the same pair are symmetrical relative to the axis of said body are fixed to the latter in two diametrically opposite zones and have their concavity turned in the same direction about the axis of said body, wherein the orientation of the concavity of the blades of the same pair of blades around the axis of the cylindrical body is opposite to that of the blades of the other pair.The said tail unit makes it possible to improve the stability of the trajectory of the missile on which it is mounted, when a rotary movement is given to the missile.

Abstract: A device for detecting and correcting a radial oscillations of a rotor, particularly a rotor in a magnetic suspension, for the purposes of creating a restoring force to hold the rotor centrally of the stator, wherein several pairs of radial displacement detectors are coupled together and are relatively spaced such that the signals emanating from diametrically opposite detectors of each pair are cancelled out and the signals emanating from adjacent detectors of each pair are averaged to eliminate the effects of variations in the radius of the rotor.

Abstract: An assembly for launching a projectile comprises a launching tube having a smooth or rifled bore, a charge of gunpowder located in the tube for firing a projectile which is loaded in the tube in front of the charge, and a body of braking propellent which is located in the tube behind the gunpowder charge and which consists almost entirely of combustible substances. The body of braking propellent may be connected to the projectile by means of a cylindrical sleeve to form a rigid unit which is loadable as a round in the launching tube, the sleeve containing the gunpowder charge.

Abstract: This invention relates to magnetic bearings and particularly to active magnetic bearings having a very low "friction couple". In accordance with the invention the active magnetic bearing is of the type which has a stator formed by an electromagnetic circuit having at least one pair of north and south poles, and wherein said electromagnetic circuit of said stator includes at least one electromagnet of U-shaped section. The arms of said U form north pole and south poles respectively and the electromagnet is so arranged that the plane of symmetry which separates the north pole from the south pole lies perpendicularly to the axis of rotation of the magnetic bearing.