Abstract: The present invention relates to a device for reducing vibration generated on the structure (2) of a rotary-wing aircraft, particularly a helicopter. According to the invention, the device (1A) comprises at least one flapping mass (3) connected to the structure (2), at least one controllable actuating device (5A) capable of causing the flapping mass (3) to flap, and a control unit (UC1) intended to control the actuating device (5A) in such a way that it causes the flapping mass (3) to flap at a frequency and at an amplitude which allows the vibrations to be reduced and minimized.

Abstract: The present invention relates to an antivibration device intended to reduce the transmission of vibration between two bodies (2, 3). According to the invention, the antivibration device comprises an elastic annular element (4) which is connected to two bodies (2, 3) so as to serve as a connection between them and which is capable of being deformed under the action of vibration generated in at least one of the bodies, and a resonator (5) connected, via at least two leaves (6, 7) which are flexible in terms of bending and rigid in terms of tension and in terms of compression, to the internal face (8) of the annular element (4) so as to be set in oscillating rotation when the annular element (4) is deformed, by the action of vibration so that, by this oscillating rotation, the resonator (5) generates an antivibration inertia force which opposes the vibration and thus reduces its transmission from one body to the other.

Abstract: The instrument comprises two rigid yokes 1 and 2 capable of sliding one with respect to the other in the direction of the clearances to be measured between two components (R, 5) and 8. First of all, using an operating member 3, enough force to bring the ball R against the stop b1 of its socket is exerted on the component 5 by means of a spring 10. The comparator 9 is zeroed. Enough force is then exerted on the component 5 to bring the ball R to rest on the opposite stop b2 of its socket, this being done using an operating member 4 that acts in the opposite sense, the clevis mount 8 still being held between two resting faces 6, 7 of the yokes 1, 2. The clearance of the ball R in its socket is then read directly off the comparator 9. Application to measuring clearances in ball joints.

Abstract: The present invention relates to a device (1) for damping the vibrations of a structure (2) subjected to dynamic stresses, of the type including a main mass (3) mounted on an elastic plate (4) which is itself fitted into the structure (2) whose vibrations are to be damped.According to the invention, the damping device (1) additionally comprises at least one auxiliary mass (5) connected to said main mass (3) and capable of being moved at least substantially parallel to said elastic plate (4) as a function of the control pulses which are received from a computer (9) and are computed from signals output by a first (10) and/or a second accelerometer (11) respectively measuring the vibrations of said structure (2) and those of said main mass (3).

Abstract: A hingeless rotor including a rotor mast driven in rotation about an axis of the rotor, a hub secured in terms of rotation to the mast, and at least two blades, each of which is, firstly, joined to the hub by a root attachment part comprising at least one arm which can twist about a longitudinal pitch-change axis of the blade and, secondly, equipped with a cuff which is rigid in torsion, surrounding the at least one twistable arm, and the radially external part of the cuff, with respect to the rotor axis is secured in terms of torsion to the blade and to the twistable arm about the pitch-change axis, while the radially internal part of the cuff surrounds, without contact, the at least one twistable arm and exhibits a pitch lever projecting towards the outside of the cuff and joined to a pitch-control rod, wherein, for each blade, an intermediate pitch-control ring which is rigid in terms of torsion about the corresponding pitch-change axis, and which surrounds the corresponding at least one twistable arm is a