Abstract: The invention relates to a resonant device comprising a mass/spring system composed of a main mass comprising at least one main mass element, and of at least one spring element (3). The device is one which comprises at least one additional mass (10) comprising at least one additional mass element (102) and a coupling device (204) able to couple the additional mass (10) to the main mass (1) and to decouple it therefrom, so as to modify the tuning frequency of the device.

Abstract: The invention relates to a generator of dynamic loads comprising a main mass/spring system composed of a main mass comprising at least one main mass element of mass M2 and of at least one main spring element of stiffness K2. The device is one which comprises an additional mass/spring system, which is coupled to the main mass/spring system and which is composed of an additional mass of mass m3 and of at least one additional spring element of stiffness K3, the assembly exhibiting a first and a second resonant frequency f0 and f2 respectively, and an anti-resonant frequency f1, with f0<f1<f2.

Abstract: An avionic tray is fixed to a shelf and comprises a base plate, side rails and a back plate. At least a forward end of the base plate of the tray is reinforced by a reinforcing plate fixed to the upper surface of the base plate. The part of the base plate carrying the reinforcing plate is stepped downwards so that the upper surface of the reinforcing plate is level with the surface of the base plate to the rear of the reinforcing plate. Fixing holes are provided in the reinforcing plate and the base plate for fixing the tray to the shelf by means of screws whose heads are housed in housings in the reinforcing plate.

Abstract: Method of manufacturing a cylindrical type frequency adapter including at least one assembly in the form of an elastomer ring molded between and adhering to an inner armature and a cylindrical ring wherein the assembly or each of the assemblies is sleeved into an outer sheath. After the elastomer ring is molded between the inner armature and the cylindrical ring and the resulting assembly is cooled, without carrying out any diameter reducing operations, the assembly is sleeved into the outer sheath after which the diameter of the complete adapter is reduced by plastic deformation of the outer sheath which also reduces the diameter of the cylindrical ring.

Abstract: A vibration and shock absorber device, comprising a metal body constituted by one or more helically wound lengths of cable (1) and two bars (10, 20) interconnecting the turns in two diametrically opposite zones, with a layer of elastomer material (30) coating the structure and leaving a central orifice (31, 32, 33, 34). The turns of the lengths of cable (1) are greased or otherwise treated to prevent them from adhering to the elastomer material (30).

Abstract: A device for locking an electronic equipment housing (1) on a tray (11). The device for a moving carriage (20) connected to the front wall (2) of the housing (1). A threaded shaft (21) along which the carriage moves has a hinge pin (22) fixed perpendicularly to one of the ends thereof. A fork (17) is disposed beneath the tray and provided with two inclined slots (30) in which the hinge pin (22) is displaced. Each slot (30) includes at least one stop notch (31, 32, 33) at one or other of its ends for holding fast the hinge pin (22) of the threaded shaft (21).

Abstract: A device for holding an electronic equipment housing (1) on a tray (10) comprising a bottom (11), a vertical backplate (12) provided with the male portion (15) of a connector, and two side flanks (13), the device including at least one locking device (20) situated at the front of the tray and mechanically connected to the front face (2) of the housing (1), and a sideways locking element for the housing, said locking element being constituted by at least one tab (30) fixed to the tray (10) and operatively engaging a corresponding at least one notch (2A) provided in the front face (2) of the housing. The invention is applicable to housings mounted in aircraft.

Abstract: The covering is immersed in water (2). A viscoelastic substance (4) is disposed in ducts formed by rigid auxiliary walls (5) fixed to the base wall (1). The ends of these ducts (6) contain air. The invention is applicable, in particular, to providing protection against under-sea noise.

Abstract: A gas turbine exhaust device installed at the outlet from the guide vane stage (5) of the turbine and upstream from an exhaust duct (10), said device comprising a jet diffuser (20) having orifices (25) perforated therethrough, with the axis of the diffuser being the same as the axis of the turbine.

Abstract: One or more microswitches (9) are mounted on the back wall (2) of an aircraft electronics equipment pallet or tray, to be actuated by the rear panel (7) of a slide-in electronics unit (6) when the latter's rear panel connectors correctly mate with the connectors on the back wall of the receiving tray, thus electrically or optically connecting photosensitive means with luminous indicating means.

Abstract: The present invention relates to an electroluminescent panel (10), composed of an electroluminescent lamp (1) and two plates (2, 3) enclosing said lamp, one of which (2) generally is not required to transmit light and the other (3) which is provided with lighting elements, comprising at least one opening for the passage of an operating control (6, 8), wherein the active part of the electroluminescent lamp is tangential to the periphery of one or several openings. It also relates to a method of manufacture of such a panel, and for application for control and command panels (pilot cockpits, dashboards, synoptics, . . . ).

Abstract: An annular seal is positioned in an opening of a shelf for supporting electronic equipment. The annular seal has an outer portion which is clamped between an air flow control plate and the shelf to seal the plate to the shelf, and has an inner seal portion of greater height than the outer portion which extends through the opening in the shelf. The inner seal portion extends above the shelf and is sufficiently resilient to seal against the underside of electronic equipment which can be slid into position the shelf.

Abstract: The indicator light has an insulating support (1) of flattened shape defining a cylindrical edge (9) with an extension (8) in the form of a flange adapted to be applied against one of the sides of the printed circuit, and resilient strips (18) provided with ends in the shape of a ramp for application against the other side of the printed circuit carrying the paths, clipping devices permitting a locking in the required position in cooperation with notches of the aperture of the printed circuit.

Abstract: The device comprises two rigid elements 1a, 1b, 2 and an elastomer mass 10 interposed therebetween so as to be deformed when the elements move relative to each other in a longitudinal direction. The device includes a closed space with a restriction element 16 defining two chambers 23, 24 whose volumes vary inversely upon movement of the chamber walls, the two chambers being interconnected by one or more passages, the empty space being filled with a viscous fluid material so as to produce a damping effect in the passages. Application to helicopter blade frequency adapters.

Abstract: The recoil cushioning device comprises a recoiling member guided in a fixed member with cushioning means comprising a constant volume chamber placed between two diaphragms, said chamber being subdivided into three areas separated by constrictions. A recovery spring is compressed during recoil. When the recoil amplitude is adequate a bearing surface is applied against a cushion, which increases rigidity.

Abstract: A shock and vibration insulator comprises an axial rigid element fastenable to an installation to be damped, a peripheral rigid element also fastenable to said installation and a radial rigid element extending radially between said elements and comprising a first radial part having an internal recess in the shape of an annular groove and a second radial part having a peripheral edge penetrating into said recess in which it can move radially so as to provide a fairly closed annular chamber.