Abstract: A needled fiber structure is made by stacking fiber plies on a platen, by needling the plies as the stack of plies is built up by means of needles driven with reciprocating motion in a direction that extends transversely relative to the plies, and by varying the distance between the platen and an end-of-stroke position of the needles while building up the stack so as to obtain a desired distribution of needling characteristics through the thickness of the fiber structure. The instantaneous force exerted during needle penetration is measured (sensors) and a magnitude representative of needling force or penetration energy is evaluated on the basis of the instantaneous force, and the evaluated magnitude is verified for compliance with at least one predetermined condition to monitor proper operation of the process or to act on the way the distance between the platen and the end-of-stroke position of the needles is varied.

Abstract: A machine for needling a textile structure built up from a helical strip delivered by strip supply means, said machine comprising a needling table, a needling head, cutting means for cutting the helical strip, and conical roller drive means for rotating said strip on the needling table, at least a fraction of said conical roller drive means being retractable so as to release an empty space on said needling table enabling ejector means to remove the textile structure from the needling table.

Abstract: The invention relates to a hydraulic pump having axial pistons, the pump being of the type having intersecting axes, and comprising a rotary rotor with a central axis co-operating with an associated distribution seat via a bearing surface that is substantially perpendicular to said axis, said rotor presenting a plurality of axial bores slidably receiving corresponding pistons. According to the invention, a driver separate from the rotor is provided to rotate about an axis of rotation that essentially coincides with said central axis, said driver serving firstly to center and rotate the rotor about said axis of rotation, and secondly to apply resilient thrust to press the bearing surface of the rotor against the distribution seat.

Abstract: The friction device comprises a non-rotary casing (50) in the form of a cage in which there are received a thrust structure (30), a set of friction disks (21, 22, 23, 24, 25) on a common axis, and a backing structure (40), the casing having a peripheral wall provided with ventilation openings (54). The friction device is actuated by a pneumatic actuator (60) mechanically connected to the central portion of the thrust structure through a central opening in an end wall (51) of the casing. Thermal insulation is arranged between the set of disks (21, 22, 23, 24, 25) and the outside of the casing adjacent to the end wall provided with the bearing unit (11) for the rotary shaft (10), and comprises at least one heat barrier (76-77, 78-79) situated at the bearing unit (11).

Abstract: A rotor disk (20) is arranged between two stator disks (30, 40; 130, 140), the disks being made in thermostructural composite material at least for the wear parts. A first supporting structure (50, 150) has a bell shape with a bottom part (52) whereon rests the first stator disk (30, 130) and part of the skirt (70, 170) linked to the bottom part (52) and encloses the disks (20, 30, 40), the bell-shaped structure having cooling means (170, 174) for evacuating the heat generated by the mutual friction of the disks. A second supporting structure (80, 180) has a part in the shape of an annular support plate whereon rests the second stator disk (40, 140); and the bell-shaped structure bottom part (52) and the support plate (80, 180) are provided with cotters (60) or radial ribs (84) co-operating with the corresponding radial housings (36) formed in the outer surfaces (33, 44) of the stator disks (30, 40; 130, 140) to block the latter in rotation relative to the supporting structures (50, 150; 80, 180).

Abstract: The invention relates to apparatus for braking a set of aircraft wheels, the apparatus comprising a normal hydraulic circuit and an emergency hydraulic circuit, both circuits leading to each of the various brakes via associated brake valves. According to the invention, the brake valves of the normal circuit and/or of the emergency circuit are constituted by direct drive valves that are electrically controlled by an associated electronic control unit.

Abstract: A three-dimensional fiber structure is formed by superposing layers of felt and by bonding them together by needling, then the structure is compressed to obtain a preform having a fiber volume fraction of not less than 20%. The preform is held in its compressed state by being impregnated with a liquid composition containing a bonding agent capable of bonding the fibers of the preform together. Thereafter, the preform consolidated in this way is densified, e.g. by chemical vapor infiltration.

Abstract: A fabric made of fibers of a carbon-precursor cellulose material is impregnated with a composition containing at least one inorganic ingredient having a function of promoting dehydration of cellulose, and the fabric is subjected to heat treatment. This treatment consists in raising temperature at a speed lying in the range 1.degree. C./min to 15.degree. C./min followed by keeping the temperature constant in the range 350.degree. C. to 500.degree. C., and it is followed by a step of washing the fabric. This produces directly an activated fabric of carbon fibers having a specific surface area of not less than 600 m.sup.2 /g, without subsequent activation treatment at a higher temperature.

Abstract: The invention encompasses a friction-in-oil device having a plurality of coaxial disks comprising metal rotor or driving disks, metal stator or driven disks, and loose disks of carbon/carbon ("C/C") composite material, each loose C/C disk lying between a metal rotor or driving disk and a metal stator or driven disk. Each loose C/C disk is centered by a bearing surface formed in an adjacent metal rotor or stator disk, which bearing surface has passages for feeding oil to the interface between the loose C/C disk and the metal rotor or stator disk.

Abstract: The invention relates to an arrangement of carbon brake disks for an aircraft brake unit comprising stators coupled to a torsion tube alternating with rotors coupled to the corresponding wheel. The arrangement is organized in two configurations corresponding to operation over two successive wear strokes of the pistons of the brake ring, with a first of the configurations comprising a central group of rotors and stators arranged between a front lateral stator and a rear lateral stator, and with a second of the configurations comprising the same front lateral stator and the same rotors and stators of the central group, but arranged between a spacer disk of thickness less than the wear stroke of the pistons, and a new rear lateral stator of thickness greater than that of the preceding rear lateral stator.

Abstract: The invention relates to a reinforcement device for reinforcing the open slots of a carbon brake disk. According to the invention, each slot is provided both with a U-shaped insert whose two lateral limbs are disposed to face the lateral faces of the corresponding coupling bar, and with two channel-section caps that extend towards each other so as to surround the two lateral limbs of the insert completely, each cap having a free end edge that occupies a plane that is parallel to the corresponding inside face and that, on initial assembly, stands slightly projecting relative to said face, thereby enabling said free end edge to be brought exactly into the plane of said inside face after the brake has been used during a running-in period.

Abstract: The invention relates to a safety device for a system transported on board a vehicle, in particular an aircraft, said system being connected to the structure of the vehicle via at least one element having a cylindrical body and a telescopic rod. According to the invention, the body and the rod of each element together define two internal fluid chambers which are normally isolated from each other, a communication passage being provided between the two chambers and normally being closed by an associated throttling valve, the throttling valve being controlled by acceleration-sensing means using a mass that is movable in the axial direction of the telescopic element and that is associated with a rated spring. The means is organized to cause the throttling valve to open as soon as the sensed acceleration exceeds a threshold which is predetermined as a function of the system to be protected, the acceleration of the system thus being kept below the threshold by the telescopic element changing in length.

Abstract: The invention relates to a raisable undercarriage comprising a hinged leg and associated bracing means. According to the invention, the undercarriage is of the leg-shortening type, and the bracing means are organized in the form of a foldable brace having its bottom arm hinged to bottom end of the sliding rod of the hinged leg, said brace further being organized so that, in the undercarriage down position, the lowered leg slopes towards the front of the aircraft.

Abstract: The invention relates to controlling an electrohydraulic braking apparatus of a wheel set in which each wheel is fitted with a brake that is actuated from brake pedals by way of a servo-valve that is electrically controlled by a control unit which measures information relating to the degree of depression of the pedals. According to the invention, when an aircraft is taxiing, braking for the wheels in a first group is organized separately from braking for the wheels in a second group, applied braking pressure varying as a function of brake pedal depression in compliance with respective relationships specific to each of the groups of wheels, which relationships operate over the entire active range of brake pedal depression.

Abstract: The invention relates to an electro-hydraulic braking system for the wheels of aircraft landing gear. The system comprises two hydraulic pressure sources each feeding a hydraulic circuit that leads to the brakes of two groups of wheels via a single braking control stage. A circuit connects either a solenoid valve electrically controlled by the control unit or else a double metering valve mechanically controlled by the brake pedals via two shuttle valves, to one inlet of each control stage. A second circuit directly connects a solenoid valve to a second inlet of each of said control stages. Each control stage includes two symmetrical internal circuits having one servo-valve per corresponding brake, which servo-valves are cross-connected by means of a respective corresponding controlled valve. In the event of one of the circuits breaking down, the servo-valves associated with the other circuit then serve, after automatic reconfiguration, also to provide braking and anti-skid control in a paired tandem mode.

Abstract: The strut of the leg has a lateral extension on its outside above the rotary sleeve, the cylinder of a steering actuator is suspended from the lateral extension by means of a universal joint, the end of the rod off said actuator is hinged to a lateral steering lug of the rotary sleeve. This flexible disposition puts fewer constraints on implementation of the scissor linkage, and it improves guidance of the rotary sleeve.

Abstract: A linear actuator, in particular for driving an aircraft landing gear leg, the actuator comprising a main body with a screw that is prevented from moving axially and that is constrained to rotate with a coaxial gear wheel that meshes with the outlet gear wheel of a driving motor and gear box assembly, and a nut that is secured to a sliding guide rod inside said main body. According to the invention, the rotary connection between the screw and the coaxial gear wheel is provided by declutchable coupling means, which means is declutched in an emergency for the purpose of releasing the screw by associated trigger means whose operation requires very little energy.

Abstract: The running gear comprises a tilting beam having one end hinged to the vehicle about a tilt pin and supporting a rotary axle for at least one wheel, a blade spring having a first end fixed to the vehicle and a second end hinged to a first end of a shock absorber having a second end hinged to the vehicle, and a control actuator hinged firstly to the second end of the blade spring and secondly to a tilting control pin carried by the tilting beam at a point that is spaced apart from the tilting pin in order to control the tilt of the tilting beam.

Abstract: A locking device including a box, a primary latch made in the form of a tilting hook, and a retractable locking member. The locking device further includes a secondary latch made in the form of a sliding member. The sliding member is displaceable between a retracted, open position and an extended, closed position in which the sliding member is in the direct vicinity of an associated catch member. The locking device is particularly applicable to locking the thrust-reversing flaps of aircraft jets.

Abstract: The invention relates to raisable landing gear including a shock absorbing leg that is pivotally mounted, and to a driving actuator associated therewith. According to the invention, the leg is implemented in the form of two elements that are hinged to each other about an axis parallel to the pivot axis of the leg and that are connected together by means of a shock absorber, the bottom element forming a rocker and the top element forming a panel whose free end is connected to a drive actuator which is a shock-absorbing actuator having a force threshold, said shock-absorbing actuator serving to apply a predetermined torque that maintains the leg in position during normal landing, while allowing said leg to be raised against a controlled force in the event of a crash landing.