Abstract: The invention relates to an architecture for a hydraulic braking system suitable for an aircraft of the type having at least one group of main landing gear units, each landing gear unit comprising a determined number of wheels each provided with a hydraulically actuated brake, the or each landing gear group being associated with a hydraulic circuit provided with hydraulic equipment and adapted to deliver hydraulic fluid under pressure to all of the brakes of the landing gear group, the hydraulic fluid being pressurized by at least one aircraft pressure generator system associated with an aircraft hydraulic fluid supply. According to the invention, accumulators are connected on the or each circuit in sufficient number for each accumulator to feed two pairs of brakes, each pair of brakes being mounted on a distinct landing gear unit, and an electrically-driven pump being arranged to maintain a predetermined pressure level in all of the accumulators of the circuit in question.

Abstract: The invention provides a method of anodizing a part made of aluminum alloy.

Abstract: The invention relates to a hydraulic steering system architecture comprising at least one steering control actuator having chambers connected to the outlets of a directional-control valve, an accumulator, and an electrically-driven pump unit associated with an emergency supply. The hydraulic system also comprises a general selector arranged, in a normal mode of operation, to connect the feed port of the directional-control valve to a pressure-generator device and the return port of the directional-control valve to a main supply associated with the pressure-generator device, while also ensuring that the emergency supply is filled, and in an alternate mode of operation, to connect the feed port of the directional-control valve to the accumulator.

Abstract: A latch device, in particular for latching an airplane landing gear or an airplane landing gear hatch, the device comprising a box containing a set of hinged elements mounted to pivot about respective parallel axes, said assembly including at least one hook and a locking lever connected to said hook by associated elastically deformable return means, said hook being capable of being unlocked by acting on said locking lever either via first actuator means in a normal mode of operation, or via a second actuator means in an emergency mode of operation when said first actuator means fails to unlock the hook.

Abstract: The invention relates to an architecture for a hydraulic steering control system including at least one actuator; the hydraulic system comprises a directional-control valve connected to a pressure-generator device and to an associated main supply, the hydraulic system further comprising a reversible electrically-driven pump unit having two ports and being fitted with a general selector arranged, in a normal mode of operation, to put the chambers of the actuator into communication with the directional-control valve, and in an alternate mode of operation to put the chambers of the actuator into communication with the ports of the pump unit. A compensation device makes it possible in the alternate mode to compensate for any flow differential between the flow drawn in by the pump unit from one of the chambers of the actuator and the flow delivered by the pump unit into the other chamber of the actuator.

Abstract: A gas preheater for a CVI furnace designed for the densification of annular porous substrates arranged in a plurality of vertical annular stacks of substrates, comprising: a sleeve made of heat conductive material resting upon the bottom wall of a susceptor and delimiting a gas preheating chamber, with a gas inlet opening in the gas preheating chamber; a heat exchange assembly located in the gas preheating chamber; a gas distribution plate resting upon the sleeve, covering the gas preheating chamber and provided with a plurality of passages for preheated gas; a load supporting plate for supporting stacks of annular substrates and provided with a plurality of passages in communication with respective passages of the gas distribution plate and registration with internal volumes of respective stacks of annular substrates; and nozzles inserted in passages communicating the gas preheating zone with the internal volumes of respective stacks of annular substrates for adjusting the flows of preheated gas respectively

Abstract: A fiber structure for needling is driven so as to impart a speed of advance thereto past a needling head carrying a plurality of needles that are driven with reciprocating motion during which they penetrate into the fiber structure and are extracted therefrom. The instantaneous speed of advance of the fiber structure decreases in response to the resistance to advance caused by the needles penetrating and subsequently increases on the needles being withdrawn. The force exerted on the needles by the advance of the structure is thus limited, without completely interrupting advance throughout the time that needles are present within the structure. The fiber structure can be caused to advance by means of a transmission presenting mechanical slack suitable for absorbing the decrease in the speed of advance caused directly by the resistance to advance that is exerted by the needles.

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 invention concerns a safety locking device intended to equip electromechanical equipment provided with a rotating shaft, the device comprising a first friction element connected rotationally to the said shaft, and a second friction element immobile rotationally and extending opposite the first friction element, one of the two friction elements being able to move in translation, under the action of controllable actuation means, between a locking position and a release position.

Abstract: A fiber structure for needling is driven so as to impart a speed of advance thereto past a needling head carrying a plurality of needles that are driven with reciprocating motion during which they penetrate into the fiber structure and are extracted therefrom. The instantaneous speed of advance of the fiber structure decreases in response to the resistance to advance caused by the needles penetrating and subsequently increases on the needles being withdrawn. The force exerted on the needles by the advance of the structure is thus limited, without completely interrupting advance throughout the time that needles are present within the structure. The fiber structure can be caused to advance by means of a transmission presenting mechanical slack suitable for absorbing the decrease in the speed of advance caused directly by the resistance to advance that is exerted by the needles.

Abstract: An axial fixing device for axially fixing an annular brake disk on a wheel hub of a motor vehicle, the annular brake disk having the same axis of rotation as the hub and including radial ventilation ducts regularly distributed about its periphery. According to the invention, the hub has axial guide pieces in relief, or “lugs”, for co-operating with fluting in an inner peripheral edge of the disk to center the disk, to lock it angularly, and to guide it axially relative to the hub, each lug of the hub having a radial through channel for co-operating with a corresponding ventilation duct of the disk, and the disk is held axially in the hub with play by axial holding means disposed between the disk and the hub.

Abstract: Apparatus for automatically controlling the spreading of a textile sheet made up of a plurality of tows coming from a tow feed module and serving to feed a drive module, the apparatus comprises means for measuring the positions of the longitudinal edges of each tow, means for individually adjusting the width of each tow, means for individually adjusting the position of each tow in a direction perpendicular to a tow advance direction, and digital processor means responsive to said position measuring means to control the adjustment means in such a manner that the textile sheet presents determined width and position.

Abstract: Apparatus for automatically presenting a generally pre-needled textile sheet coming from an upstream module and intended to feed a cross-layer module, the apparatus comprising means for measuring the positions of the longitudinal edges of the textile sheet, means for adjusting the width of said textile sheet, means for adjusting the position of said textile sheet, and processor means responsive to the position measuring means to control the adjustment means in real time in such a manner that the textile sheet presents determined width and position.

Abstract: A gas diffusion electrode comprises a cloth (12) of activated carbon fibers having a first face coated in a hydrophobic material (14) and a second face on which particles of catalyst (16) are fixed directly and are dispersed in substantially uniform manner over the fibers. The electrode can be used in an electrochemical cell of a proton exchange membrane fuel-cell battery, or in an electrochemical reactor, e.g. for making chlorine and caustic soda.

Abstract: The invention relates to an architecture for a hydraulic braking system suitable for an aircraft of the type having at least one group of main landing gear units, each landing gear unit comprising a determined number of wheels each provided with a hydraulically actuated brake, the or each landing gear group being associated with a hydraulic circuit provided with hydraulic equipment and adapted to deliver hydraulic fluid under pressure to all of the brakes of the landing gear group, the hydraulic fluid being pressurized by at least one aircraft pressure generator system associated with an aircraft hydraulic fluid supply. According to the invention, accumulators are connected on the or each circuit in sufficient number for each accumulator to feed two pairs of brakes, each pair of brakes being mounted on a distinct landing gear unit, and an electrically-driven pump being arranged to maintain a predetermined pressure level in all of the accumulators of the circuit in question.

Abstract: A carbon fiber fabric having large specific surface area is made using a rayon precursor, and a catalyst is fixed on the fabric by impregnation or by cationic exchange. The carbon fiber fabric has pores with a mean size lying in the range 0.3 nm to 3 nm, a carbon content greater than 99%, and a high density of functional groups per unit area which favors the dispersion of metal catalyst in the form of fine particles and which is good for highly selective catalytic reactions in fine chemistry.

Abstract: A machine for needling a textile structure made up of a plurality of superposed layers comprises a vertically movable needling table, a needling head having a determined number of barbed needles and disposed vertically above the needling table, and drive means for imparting vertical reciprocating motion to the needling head, defining a low point of maximum penetration of the needles. Measuring means are provided in the machine located in the needling head to measure the position of the top surface of the textile structure at the low point of maximum penetration of the needles. The measuring means are preferably disposed in a midplane of the needling head perpendicular to an advance direction of the textile structure.

Abstract: In a circular needling machine for needling an annular preform and comprising both a vertically movable needling table serving as a horizontal support for said annular preform, and a needling head having a determined number of barbed needles disposed over the needling table in a needling zone and driven with vertical reciprocating motion, provision is made for the annular preform to be placed directly on the needling table and for it to be driven in rotation on the needling table by drive means while the needling table remains rotationally stationary during said rotation. The drive means comprise a set of conical friction rollers kept continuously in contact with the annular preform.

Abstract: A machine for needling a textile structure built up from a wound strip of material to be needled that is delivered by strip supply means comprising a storage drum containing said wound strip of textile material, an unwinding assembly for continuously extracting said strip from said storage drum, and a helical chute or “twist” for taking up said extracted strip unwound from said drum and for bringing it up to a needling table where there are friction drive means. The storage drum and the helical chute have the same axis C as the needling table.

Abstract: The carbon fibers present a mean lattice surface spacing (d002) not less than 0.36 nm, preferably 0.38 nm, at a crystallite size such that the mean height (Lc) lies in the range 0.7 nm to 0.3 nm and the mean width (La) lies in the range 2 nm to 6 nm, and it presents total porosity lying in the range 10% to 30%. The electrode is preferably a rayon-precursor carbon cloth and it constitutes the anode (10) of a secondary cell having a cathode (20) which includes lithium enabling lithium ions to be inserted and de-inserted, and an electrolyte (30).