Abstract: The invention relates to a method of burnisning for the purpose of imparting surface compression stresses to metal parts. The surface state of the region of the part that is to be burnished is measured initially, and the width of the disk to be used in the burnishing is deduced therefrom. Thereafter, the disk selected in this way is installed on a tool carrier, at the end of an associated flexure bar. Once installed in this way the disk is pressed against the part to exert a predetermined force thereon as a function of the desired surface compression stresses. Finally, burnishing proper of the part is performed using the disk. The burnishing method of the invention is particularly advantageous for use with light alloy wheels, e.g. wheels made of magnesium or of aluminum alloy.

Abstract: The invention relates to a force-limiting device for aircraft landing gear shock absorbers, in particular for helicopters, and also to a shock absorber fitted with such a device. According to the invention, a box 201 is provided that forms a partition in the main body 101 of the shock absorber, the box having a bottom 202 whose central portion has a diaphragm 210 with small throttling orifices 211 and force-limiting members also being provided comprising firstly an annular valve member 225 disposed around the diaphragm 210 such that when open it allows a large volume of hydraulic fluid to pass through the box in a very short time, and a resilient return member 226 holding the annular valve member 225 in its closed position, but allowing the valve member to open above a predetermined threshold.

Abstract: The invention relates to an oscillating arm suspension assembly for a heavy vehicle, in particular for a track vehicle. According to the invention, the oscillating arm comprises a housing receiving firstly a shock absorber of the type in which a semi-solid elastomer is hydrostatically compressed, said shock absorber being mounted coaxially about the oscillation axis of said arm, and secondly an oleo-pneumatic spring of the two-chamber type, having a hydraulic chamber closed by a sliding piston with a piston rod hinged thereto whose end opposite from the piston is hinged to a fixed member inside said housing.

Abstract: The invention relates to a shock absorber for a landing gear leg, the shock absorber being of the type comprising a cylinder and a sliding rod, and including a disk that delimits a lower hydraulic fluid chamber which communicates via a diaphragm with an upper hydraulic fluid chamber adjacent to a pressurized gas chamber formed in the top portion of the cylinder. According to the invention, the sliding rod 102 is implemented in telescopic form, having an outer rod 131 and an inner rod 132 which bears directly against an intermediate partition 112 constituting the above-mentioned disk when the shock absorber is relaxed or under static load. The shock absorber also includes a linear actuator 150.1 received in the inner rod 132, and which, when triggered, serves to extend the landing gear providing the airplane is stationary or is moving slowly on the ground. Two scissors linkages 124 and 127 are also provided for conveying structural twisting forces.

Abstract: The invention relates to a shock absorber of the type comprising a cylinder and a sliding rod, together with a moving disk that defines a bottom hydraulic chamber that communicates via a diaphragm with a top hydraulic fluid chamber that is adjacent to a pressurized gas chamber formed in the top of the cylinder. According to the invention, a self-contained linear actuator is disposed coaxially inside the sliding rod, being interposed between the moving disk and a lower abutment secured to said sliding rod, independent control means being also provided to control the linear actuator, such that when said means are engaged they enable the landing gear to be extended when the aircraft is stationary on the ground.

Abstract: The invention relates to raisable landing gear having a shortenable leg, including a shock absorber fitted with a plunger rod, and a linkage connecting said plunger rod to the strut of the shock absorber, under the control of a resilient connecting rod having a threshold, serving to pull on the shock absorber when the leg is raised. According to the invention, the linkage includes two arms forming an alignment, with a first arm hinged on the plunger rod and having a lateral appendix whose free end is capable of co-operating with a stationary cam secured to the structure of the airplane, and a second arm which is hinged to the strut. The lateral appendix and the stationary cam are organized to operate in an emergency, in the event of the threshold connecting rod failing, thereby ensuring that the shock absorber is extended and that said lengthened shock absorber is locked in the undercarriage-down position.

Abstract: The invention relates to a shock-absorbing actuator including a cylindrical body and a hollow rod having an annular piston. The cylindrical body includes a separator piston delimiting two hydraulic fluid chambers, one of which communicates via a distributor valve with the hydraulic circuit of the aircraft, said distributor valve being closed automatically at the end of lowering the landing gear; the annular chamber communicates via a second distributor valve with said hydraulic circuit. The distributor valves thus make it possible to extend and retract the shock-absorbing actuator. In addition, a force peak-limiting means is disposed in an extension extending beyond an end wall of the body that forms one of the abutments for the separator piston.

Abstract: The invention relates to a catch device of the type comprising a main casing that houses a hinge hook and a locking lever having one branch carrying a thrust wheel that co-operates with the hook and having its other branch connected by means of a linkage to the outlet from a driving motor and gear box assembly. According to the invention, the linkage (112) includes an oblong slot (122) for enabling the locking lever (106) to pivot in the event of the outlet shaft (113) of the motor and gear box assembly being jammed, and, in addition, an independent trigger (130) is associated with the locking lever (106) so that when triggered in an emergency it causes said lever to pivot far enough to disengage thrust wheel (109) from the associated camming surface (110.1) of the hinged hook (102), thereby releasing it.

Abstract: The invention relates to a system for powering the driving actuator of an aircraft undercarriage, the system including a hydraulic generator capable of delivering fluid under pressure to one or the other of two chambers of the driving actuator. According to the invention, the power supply system includes a safety device enabling any overloading of the actuator rod under the effect of pressure peaks to be avoided: said device comprises two pressure relief valves, the first valve limiting the pressure delivered to the annular chamber and being under the control of the pressure in the full-section chamber, and the second pressure relief valve being of the differential type and continuously controlling the pressure difference between the two chambers of the actuator. The invention is applicable to providing very safe power supply systems for aircraft undercarriages.

Abstract: The invention relates to a shock absorber comprising a main body and a rod-piston, with the rod-piston being retracted when the landing gear is down and extended when the landing gear is up. The main body comprises, in succession, three chambers that are separated by associated partitions, and that comprise: a first hydraulic chamber in which the rod-piston slides freely; a chamber in which a separator piston slides, delimiting a second hydraulic chamber; and a chamber in which another piston slides, delimiting both a third hydraulic chamber and a chamber containing gas under high pressure. Communication means are provided between said chambers together with two associated electrically controlled valves enabling corresponding fluid connections to be selectively established.

Abstract: The shock absorber comprises a strut, a sliding rod slidably mounted relative to the strut and co-operating therewith to define both a shock absorbing chamber and a raising chamber which is connected to a member for feeding it with raising liquid, a dip tube defining a lowering chamber and connected to a member for feeding it with a lowering liquid, and in which a lowering piston is disposed, which piston has one face in contact with the shock absorbing liquid, and an anti-crash tube mounted to slide relative to the sliding rod and including an energy-absorbing member.

Abstract: The invention relates to raisable landing gear including a shock absorber having a strut and a sliding rod, together with a two-alignment hinged side-brace. According to the invention, unlocking means are provided to break the secondary alignment, thereby breaking the main alignment while the landing gear is being raised, said means being essentially constituted by a lever mounted to rotate on one of the arms of the main alignment, and by a motor and gear box assembly for driving said rotary lever in rotation and further including an unlocking arm that, when said motor and gear box assembly is in action, co-operates with the lower arm of the secondary alignment to break said secondary alignment. Return means are also associated with the rotary lever to ensure that it returns to its initial position when the landing gear is raised.

Abstract: The invention relates to raisable landing gear having a shock absorber strut and a sliding rod. According to the invention, the landing gear includes a lateral stabilizer hinged to the strut and fitted with a wheel at its free end, together with mechanical coupling means associated with said lateral stabilizer, in such a manner that: firstly lowering the landing gear deploys the lateral stabilizer so that its wheel, when the landing gear is in its lowered position, provides support additional to that provided by the wheels of the wheel set, and also constitutes a lateral stabilizer proper during taxiing of the airplane; and secondly raising the landing gear folds the lateral stabilizer so as to enable the entire landing gear assembly to be housed when in the raised position. It then becomes possible to organize the landing gear beneath the fuselage of the airplane, thereby making it possible to obtain landing gear that is extremely short.

Abstract: The locking device comprises a first hook cantilevered out from a rocking pin to support a catch member and bearing against a retractable locking member that opposes rocking movement of the first hook, and a second hook adjacent to the first hook and associated therewith by a link member so that when the first hook is closed, the second hook is kept in a position close to a position in which the second hook supports the catch member.

Abstract: In the preferred embodiment, the device comprises a body, a sliding rod mounted to slide inside the body, and a control rod including both compression and expansion end-of-stroke abutments associated with a control piston for displacing the control rod to a position which is retracted or extended relative to the body. The stroke c of the sliding rod is greater than the distance d between the compression end-of-stroke abutment and an immediately adjacent end of the corresponding chamber when the control rod is in an extended position.

Abstract: A device for controlling the braking of a wheel train is disclosed and includes an actuating mechanism for alternating actuating symmetrically disposed groups of wheel brakes, temperature sensors disposed or at least one wheel brake in each of the groups of wheel brakes with the control mechanism actuating the coolest group of wheel brakes several times when the temperature difference between the groups of wheel brakes reaches a threshold temperature difference and for actuating the groups of wheel brakes cyclically so long as the threshold temperature difference is not reached.

Abstract: The locking device of the invention comprises a locking device mounted to pivot relative to a beam and having ends associated with an axle to lock the axle in a first position of the locking device and to release the axle by the locking device pivoting towards a second position, together with a control actuator and a set of two links for controlling the position of the locking device.

Abstract: The rotary machine of the invention includes a series of cylindrical chambers swept by pistons in hydraulic liquid admission-and-discharge cycles and alternately connected to high pressure openings and to low pressure openings during each revolution of the machine, wherein said machine it includes a pre-discharge opening disposed between the high pressure opening and the low pressure opening in that order relative to a direction of rotation of the machine, and wherein the pre-discharge opening is connected by a connecting duct to rotary support devices to cause hydraulic fluid to pass through the rotary support devices.

Abstract: A shock absorber of the invention comprises a strut, a inner cylinder fixed to the strut and extending inside the strut, and a sliding cylinder mounted to slide inside the strut and associated with the inner cylinder to communicate with the inside thereof via throttling orifices and short-circuit orifices, a pump and control arrangement being provided to pump hydraulic liquid from the sliding cylinder into the inner cylinder so as to produce a retraction of the sliding cylinder into the strut when both the throttling and short-circuit orifices are closed. The throttle orifices produce a communication between the sliding cylinder and the inner cylinder which produces a normal damping operation of the strut while the short-circuit orifices provide a rapid release of the sliding cylinder from a retracted position and a control member selectively closes one or both of the orifices.

Abstract: A retractable landing gear is arranged so as to provide, in use, a highly inclined shock absorber while avoiding high shearing stresses on the shock absorber. The landing gear includes a pivoting panel fixed to an aircraft structure to pivot about a raising axis; a shock absorber including a strut fixed to the pivoting panel so as to pivot relative thereto about a tilt axis, and a sliding rod mounted to slide in the strut and carrying a set of wheels at its bottom end; and a coupling member connected to the pivoting plate and to the bottom end of the sliding rod. Also included is a mechanism for raising and holding the landing gear.