Abstract: An electrorheological damping device for reducing translational vibration between two bodies comprises a rotary electrorheological damper and transmission means for converting the translational vibration between the two bodies to the rotary motion of the rotary electrorheological damper. The rotary electrorheological damper includes a stator and a rotor that are coaxially arranged. The stator have a plurality of stator electrodes, and the rotor have a plurality of rotor electrodes. The stator electrodes and the rotor electrodes face each other alternatively within at least one fluid chamber. The fluid chamber is filled with an electrorheological fluid that varies its rheological properties when exposed to an electric field. The electrorheological fluid fills spaces between each pair of the stator and rotor electrodes.

Abstract: A shock absorber, optionally operable as a retractable landing gear actuator, includes a sealed cylinder divided by a cylinder head to define an upper chamber and a lower chamber, the lower chamber further divided by a piston having a piston rod passing in sealed manner through the lower cylinder end. The cylinder head includes one or more orifices, the effective opening of each orifice controlled by a valve, the valve having a stem attached to and passing through the upper cylinder end to the atmosphere, such that the pressure between the piston and the cylinder head is limited to a certain value above atmospheric pressure, regardless of the velocity or position of the piston. The valve is forced toward the closed position by a spring against a stop such that it is always at least partially open. During hard or crash landings, high fluid pressure on the piston or in the upper chamber forces the valve further open.

Abstract: Very large aircraft landing gear using single mounted eight wheel bogie on dual shock struts. A primary or main two-stage shock absorber and a semi-articulating secondary or auxiliary single-stage shock absorber, each of which are mounted using the second and third axles as pivot joints in a four axle, eight wheel truck beam.

Abstract: A shock strut assembly for an aircraft landing gear includes a trunnion fitting, a compressible oleo strut subassembly, a wheel subassembly, an energy dissipating subassembly, and a mechanical load control subassembly. The oleo strut subassembly includes a cylinder member having an upper end mounted in combination with the trunnion fitting by means of the mechanical load control subassembly and a piston member having a lower end affixed in combination with the wheel subassembly and an upper end slidably inserted in the cylinder member. The energy dissipating subassembly includes a cylindrical cutter member secured in combination with the cylinder member and the trunnion fitting and a frangible tube member mounted in concentric combination with the cylinder member so that the lip of the upper end thereof is disposed in abutting engagement with the cutter member.

Abstract: An apparatus for determining the weight and/or center of gravity of an aircraft is disclosed and includes a plurality of fittings attached to each oleo strut on the aircraft for accessing the working fluid in the oleo strut, a computer, a first, electronically-responsive valve coupled to each fitting for controlling the fluid flow through the fitting in response to control signals from the computer, a pressure transducer coupled downstream of the first valve for measuring the pressure of the working fluid therein and coupled to the computer to provide a pressure measurement signals to the computer for each strut, and an inclinometer attached to the aircraft and electronically coupled to the computer for providing incline information to the computer.

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.

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 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 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 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: An aircraft landing gear damping mechanism improvement of a damper containing piston means in a chamber of a housing, an orifice in the piston means and Belleville springs disposed in the chamber between the wall of the chamber and the piston means on opposite sides thereof. The improvement comprises means, e.g. in the form of a member having slots therein, and disposed between one end of the Belleville springs and the adjacent chamber wall, providing fluid communication of the inner cavity and outer cavity of the chamber below and above the Belleville springs.

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 high pressure hydropneumatic shock absorber (10) includes a cylinder (12) with a piston (16) slidably positioned within the cylinder (12). The piston (16) and cylinder (12) are configured as a telescopic suspension unit. The piston (16) defines a first variable volume chamber (28) within the cylinder (12) and is filled with a working liquid. A reservoir (44) includes an interior movable barrier wall (62) defining first (60) and second (64) separated variable volume reservoir chambers. The first reservoir chamber (60) is filled with working liquid and the second reservoir chamber (64) is filled with a working gas. A flow-controlling damper valve (58) communicates the first cylinder chamber (28) with the first reservoir chamber (60).

Abstract: The invention relates to a device for reducing the damping flexibility of a suspension shock absorber for an undercarriage, in particular the main undercarriage of a helicopter, and a shock absorber and an undercarriage including it.The shock absorber is of the oleo-pneumatic type, and at least one of the incompressible and compressible fluids of the shock absorber is at least partially transferred from an expansion chamber (31) of the latter into a transfer chamber (42) of an accumulator (40) external to the shock absorber (1, 8), and in which the transfer chamber (42) is isolated from a return chamber (43) by a separating piston (41). The connection between the transfer chamber (42) and the corresponding expansion chamber (31) can be cut off by an electro-valve (44), in order to isolate the shock absorber (1, 8) from at least part of the low pressure gas chamber (34) of its expansion chamber (31).Application to the undercarriage equipment, in particular the main undercarriages of ship-borne helicopters.

Abstract: A shock absorber comprising a strut (1), a sliding rod (3) mounted to slide inside the strut, at least one gas chamber (13, 17) under pressure, an oil chamber (6) associated with the gas chamber, and an expansion chamber (5) connected to the oil chamber via expansion throttling valve (8), the volume of the expansion chamber (5) varying as a function of the extent to which the sliding rod is received in the strut. The shock absorber also includes an expansion short circuit passage (18) between the oil chamber (6) and the expansion chamber (5), the expansion short circuit passage having a cross-section which is greater than the flow section of throttling valve (8), and the shock absorber includes controlled closure partition (32) for closing expansion short circuit passage (18).

Abstract: A two-stage aircraft gear. The landing gear includes a cantilever landing gear whose lower end is attached to a trailing arm (or articulated) landing gear. The cantilever gear is a collapsible piston-cylinder assembly, and the trailing arm gear also has a shock absorber connected between a fixed portion of the trailing arm gear and the movable wheel support arm. When landing, the load imposed is first absorbed by the trailing arm landing gear. After the trailing arm gear has been fully compressed, the cantilever gear begins to compress. The cantilever and trailing arm landing gear can be combined to provide the desired performance. The landing gear static position can be designed to be in the static load curve of the first component, allowing the aircraft to be stably supported and yet difficult to overturn. Adjustable orifice plates contained within one or both of the cantilever and articulated stages can be controlled as a function of the vertical descent velocity and/or distance.

Abstract: A telescopic hydraulic damper includes an outer tube filled with working oil, a pipe member mounted on the bottom of the outer tube, and an inner tube slidably disposed in the outer tube. A valve structure disposed in an inner end of the inner tube comprises a valve body lossely fitted over the pipe member, and a plurality of valve seats mounted in the inner end of the inner tube and spaced from each other across the valve body. The valve seats include an oil locking seat for shutting off working oil between the oil locking seat and the valve body upon engagement with each other, and a rebound seat for allowing working oil to flow between the rebound seat and the valve body upon engagement with each other. The oil locking seat having a surface for engaging the valve body, the surface being inclined at an acute angle with respect to the longitudinal axis of the damper.

Abstract: The shock absorbing jack of the invention includes essentially a rod in which a sliding piston defines an extension chamber and which itself slides in a body by means of a piston defining a retraction chamber, the body including a throttling device and, on the side opposite the rod, two high and low pressure gas chambers, these chambers being separated by a membrane bearing, at rest, on a support with hemispherical perforated bottom.

Abstract: Landing gear mechanism includes a variable area orifice to obtain the desired rebound damping of the landing gear mechanism during landing, and one or more check valve assemblies that operate in conjunction with the variable area orifice to provide the desired controlled instroke of the landing gear mechanism during landing. Also, the landing gear mechanism is provided with a relief valve assembly that permits bypass flow at a pre-set pressure drop only during an intermediate portion of the instroke of the landing gear mechanism to attenuate severe bumps and the like without adversely affecting the controlled instroke and rebound damping of the landing gear mechanism during landing.

Abstract: A two-stage aircraft gear. The landing gear includes a cantilever landing gear whose lower end is attached to a trailing arm (or articulated) landing gear. The cantilever gear is a collapsible piston-cylinder assembly, and the trailing arm gear also has a shock absorber connected between a fixed portion of the trailing arm gear and the movable wheel support arm. When landing, the load imposed is first absorbed by the trailing arm landing gear. After the trailing arm gear has been fully compressed, the cantilever gear begins to compress. The cantilever and trailing arm landing gear can be combined to provide the desired performance. The landing gear static position can be designed to be in the static load curve of the first component, allowing the aircraft to be stably supported and yet difficult to overturn.

Abstract: The present invention is concerned with tilting-beam undercarriages.The undercarriage is characterized in that the shock absorber means (7) comprise a hollow cylinder (11) entered by a plunger stem (14) at its first end (12) and by a piston (18) at its second end, while the hollow cylinder (11) has a hinge member (22) onto which the beam (8) is hinged at a point C differing from the center of it and the piston (18) is connected to the beam at a point D differing from the point of hinge C.

Abstract: The element comprises a tubular body connected to the hub of a wheel and pivotally connected to the base of the chassis (5) by an arm. This body is slidably mounted on a rod (4) pivotally connected to the chassis (5) of the vehicle, the tubular body containing a gas chamber (11) and a hydraulic liquid chamber (13) divided into two compartments by a central ring (25) fixed to the rod (4). According to the invention, there is provided a device (15) for drawing the hydraulic liquid and disposed outside the tubular body (2) which is slidably mounted on the rod (4) by two fluidtight bearings (42, 55) forming the ends of the hydraulic chamber (13) and spaced apart by a constant distance. The drawing device (15) permits the dissipation to the exterior of the hydraulic chamber (13) of the heat stored by the oil during the reciprocating motions of the suspension element and thus avoids the disadjustment of the ground clearance of the vehicle.

Abstract: Landing gear mechanism includes a restrictor assembly containing a main orifice for controlling the rate of instroke of the landing gear mechanism during landing and a taxi instroke bypass valve which provides for increased flow of hydraulic fluid within the landing gear mechanism whenever the landing gear mechanism engages a bump during taxiing to reduce the damping loads that would otherwise occur if all of the hydraulic fluid were required to flow through the main orifice. The taxi instroke bypass valve assembly includes a slide member axially movable relative to the restrictor assembly for opening and closing one or more bypass orifices in the restrictor assembly. The slide member is held in the closed position whenever the landing gear mechanism is in a specified stroke range from fully extended by a secondary piston which is acted upon by the pressure in a precharged secondary chamber urging the secondary piston into engagement with a probe connected to the slide member.

Abstract: A light-weight, gas chargeable, self-contained, shock absorber piston assembly which can be retrofitted to various landing gear. The invention permits taxi and take off in either a "normal" or "rough" runway configuration, followed by subsequent landing, taxi and take off again in either mode. The reconfiguration of the gear for these modes is at the option of the aircrew. There is no need to resupply the landing gear with gas from an external source until completion of a number of system actuations.

Abstract: A rapidly extendible, rough-field attenuating shock-absorbing strut, particularly adapted for use with an aircraft having a tricycle landing gear, is used during takeoff and is adapted for rapid extension to provide angular or upward momentum to the aircraft and thus facilitate takeoff. The strut comprises an outer cylinder which is secured to the aircraft and an inner cylinder adapted for longitudinal reciprocation within the outer cylinder. The inner cylinder has a wheel mounted thereon at the end opposite that of the outer cylinder. A piston is secured for longitudinal reciprocation within both the outer and inner cylinders. The piston has a piston head adapted for reciprocation within the outer cylinder.

Abstract: An extendable shock strut comprising a strut housing having an open end and a closed end and a piston including a piston housing and a piston head slidable in the strut housing. The piston housing and the strut housing are adapted to move a selected distance relative to one another under normal usage. A source of high pressure gas is provided coupled to the shock strut for rapidly driving the strut housing and the piston housing relative to one another to an extended position. In a particular embodiment of the invention, an expandable chamber is formed from the closed end of the strut housing and a secondary piston slidable in the strut housing and positioned between the closed end of the strut housing and the piston head. The high pressure gas rapidly expands the chamber and drives the secondary piston toward the piston head to cause the piston housing and the strut housing to move relative to one another to the extended position.

Abstract: The landing gear comprises: a rod including nested first and second tubes between which there slides a cylinder whose outer end supports a running gear; a strut surrounding the top of the rod and including a steering mechanism cooperating with a rotary tube disposed between the rod and the strut; and a fluid actuator constituted by at least one chamber between the strut and the rod and having a feed inlet only. The landing gear is particularly applicable to helicopters that are required to "kneel down" camel fashion, e.g., for storage in the hold of an aircraft carrier or a cargo plane.

Abstract: Shock absorbing struts for use on aircraft landing gear which include a pair of fluid containing chambers defined by a pair of telescoping cylinders. Fluid flows from one of the chambers to another through a metering orifice proportional to the differential in pressure generated by impact loads created upon landing or taxiing of the aircraft. Upon the differential pressure exceeding a predetermined threshold level an additional flow path positioned in parallel to the metering orifice is opened by an amount proportional to the amount of differential pressure in excess of the threshold to thereby maintain a substantially constant load on the landing gear irrespective of impact loads imparted thereto.

Abstract: Landing gear mechanism includes a restrictor assembly containing a primary orifice for controlling the rate of instroke of the gear during landing and a taxi instroke bypass valve which provides for increased flow of hydraulic fluid within the gear whenever the gear engages a bump during taxiing to reduce the damping loads that would otherwise occur if all of the hydraulic fluid were required to flow through the primary orifice. The taxi instroke bypass valve assembly includes a bypass passage around the primary orifice, and a slide member which is axially movable relative to the orifice restrictor assembly for opening and closing the bypass passage.

Abstract: The nose wheel landing gear has the wheel (23) coupled to the rest of the landing gear by a deformable parallelogram (20, 37, 33, 13) which is located to one side of the wheel (23), the wheel lever (20) which supports the wheel is only slightly longer than the wheel radius. This arrangement enables the landing gear to be shortened when retracted without the wheel itself being offset sideways, thereby occupying less space overall.

Abstract: Skid landing gear provided with components having a device for absorbing energy by plastic deformation and/or for limiting stress, and components of this type.According to the invention, each of two undercarriage parts comprises a skid 170 connected to the structure to two crosspieces 175 and 176 that are hinged on the structure about an axis parallel to the hinge axis on the structure of the other crosspiece of the same undercarriage part, and at least one component 181 that has a main mechanical and/or hydraulic function, such as a strut, a cross-bracing or control jack, a shock absorber or a shock absorber jack, the component being provided with a device for absorbing energy by plastic deformation and/or for limiting stress, and is connected on the one hand to a crosspiece 176 of the respective undercarriage part and on the other hand either to the corresponding skid 170 or to the structure of the aerodyne.The invention is especially suited to use on helicopters.

Abstract: Landing gear mechanism includes a built-in hydraulic actuator which may be actuated to provide a heavy load range, soft spring rate during take-off with a heavy take-off weight and a lower load range, softer spring rate after take-off and prior to landing with a lighter landing weight to yield more shock strut stroke for a given range of vertical load during landing. A special taxi valve allows for some fluid to bypass the main orifice more freely to and from the lower piston damping chamber to the shock strut air-oil chamber as soon as the landing energy stroke is complete to greatly reduce or eliminate high damping loads that might otherwise take place as the gear negotiates bumps. Such a valve may automatically be set to close for landing by the action of the gear extension during a subsquent take-off, thus reactivating the main orifice.

Abstract: A thermally efficient shock absorber comprising a strut housing having an open end and a closed end, a piston including a piston housing and a piston head slideable in the strut housing, and a preselected volume of fluid and gas located in the strut and piston housings. A compensating system is provided coupled to the fluid for maintaining a constant fluid-to-gas volume ratio irrespective of thermal variations and a valve is provided for isolating the compensating system from the fluid. In a particular embodiment of the invention, the compensating system includes a gas compensating chamber and a fluid compensating chamber having a movable separator piston therebetween, the fluid compensating chamber being coupled to the fluid in the strut and piston housings. The gas and fluid compensating chambers are contained within the strut housing separate from the gas and fluid in the strut and piston housings.

Abstract: A telescoping energy-dissipating oleo landing gear shock strut set which can provide both the main landing gear and forward landing gear function, and which is affixed to an airplane, is restrained in an unenergized, shortened condition. A high pressure gas charge is then provided between the extendible element of the strut and the element affixed to the airplane. Early in the takeoff run, the charge gas in the forward strut is released so as to jump the nose and rotate the airplane to a high angle of attack appropriate for takeoff. Subsequent to this rotation, but before the conventional takeoff speed is reached, the charge gas in each of the main struts is released to impart a vertical velocity to the entire airplane, thus jumping it into the air. Both the forward strut and main struts incorporate a hydraulic flow bypass function, so that the landing shock dissipation function does not compromise the aforesaid energy release.

Abstract: Each landing gear of the undercarriage of an aircraft includes an hydraulic cylinder, and the hydraulic cylinders are interconnected through hydraulic restoring devices. The hydraulic restoring devices yieldably urge the pistons in each of the hydraulic cylinders to an equilibrium position, thereby restoring the length of each landing gear to an equilibrium length following a disturbance. In non-level landings, the hydraulically interconnected system causes the landing gear that strikes the ground first to be compressed and the other landing gears to be extended; this absorbs some of the energy of the impact. Extension of the other landing gears tends to limit the extent to which landing energy is converted to angular velocity of the aircraft caused by pivoting of the center of gravity of the aircraft about the first landing gear to contact the ground.

Abstract: The shock absorber is characterized by the fact that it comprises a rod (1) sliding in a cylinder (2) through a piston (3) to determine at least two variable-volume chambers (4,6), ports (40,41) for placing the two chambers in communication, one of the two chambers (4) comprising first elastic fluid (44) at a first given pressure, the other chamber (6) comprising second elastic fluid (10) at a second given pressure, controllable according to at least one parameter, corresponding to a force to be absorbed.

Abstract: An oleopneumatic suspension with variable throttle orifices, particularly for aircraft landing gear comprising a rod (1) enclosing a pneumatic spring (2) and being fixed with respect to a piston (4) sliding in a cylinder (3), two valves (6) and (7) with permanent throttle orifices, the valve (6), which is of greater cross-section, throttling in the compression phase and the valve (7), which is of lesser cross-section, throttling in the extension phase, the suspension comprising in addition a throttle device, the section of whose orifice varies in dependence on the position and the direction of displacement of the piston (4) in the cylinder (3) so that over a given distance around a predetermined equilibrium position the orifices ensuring throttling in the compression and extension phases are of cross-sections respectively greater than the corresponding orifices over the remainder of the distance covered by the piston (4) in the cylinder (3).

Abstract: An aircraft undercarriage unit which includes an upper leg member 1 arranged for attachment to an aircraft body 4, a lower leg member 2 in axially slidable association with the upper leg member 1 to form a telescopic shock absorber, ground wheel means 6 carried by the lower leg member 2 and a sleeve member 13 through which the lower member extends and into which the upper leg member 1 may protrude. The sleeve member has anchorage means 17, 18 through which towing loads may be accepted and transmitted respectively.

Abstract: The invention concerns a landing gear. The landing gear is characterized essentially by the fact that it comprises at least one shock absorber (15), this shock absorber being mounted in the leg (1) and casing (2) assembly by means of two convex surfaces (22, 31) made on the cylinder (16) of the shock absorber (15) and cooperating with two concave surfaces (25, 32) integral respectively with the leg (1) and the casing (2). This landing gear finds an application as a nose gear of the rocker-beam type.

Abstract: An improved air/oil shock absorber (16) especially adapted for aircraft landing gears (11) is provided whereby the rate of strut (14) compression is programmed separately for the landing impact and for rollout after the landing. During the landing impact, increased tail clearance is achieved by temporarily delaying the last few inches of compression. After the aircraft rotates on to the nose landing gear, the shock absorber (16) slowly compresses to its static position where it then functions in a conventional manner. The shock absorber assembly (16) may be oriented in any position with respect to the aircraft (10) by virtue of two internal air/oil separator pistons (24 and 29).

Abstract: The invention relates to a shock absorber mounted between a suspended part and an unsuspended part of a vehicle and specifically a telescopic hydraulic shock absorber comprising a damping piston slidingly mounted in a cylinder. A compensation piston cooperates with the cylinder in order to maintain the damping piston and the cylinder in a given relative position during a variation in the load or centering of the vehicle. The compensation piston has at least one passage controlled by at least one valve sealing the passage to permit the normal operation of the shock absorber during a rapid deformation of the latter as a result of unevennesses of the road. One or more return springs maintain the damping piston at rest in a middle position relative to the cylinder facing a given zone of the latter.Application to vehicle shock absorbers.

Abstract: This shock absorber strut incorporates an annular piston between the lower and upper bearings of the shock absorber piston; together with a separator piston in the bore of the shock absorber piston. The volume below the separator piston is filled with hydraulic fluid and is connected to an external hydraulic power source. An external hydraulic power source is also connected between the annular piston and the shock absorber lower bearing. Application of external hydraulic pressure to the underside of the annular piston, while simultaneously draining off fluid below the separator piston, causes the shock absorber to contract. The volume vacated by the fluid below the separator piston provides a reservoir for displaced shock absorber fluid which pushes the separator piston down the bore of the shock absorber piston. The contracted strut is then locked hydraulically. The procedure is reversed for shock absorber extension.

Abstract: Shock absorbers and shock absorber jacks each of which comprises a shaft containing a low-pressure chamber and sliding in a first chamber of a first cylinder which is separated from another or second chamber which contains a high-pressure chamber, by means of a partition which is traversed by a grooved shaft borne by a separator piston in the other chamber and guided in a sleeve borne by the partition. In the event of the penetration of the shaft into the first cylinder at a rate of very much higher than normal, then the two grooves in the shaft communicate with each other and permit the flow of oil from the first chamber towards the second chamber and towards the low-pressure chamber because of a radial passage through the sleeve near the partition.

Abstract: A duo mode gas hydraulic shock absorbing landing gear strut with a pneumatic spring in combination with a hydraulic fluid controlling orifice for touchdown and automatic means for changing mode after touchdown to impart new pneumatic spring characteristics and to provide duo paths for controlling hydraulic fluid flow.

Abstract: A wing mounted retractable aircraft undercarriage with a trailing wheel or wheels comprising a rigid leg casing, pivotally mounted on the wing about a retraction axis, a rocking lever pivoted on the leg casing, supporting the wheel or wheels and mounting the lower pivot connection of a shock absorber located behind the leg casing, an upper pivot connection of the shock absorber to a lever, which lever is pivotable on the leg casing about an articulation axis which is distinct from the retraction axis, a rod of fixed length pivoted at one end to the lever and at the other end to a fixed position on the wing, so that upon retraction of the undercarriage by the action of a retraction jack, the rod causes rotation of the lever with respect to the leg casing, which rotation, by traction of the expanded shock absorber causes pivoting, with respect to the leg casing, of the rocking lever mounting the wheel or wheels towards the retraction axis, and thus an overall shortening of the undercarriage.

Abstract: A shock-absorber of the piston-and-cylinder kind for use in the landing gear of an aircraft and comprising a cylinder, a piston-rod and a shock-absorbing rod which encloses a chamber for compressed gas and is provided with a valve having a throttling orifice, in which the shock-absorbing rod is mounted to slide, in a fluid-tight manner, in a first chamber, filled with hydraulic fluid, of the cylinder or of the piston-rod, to form a oleopneumatic shock-absorber; the piston-rod is mounted to slide, in a fluid-tight manner, in the cylinder and is solidly connected to a piston-head which, with the cylinder, defines a descent chamber to control lowering of the landing gear when hydraulic fluid is admitted to the descent chamber; the shock-absorber also comprises a lifting piston to load the shock-absorber and mounted to slide within a second chamber of the cylinder or of the piston-rod, so defining a lifting chamber to control lifting of the landing gear when hydraulic fluid is admitted to the lifting chamber thro

Abstract: An aircraft undercarriage suspension includes a liquid filled telescopic suspension strut and a gas spring. Liquid displaced by the strut into the gas spring is selectively directed through alternative flow restrictors, one of which is matched for optimum damping during aircraft landing and the other of which is matched for optimum damping during taxing. A ride control valve operates on the nose wheel undercarriage to control aircraft pitching, the ride control hydraulic system being separated from the damping oil by a floating piston.

Abstract: An aircraft undercarriage suspension includes a liquid filled telescopic suspension strut and a gas spring. Liquid displaced by the strut into the gas spring is selectively directed through alternative flow restrictors, one of which is matched for optimum damping during aircraft landing and the other of which is matched for optimum damping during taxing. A ride control valve operates on the nose wheel undercarriage to control aircraft pitching, the ride control hydraulic system being separated from the damping oil by a floating piston.