Messier-bugatti-dowty

Safran Landing Systems

Arnaud Lafitte

Sabien Verlyck

Guy Valembois

Philippe Henrion

Gérard Balducci

Sabien Verlick

An encapsulated shock absorber of an aircraft undercarriage includes a sliding rod slidably mounted in a leg strut of the undercarriage and an inner cylinder extending inside the strut. The inner cylinder is fastened to the strut via a top end, and the rod slides around the inner cylinder. The inner cylinder is terminated inside the sliding rod by a diaphragm that defines an oil chamber in the shock absorber and inside the sliding rod. A mixed oil/gas chamber is located in the inner cylinder, and an expansion chamber extends between the sliding rod and the inner cylinder. A hole being made in the inner cylinder in register with the expansion chamber is connected by a pipe to a pressure sensor situated outside the strut. The pipe extends inside the inner cylinder from the hole to the top end of the inner cylinder.

Measuring the pressure in the expansion chamber of an encapsulated shock absorber in an aircraft landing gear

The invention relates to a device for selectively transmitting force, the device comprising a first element and a second element that is movably mounted on the first element, a friction member being arranged between the first element and the second element to exert a friction force between them, which force presents a maximum value that depends on prestress imparted by a presser member. The device includes control means for varying the prestress imparted by the presser member to the friction member and arranged, where appropriate, to substantially release the prestress imparted by the presser member so that the prestress becomes substantially zero.

Selective force transmission device and an undercarriage consisting of an application thereof

A mechanical transmission device for transmitting a threshold force, comprising first and second elements rotatably mounted relative to each other about an axis of rotation, and having a transmitter member interposed between them to constrain the two elements to rotate together when a torque is imparted to one up to a threshold torque beyond which the two elements become movable in rotation. The transmitter member has a first friction disk constrained to rotate with the first element, and a second friction disk facing the first disk. It also has a bearing member that is axially movable to press the disks together and against a bearing turntable of the first element under drive from a presser member. Finally, it has a rotary drive, interposed between the bearing member and the second element, which are arranged to cause the bearing member to move axially against the presser member during rotation.

Mechanical device for the transmission of a force with a threshold

A controlled-friction device comprising a first element having a second element mounted thereon to slide in a sliding direction, and friction retaining means arranged to exert between the two elements an opposing force against relative movement of the two elements. The friction retaining mechanism comprises a friction member mounted securely to the first element to rub against the second element via a friction surface extending parallel to the sliding direction, a presser member for exerting a thrust force on the friction member, urging the friction member against the second element in a direction normal to the relative movement of the elements, and a linkage linking the friction member to the first element causing the friction member to separate from the second element during movement in either direction of the second element relative to the first element.

Controlled-friction linear device in which a press force is applied perpendicular to the movement

The invention relates to a controlled-friction device comprising first and second elements mounted to move relative to each other in a sliding direction, wherein the device of the invention includes first and second friction members arranged symmetrically between the two elements in order to rub selectively against the second element, each of the friction members being urged towards a wedging position by a presser member, the first friction member being arranged, in a first direction of relative movement between the two elements along the travel direction, to tend to prevent relative movement between the two elements, and in a second direction to exert on the two elements an opposing friction force that depends on a stress applied against the first wedge member by the presser member; while the second friction member is arranged in the second direction to tend to prevent relative movement of the two elements, and in the first direction to exert on the two elements an opposing friction force that depends on a stress applied to the second wedge element by the presser member; the device further comprising neutralizing means for neutralizing that one of the friction members that is suitable for blocking relative movement of the element in one direction or the other, while leaving the other friction element to exert the opposing friction force.

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Chaville, France

Arnaud Lafitte