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 mechanical-hydraulic damper for a load which is subject to shocks and vibrations, comprising a co-operating pair of elements, the first of the pair of elements being mounted in a body for relative axial movement in relation to the body and the second of the pair of elements being rotatably mounted in the body and so coupled to the first element that relative axial movement of the first element causes rotation of the second element which is coupled to a hydraulic system which resists sudden or rapid rotation of the second element. The pair of co-operating elements may comprise a screw-nut assembly. The hydraulic system may comprise a reversible pump driven by the rotatable element and pumping hydraulic fluid round a closed circuit including a throttling orifice. Alternatively the hydraulic system may comprise a rotary laminar hydraulic damper filled with high viscosity oil.

Abstract: Process and apparatus for control of the climatic environment of an underground enclosure having at least one source tending to emit a quantity of extraneous heat and associated with premises presenting a potential need for heating. Utilization is made directly of the regulating characteristics of the ground at a depth taking account of thermal inertia in order to enable the ground to operate as a heat source or thermal absorbent. For this purpose, apparatus is provided which is arranged entirely under the level of the ground at a mean depth which should not exceed 10 m, at latitudes in France, but this depth is variable according to the particular geological nature of the terrain. To take advantage of the thermal buffer the temperature of which is generally about 12.degree. C. in the Parisian region, the apparatus includes a wall structure with some of the walls formed of a material with a high coefficient of thermal exchange.

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 retractable fuselage mounted undercarriage comprising a leg casing mounted to pivot on a main universal joint about an axis which extends longitudinally of the aircraft, the leg casing mounting a wheel assembly which can pivot on the leg casing, a lateral deflection shock absorber and a manoeuvreing and wind bracing jack each connected to the leg casing by a joint and each connected to the fuselage by a joint, the main universal joint being mounted to pivot on the fuselage about an inclined retraction axis which does not pass through the point where the shock absorber is connected to the fuselage, so that, during lowering and retraction of the undercarriage effected by extending or retracting the manoeuvreing and wind bracing jack, the shock absorber acts as a directer bar and orientates the axis of the leg casing, which leg casing is rotated as the main universal joint pivots on the fuselage about the inclined retraction axis.

Abstract: A central heating plant having a principal heat source and a make-up heat source which can operate simultaneously. A series of principal heat diffusers are connected in parallel and arranged to be supplied with heat-carrying fluid from either or both of the heat sources, and a series of make-up heat diffusers are connected in parallel and arranged to be supplied from either one or both of the heat sources. The two series of diffusers are arranged to be supplied with heat at the same time, separately, or alternately.

Abstract: An apparatus for adjusting the braking force of brakes applied to vehicle wheels in which the brakes are operated under the control of an electromagnet as a function of the deceleration and acceleration of the wheels. For a given braking signal, the braking force is eliminated when the deceleration of the braked wheel exceeds a predetermined threshold value, which may occur, for example, when the wheel starts to freely skid, and the reapplication of the braking force is delayed for a period of time proportional to the magnitude of deceleration of the wheel and inversely proportional to the subsequent magnitude of acceleration of the wheel when it picks up speed only when such acceleration exceeds a threshold which permits the wheel to gain speed irrespective of the frictional adherence of the wheel to the ground.

Abstract: A landing gear undercarriage which attaches to and retracts into the fuselage of an aircraft. The undercarriage has left and right matching portions, each of which includes a forward strut and a rearward hydraulic jack, both of which are coupled to the fuselage by cardan joints. A shock absorber is mounted on the fuselage outside of the strut and converges downwardly towards the strut to which it is coupled at the bottom by a cardan joint. A cylindrical sleeve is mounted at the bottom of the strut, and a spindle which supports a landing wheel is rotatably mounted in the sleeve. The bottom of the hydraulic jack is coupled to the spindle, and the arrangement is such that as the jack causes the undercarriage to retract into the fuselage, the spindle and wheel are rotated into a flat position in which they may be stored in a relatively small landing gear well.

Abstract: A disc brake comprising a plurality of alternating stators and rotors each comprising a friction lining at least one of which is constituted by a support and a shoe engaged in the support. Each shoe comprises a first part of larger cross-section and a second part of smaller cross-section extending from the first part and defining therewith a shoulder, the shoe being mounted in a support having an aperture constituted by a first bore of larger diameter extending partly in the depth of the support and a second bore of smaller diameter extending in the remainder of the depth of the respective support so as to define a shoulder against which the shoulder of the shoe can bear. Two adjacent shoes are disposed in respective supports to face in opposite directions in such supports. Furthermore, the shoes in adjacent supports are geometrically identical.

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 undercarriage for an aircraft has a safety device which fails under a predetermined breaking load to separate a leg member of the undercarriage from a rigid element of the undercarriage, the rigid element remaining on the aircraft. The aircraft has on the frame thereof a front mounting and a rear mounting for mounting the undercarriage and said undercarriage comprises said leg member and said rigid element which is mounted in and extends between said front and rear mountings and forms an axle about the axis of which the leg member of the undercarriage can be pivoted for raising the lowering the undercarriage.

Abstract: An oleo-pneumatic damper comprises a hollow rod slidable within a cylinder, and a low-pressure gas chamber defined within the cylinder adjacent to a first variable volume of hydraulic fluid, which volume is essentially provided in the hollow rod. A second variable volume of hydraulic fluid in the rod is separated from the first fluid volume by a valve device, and a separating piston separates the second fluid volume from a high-pressure gas chamber, also in the hollow rod. A spring in the first fluid volume urges the hollow rod into the cylinder, thereby to form an anti-threshold spring to reduce the threshold or minimum loading on the damper, at which the damper will commence a compression stroke movement for damping purposes.

Abstract: A method and apparatus for effecting double-acting braking for a wheel or a set of wheels permitting compensation of failures of at least one of the braking circuits of a double-acting braking arrangement of the type comprising at least two sets of braking members and two braking circuits for each brake. A single control action achieved by a single actuating member acts simultaneously on the two braking circuits of each of the brakes and in the case of a failure of one of the two braking circuits resulting in a drop in pressure in the failed braking circuit and consequently in a reduction of the braking torque applied by the brake, the remaining circuit has its pressure increased whereby the braking torque is automatically increased by a predetermined value. For this purpose the control action is applied simultaneously to two relays having at least two operating pressure levels, each relay acting on one of the two sets of braking members via the two braking circuits.

Abstract: A landing gear for an aerodyne which is raised towards the rear of the aerodyne, including a structural member with a shock absorber for each undercarriage and connected to at least one wheel, and at least one truss actuating jack operative to employ aerodynamic forces opposing the lowering of the undercarriages to aid in the locking of the truss actuating jack and thus the undercarriages in the landing gear down position.

Abstract: A pump installation has a first heat exchanger for heating a fluid, a compressor unit connected to the first exchanger and having static mechanical means for pre-compression and temperature increase of the fluid, a motor-driven compressor connected to the compressor unit, for compressing the fluid, and a second heat exchanger for passing heat from the fluid to a working circuit fluid. A first valve passes fluid from the outlet of the compressor to the second exchanger selectively directly or indirectly through the compressor unit, and a second valve passes fluid from the outlet of the second exchanger to an expansion means for feeding the fluid back to the first exchanger selectively directly or indirectly through the compressor unit.

Abstract: A disc brake comprising a rotor and a stator wherein the rotor and/or the stator includes a mounting member provided with a friction lining formed at least in part by a plurality of graphite plates, each plate having two flat side faces and a peripheral surface which is perpendicular to the two flat side faces, each plate being received in a recess in a side face of the mounting member, each recess having a flat bottom surface and being of a depth less than the thickness of the plate, the side wall of the recess being parallel to the peripheral surface of the plate and spaced from the peripheral surface of the plate by a distance greater than that necessary to permit thermal expansion and contraction between the mounting member and the plate. The graphite plates of one of the rotor and the stator are formed of polycrystalline graphite and the other of the rotor and the stator is formed and/or has graphite plates formed of structural graphite.

Abstract: A device for opening and closing a rotary valve by remote control comprising a cylinder having a main bore in which a movable unit is slidably mounted in fluid tight manner and which can be displaced in opposite directions by a pressurized fluid supplied by either of two pressurized fluid sources which can be remotely actuated in independent fashion. A sequencing mechanism is mounted in the cylinder for simultaneously applying the pressurized fluid from an activated source to a corresponding end face of the movable unit while connecting the other end face with the atmosphere. The movement of the slidable unit is transmitted to the rotary valve through a rack and pinion arrangement and a linkage composed of cranks and a connecting rod so arranged that when the valve is in either of its end positions it cannot produce movement of the linkage due to alignment of the axis of rotation of the pinion and the connection points of the rod to the cranks.

Abstract: A ski device adapted to be mounted on a landing gear provided with front and rear sheets each of which carry a wheel with the wheels being positioned in tandem. The device includes a monobloc ski assembly having an aperture therethrough through which the wheels move to raise and lower the skis off the ground and provide for ease of manoeuverability on a runway and a snow covered terrain.

Abstract: Apparatus for eliminating cavitation in a main pump in which the rotor of a supercharging pump is connected to the rotor of the main pump such that the latter rotor drives the rotor of the supercharging pump. Permanent communication is established between the delivery side of the supercharging pump and the induction inlet of the main pump. A hydraulic fluid reservoir is connected to the inlet of the supercharging pump and it is also connected to the delivery side of the supercharging pump through the intermediary of a valve which controls the flow of hydraulic fluid to the reservoir from the delivery side of the supercharging such that when the pressure at the induction inlet of the main pump exceeds a predetermined value flow is established to the reservoir in order to avoid the appearance of cavitation in the main pump. Leakage flow within the main pump is also recycled to the reservoir continuously through the valve.

Abstract: An actuating and bracing jack comprising a cylinder and a rod which are pivotably connected at their free ends to a fixed member and to a moveable member respectively. The cylinder has at least at one of its extremities, an internal resilient catch member, and the rod carries a projection capable of coming into engagement behind the catch member. The cylinder has an enlarged cylindrical chamber housing a displaceable locking device capable of being driven by the rod upon retraction movement thereof, to a first position to which the catch member is firmly applied against the projection. The locking device is displaceable in the opposite direction in the cylinder under the action of an actuating fluid to a second position to which the catch member is freed. The rod is provided with a device for taking up play between the rod and cylinder, such device including a displaceable draw member which acts upon a member urging a slotted portion of the rod outwardly into close proximity to the cylinder.