Abstract:
A semi-levered landing gear for an aircraft comprises a main shock absorber strut (1) connected to the airframe; a bogie beam (4) extending fore and aft of the airframe with forward and aft wheels (J, T) and a main pivot connection (5) to the strut (1) between the forward and aft wheels (7, T) and an auxiliary actuator (49) connected between the strut (1) and the front of the bogie beam (4) at an auxiliary pivot (14). The auxiliary actuator (49) comprises a two stage telescopic hydraulic unit comprising a first stage piston and cylinder actuator (59, 63) and a second stage piston and cylinder actuator (56, 50) operating coaxially within an outer casing (50). A respective piston rod (65, 60) each extends from each end of the casing (50) and is connected to a respective one of said (strut 1) and bogie beam (4). The first stage actuator (59, 63) is operable to an extended position, and the second stage actuator (56, 60) is operable between a retracted position (Fig. 11) and an extended position (Fig. 12) defined by respective end stops (75, 77) within the outer casing (50) and serves to control the tilt position of the bogie beam (4) relative to the strut (1). The second stage actuator (56, 60), when in the retracted position with the first stage actuator (59, 63) in the extended position, limits the length of the auxiliary actuator (9) between its connections (62, 67) to the strut (1) and bogie beam (4), so as to assume a predetermined intermediate length in which the bogie beam (4) is restrained to tilt about the auxiliary pivot (14) and thereby lengthens the landing gear during take-off. The second stage actuator (56, 60), when in the extended position with the first stage actuator (59, 63) in the extended position, allows the length of the auxiliary actuator (49) to assume a predetermined maximum length in which the bogie beam (4) is tilted about the main pivot (5) to a stowing position for stowing the landing gear in the aircraft.
Abstract:
A pin joint assembly for an aircraft landing gear comprising: an elongate joint pin (206); at least one first lug (202a, 202) through which the joint pin passes; and at least one second lug (204) through which the joint pin passes; wherein the joint pin includes first (212) and second (212a) retaining elements located at opposite ends of the joint pin and arranged to maintain the location of the joint pin relative to the first and second lugs, and wherein the pin joint assembly further comprises a respective resilient member (214, 214a) located between each of the retaining elements and a respective one of the first and second lugs, each resilient element being elastically deformable.
Abstract:
An aircraft landing gear including a shock absorber and a fluid replenishment device, the shock absorber having a compression chamber containing hydraulic fluid and the fluid replenishment device including a recuperator chamber for providing hydraulic fluid to the compression chamber of the shock absorber, the recuperator chamber including: a closed container defining an internal space and having: a first port coupled in a fluid tight manner to the compression chamber of the shock absorber; a second port arranged to be coupled in a fluid tight manner to a pressurised source of auxiliary hydraulic fluid; and a third port arranged to be coupled in a fluid tight manner to a second source of pressurised fluid; a movable element movably mounted within the container and arranged to divide the internal space into first and second subspaces, the first and second ports being in fluid communication with the first subspace and the third port being in fluid communication with the second subspace; and a valve having a open configuration in which the auxiliary hydraulic fluid may pass into the first subspace and a closed configuration wherein the second port is sealed in a fluid tight manner, wherein the fluid replenishment device is arranged such that, when the pressure of fluid within the second subspace is greater than the pressure of fluid within the first subspace, the movable element moves towards the valve such that it can mechanically couple with the valve so as to open the valve.
Abstract:
An aircraft landing gear assembly comprising a bogie beam (2), an axle (4) extending through the bogie beam and a jacking dome fitting (6) extending through a sidewall (8) of the bogie beam and arranged to transfer vertical loads applied to the jacking dome fitting to the axle.
Abstract:
A bearing assembly (2') comprising a housing (3') supporting first and second bearing ring portions (4, 4') with bearing surfaces to engage an inner tubular member (1') at axially spaced regions, characterised in that either: said bearing ring portions are provided by separate bearing rings (4') supported in the housing member (3') with bearing surfaces of different diameters; or said bearing ring portions are provided by a single bearing ring (4'') that is free to flex radially and is supported so that the second bearing ring portion is free to flex radially under load and its bearing surface than assumes a position with a greater diameter than that of the first bearing ring portion (4'').
Abstract:
An overload detecting assembly comprises a first load bearing member (10) adapted to flex laterally in response to a load to be monitored, a second load bearing member (11) spaced from the first under normal load conditions and which is contacted and loaded by the first load bearing member (10) when it is loaded beyond a load limit. Preferably, the first load bearing member (10) has a yield point below the load limit and takes a permanent set once the yield point has been exceeded. A lateral probe (18) cooperates with the first load bearing member as it moves towards the second load bearing member and in turn deflects an indicator member (20) which takes a permanent set when a yield point is exceeded. Ready inspection of the indicator member then reveals whether or not it has been bent.
Abstract:
An aircraft landing gear assembly including a bogie beam, a landing gear strut (1) having a first end arranged to be pivotally coupled to an aircraft and a second end pivotally coupled to the bogie beam (3), and a stop (13) arranged to limit pivotal movement of the bogie beam relative to the landing gear strut, wherein the stop comprises at least one elongate member arranged to be deflectable in bending when the bogie beam reaches a pivotal limit.
Abstract:
A landing gear (70) for an aircraft, the landing gear including an axle (14) pivotally connected to a bogie beam (12) and a locking device (11c), the locking device being arranged to couple the axle to the bogie beam, the locking device including a movable member and a follower (22), the movable member (60) being arranged to be moved by an actuator between first and second configurations, the locking device being arranged such that movement of the movable member towards the second configuration causes corresponding movement of the follower so as to transfer a steering force to the axle through the follower which causes the axle to rotate in a first direction, wherein, with the movable member in the first configuration, the locking device is arranged with the follower in a first configuration that inhibits the movable member being moved by an external force applied to the axle and, with the movable member in the second configuration, the locking device is arranged with the follower in a second configuration that permits the movable member to be moved by an external force applied to the axle.
Abstract:
A main landing gear assembly for an aircraft comprising: an elongate beam pivotally coupled about its longitudinal axis to the aircraft such that the axis of rotation of the elongate beam is generally parallel to the longitudinal axis of the aircraft fuselage; a shock strut pivotally coupled at a first end to the elongate beam and coupled at a second end to a wheel assembly; a folding forward stay pivotally coupled at a first end to the elongate beam and pivotally coupled at a second end to the shock strut; and a rigid rear stay pivotally coupled at a first end to the aircraft and pivotally coupled at a second end to the shock strut, the rigid rear stay being arranged to restrain the path of the shock strut when moving between a deployed and a retracted position such that the wheel assembly is located forward and inboard in the retracted position in comparison with its location in the deployed position.
Abstract:
A landing gear for an aircraft comprises: a shock absorber strut (1) with upper and lower telescoping portions (2, 3), the upper portion (2) being connectable to the airframe of the aircraft; an arm (4) to extend fore and aft relative to the aircraft and carrying a landing wheel, (7, 7 1 ), and pivotally connected by a main pivot (5) to the lower portion (3) of the shock absorber strut; and a load reacting unit (9) connected between the arm (4) and the shock absorber strut (1) for reacting to load applied between the arm and shock absorber strut on landing, and an indicator (60) for monitoring the load applied to the load reacting unit (9) on landing. The load reacting unit (9) may be connected between a forward end of the arm (4) and the upper portion (2) of the shock absorber strut to make the gear act as a semi-levered landing gear. Alternatively, the load reacting unit (9) may be connected between the arm (4) and the lower portion (3) of the shock absorber strut to act as a pitch trimmer. The arm (4) may comprise a bogie beam with fore and aft landing wheels (7, 7 1 ) with the main pivot (5) therebetween. The load reacting unit (9) preferably comprises a fluid pressure unit and the indicator (60) comprises a mechanical indicator that operates at a predetermined pressure threshold.