GB539405A - Improvements in or relating to aeroplane landing gears having a steerable landing wheel - Google Patents

Abstract

539,405. Aircraft undercarriages. MERCIER, P. E. April 25, 1940, Nos. 7489 and 7490. Convention dates, April 25, 1939, and July 5, 1939. [Class 4] [Also in Group XXXIV] In landing gear for aircraft having steerable wheels, the energy for effecting the steering is derived from the movement of rotation of the wheels, the energy being transmitted by hydraulically, mechanically, electrically, or pneumatically operated means. As applied to a single castor wheel 1 to which the transmitting means are hydraulically operated, a roller 12 having a hydraulic pump mounted therein is frictionally driven by the wheel and the pipe system 21, Fig. 4, from the pump, shown at 24, communicates with the cylinders 6 of a pair of pistons 20 the rods of which are pivoted to the ends of a double armed lever 8 which controls the rotation of the wheel shaft 3 through gearing. The centrally pivoted lever 8 is provided with a toothed sector connected thereto which meshes with a pinion on the shaft 3. In the position shown in Fig. 4, the wheel is kept along a straight course. The servomotor is completed by a four-way valve 23, a weighted valve 25 and a reservoir 26. The pipe system 21 is connected in parallel by pipes 27 which a pair of variable tension valves controlled by roller push rods 28 and a cam disc 29. The cam disc 29 and the valve 23 are co-axially mounted and remotely controlled by the pilot. To effect a turn, both these members are simultaneously rotated; liquid is then only admitted to one of the cylinders the liquid from the other cylinder being free to drain into the reservoir 26 by the release of the corresponding cam controlled valve. The wheel and its accessories may be retractable. In the application to a landing gear of two wheels, the vertical controlled shaft of the latter is integral with a casing 36, Fig. 9, which forms the swivel carrier of the axle 35 of the twin wheels and is adapted to house a pinion 14, Fig 6 (not shown) which actuates the hydraulic pump and is itself driven by a chain from the axle 35 and also to house a braking system comprising movable discs 45 and fixed discs 46 with an expansible chamber 47 to which pressure fluid may be admitted. The movable discs are provided with channels for air cooling which align with channels in the hollow axle and the casing 36, air being admitted through intakes 50 in the hubs. As an example of the mechanical operation of the transmitting means, the drive from the axle of the wheels is transmitted to opposite handed worms 56, 57, Fig. 12, which drive through sleeves 60, 61, the brake drums 62, 63, braking of which causes turning of the swivel carrier for steering the wheels. Specification 548,067 is referred to.