GB756111A - Improvements in retractable landing gears for aircraft - Google Patents

Abstract

756,111. Aircraft undercarriages. MORANE-SAULNIER. Aug. 5, 1954 [Aug. 11, 1953]. No. 22802/54. Class 4. A retractable and steerable undercarriage for aircraft comprises a supporting member 5 which carries bearings 6, 7 for the rotatable mounting of a strut 4 formed with an offset pivot 3 for a wheel-carrying lever 2 in turn formed with a lug 19 for the pivotal connection of the lower end of a shock absorber 18 which is pivotally mounted at its upper end 20 in the strut 4. The member 5 carries laterally projecting arms terminating in bosses 12, 13 which are pivotally mounted on the aircraft structure and a fixed shaft 29. This shaft carries a sleeve 27 capable of axial and rotary movement and formed on its outer surface with teeth 26 which lie in planes normal to the axis of the sleeve and extend round half of its circumference. The sleeve carries a lug 39 connected by a link 38 to a bell-crank 34-35 to which a control rod 33 is connected, whereby movement of the rod 33 by the pilot causes axial movement of the sleeve 27. The strut 4 carries an upward projection formed with serrations that engage internal serrations on an annular collar 8 and this in turn carries external serrations engaging internal serrations 24 on a further annular collar 23 which, on its skirt, is formed with teeth 25 to mesh with the teeth 26 on sleeve 27. The teeth 25 are urged into engagement with the teeth 26 by a spring 46 acting on the collar 23 which, on opposed parts of its skirt clear of the teeth 25, is formed with two cam surfaces engaging fixed rollers. The undercarriage is retracted about the axis Y-Y by a jack (not shown) connected at 16 to a lug 17 on the member 5 and during retraction the teeth 25 on collar 23 remain in mesh with the teeth 26 on sleeve 27. When the undercarriage is lowered, steering is effected by manual or servo operation of the rod 33 which causes the strut 4 to rotate within the member 5. If the undercarriage tends to caster through an angle greater than the maximum angular deflection of the steering mechanism, the cam surfaces on the collar 23 engage the fixed rollers to raise the collar against the spring 46, thereby disengaging the teeth 25 from the teeth 26.