GB495759A - Improvements in operating mechanism for retractable members on board aircraft - Google Patents

Abstract

495,759. Springs; shock-absorbers. AIR-EQUIPEMENT. Feb. 18, 1937, Nos. 4872 and 4873. Convention dates, Feb. 18, 1936 and Aug. 12, 1936. [Class 108 (iii)] [Also in Groups XXXIII and XXIV] A motor unit disposed at the hinge of a folding strut used to retract an aircraft under carriage includes a damping device comprising a cylinder 120 secured to housing 15 and to element 5. A double vane 121 works in cylinder 120 and is connected to element 4 by a lever 123. A second double vane 124 is displaceable between stops 125, 126 formed by the edges of recessed parts of cylinder 120. The blades of vane 124 extend to the full diameter of the recessed portions but are provided on one face with a flange of the same diameter as the cylinder bore. Radial holes 127 in the hub of vane 121 place the four compartments of the cylinder in communication with a central bore 128 in hub extension 122 containing an adjustable piston valve. Valves 130 in blades of double vane 124 operate only in the direction f <1> ; these ensure that the movement of vane 121 is undamped during retraction. During extension damping only takes place when vane 124 moves round to the ends of the recessed parts of the cylinder, and ceases when the blades of vane 121 themselves reach the recessed portions except that the action of the flange formed on the faces of vane 124 is to damp the impact of the vane with the stop 126. The elements 4 are interconnected by a bracing tube 130 in which is housed a torsion rod 140, Fig. 10, connected to one element 4 at one end and carrying a lever 142 at the other, coupled by a link 145 to a pin 146 on one element 5. Pin 146 is offset from the hinge axis and the angular disposition of lever and link are that as the strut folds, the torsion rod is first twisted and then untwists assisting retraction in the second stage, whilst on extension the rod first opposes and next assists extension of the strut. Specification 442,133, [Group XXXIII], is referred to.