GB486936A - Improvements relating to locking means for retractable undercarriages of aircraft - Google Patents

Abstract

486,936. Aircraft landing-gear. DOWTY, G. H. Dec. 9, 1936, Nos. 36014/37,36015/37, and 36016/37. Divided out of 473,202. [Class 4] In a fluid-pressure jack-operated retractable undercarriage for aircraft, one or more locking members or latches coacting with elements on the fuselage or undercarriage radius rod or stay are operated in series with the stay, a lost-motion device being incorporated so that, in retracting or extending the undercarriage, the operation of the stay is preceded and /or followed by unlocking or locking of the latch in the necessary sequence. In the construction shown in Fig. 2, the wheel-carrying leg 20 is pivoted to the fuselage at 20A and maintained in extended position by a twopart stay 21, 22 controlled by a jack 23, a locking-pawl 27 having two notches 27A, 27B being pivoted on the part 21 and being actuated by a telescopic spring link 28 connected to a lug 24B on the end of the jack piston 24. The lug 24B has a slot in which a pin 25 on the part 21 engages with lost motion. If, from the extended position shown in full lines, the jack piston is moved inwardly, the initial movement of the lug 24B and link 28 causes the notch 27A to be disengaged from a pin 22D on the part 22, thus freeing the stay 21, 22 for folding. At the end of the retractive movement, the other notch 27B engages a pin 29A on a bracket 29 on the fuselage. Similarly, in extending the leg 20, the initial outward movement of the jack piston disengages the notch 27B from the pin 29A. In a simpler construction, Fig. 1 (not shown), the locking- pawl is single-acting and serves to lock the stay in an extended condition only, while in a further construction the jack piston co-operates with a bell-crank lever, and separate locking- pawls are provided for retaining the leg in its two extreme positions. If desired, the jack cylinder and piston may, as shown in Fig. 5, be incorporated in one part 52 of the stay 51, 52, the outer end of the piston moving in a slot 52A and being connected through a rod 55 to a link 56 which controls the locking-pawl 57. Specification 457,982 is referred to.