GB793329A - Improvements in or relating to aircraft landing gear - Google Patents

Abstract

793,329. Aircraft undercarriages. SOC. D' INVENTIONS AERONAUTIQUES ET MECANIQUES S.I.A.M. Jan. 23, 1956 [Jan. 22, 1955], No. 2217/56. Class 4. An aircraft undercarriage having a leg 1 pivoted at I to the airframe is braced by a backstay 4 and retracted by a jack 5. The backstay is pivoted to the airframe at II and at V to the leg 1, this latter pivot being located at the lower extremity of a crank-arm 3 pivoted at IV to the leg. The crank-arm is hollow to enclose a plunger 6, the lower end 8 of which is urged into locking engagement with a recess 9 formed as an extension of the leg 1. An arm 10, pivoted at VI to the crank-arm 3, carries a finger 11 which engages a recess 12 in plunger 6, an extension for engaging a stop 14 on arm 3 and a pivot VII for attachment to the piston rod of jack 5. The other end of the jack is connected at III to the stay 4. With the apparatus in the position shown in Fig. 2, the undercarriage is locked in its extended position. Extension of jack 5 for retraction first rocks arm 10 to cause finger 11 to withdraw plunger 6 from locking engagement with recess 9 until the arm 10 bears on a stop 13, subsequent extension of the jack forcing arm 3 and leg 1 upwardly to the position shown in Fig. 3 wherein the pivots II, V arid IV are in alignment, thereby locking the undercarriage in its raised position. The undercarriage is lowered by reverse movement of the jack but in a further embodiment, not shown, the said pivots are not in alignment so that the undercarriage may descend under the action of its own weight.