GB726282A - Improvements relating to steering jacks on aircraft undercarriages - Google Patents

Abstract

726,282. Hydraulic machines. DOWTY EQUIPMENT, Ltd. July 6, 1953, No. 18709/53. Class 69 (2). A double-acting jack having centring means for returning the jack to its mid-stroke position comprises an auxiliary piston 27 mounted on an extension of the jack piston-rod 10 projecting through the end 3 of the jack cylinder 1, an auxiliary cylinder 6 extending from the cylinder 1, and an annular centring piston 28 slidable on the rod 10 and in the cylinder 6 and having a hollow stem 29 extending through the end wall of the cylinder 6 and in slidable engagement with the piston 27 and having an auxiliary piston stop 31 within its end. The cylinder 6 is vented at 34 and has a pressure liquid inlet at 36. The interior of the stem 29 communicates with the cylinder space 6 through a passageway 37. Pressure liquid supplied to the inlet 36 is applied to the underside of the piston 28 and to the piston 27 which is thereby forced into the half-stroke position. The cylinder 1 is supported on spigots 14, 15. The spigot 14 is drilled to provide connections to opposite sides of the main jack piston 7 and also a connection 22 which communicates with the upper side of a piston 40 which loads a valve 45. which is subjected on separate faces to the pressures on opposite sides of the piston 7 and is arranged to open on a predetermined excess pressure developing on either side of the piston 7. A passageway 24 in the spigot 15 is connected to the inlet 36.