US Patent 11187023 Piston assembly for aircraft door

Disclosed is an aircraft piston assembly, having: a piston housing fluid port formed in a piston housing; a piston shaft, disposed within the piston housing, configured for translation in either forward or aft directions when fluid is respectively supplied to or removed from the piston housing; a screw shaft, disposed within the piston housing, that includes a first gear that rotates without translation while the piston shaft translates; and a slider, disposed within the piston housing, that includes a second gear, and that is configured for translation without rotation, wherein: the slider moves between a first position where the first gear and the second gear are separated from one another to allow the piston shaft to translate and a second position where the second gear surrounds the first gear so that the first and second gears are engaged with one another and the piston shaft is prevented from translating.