Landing gear drag strut actuator having self-contained pressure charge for emergency use

An extendable and retractable actuator automatically retractable by operation of a self-contained pressure source, comprising:

• a first pressure source;
• a second pressure source forming said self-contained pressure source;
• means responsive to communication with the first pressure source for extending a portion of the actuator and releasably holding high pressure in said second pressure source, wherein the extended portion of the actuator contains said second pressure source and at least part of said first pressure source;
• means for manually releasing the second pressure source;
• and
• means responsive to release of the second pressure source for retracting the actuator.

An extendable and retractable actuator for raising and lowering aircraft landing gear in accordance with an extended and retracted state of the actuator, comprising:

• a casing having a longitudinal axis;
• a source of pressurized hydraulic fluid;
• a free piston moveable along the casing axis within a sealed pressurizeable space, separating said space into a first chamber potentially containing a second source of pressure and a second chamber;
• first passage means for connecting the fluid pressure source and the second chamber;
• a piston assembly located within the casing, slidable along the axis of the casing between fully extended and fully retracted positions, having an extension face connectable to the fluid pressure source and a retraction face axially opposite the extension face connectable to the fluid pressure source and the second pressure source;
• second passage means for connecting the second chamber to the retracting face of the piston assembly;
• means for manually opening the second passage means, closing the first passage means, and releasing the second pressure source to expand;
• means responsive to expansion of the second pressure source for moving the free piston to exhaust the second chamber;
• and
• third passage means communicating the fluid pressure source and the retraction face of the piston assembly.