Dual chamber shock absorbers for aircrafts and the like

A dual chamber shock absorber comprising:

• a cylinder having an open end and a closed end;
• a hollow rod having a piston at one end slidable in said cylinder and dividing said cylinder into a first chamber formed in said hollow rod, a second chamber between said rod and said cylinder and a third chamber in said cylinder between said piston and said closed end of said cylinder, said third chamber comprising a first section, a second section, a third section and a fourth section;
• and
• first port means in said piston connecting said first and third chambers, and second port means in said piston connecting said second and third chambers;
• said first section being defined by a transverse wall in said third chamber and by said piston, said transverse wall including pressure-relieving means;
• said second section being formed by said transverse wall and a separating piston slidable between first and second stops, said first stop being said transverse wall and said second stop being a projection in said cylinder located at the proximity of said closed end thereof;
• said third section being defined by said separating piston and a movable head slidable between said projection and said closed end of said cylinder;
• said fourth section being between said movable head and said closed end and forming a jack chamber, said fourth section including an orifice extending through said closed end into said jack chamber for supplying an incompressible fluid through said orifice;
• said first chamber containing first elastic means at a first given pressure;
• said third section containing second elastic means at a second given pressure;
• and
• said second elastic means being controlled by movement of said movable head according to at least one parameter corresponding to the performance of said shock absorber and characteristic of a force to be absorbed.