Fluid operated mechanical power amplifier

A fluid-operated mechanical power amplifier for multiplying the input force applied to the power amplifier comprising:

• a housing having a main bore formed therein;
• a main piston slidably mounted within said main bore;
• a first end cap mounted on said housing and defining a working chamber between said first end cap and a first end of said main piston;
• a secondary bore formed within said main piston coaxial with said main bore;
• a second end cap mounted in a second end of said main piston in said secondary bore to close said bore and define a regulating chamber;
• a regulating piston slidably mounted in said secondary bore;
• an input shaft aligned with the axis of said main bore, said shaft attached at a first end to said regulating piston, said shaft having an axial passageway formed therethrough in communication with a source of pressurized fluid, said input shaft extending in sealed relationship through said second end cap;
• a control passageway formed in said main piston in communication with both said working chamber and said regulating chamber;
• a control valve means connected to said first end of said input shaft and operable to control flow of pressurized fluid from said axial passageway to said control passageway, said control valve means constructed and arranged to prevent flow of pressurized fluid into said secondary bore until said regulating piston begins to move and then to allow said pressurized fluid into said main bore to assist movement of said main piston in the direction of said input force;
• a bias spring within said regulating chamber, said bias spring providing the sole bias force to keep said regulating piston spaced from said second end cap;
• and
• an output shaft connected to said main piston and extending in sealed relationship through said first end cap.