Patent ID: 6584885
Filing Date: 2003-07-01
Classification: F01L

Abstract:
An actuator comprising:a cylinder defining a longitudinal axis and comprising a first and second end; a first port communicating with said first end of said cylinder, a second port communicating with said second end of said cylinder, and a third port communicating with said cylinder between said first and second ends; an actuation piston disposed in said cylinder and moveable along said longitudinal axis in a first and second direction, said actuation piston comprising a first and second side; a control piston disposed in said cylinder, said control piston moveable along said longitudinal axis in a first and second direction and comprising a first and second side, wherein said first side of said control piston faces said second side of said actuation piston; and a control spring biasing said control piston in at least one of said first and second directions, wherein said control spring biases said first side of said control piston.