Patent ID: 7421987
Filing Date: 2008-09-09
Classification: F01L

Abstract:
1. A fluid actuator, comprising a housing having first and second fluid ports; an actuation cylinder in the housing defining a longitudinal axis and having first and second ends in first and second directions; an actuation piston in the cylinder with first and second surfaces moveable along the longitudinal axis; a second piston rod operably connected with the actuation piston; a spring subsystem biasing the actuation piston to a neutral position; a first fluid space defined by the first end of the actuation cylinder and the first surface of the actuation piston; a second fluid space defined by the second end of the actuation cylinder and the second surface of the actuation piston; a first flow mechanism in fluid communication between the first fluid space and the first port; a second flow mechanism in fluid communication between the second fluid space and the second port; a flow bypass that substantially short-circuits the first and second fluid spaces when the actuation piston is in its entire operating range except for being within a predefined distance from only one of the first and second ends of the actuation cylinder; and at least one of the first and second flow mechanisms being substantially closed when the flow bypass substantially short-circuits the first and second fluid space.