Variable valve actuator with a pneumatic booster

An actuator, comprising

• a fluid driver including a housing defining a longitudinal axis and first and second directions, an actuation mechanism comprising an actuation cylinder and an actuation piston slideably disposed in the actuation cylinder, with the actuation mechanism generating actuation force at least in the first direction;
• at least one return spring operably connected with the actuation mechanism and biasing the actuation mechanism in the second direction;
• and
• a pneumatic booster operably connected with the actuation mechanism and biasing the actuation mechanism in the first direction, whereby giving the driver a boost force in the first direction;
• and wherein:
• the pneumatic booster further including a pneumatic cylinder;
• a pneumatic piston, slideably disposed in the pneumatic cylinder for at least part of its travel range;
• and a charge mechanism, whereby charging the pneumatic cylinder and balancing its pressure with pressurized air from a high-pressure gas source during at least part of an actuation cycle of the actuator;
• the pneumatic booster further including a bleed mechanism, whereby bleeding off excess air from the pneumatic cylinder to a low-pressure gas sink during at least part of an actuation cycle of the actuator;
• and
• the bleed mechanism being at least one bleed passage, which becomes substantially exposed to the pressurized air in the pneumatic cylinder when the pneumatic piston travels beyond a predefined distance from an initial position, whereby bleeding off excess air.

An actuator, comprising

• a fluid driver including a housing defining a longitudinal axis and first and second directions, an actuation mechanism comprising an actuation cylinder and an actuation piston slideably disposed in the actuation cylinder, with the actuation mechanism generating actuation force at least in the first direction;
• at least one return spring operably connected with the actuation mechanism and biasing the actuation mechanism in the second direction;
• and
• a pneumatic booster operably connected with the actuation mechanism and biasing the actuation mechanism in the first direction, whereby giving the driver a boost force in the first direction;
• and wherein:
• the actuation piston dividing the inner volume of the actuation cylinder into first and second fluid spaces and being operably connected with a piston rod;
• and
• the actuation mechanism further comprising first and second ports in fluid communication with the first and second fluid spaces, respectively.

A method of controlling an actuator comprising:

• (a) providing an actuator including the following components:
• a driver further including
• a housing defining a longitudinal axis and first and second directions,
• an actuation mechanism capable of generating actuation force at least in the first direction, and
• a rod with one end operably connected with at least one part of the actuation mechanism and with the other end available for an operable connection with a load of the actuator;
• at least one return spring operably connected with the rod and biasing the rod in the second direction;
• and
• a pneumatic booster further including
• a pneumatic cylinder,
• a pneumatic piston operably connected with the rod and biasing the rod in the first direction, and
• a charge mechanism, whereby providing a controlled fluid communication between the pneumatic cylinder and a high-pressure gas source;
• (b) holding the load of the actuator to a second-direction end position
• with the force from the at-least-one return spring biasing in the second direction and overcoming the sum of the rest of the forces including those from the pneumatic booster and the load,
• without generating the actuation force in the first direction from the actuation mechanism, and
• with the pneumatic booster being charged through the charge mechanism to yield a substantial force in the first direction to oppose a substantial load force in the second direction;
• (c) initiating the travel of the load of the actuator in the first direction by generating the actuation force in the first direction from the actuation mechanism, with the combination of the actuation force and the force from the pneumatic booster being able to overcome the sum of the rest of the forces including those from the at-least-one return spring and the load and accelerate the load in the first direction;
• (d) continuing the travel in the first direction with the actuation force in the first direction at least until reaching the target stroke;
• (e) initiating the return travel of the load of the actuator in the second direction at least by turning off the actuation force in the first direction so that the load is accelerated in the second direction at least by the return spring;
• (f) completing the return travel with a decreasing force from the return spring and an increasing force from the pneumatic booster, whereby slowing down the load.