Multi-axis rotary piston actuator

A rotary piston actuator assembly comprising:

• a first rotary actuator comprising:
• a first housing defining:
• a first central bore;
• and
• a first arcuate chamber comprising a first cavity having a first actuator fluid port in fluid communication with the first cavity and the first central bore;
• a rotor arm;
• an arcuate-shaped first piston disposed in said first housing for reciprocal movement in the first housing, wherein a first seal, the first cavity, and the first piston define a first pressure chamber comprising part or all of the first arcuate chamber, and a first portion of the first piston contacts the rotor arm;
• a rotor assembly rotatably surrounding said first housing and comprising a rotary output tube, wherein the rotor arm extends radially outward to the rotary output tube and the rotor arm is coupled to the rotary output tube;
• and
• a fluid delivery shaft having an elongated body disposed in said first central bore and defining a first shaft fluid delivery path.

A method of rotary actuation comprising:

• providing a first rotary actuator comprising:
• a first housing defining:
• a first central bore;
• and
• a first arcuate chamber comprising a first cavity having a first actuator fluid port in fluid communication with the first cavity and the first central bore;
• a rotor arm;
• an arcuate-shaped first piston disposed in said first housing for reciprocal movement in the first housing, wherein a first seal, the first cavity, and the first piston define a first pressure chamber comprising part or all of the first arcuate chamber, and a first portion of the first piston contacts the rotor arm;
• a rotor assembly rotatably surrounding said first housing and comprising a rotary output tube, wherein the rotor arm extends radially outward to the rotary output tube and the rotor arm is coupled to the rotary output tube;
• and
• a fluid delivery shaft having an elongated body disposed in said first central bore and defining a first shaft fluid delivery path in fluid communication with a first shaft fluid port;
• providing pressurized fluid to the first shaft fluid port;
• urging pressurized fluid to the first pressure chamber through the first shaft fluid delivery path, the first shaft fluid port, and the first actuator fluid port;
• and
• urging the first piston partially outward from the first pressure chamber to urge rotation of the rotor assembly in a first direction.

An arm of a machine apparatus comprising:

• a first arm portion;
• a second arm portion;
• and
• a joint portion pivotally connecting the first arm portion to the second arm portion, the joint portion comprising a first rotary actuator comprising:
• a first housing defining:
• a first central bore;
• and
• a first arcuate chamber comprising a first cavity having a first actuator fluid port in fluid communication with the first cavity and the first central bore;
• and
• a rotor arm;
• an arcuate-shaped first piston disposed in said first housing for reciprocal movement in the first housing, wherein a first seal, the first cavity, and the first piston define a first pressure chamber comprising part or all of the first arcuate chamber, and a first portion of the first piston contacts the rotor arm;
• a rotor assembly rotatably surrounding said first housing and comprising a rotary output tube, wherein the rotor arm extends radially outward to the rotary output tube and the rotor arm is coupled to the rotary output tube;
• and
• a fluid delivery shaft having an elongated body disposed in said first central bore and defining a first shaft fluid delivery path.