Patent attributes
Combination linear and rotary actuators are disclosed. The linear and rotary actuators have a housing defining a cylindrical interior space and a pair of pistons located inside the cylindrical interior space. An inner bearing cylinder is provided that has spaced-apart ball bearings arranged in a helical pattern on its surface that engage with a structure having an inner surface with helical grooves therein. The structure at least indirectly engages a linear drive piston that is slidably mounted in the housing, and provides rotational movement thereto. The linear drive piston has an input shaft that has ball bearings on its surface, and is inserted inside the output shaft of a revolution piston that has an inner surface with linear grooves. The actuators use hydrostatically charged integral bearing races that activate during operation to reduce friction. Combination linear and rotary actuators with double actuation output shafts are also provided.
