Adjustable rotary actuator

Claim 1

A fluid-powered, splined rotary actuator for providing precise, adjustable, end-limited rotational drive to another device, such as a valve through a rotatable valve stem, comprising: an outer, elongated, cylindrical body having ports for introducing pressurized fluid therein; a splined output shaft rotatably supported within said body and having at least one drive end adapted for coupling to said other device to provide rotational drive thereto, said shaft drive end being positioned toward a drive end of said body; a linear-to-rotary transmission means disposed within said body and operable to provide relative rotational movement between said body and said output shaft, said transmission means including a splined piston sleeve having a piston head for application of fluid pressure to a first side of said head to produce linear movement of said piston sleeve in a first direction, and for application of fluid pressure to an opposite second side of said head to produce linear movement of said piston sleeve in an opposite second direction, and a splined ring gear joined to said body, said ring gear splines meshing with said piston sleeve splines and said piston sleeve splines meshing with said shaft splines to translate linear movement of said piston sleeve into rotational movement of said shaft; an adjustable, threaded end cap disposed within said body at an end of said body remote from said drive end, said end cap threads cooperating with corresponding threads of said body to permit selective longitudinal positioning of said end cap relative to said body, said end cap having a stop surface for engaging said second side of said piston head as it travels in said first direction and limiting linear travel of said piston sleeve in said first direction to provide an end limit to rotational movement of said shaft in a first rotational direction, said first stop being adjustable from said remote end; and an adjustable, elongated stop sleeve positioned about said shaft for rotational movement therewith, said stop sleeve extending from a position outward of said end cap at said remote body end to a position beyond said piston head, and having a stop shoulder for engaging said first side of said piston head as it travels in said second direction and limiting linear travel of said piston sleeve in said second direction to provide an end limit to rotational movement of said shaft in a second rotational direction, said stop sleeve being threaded for cooperation with corresponding threads of said shaft to permit selective longitudinal positioning of said stop shoulder relative to said shaft, said stop shoulder being adjustably positioned by rotation of said stop sleeve from said remote end.