The invention relates to a
rotary actuator. A
rotary actuator includes a manifold block and a rotor
assembly including a rotor shaft and a plurality of arcuate pistons attached to the rotor shaft, each arcuate
piston curved at a set radial distance from the rotor shaft, and each
piston attached to the rotor shaft via a
crank arm. A pressure chamber
assembly coupled to the manifold block defines a plurality of
piston pressure chambers that receive and at least partially surround each arcuate piston, including a plurality of gland seals disposed adjacent an inlet of each piston pressure chamber to create a seal between an inner surface of the pressure chambers and an arcuate piston outer surface. Each gland seal includes an inner seal that engages a piston surface of the arcuate piston and a plurality of outer seals that engage an inner surface of the piston pressure chamber, thereby forming a
hydraulic seal.