Abstract

A fluid powered rotary actuator having a body with first and second ends. The body has a generally cylindrical interior sidewall with a grooved, inwardly facing circumferential portion. The body is adapted for coupling to a first external member. A drive member extends generally coaxially within the body and is supported for rotation relative thereto. The drive member has an end flange positioned toward the body first end adapted for coupling to a second external member, and a shaft rigidly attached to the end flange. The shaft has a grooved, outwardly facing circumferential sidewall portion positioned within the body toward the body second end and a smooth, outwardly facing circumferential sidewall portion positioned within the body between the end flange and the shaft groove sidewall portion. The end flange extends laterally outward beyond the shaft smooth sidewall portion and the shaft grooved sidewall portion has an outer diameter equal to or less than the outer diameter of the shaft smooth sidewall portion. The shaft grooved sidewall portion is formed as an integral part of the shaft, and the end flange as an integral unit with the shaft. The actuator further includes an annular piston sleeve positioned within the body and having a central aperture receiving the shaft therethrough. The piston sleeve is mounted for reciprocal axial movement within the body in response to selective application of pressurized fluid to a piston portion thereof in sliding sealed engagement with the shaft and body smooth sidewall portions to define fluid compartments to each side thereof. The sleeve portion has a grooved, inwardly facing circumferential sidewall portion engaging the shaft grooved sidewall portion, and a grooved, outwardly facing circumferential sidewall portion engaging the body grooved sidewall portion as the piston sleeve reciprocally moves within the body to translate axial movement of the piston sleeve into rotation of the drive member.