PISTON ACTUATOR ASSEMBLY FOR AN ORIENTING DEVICE

摘要

An actuator for an orienting device for orienting a borehole apparatus in a borehole and an orienting device comprised of the actuator, wherein the orienting device is comprised of an orienting mechanism which is actuated by longitudinal movement. The actuator is comprised of a housing having a first end and a second end and a fluid passageway extending through the housing from the first end to the second end. Further, a longitudinally reciprocable piston, positioned within and providing a first partial obstruction of the fluid passageway, engages with the orienting mechanism such that longitudinal movement of the piston actuates the orienting mechanism. Finally, a flow restrictor, positioned within and providing a second partial obstruction of the fluid passageway, is associated with the piston such that the first partial obstruction is longitudinally aligned with the second partial obstruction fo r a portion of a longitudinal range of travel of the piston to provide a combined obstruction of the fluid passageway.