US Patent 7487829 Wellbore valve having linear magnetically geared valve actuator

A wellbore valve includes a valve operator arranged to move axially along an interior of the wellbore, the valve operator arranged to operate a valve. A valve actuator is disposed proximate the valve operator. The valve actuator is arranged to move from one longitudinal position to another. A linear magnetic gear is coupled at an input element thereof to the valve actuator. The gear is coupled at an output element thereof to the valve operator such that motion of the valve actuator is transferred to the valve operator.