{HEAD ~ A hydraulic or pneumatic actuator} wherein {TAIL ~ the movement} of the power transfer shaft is controlled by a movable vent 
{ HEAD ~ A hydraulic or pneumatic actuator } wherein { TAIL ~ the movement } of the power transfer shaft is controlled by a movable vent
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH