An apparatus for covering an open container of a vehicle includes a pair of arm assemblies. Each arm assembly has a first arm, a second arm, and a linking assembly coupling the first and second rotatable members to one another. A first actuator is attached to the first arm, and a cover is connected to the second arm. The first arm is driven by the first actuator, which causes the linking assembly to passively drive the second arm and to thereby to substantially vertically raise the cover. The apparatus may include a second actuator for rotating the second arm relative to the first arm for moving the cover across an open top of the open container. A method is also provided for covering an open top container supported by a vehicle.