Abstract: An apparatus for covering the open top of a container positioned on a vehicle for transportation includes a fluid actuated motor for a spool on which a flexible cover is wound, and a pair of fluid actuated cylinders to pivot a pair of elongated arms that convey the cover away from the spool. The motor is arranged to drive the spool to release the cover slightly slower than the arms are pivoted, so that the arms are not subjected to a large counter force. In addition, the spool is mounted for vertical movement so that containers having different heights may be properly closed.