Abstract: A take-up roll is mounted transversely on the headboard or cab of a truck and a flexible tarpaulin-like cover is rolled up on the take-up roll, which is rotatably mounted on the cab. A free end portion of the cover is connected to the cross bar of a bail, which is pivotally mounted outboard the side walls of the open bed of a truck. In the forward position of the bail, the cover remains rolled up on the take-up roll. The rolled up cover on the take-up roll exerts a force overcoming a rearward spring force on the bail to maintain the bail in the forward position. A reversible motor is drivingly connected to the take-up roll to rotate the take-up roll in a first direction and unroll the cover by releasing the spring force normally applied to the bail to thereby pivot the bail on the truck side walls and unreel the cover in overlying relation with the open bed until the bail has pivoted to its rearwardmost position and the bed is covered.