Abstract: A truck cover having an improved telescopic arm assembly for drawing a cover across an open topped truck body or other vessel or container. The assembly is powered by a pneumatic, hydraulic or other power source and comprises a pair of pivoting telescopic arms motivated by actuators The activators cause the telescopic arms to move pivotally from one end of the container to the opposite end and during the pivotal movement to cause the telescopic arms to retract as they move to a vertical position and to extend as they move from the vertical position to the opposite end of the container. The extension and retraction of the telescopic arms during pivotal movement from one end of the container to the opposite end causes a flexible cover carried by the upper ends of the telescopic arms to be drawn across the container in a low trajectory resulting in improved ease and safety of operation and reduced opportunity for damage to the flexible cover.