Abstract: A contractible cover assembly for the load carrying body of a vehicle includes canopy frame cover structure mounted upon a plurality of drive train team members longitudinally moveable along laterally spaced guide track rails to extend or retract the canopy frame cover structure from an open stored position wherein the truck bed is substantially uncovered and the closed covering position wherein the truck bed is closed by the canopy frame cover structure. The laterally spaced guide rails may be mounted along the longitudinal side surface of a vehicle bed or the vertically extending sidewall portions of a vehicle bed for supporting the drive train team members during movement thereon. The canopy frame cover structure includes canopy frames having a rib portion integral with and bridging a pair of support legs, the rib portion having a length sufficient to extend traversely across the width of the vehicle cargo bed and the support legs being attached to and supported by the plurality of drive train members.