Belt Conveyor Holdbacks - Altra Literature PortalThe higher initial cost of the belt conveyor is offset by the higher, on- going expense of trucks, such as . Without a backstop, a reversing conveyor can rapidly accelerate to a runaway condition, which can . types of overrunning clutch style backstops; roller on inclined planes and sprag clutches. Roller Clutch. The roller on.sprocket style conveyor holdback,Flextrac Plastic Belt Conveyors | QC IndustriesConveyors built on a rugged steel frame with plastic chain belting for moving heavy loads longer distances.