... . It resembles a roller bearing, but instead of cylindrical rollers, non-revolving asymmetric figure-of-eight shaped sprags are used. When the ... direction, the rollers tilt slightly, producing a wedging action and binding because of friction. The sprags are spring-loaded so that they ... drive, Conveyors, Overrunning, Indexing, Backstopping, Hoist load brake. Skull clutch of sprag freewheels DC series