Abstract: A device for driving an endless chain or the like, particularly, though not exclusively, a chain of the flat-link kind used in bucket elevators, the device comprising a reciprocating slipper having locking means which grips the chain in one direction of reciprocating movement but runs freely with respect to the chain in the reverse direction, there being means for preventing reverse movement of the chain whereby the slipper advances the chain intermittently in one direction. In an alternative embodiment, two slippers may be provided working in opposition to each other so that the chain may be continuously driven thereby.