As one of the combination of three equipment, drag chain conveyor with hydraulic support is the most important machine for digging mining. The working principle of drag chain conveyor is to fix the bearing parts on the scrapers and chains . The bearing parts refer to the open chute.As the drag parts ( chains & scrapers ) ,when the machine head drive is started , it can lead the chain sprocket rotate ,to push drag chain conveyor make reciprocating movements with materials inside the chute. It will not stop until the machine tail. The drag chain will bypass the chain sprocket and make the closed recycling motion.