Feeder breaker is a multi-functional mining equipment that integrates crushing, screening, feeding, etc., widely used in coal, mining, metallurgy, chemical industry, building materials and other industries. Its working principle is mainly to break the chain by driving the drag chain and the scraper to run forward to the rotating crushing hammer or crushing tooth roller. The long-term operation of the chain will cause the chain to loosen and slip, etc. Therefore, we add a night screw tension device in the conveyor part of the chain. By adjusting the tension unit, the chain is dragged backward and then the drag end is shifted to the sprocket. This causes the chain to tighten. So as to avoid the emergence of the above problems.