Failure: One of the main functions of the scraper conveyor in the fully mechanized mining face is to transport the coal blocks cut by the shearer, which is realized by the chain installed on the scraper conveyor.The chain itself is an elastic body, and the amount of coal cut by the shearer is uncertain, resulting in inconsistent weight of coal blocks carried by the scraper conveyor chain.After a long period of operation, the chain of the scraper conveyor will loosen. If it is not dealt with in time, it will lead to safety accidents such as chain breakage, chain jamming, and chain stacking. In severe cases, it will affect the coal mining efficiency of the fully mechanized mining face.Solution: add an automatic chain tensioning device at the tail of the scraper conveyor, which consists of a PLC controller, a tail tensioning cylinder, a solenoid valve, a pressure sensor, and a travel sensor.When the system detects that the pressure value of the pressure sensor is not within the expected range, the PLC controller controls the action of the solenoid valve, drives the action of the tail tensioning cylinder, and adjusts the pressure value of the cylinder to return to the expected range. At the same time, the stroke sensor detects the tail tensioning. Tighten the moving distance of the oil cylinder and report it to the PLC controller to participate in the logic control of the PLC controller.When the scraper conveyor runs for a period of time, the chain of the scraper conveyor will be too loose, and the chain cutting operation is required.