Central rotary catch rock machine by the grab, lifting mechanism, slewing, luffing mechanism, support systems and chassis and other components. Practice: preparation before the operation. Grab rock machine must scrutinize each fastener Shaanxi center go down before rotating grab rock machine, and not loose. Check wire rope wear and broken wires, and found broken wire, loose should be replaced immediately. Grab preparation work before the rock machine: someone to develop hanging plate, grab rock machine cleaning, the disc may not have debris, gravel exist. Inner Mongolia succession after the driver rotated through grasping rock machine, a detailed examination of the suspension device to improve the degree of organization brake smoothly, bolts and hanging plate, as well as Shengka, weld, lift arm rod advice, identify problems and timely handle before use.