Crane structure: crane operating agencies generally only four driving and driven wheels, if great weight Guangdong construction crane, used to increase the wheel Measures shall be reduced wheel pressure. When the wheels than four, must be balanced hinged frame means that the crane load is evenly distributed on each wheel. Crane safety devices: safety devices luffing jib. When the mishap occurred, boom luffing cylinder loop burst high-pressure hose or tubing or cut off construction cranes, hydraulic circuit balancing act Buying on construction cranes, the lower chamber of the cylinder lock from the working oil to make hanging arm will not fall, so as to ensure the safety of operations.