Crane Note: crane are not allowed to use supercharged. Allowed lifting case: Bundle is not strong; mechanical overload; signal is unknown; the oblique; buried or frozen in the ground thing; somebody was hanging on objects; there is no security measure is flammable, explosive and dangerous goods; too full of liquid items; wire rope does not meet the safety requirements; lifting mechanism is faulty. Crane safety devices: safety devices luffing jib. When unexpected car accident crane brand, boom luffing cylinder loop high-pressure hose or pipe burst or cut off large automobile cranes, hydraulic circuit balancing act on auto crane, locked from the fuel tank under the working oil chamber so that the boom will not fall, so as to ensure the safety of operations.