Crane safety devices: Lifting Characteristics table. Set in the control room on the front side wall 50 t crane, which lists the nominal weight and lifting height of various arm lengths and various operating amplitude under for inspection during operation. When the lifting operation, must not exceed the values ??specified in the table. 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.