Rope breakage caused the accident

a, Wire Ropes, broken stocks not in time, replace
b, a sudden fall hook, hook, trolley, etc. retaining rope pulley or no damage to 0 lead rope off the tank,bridge gantry crane thereby squeezing off the ropes
c, height limiter does not work, pull off the hook rope touch trolley beams

Other safety device is damaged, removed or malfunction caused the accident

Such as brakes, weight limiter, height limiter, slewing limit, luffing limit, limit walking carts and so on.

Design, manufacturing defect caused the accident

1, the design deficiencies such as lack of stability of the tower crane, one-sided pursuit of arm length performance,bridge crane tower rigidity or insufficient strength
2, manufacturing defects, random substitute materials or main material does not meet the criteria
3, does not comply with the welding process standards, there is slag, cracks, key size, or there is not enough Weld weld defects such as
4, the safety device failure,gantry crane and other protective devices are not perfect