Common types and causes of crane loss accidents
There are several types of common loss accidents:
1. Detachment accident
A rope-off accident refers to a casualty and destruction accident when a heavy object falls off and collapses from the tied hoisting rope. The main reason for the detachment accident is the improper binding method and essentials of the heavy objects, which caused the heavy objects to slip; improper selection of the lifting center of gravity, resulting in partial load lifting or the instability of the lifting center causing the heavy objects to fall off; the lifting is subjected to collisions, impacts, Unsteady due to vibration, etc., causing heavy objects to fall.
2. Decoupling accident
Unhooking accidents refer to accidents of heavy objects falling out caused by heavy objects, hoisting ropes or special slings coming out of the hook openings. The main cause of unhooking accidents is the lack of hook protection device on the hook; the malfunction of the hook protection device; the improper lifting method and the deformation of the hook mouth of the hook which cause the opening to be too large.
3. Rope broken accident
The main reasons for the breaking of the hoisting rope are mostly overloaded lifting and breaking the wire rope; the failure of the lifting limit switch causes the wire rope to be broken by overwinding; the oblique hoisting and diagonal pulling cause the rope to crush and cut the wire rope; the wire rope lacks maintenance due to long-term use Breaking accidents caused by fatigue deformation, wear damage, etc. that meet or exceed the scrap standard and still use.
The main reason for the breaking of the hoisting rope is that the hoisting angle is too large> 120 degrees, which causes the hoisting rope's tensile strength to exceed the limit value and break; the hoisting wire rope is not properly selected, or the wire rope that has reached the scrap standard is still used to bind and hoist heavy objects. Causes the lifting rope to break; there is no protective measures such as gaskets in the contact between the lifting rope and the heavy object, which causes the edges and corners to cut the wire rope and the lifting rope breaks accident.
4. Hook breaking accident
Hook breaking accident refers to the accident of heavy objects falling caused by the breaking of the hook. The cause of the breaking accident of the hook is mostly due to the defective material of the hook. The hook is still in use or is often overloaded due to long-term wear and tear, and the section has been reduced.
The accident of lifting machinery loss mainly occurs in the winding system of the hoisting mechanism. In addition to the detachment, disconnection, rope breakage and broken hook, the fixing of the two ends of each hoisting wire rope is also very important, such as the wire rope on the reel. Whether the limit safety ring can be guaranteed to be more than 2 laps, whether there is descent limit protection, whether the steel wire rope is fixed by the pressure plate on the drum device and the wedge fixing structure is safe and reasonable. In addition, the wire rope slips off the groove (off the drum rope groove) or off the wheel (off the pulley) accidents will also cause loss.
