When winding 2 or more layers of wire rope on the drum, the following requirements must be met:
The height of the drum rope edge above the outermost 1 layer is at least 2.5 times the diameter of the rope.
The drum must have a pad with a groove.
The steel wire rope from the lower layer to the upper critical section (equivalent to 1/4 of the length of the loop) must be inspected frequently and the rope should be moved by 1/4 of the loop every quarter.
For existing winches with no rope groove liners, as long as rope grooves are engraved on the roller plate or a 1-layer steel wire rope is used as the bottom rope, it can be used continuously.