5.2　Winch

5.2.1　The wire rope of a winch shall be fixed on the drum，and shall have at least full 5 wraps remained on the drum.

5.2.2　When the winch is in service，the horizontal straight distance from the drum to the closest guide sheave shall not be less than either 20 times the drum length or 15m，whichever is greater.The first guide sheave shall be located on the perpendicular bisector of the drum.

5.2.3　If the wire rope is wound around the drum in several layers，it shall be firmly wound around the drum layer by layer，with the outermost layer lower than the height of flanges at both ends of the drum by one rope diameter.

5.2.4　Winches shall be fixed against any movement under forces.The design and construction of ground anchors for fixing winches shall comply with Chapter 7:Ground Anchors herein.

5.2.5　Winch drum and its components shall be replaced if any of the following defects is observed:

a）A 10% reduction in the wall thickness of the drum compared with its original wall thickness；

b）Crack in the cylindrical surface or casing of the drum；

c）Gap between drum bushing and shaft due to abrasion exceeding one time the abrasion tolerance；

d）Abrasion in the drum shaft exceeding 5% of its nominal diameter.

5.2.6　Brake components shall be removed from service if any of the following defects is observed:

a）Crack；

b）Abrasion in the brake band lining reaching 50% of its original thickness；

c）Plastic deformation in the spring；

d）Abrasion in the shaft or shaft bore reaching 5% of its original diameter.