Technical Inspection and Scrap Standards for Wire Rope Drums

• Steel Wire Rope End Fixing Device. The fixing device at the end of the steel wire rope on the drum must be designed to prevent loosening or should have self-tightening features. The condition of the wire rope's fixation should be checked monthly.

• Multi-layer Winding Drum. A multi-layer winding drum must have a flange at the end. The height of this flange should be at least twice the diameter of the steel wire rope or the width of the chain, extending higher than the outermost layer. This requirement also applies to single-layer winding drums.

• Drums for Lifting and Variable Amplitude Mechanisms. If the drum used for lifting or variable amplitude mechanisms does not feature a through support shaft inside the drum, it is recommended to manufacture the drum from steel for enhanced durability.

• Steel Wire Rope on the Drum. When the steel wire rope is fully extended during operation, the remaining portion on the drum should be wrapped at least 2-3 times, in addition to the number of turns required to secure the rope tail. This is to prevent stress on the rope tail pressure plate, wedge sleeve, or wedge block.

• Drum Wear and Cracks. If cracks appear on the drum or if the wall thickness of the drum has worn down by 20% or more from the original thickness, the drum should be considered for scrapping.

Key Points and Methods for Inspecting the Drum

1. Steel Wire Rope End Fixing Devices. The steel wire rope on the drum is typically secured using a pressure plate or wedge block. During inspection, check that each pressure plate applies even pressure on two ropes, not just one. Each end of the rope should have at least two pressure plates. Additionally, the pressure plate bolts should include anti-loosening devices, such as spring washers or double nuts. If wedge blocks are used, ensure the taper of the wedge block and wedge sleeve are consistent, ensuring the rope is evenly stressed across the clamped section.

2. Wall Thickness and Wear Measurement. Before inspecting for wear, clean any oil stains from the drum. Use a caliper to measure the wall thickness (δ₀) of the unworn section of the drum, as well as the diameter (D₀) of the unworn part. Then, measure the diameter (D) of the most worn section. The following condition should be met: △=δ₀－δ=(D₀-D)/2<0.2δ₀​

3. Crack Inspection. After cleaning off any oil stains, visually inspect the drum for cracks using the naked eye or a magnifying glass.

4. Drum Shaft Inspection. Regular maintenance may not provide access to inspect the drum shaft. It should be thoroughly inspected during major crane repairs. During inspection, the shaft should be removed, cleaned, visually inspected for cracks, and, if necessary, undergo non-destructive testing. If cracks are found, the shaft should be scrapped.