Wire rope pressing is an essential working component of lifting machinery and a commonly used lifting tool, widely applied in lifting operations. Below are the key guidelines for its use and maintenance:
1. **Technical Data Compliance**: Wire rope pressing should be used according to the technical data provided by the factory. If no technical data is available, a single-wire breaking tensile test must be conducted.
2. **Mechanical Performance and Safety Factor**: Selection of wire rope pressing should be based on its mechanical properties, with a certain safety factor. The diameter of the wire rope and its matching pulley must not be smaller than the specified data.
3. **Regular Oil Immersion**: Wire rope pressing should be regularly immersed in oil to maintain its flexibility and longevity.
4. **Clamping of Wire Rope Ends**: When securing the end of the wire rope with clamps, the clamp plates must be placed on the main load-bearing side of the wire rope and should not be crossed. The spacing between clamps should be at least six times the diameter of the wire rope, and the number of clamps must meet the required specifications.
5. **Splicing and Sleeve Length**: The splicing length of inserted wire rope pressing or the sleeve length should not be less than 15 times the diameter of the wire rope and must not be shorter than 300 mm. Newly installed rope slings should be sampled and tested under 125% of the allowable load.
6. **No Joints in Wire Rope**: Wire rope passing through pulleys or drums must not have any joints. The ratio of the pulley or drum groove diameter to the wire rope diameter should comply with the following: for mechanically driven hoists, the ratio should not be less than 11, and for manually driven hoists, it should not be less than 10.
7. **Unreeling New Wire Rope**: Before using new wire rope pressing, it should be unreeled correctly. Place the wire rope reel on a rotating shaft, pull one end of the rope to slowly rotate the reel, and straighten all loops. Wire rope reels should not be placed vertically on the ground and then horizontally stretched, as this can cause residual torsional forces, leading to breakage, twisting, or severe damage. During use, the crane pulley may not function properly due to improper unreeling.
8. **Storage Conditions**: Wire rope pressing should be stored in a well-ventilated, dry indoor space and placed on racks or suspended.
9. **Avoid Contact with Electrical Wires**: Wire rope should not come into contact with welding wires or other electrical wires, as this can easily damage the wire rope and create hazards.
10. **Prohibition of Braided Extension Rope**: Braided extension wire rope must not be used in the lifting and luffing mechanisms of cranes.
11. **Scrap Criteria**: Wire rope pressing should be scrapped if any of the following conditions occur:
- Wear or corrosion exceeding 40% of the original diameter, or severe annealing or localized arc burn damage.
- Core damage or strand extrusion.
- Severe deformation or bending.
- Flattened deformation with severe surface burrs.
- Few broken wires but rapid increase in breakage.
12. **Disposal of Scrapped Wire Rope**: Scrapped wire rope should be cut and placed in a designated location to avoid accidental reuse and potential accidents.
13. **Avoid Friction During Operation**: Wire rope in operation should not rub against other objects, as friction can lead to damage, breakage, or overload.
14. **Splicing Connections**: When connecting wire rope using splicing:
- For wire ropes with a diameter less than 15 mm, each must have at least 4 splices.
- For wire ropes with a diameter between 15–28 mm, at least 5 splices are required.
- For wire ropes with a diameter between 28–60 mm, at least 6 splices are required.
- The strength of wire rope fixed by braiding is 75%–90% of the original strength. The impact of this connection method should be considered carefully.
