Structural Strands

The structural strands ofthe 1370WWalkingDragline (figure 68) consist of the upper structural strands connecting the boom point to the mast head; the upper and lower intermediate structural strands which connect the boom at intermediate points to the mast head; the lower structural strands connecting the mast head to the A-frame head; the A-frame safety structural strands connecting the A-frame head to the rotating deck.

The purpose of these structural strands is to support the boom in its working position.

All structural strands should be inspected weekly for deterioration. Deterioration will usually show up in the form of broken outer wires, the presence of rust, or reduction in rope diameter. The area All broken wires should be tied down to prevent further unraveling or wear to the strands of the rope. To prevent rusting periodic applications of a good penetrating oil at the rope socket is required. This oil should have high penetrating properties and contain about 50% lubricating oil as well as a penetrating solvent. The oil should be able to displace water on the surfaceofsteel in such a way as to positively prevent corrosion from moisture already present within the strand at the time of application, or moisture that might accumulate later.

The typical life span of structural strands is approximately8 years, however, this does notvoid the requirement ofperiodic inspection and replacement at shorter intervals if necessary.

1. BOOM 2. LOWER TOWER 3. UPPER TOWER 4. POINT SHEAVES 5. MAST 6. DEFLECTION SHEAVE 7. A-FRAME 8. FAIRLEAD

UPPER STRUCTURAL STRAND 10. LOWER STRUCTURAL STRAND 11. SAFETY STRUCTURAL STRAND 12. HOIST ROPE

FRONT END EQUIPMENT

FIGURE 68 13. DRAG ROPE 14. BUCKET 15. BUCKET RIGGING 16. UPPER INTERM. STRUCTURAL STRAND 17. LOWER INTERM. STRUCTURAL STRAND