RIGGING EQUIPMENT- wire rope & sling

Wire rope cores - The core of a wire rope is the central member around which the main strands are laid to support the strands and maintain them in their proper position when loads are applied. The two types of cores commonly used in wire ropes are metallic cores [ independent wire rope cores ( IWRC) & wire strand cores ( WSC) ] and fiber cores ( FC) of either natural ( jute. Manila or sisal) or synthetic fibers like polypropylene ( pp) or polyethylene. For ropes of dia 13mm and below. Nsc is generally used as the metallic core unless otherwise specified. When fiber core is specified. Jute is generally used except for fishing ropes where polypropylene is used Zinc - coated wire ropes - Galvanized ropes have their wires uniformly coated with zinc for protection against corrosion where atmospheric condition is saline or the rope is exposed to other corroding agents as well as when it is used in water. Where periodic lubrication is possible in engineering ropes. Heavily lubricated bright ropes are usually preferred to galvanized ropes. Lion brand fishing ropes are coated with an extra heavy coating of zinc and heavily coated with cadmium compound. Preformed wire ropes - In a preformed wire rope, the individual wires in the strands and strands composing the rope are properly pre-shaped by a performing head before. They are assembled into the finished rope and preforming prevents the wire and strands from straightening and leaves them relaxed in their normal positions in the rope. Preformed ropes have the following merits as compared with non-preformed ropes Features Does not require seizing as they retain the rope structure Superior flexibility compared to non-preformed ropes and wire ropes kinks scarcely ever occur during use Longer life because preformed wire ropes have a great endurance to bending Broken wire ends do not protrude to injure workmen' s hand. Distort adjacent wires or cause wear to sheaves and drums Grades of wire ropes - Wire ropes are manufactured in various tensile grades to meet the varied requirements of many applications. Each grade provides a different combination of tensile strength. The grades are 1230. 1420. 1570, 1770 & 1960 n/ mm2.