Lightweight ropes for lifting applications
The level of wire rope technology used in lifting or hoisting applications has a significant effect on the overall efficiency of the system. This paper presents various examples which show the different benefits which may be accrued from the use of lightweight ropes. Most hoisting operations by their very nature involve long suspended lengths of rope in the system. In the deep mining application, these lengths can easily be up to 3000 m. At this length the rope self weight becomes a significant component of the total payload which it has to support. A 20% reduction in the rope mass per metre for a typical hoist rope (of the same strength) will allow an increase in the skip payload of 30% at 3000 m. In the case of a crane, the weight of the rope can form a large part of the whole machine weight. Here, reduction in rope weight can allow benefits in terms of stability and in the case of mobile cranes, significant savings in axle loads. Another area where composite ropes may provide advantages is in the offshore environment where the lightweight benefits of fibre may be combined with the ruggedness of steel wire. The paper closes by giving a brief discussion of the issues of NDT inspection of such ropes.