Wire ropes are made up by laying wire strands around a core. The strands themselves are made up of between 3 - 91 wires. The more wires per strand the more flexible the rope will be.
The purpose of the core is to provide support and maintain the position of the outer strands during operation. The core provides an elastic bed to enable movement or relative displacement and allow deformation of the wire strands when the rope is flexed round a sheave. A core of incorrect size or inferior material will cause a rope not to function properly and will shorten its life.
There are two main types of rope core – Fibre (FC) and Steel (IWRC or WSC)
FC Fibre core around which wire strands are laid.
FC ropes provide excellent flexibility. Additionally, the fibre core is impregnated with lubricant during manufacture thus providing internal lubrication to reduce internal corrosion and wear between wires.
IWRC Independent wire rope core around which wire strands are laid. IWRC ropes have increased strength and provide good resistance to crushing, distortion and heat. The steel core also provides better support for the outer strands thus ensuring even stress distribution and retention of the rope shape.
WSC Wire strand core around which wire strands are laid.
Wire rope consists of a group of strands laid helically around a core. The strands of a wire rope consist of a number of individual wires laid about a central core.
Wire rope is versatile. It can be used to transmit motion through almost any plane or angle, to guy or tie down, to hold back, launch or control; to counterbalance, to guide or to lift or to do hundreds of other jobs.
Most people do not think of wire rope as a machine, but it is. It is a machine composed of precise, moving parts, all designed to bear a very definite relation to one another. In fact, some wire ropes contain more moving parts than many complicated mechanisms. A six strand rope consisting of 36 wires per stand with an independent wire rope core contains a total of 265 individual wires. All of these must be able to bend and move with respect to one another if the rope is to have the flexibility necessary for successful operation.
