Wire rope consists of several strands of metal wire laid(twisted) into a helix. The term "cable" is often usedinterchangeably with "wire rope", but narrower senses exist in which"wire rope" refers to diameter larger than 3/8 inch (9.52 mm),whereas sizes smaller than this are designated cable or cords. Initiallywrought iron wires were used, but today steel is the main material used forwire ropes.
Historically wire rope evolved from wrought iron chains,which had a record of mechanical failure. While flaws in chain links or solidsteel bars can lead to catastrophic failure, flaws in the wires making up asteel cable are less critical as the other wires easily take up the load.Friction between the individual wires and strands, as a consequence of theirtwist, further compensates for any flaws.
Wire ropes were developed starting with mining hoistapplications in the 1830s. Wire ropes are used dynamically for lifting andhoisting in cranes and elevators, and for transmission of mechanical power.Wire rope is also used to transmit force in mechanisms, such as a Bowden cableor the control surfaces of an airplane connected to levers and pedals in thecockpit. Only aircraft cables have WSC (wire strand core). Also, aircraftcables are available in smaller diameters than wire rope. For example, aircraftcables are available in 3/64 in. diameter while most wire ropes begin at a 1/4in. diameter. Static wire ropes are used to support structures such assuspension bridges or as guy wires to support towers. An aerial tramway relieson wire rope to support and move cargo overhead.