Steel Wire Rope

General Information on Wire Ropes

Wire rope is made of plaiting strands of wire – normally medium carbon steel – into a thick cable. The strands are formed around a core. The strands in wire ropes are made of wore twisted together. Strands with smaller diameter wires are less abrasion resistant and more fatigue resistant. Strands made with thicker length of wore are more abrasion resistant and less fatigue resistant.

Construction

The main components of a wire rope is shown below

In the above example, each individual wire is arranges around a central wire to form a 7-wire strand.

Six of these strands are formed around a central core to make a wire rope. The rope is specified as 6x7 (6/1)

–i.e. six strands each of seven wires.

Terminations

The end of a wire rope tends to fray readily, and cannot be easily connected to plant and equipment. A number of different mechanisms exist to secure the ends of wire ropes to make them more useful. The most common and useful type of end fitting for a wire rope is when the end is turned back to form a loop. The loose end is then fixed by any number of methods back to the wire rope.

Thimbles (If you are interesting ,please click)

When the wire rope is terminated with a loop, there is a risk that the wire rope can bend too tightly, especially when the loop is connected to a device that spreads the load over a relatively small area. A thimble can be installed inside the loop to preserve the natural shape of the loop, and protect the cable from pinching and abrasion on the inside of the loop. The use of thimbles in loops is industry best practice. The thimble prevents the load from coming into direct contact with the wires.

Wire rope clamps (DOG CLAMPS)--- (If you are interesting ,please click)

A wire rope clamp, also called a clip, is used to fix the loose end of the loop back to the wire rope. It usually consists of a u-shaped bolt, a forged saddle and two nuts. The two layers of wire rope are placed in the u-bolt. The saddle is then fitted over the ropes on to the bolt (the saddle includes two holes to fit to the u-bolt). The nuts secure the arrangement in place. Three or more clamps are usually used to terminate a wire rope.

Swaged terminations

Swaging is a method of wire rope termination that refers to the installation technique. The purpose of swaging wire rope fittings is to connect two wire rope ends together, or to otherwise terminate one end of wire rope to something else. A mechanical or hydraulic swager is used to compress and deform the fitting, creating a permanent connection. There are many types of swaged fittings. Threaded Studs, Ferrules, Sockets, and Sleeves a few examples.

Sockets (If you are interesting ,please click)

A socket termination is useful when the fitting needs to be replaced frequently. For example, if the end of a wire rope is in a high-wear region, the rope may be periodically trimmed, requiring the termination hardware to be removed and reapplied. An example of this is on the ends of the drag ropes on a dragline. The end loop of the wire rope enters a tapered opening in the socket, wrapped around a separate component called the wedge. The arrangement is knocked in place, and load gradually eased onto the rope. As the load increases on the wire rope, the wedge become more secure, gripping the rope tighter.

Eye splice