Towing Wire Rope
One of the most common products produced using wire springs is cable slings for various applications such as elevator cables, crane cables, suspension bridges, etc.
The construction of cable slings involves different combinations of wires and their sizes to ensure the necessary resistance against fatigue and wear. In general, if a strand has fewer larger wires, it will have greater resistance to wear, but at the same time, it will have less resistance to fatigue compared to a strand with a larger number of smaller wires.
The wire or wire strand in the center of the cable is called the core. The core of the cable can also be non-metallic, which leads to the production of more flexible and pliable cables but with less tensile strength compared to cables with a steel core. Typically, fiber ropes and strands are used to produce flexible cables.
By braiding cables around a single wire or another cable, larger and stronger cables can be produced.
Several common types of cable sling weaves are as followings:
Single Size Cable Sling Weave The main strand consists of wires of the same size that are twisted around a central wire. The cross-sectional view of a single size cable sling is depicted in the image below.
Seale Cable Sling Weave In this weave, larger outer wires and smaller inner wires are placed around a central wire in equal numbers. This type of weave provides excellent resistance to wear but has less resistance to fatigue. When an Independent Wire Rope Core (IWRC) is used in this weave, it exhibits excellent resistance against damage on the drum.
Filler Cable Sling Weave In this weave, small wires fill the spaces between larger wires. The purpose of this is to create resistance against damage and achieve a good balance of strength, flexibility, and wear resistance.
Warrington Cable Sling Weave In this weave, the outer layer of the cable sling consists of a sequence of larger and smaller wires, creating good flexibility and strength. However, it has less resistance to wear and is less durable against damage.
Many common cable slings make use of a combination of these weaves.
Lay The way wires are laid in a cable also has an impact on its strength and resistance to wear and abrasion. Let’s familiarize ourselves with different lays of cables.
Regular Lay (A Lay) In this type of lay, the wires are twisted in one direction while the strands are twisted in the opposite direction. With this lay, the probability of twisting and unraveling of the strands is very low, and it is more resistant to damage compared to a Lang lay.
Lang Lay (B Lay) In this lay, both the wires in the strands and the strands in the cable sling are twisted in the same direction. This increases resistance to wear, flexibility, and fatigue compared to regular lay, but it may be more prone to twisting and unraveling of the strands.
Right Hand Lay (C Lay) The strands are twisted in a right-hand direction around the core. This is the most common type of lay.
Left Hand Lay (D Lay) The strands are twisted in a left-hand direction around the core. This is used in specific situations, such as in drilling cables.
Alternate Lay (E Lay) This type of lay consists of alternating regular right-hand lay and Lang lay strands, combining the best qualities of both regular and Lang lay for applications like boom hoist ropes or winch lines.