Wire Ropes For Bridge Cranes/Gantry Cranes

Wire Ropes for Bridge Cranes/Gantry Cranes

 

The steel wire rope has high strength, light weight, good flexibility, impact resistance, safety and reliability. The wire rope used under normal conditions will not break suddenly, but it may be damaged due to the load exceeding its ultimate breaking force.

 

There are precursors to the damage of the wire rope, which always starts from the broken wire, and the sudden break of the whole rope rarely occurs. Wire ropes are widely used in cranes. The damage of the wire rope will lead to serious consequences, so the wire rope is not only one of the important parts of the hoisting machinery, but also a key link to ensure the safety of the hoisting operation.

 

1. Structure of wire rope
 

The steel wire rope is twisted into strands by multi-layer steel wires, and then centered on the rope core, twisted into a helical rope by a certain number of strands.
 

(1) steel wire
 

The steel wire rope plays the role of bearing the load, and its performance is mainly determined by the steel wire. Steel wire is a round (or special-shaped) wire made of carbon steel or alloy steel by cold drawing or cold rolling. It has high strength and toughness, and the surface treatment of the steel wire is carried out according to different environmental conditions.

 

(2) rope core
 

It is used to increase the elasticity and toughness of steel wire ropes, lubricate copper wires, reduce friction, and increase service life.
 

Materials such as organic fibers (such as hemp and cotton), synthetic fibers, asbestos cores (high temperature conditions) or soft metals are commonly used for rope cores.

 

 

2. Type of wire rope
 

The steel wire rope for cranes adopts double-twisted multi-strand round steel wire rope.
 

(1) According to the contact state of the steel wire, it can be divided into point contact, line contact and surface contact wire rope.

 

① Point contact wire rope (also known as ordinary type) is twisted with steel wires of equal diameter.
 

Because the twist distance of each layer of steel wire is not equal, point contact is formed between each layer of steel wire and steel wire. When loaded, the contact stress of the steel wire is very high, it is easy to wear and break, and the service life is low. The advantage is that the manufacturing process is simple and cheap.
 

Point contact wire ropes are often used as binding slings for lifting operations, and are also used in the working mechanism of cranes.

 

② Line-contact steel wire ropes are twisted with steel wires of different diameters.
 

Properly arrange the steel wires of the inner and outer layers to form a line contact between the steel wires of different layers and the steel wires to reduce the contact stress of the steel wires when loaded.
 

The wire contact rope has high bearing capacity, good flexibility and long service life. Commonly used line contact wire ropes include Searle type (also known as outer thick type), Valentun type (also known as thick and thin type), filled type (also known as dense type) and so on. In the working mechanism of the crane, the line contact wire rope is preferred.

 

③ Surface contact with wire rope (also known as sealed type).
 

Usually round steel wire is used as the strand core, and the outermost layer or layers are made of steel wire with special-shaped cross-section. The layers are in surface contact and are wound by extrusion.
 

It is characterized by smooth surface, good flexibility and high strength. Corrosion-resistant, but the manufacturing process is complicated and the price is high. It is rarely used on cranes. It is often used as the load-bearing cables of cable cranes and aerial ropeways.

 

 

(2) Classified according to the twist direction of the wire rope.
 

According to whether the direction in which the wire rope is twisted into strands is consistent with the direction in which strands are twisted into ropes, it can be divided into:

 

① Alternate lay wire rope (also known as intertwined rope).
 

The direction in which the strands are twisted into strands is opposite to that of strands twisted into ropes. Since the direction of the strand and the rope is opposite, it is not easy to twist and loose during use, so it is widely used on cranes.

 

② Wire ropes laid in the same direction (also known as parallel winding ropes).
 

The direction in which the strands are twisted into strands is the same as that of strands twisted into ropes, and its flexibility and life are better than those of alternating twisted ropes. However, because it is easy to twist and loose, it is generally only used as a traction rope.

 

③ Do not twist the wire rope.
 

When this kind of wire rope is designed, the torsional moments of the strands and the rope are equal and the directions are opposite, which overcomes the torsion phenomenon during use. It is often used on cranes with large lifting heights, and has been paid more and more attention.

Populära Taggar: wire ropes for bridge cranes/gantry cranes, China, suppliers, manufacturers, factory, customized, buy, price, for sale