Choosing the Right Wire Rope Construction for Different Types of Hoists

Hoisting machinery is a medium lifting load compared with mine hoisting. However, due to the compact arrangement of mechanical components, the wire rope needs to be wound around a larger number of pulleys, and the diameter of the drum and pulley is small, making the winding diameter ratio (D/d) is limited. Therefore, in the selection of wire rope should focus on bending fatigue resistance, the selection of smaller diameter, uniform thickness, better flexibility of the wire rope. Usually 6 strands, 8 strands of wire contact strand wire rope as the first choice. Due to the crane’s load-bearing mode for the free suspension of heavy loads, should choose interactive twisted wire rope to reduce the torsion of the wire rope.

Hoisting machinery is widely used in various industries and sectors, in the selection of wire rope but also according to the conditions of use. Such as busy degree, load status and working environment, etc. treated separately, in order to select the most appropriate wire rope structure.

1. Factory crane

General factories such as machinery factories, lifting infrequent, optional: 6 × 25F; 6 × 29F; 6 × 26Ws, 6 × 36WS and 8 × 25F; 8 × 26WS

Metallurgical factories with frequent operations, large lifting loads and high working ambient temperatures.

1) 6×29F+IWR, 6×36WS+IWR, 6×41WS+IWR.

2) 8×36WS+IWR, 8×41WS+IWR.

3) Double compaction wire rope K6×K36WS+IWR

2. Construction Crane

Construction site tower cranes

Generally use the traction trolley luffing mode, the diameter of the drum and guide wheel diameter is small, requiring better flexural and bending fatigue performance. In addition, in order to adapt to the requirements of high-rise buildings, but also focus on considering the torsion resistance of the wire rope.

(1) Lifting wire rope

Lifting height is not large, can choose the structure of close, large carrying capacity, good flexibility of the interaction of twisted, wire contact round wire rope, such as: 6 × 25F; 6 × 29F; 6 × 36WS; 8 × 25F; 8 × 26WS.

Lifting height is large (H/S>35) in order to prevent the phenomenon of ‘entanglement’, it is advisable to choose a non-twisting wire rope:

Ordinary 4 strands: 4V × 395, 4V × 48S.

Multi-layer strand: 18 × 7, 18 × 19W, 35W × 7.

Double compaction 4 strands: K4×K26WS, K4×K36WS

Tip: Engineering practice has proved that double compacted 4 strands are very suitable for low-speed heavy-duty, intermittent work cranes.

(2) Luffing traction wire rope: 6×25F, 6×29F, 6×36WS

Truck cranes, tyre cranes, crawler cranes

(1) Residential and secondary lifting ropes

Truck cranes, tyre cranes and crawler cranes, the main and secondary hook lifting requirements for good rope flexibility, wire diameter moderate. Due to the wire rope and then multi-layer winding on the reel, the requirements of Nai extrusion, the choice of metal rope core. Operation of free suspension of heavy loads, the requirements of the wire rope torsion resistance, impact resistance.

Small: 6×29F+IWR, 18×7+IWS.

Medium-sized: 4V×39S+5FC, K4xK39S, 35W×7.

Large: 4V x 48S + 5FC, K4 x K36WS, 35(W) x K7.

(2) Luffing wire rope

Electric tyre cranes and crawler cranes is the use of reel wire rope luffing mechanism, due to the compact size of the reel, and bring the winding diameter ratio (D/d) is too small, and through the number of pulleys is more, the requirements of wire rope flexibility, fatigue resistance, wear resistance. Steel wire rope in the reel multi-layer winding, the requirements of extrusion resistance, the choice of metal rope core. For example: 6×K25F, +IWR, 6×29F; +IWR, 6×26WS+IWR.

(3) Telescopic boom wire rope

Truck cranes and hydraulic tyre cranes are hydraulic plus rope rows of telescopic structure. Requirements for telescopic boom wire rope breaking tension, good flexibility and fatigue resistance, especially the requirements of the work of the elongation is small, structural stability, the factory needs to be pre-tensioning process.

Such as: 6×29F; +IWR.

Full filling type: 8×K19S+PWR, 8×K26WS+PWR(K)

3. Harbour loading and unloading cranes

Harbour loading and unloading cranes are characterised by: high operating intensity, frequent lifting, free suspension of goods for the bearing mode; more complex winding system, more rope sheaves through, and small wheel diameter, especially the existence of two-way bending. In order to adapt to its working characteristics, in addition to meet the breaking tension, safety coefficient and lubrication quality conditions, especially the requirements of the wire rope has a better flexibility and bending fatigue resistance.

Container cranes (including shore and yard bridges)

(1) Lifting ropes. Comprehensive consideration should be given to the following points:

Select the wire rope with tight structure and large load carrying capacity to reduce the rope diameter and increase the D/d value.

Select the wire rope with good bending fatigue resistance, and change from 6 strands to 8 strands and multi-strand structure. Because 8 strands compared with 6 strands, good flexibility, increased contact surface with the rope wheel, reduced contact stress, bending fatigue resistance of the overall capacity is higher.

The use of metal rope core to meet the large breaking tension and multi-layer winding resistance to extrusion. For large container terminal cranes, due to the busy task, the service life of the wire rope is required to be higher, and the choice of compacted 8-strand coated (filled) plastic wire rope can be considered.

In order to reduce the swing of the cargo box when lifting, despite the installation of the swing reduction device, but in order to further reduce the swing, the two hoisting ropes should be twisted interactively and configured according to the left twist and right twist interval.

Recommended wire rope construction:

Ordinary wire contact round strand: 6 x 29F+IWR, 6 x 36WS+IWR, 8 x 26WS+IWR, 8 x 36WS+IWR.Ordinary compacted strand: 8 x K26WS+IWR, 8 x K36WS+IWR.

Compaction strand full filling type: 8xK26WS+PWR(K), 8xK36WS+PWR(K).

Compacted strand full filling type (plastic filling): 8 x K26WS+PWR (K), 8 x K36WS+PWR (K).

Tip: When choosing compacted strand wire rope, multi-strand structure should be considered. Practice has proved that 4V compacted strand wire rope has reduced fatigue resistance due to the large bending stiffness of the strand, and is not suitable for harbour cranes with bending fatigue as a failure characteristic.

(2) Trolley traction wire rope

Select 6×29F+IWR, 6×26WS+IWR, or 8×26WS+IWR, 8×36WS+IWR.

Grab Cranes

Including gantry grab cranes and bulk cargo loading and unloading bridges, in the loading and unloading process, the wire rope is often working under full load, requiring high breaking strength and fatigue strength. Especially the opening and closing ropes in the operation process, often in the tension, and then relax such a cycle state, making the wire rope is very easy to produce fatigue. Therefore, the torsion and bending fatigue resistance should be considered.

Medium and light grab: 18×7+IWS, 18×19S+IWS.

Heavy grab: 24W×7, 35W×7, or 35(W)XK7.

Gantry crane for general cargo

Compared with the loaded container crane, the rated lifting capacity is small, considering the passage of more pulleys, it is appropriate to use wire contact strand wire rope with better flexibility and moderate thickness of the outer wire;

6×29F+FC, 6×31WS+FC, 6×36WS+FC.

8×25F+FC, 8×26WS+FC, 8×31WS+FC.

Tip: In order to reduce the free swing of the goods during lifting, the two lifting ropes should be selected with interacting twists and configured according to the left twist and right twist.

Ship Crane

Ship cargo handling crane winch drum diameter is small, the requirements of the wire rope soft bending performance is good, so you should choose the steel wire is thin, metal section coefficient of large wire rope. So that in the case of small rope diameter has a larger breaking force, from the surface to meet the requirements of the D / d value, to ensure that there is a better and fatigue strength. For example: 6x25S, 6x25F, 6X26WS, 6×29F, 6×31WS or 8×25F, 8×26WS and so on.

For the general use of engineering vessels, the rope diameter of small can choose 6x24S, 6×25, 6x26WS. For salvage wire rope requires large breaking strength and impact level load, can choose 6x41WS, 6x49SWS, 6x55SWS, 6x6IF:WS, or 8x41WS, 8x49SWS, etc., and the use of metal core and galvanised steel wire.

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