What are the selection principles of spreaders?

Update:06-07-2018
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What are the selection principles of spreaders? The hoi […]

What are the selection principles of spreaders?

The hoisting machine is an important part of lifting and hoisting work. Correct and reasonable selection of hoisting tools is an important part to ensure the safety of lifting and hoisting operations. Master the structure and characteristics of the hoisting equipment in order to properly select the spreader and properly maintain and use the spreader. The main knowledge points of this article are: the structure, performance characteristics and selection container spreader parameters or steps of wire rope, pulley block, winch, balance beam.

First, the wire rope

The wire rope commonly used in lifting and hoisting operations is a multi-strand wire rope, which is made up of a plurality of strands around a core. Large-scale hoisting should adopt the wire rope of GB8918-2006 standard for "Important Wire Rope". The selection of wire rope mainly considers the following points:

1. Strength limit of steel wire rope: wire rope wire commonly used in lifting engineering

2, wire rope specifications: wire rope is made of high carbon steel wire. There are many specifications for the wire rope, and the lifting wire is commonly used in 6X19+FC (IWR), 6X37+FC (IWR), and 6X61+FC (IWR) wire ropes. 6 represents the number of strands of the wire rope, 19 (37, 61) represents the number of strands in each strand, and "+" is followed by the cord core in the middle of the strand, where FC is the fiber core and IWR is the steel core.

3, the diameter of the wire rope: in the same diameter, the wire diameter of the 6X19 wire rope is larger, the strength is higher, but the flexibility is poor, often used as a cable wind rope. The wire in the 6X61 wire rope is the finest and flexible, but the strength is low. It is often used as a sling. The performance of the 6X37 wire rope is between the above two. The latter two sizes of wire ropes are often used as running ropes and slings that run through the pulley block. The slings are commonly known as jacks or rope buckles for connecting crane hooks and hoisting equipment.

4, safety factor

The safety factor of the wire rope is the reserve tension that the wire rope is allowed to withstand the tensile force during use, that is, the safety margin of the wire rope breaking during use.

5. The allowable tension of the wire rope is calculated: T=P/K (1H412022)

In the formula P——breaking tension of steel wire rope (MPa); according to national standards or data provided by the manufacturer;

Second, the pulley block

1. There are many specifications and models of the pulley block. The H series pulley block is commonly used in lifting engineering.

2. Calculation of running rope tension;

3. According to the number of doors of the pulley block, the winding method is determined. The commonly used winding methods are: wearing, wearing and double running. Generally 3 doors and below, should be used to wear; 4-6 doors should be worn with flowers; 7 or more doors should be worn with double running heads;

4. Selection of pulley block.

Third, the winch

Fourth, the balance beam

Balance beam is also called iron pole load. When hoisting precision equipment and components, or affected by the environment of the regulation field, or when lifting multiple machines, it is generally used to hoist the balance beam.