Chain sling is a kind of rigging connected by metal chain rings, according to its form there are mainly two kinds of welding and assembling, according to its structure of single-limb and multi-limb, etc.
It adopts alloy steel, and its outstanding features are wear-resisting, high temperature-resisting, low ductility, and it will not be elongated after being stressed, etc. It is suitable for large-scale and frequent use. Its long service life, easy to bend, suitable for large-scale, frequent use of the occasion. Develop good lifting habits and plan how to hang, lift and unload before lifting work.
Make preparations: Determine the weight of the lifted object, read the accompanying documents carefully, mark the lifting points and weight data. Only after determining the center of gravity can the hook be hung in the proper position! The crane operator is to be informed of the weight of the lifted object. The crane hook is to be hung vertically above the center of gravity of the lifted object. Lifting the lifting objects should be done both to avoid damage to the lifting object and to prevent damage to the rigging itself. In order to avoid rotation or falling, the following conditions should be observed: for single-limbed rigging, the lifting point should be located vertically above the center of gravity of the lifting object. In the case of two-limbed rigging, the lifting points should be located on both sides of the lifting object, with the lifting point above the center of gravity.
In the case of three-and four-limbed rigging, the lifting point should be located uniformly at the level of the center of gravity of the lifting object and above the center of the object to be lifted. Attention must be paid to the lifting angle β (located between the plumb line and the lifting leg): the greater the lifting angle, the lower the lifting capacity. Lifting angles exceeding 60 degrees are not permitted!
If a chain rig with there or four limbs is used to lift a non-uniformly distributed lifting object, then the rated load per leg should be calculated for the object lifted by the two legs with the greatest lifting angle. If the legs of a two-limbed rig have different angles of inclination then the rated load for each leg should be calculated for the whole lifting object with only one chain.
