The distance between the crane hook and the load is known as the "Head Room". If a specific head room is required the "Reach" of the chain sling must increase as the angle between the legs increases as shown below (left).
The reach of a chain sling is the distance between bearing points of the upper and lower terminal fittings. This distance, commonly known as the "Effective Working Length" should be quoted when ordering slings. Shortening clutches may be fitted to a sling, making the reach adjustable, hence increasing the versatility of the sling.
In multi-leg slings, the angle between the legs is critical. The actual tension on each leg increases when the angle between the legs increases as shown in the diagram above. For this reason all general purpose chain slings are given a rating based upon use at 90° inc. angle. The included angle between the legs should never exceed 120°.
|Chain Size (mm)||Single Leg||Two Leg||Three and Four Leg||Endless|