A master link (often referred to as an oblong link) is a critical piece of forged alloy steel hardware used at the very top of a rigging assembly. It serves as the primary connection point between the crane hook and the lifting sling, allowing for the safe distribution of weight across single or multiple sling legs (whether chain, wire rope, or synthetic web).
The most common configuration, shaped like a flattened oval. It is ideally suited for single-leg and two-leg sling assemblies, providing ample room for the crane hook while keeping the attached legs properly seated at the bottom radius.
This consists of a primary oblong master link with two smaller sub-links attached. It is specifically engineered for three-leg and four-leg sling assemblies, preventing the individual legs from crowding or overlapping on a single ring, which could compromise the working load limit (WLL).
Narrower at the top and wider at the bottom, designed to fit snugly onto specific hook profiles. While effective, it is less commonly used in modern multi-leg chain assemblies compared to standard oblong links.
To withstand extreme stress in international shipping and industrial lifting environments, master links are rigorously manufactured:
| Type | Leg Compatibility | Structural Design | Primary Application |
|---|---|---|---|
| Standard Oblong | 1-leg, 2-leg | Single closed alloy loop | Straightforward lifts, standard overhead cranes |
| Link Assembly | 3-leg, 4-leg | Main loop with two sub-links | Complex, multi-point cargo and heavy equipment lifts |
