Which component of a chain hoist is designed to be the weakest part and will spread when overloaded?

The lower hook of a chain hoist is intentionally designed to be the weakest link in the rigging system. This design is a safety feature that ensures that, in the event of an overload, the hook will spread or deform before other more critical components of the hoist or the load will fail.

By allowing the lower hook to be the sacrificial part, it prevents potential catastrophic failures that could occur if stronger components, like the chain or the drum, were to fail under excessive load. This design principle protects not only the equipment but also enhances the safety of personnel in the vicinity of the lift by minimizing the risk of an uncontrolled drop of the load.

With this in mind, the other components, such as the upper hook, chain link, and drum, are engineered to withstand higher loads, thus ensuring the overall integrity and safety of the hoisting operation.