The metal clip that tightens as it's pulled on a lifting hook is professionally called a hook safety latch, commonly known as a hook catch, anti-detachment latch, anti-detachment device, safety buckle, or safety latch.
The core function of the hook safety latch is to prevent the load from accidentally falling during lifting. Its design is based on the principle of gravity self-locking: when a load is hooked, the tension of the chain or rope pushes the safety latch upwards, causing its end to engage with a specific groove or edge in the hook opening, forming a mechanical locking structure. Even if the load suddenly loosens or shakes, the latch will remain closed due to gravity, ensuring the hook opening cannot be accidentally opened. This passive safety mechanism requires no additional operation and automatically takes effect during lifting, significantly reducing the risk of falling objects from heights.
