A hoist hook is a sturdy, question mark-shaped piece of equipment used to attach heavy objects to ropes or chains in order to lift them. Typically, a hoist hook is made of metal. Some kinds have an open hook, while others latch shut once they've been hooked onto the object they're being used to lift.
The exact shape of a hoist hook may vary depending on its intended use. Grab hooks are designed to hold onto a link of chain, while slip hooks are designed to let the chain slide through them. Grab hooks are generally both lighter and smaller. Slip hooks are often made with a latch to keep the attached object in place.
The end opposite a hoist hook may be designed differently depending on how it will attach to the rope or chain. An eye hook has a circle at the end through which a rope can be threaded. A clevis hook has a U-shaped end with holes at the top of each branch of the U. A small pin can be slid through these holes and secured so that a cable or other piece of equipment can be securely attached. A shank hook ends in a straight bar that can be inserted into a hole in another piece of equipment.
Hoist hooks are load-rated according to how much weight they can bear. They are often stamped with numbers indicating their load rating, as well as the angle and distance between the tip of the hook and other parts of the hook. These numbers allow a hook's integrity to be verified after use. Experts recommend that hoist hooks be inspected regularly for cracking, damage from chemicals, bending, or straightening.
Various types of equipment use hoist hooks, including cranes, forklifts, and overhead hoists. Generally, a load is not hung directly from a hoist hook on one of these machines. Instead, a sling is secured under and around the object to be lifted. The sling is then attached to the hook, which is positioned directly above the load's center of gravity. This helps distribute the load evenly and keep the object steady and level as it is lifted.