Which type of chain hoist is NOT one of the four main types?

The snatch hoist is indeed not one of the four main types of chain hoists typically recognized in industrial settings. The primary types of chain hoists generally include the screw geared, differential, and pull-lift hoists. Each of these has its unique mechanism and application suited for specific tasks in rigging and lifting.

A screw geared hoist utilizes a screw mechanism for lifting, providing precise control over the load. The differential hoist allows for lifting heavier loads with less effort by using a combination of pulleys to gain mechanical advantage. The pull-lift hoist operates with a manual chain system allowing for easy operation and is commonly used in various lifting scenarios.

In contrast, a snatch hoist has a different design and is often used for quick lifting and lowering tasks but does not belong to the main categories of chain hoists. Understanding these distinctions helps in selecting the appropriate hoist for specific lifting or rigging tasks, ensuring safety and efficiency in operations.