There are many places where a hoist is used; perhaps the most common form of hoisting equipment is the chain hoist. These hoists can be used in stationary applications as well as temporary installations. These hoists are the choice piece of lifting equipment for stage sound and lighting, often there are a dozen or more hoists located above the stage. The chain hoist is also seen in many garages as it is compact and is ideal for lifting the engine from a car for repair.
There are two types of chain hoist, the least expensive is a manual version; the more expensive is powered, using traditionally either air or electricity as the power source. The hoist itself does not break that often but the drive mechanism can fail and when it does the entire unit must be sent out for chain hoist repair work to be undertaken.
A chain hoist is a lifting device that uses chain to pick up and support the load; these hoists come in varying capacities but are most commonly used when the load is under 2 or 3 tons. The manual version and the powered version have similar lifting arrangements; however, the manual version is operated by hand by pulling on an endless chain. As the chain continues to be pulled over sheave, the gearing in the hoist slowly lifts the load. The load is attached to a safety hook at the bottom of the load chain.
In the body of the chain hoist there are a number of gears that convert the human or powered lift into a mechanical advantage. The electric or pneumatic hoist is most popular when the installation is fixed, when a chain hoist is employed on a construction for example, it is usually manually operated as there is often no source of ready power.
The hoists are designed and built with a substantial safety factor which guards against failure when inadvertently overloaded. If a section of chain is rated to break at 10 tons, this is the chain that will be used on a 2 ton hoist. With the loads that are employed, the components, perhaps the gears or the ratchet and pawl mechanism can fail and at this time chain hoist repair is necessary.
