A scaffold is a temporary structure built outside of a building or structure under construction, allowing workers to access the higher levels of that building or structure. Workers often need to lift materials to those heights, so a scaffold hoist is used in lieu of lifting the materials by hand, which can be stressful and dangerous, or even impossible. Many types of scaffold hoist models exist for different purposes; some smaller units use a boom arm with a pulley mounted to it, while other systems feature entire moving platforms that can lift people and materials.
The latter scaffold hoist system is far more elaborate and must be constructed and operated carefully. The system features a lift platform mounted to specially designed scaffolding sections, and it is propelled upward using a motorized rack and pinion system. Such a scaffold hoist is likely to be used on larger building projects on which heavy materials and large numbers of workers must be transported. For smaller buildings and structures, this system generally will not be necessary.
Instead, smaller structures may require the use of a small, jib crane scaffold hoist. This system features a vertical arm that supports a horizontal arm, at the end of which is mounted a pulley. A cable will run through the pulley, usually wrapping around it several times, and then it will drop to the ground. At the lowest point on the cable is mounted a hook, which can in turn be attached to a load to be lifted. Smaller pulley systems can be operated by hand, while others are motorized and controlled with switches. Motorized units are usually reserved for larger jobs, while hand crank jobs are used only for the lightest duty jobs. Sometimes a rope will be used in lieu of a cable, though fiber ropes tend to be less durable and are not used as often or for any heavy duty jobs.
Another type of scaffold hoist may mount directly to the scaffold piping. It will work much like a winch or ceiling-mounted hoist, and it will usually be motorized. This system employs the same system as the jib crane, except without the jib crane. The system will feature a wide pulley around which a cable will be wrapped numerous times. A motor will turn the pulley, either letting out the cable or pulling it back in. A hook is mounted to the end of the cable so it can be attached to the items to be lifted.