Archimedes developed a more primitive pulley in 3 BC. C., but that first pulley system has led to the technology we have today. A chain hoist is a device used to lift very heavy objects. It can be mechanical or electrical. It uses a pulley encased in a sealed chain. The chain is like a big loop and this makes it easy to work by hand. Learning how to use a chain hoist correctly can save you time and energy.