Hoist (device)

A hoist is a device used for lifting or lowering a load by means of a drum or lift-wheel around which rope or chain wraps. It may be manually operated, electrically or pneumatically driven and may use chain, fiber or wire rope as its lifting medium. The most familiar form is an elevator, the car of which is raised and lowered by a hoist mechanism. Most hoists couple to their loads using a lifting hook. Today, there are a few governing bodies for the North American overhead hoist industry which include the Hoist Manufactures Institute, ASME, and the Occupational Safety and Health Administration. HMI is a product counsel of the Material Handling Industry of America consisting of hoist manufacturers promoting safe use of their products. The word “hoist” is used to describe many different types of equipment that lift and lower loads. For example, many people use “hoist” to describe an elevator. The information contained here pertains specially to overhead, construction and mine hoist. Overhead hoists are defined in the American Society of Mechanical Engineers (ASME) B30 standards as a machinery unit that is used for lifting or lowering a freely suspended (unguided) load. These units are typically used in an industrial setting and may be part of an overhead crane. A specific overhead hoist configuration is usually defined by the lifting medium, operation and suspension. The lifting medium is the type of component used to transmit and cause the vertical motion and includes wire rope, chain or synthetic strap, or rope. The operation defines the type of power used to operate the hoisting motion and includes manual power, electric power, hydraulic power or air power. The suspension defines the type of mounting method used to suspend the hoist and includes hook, clevis, lug, trolley, deck, base, wall or ceiling. The most commonly used overhead hoist is electrical powered with wire rope or chain as the lifting medium. Both wire rope and chain hoist have been in common use since the 1800s, however mass production of electric hoists did not start until the early 1900s and was first adapted by Germany.