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.

Overhead hoists are defined in the American Society of Mechanical Engineers (ASME) B30 [1] standards as a machinery unit that is used for lifting or lowering a freely suspended (unguided) load.

A specific overhead hoist configuration is usually defined by the lifting medium, operation and suspension.

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.

[5] The construction hoist is made up of either one or two cars (cages) which travel vertically along stacked mast tower sections.

In the United States and abroad, General Contractors and various other industrial markets rent or lease hoists for a specific projects.

[7] Modern hoists are powered using electric motors, historically with direct current drives utilizing solid-state converters (thyristors); however, modern large hoists use alternating current drives that are variable-frequency controlled.