Hoists are machines designed for lifting heavy objects on a line. They typically accomplish this using a fixed motor to wind a line fastened to an object. Industrial hoists fall into three categories: electric, pneumatic, and hydraulic; they can also be characterized by the type of line they use, such as chain or rope. Industrial hoists operate in a wide range of applications and sizes. These can be anything from lifting small paving stones to heavy shipping containers.
Originally, hoists were powered by manual labor or steam, and used block and tackle systems. Contemporary industrial hoists usually employ electric rope, wire rope, or electric chain. Relying on motors for rotational force, hoists overcome weight, or linear gravitational force, to pick up objects. The pulling motion draws the object upward and downward, while line coils around a rotating cylinder. This motion is assisted with small or large cranes to carry the object elsewhere, or by mounting units to crossbeams and allowing them to move sideways.
Industrial hoists are used in many different contexts. Electric types are the most popular, while pneumatic and hydraulic hoists are often designed to serve more specific applications. Loads with capacities from tens to thousands of pounds or kilograms can be moved by electric chain hoists, which often feature variable speeds of operation. Typically operated by remote switch, some are designed for quiet operation. This can assist in settings like theaters for raising and lowering set pieces.
Usually, industrial hoists stand in contrast to winches, which might be vehicle-mounted equipment that performs a similar function. Industrial hoists can be mounted to anything from stands for lifting car engines, or even cars themselves, to small excavators used in landscaping, to booms, cranes, and aerial lifts. These may be used in manufacturing and industry, as well as emergency operations. Some may be mounted on swing arms, while others hang from colossal straddle hoists that girder ships. Other industrial hoists are attached to Goliath cranes, harbor or gantry cranes, to assist in large-scale load lifting.
Numerous industrial hoist technologies assist in material handling for jobs ranging from manual labor to personal or industrial transport and large-scale construction projects. Despite modern advances, some continue to rely on simply turning a wheel by hand to provide lift, as with drywall ceiling hoists. Additional varieties employ lift slings, which are reinforced bands that assist in lifting objects without damaging them, such as small airplanes, boats, and people in rescue operations.