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 A rope is a group of yarns, plies, fibres, or strands that are twisted or braided together into a larger and stronger form. Ropes have tensile strength and so can be used for dragging and lifting. Rope is thicker and stronger than similarl ...

as its lifting medium. The most familiar form is an

elevator An elevator or lift is a cable-assisted, hydraulic cylinder-assisted, or roller-track assisted machine that vertically transports people or freight between floors, levels, or decks of a building, vessel, or other structure. They ...

, 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 The Occupational Safety and Health Administration'' (OSHA ) is a large regulatory agency of the United States Department of Labor that originally had federal visitorial powers to inspect and examine workplaces. Congress established the agen ...

. HMI is a product counsel of the Material Handling Industry of America consisting of hoist manufacturers promoting safe use of their products.

Types

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 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. A hoist can be a serial production unit or a custom unit. Serial production hoists are typically more cost-effective and designed for a ten-year life in a light to heavy hoist duty service classification. Custom hoists are typically more expensive and are designed for a heavy to severe hoist duty service classification. Serial production hoists were once regarded as being designed for light to moderate hoist duty service classifications, but since the 60's this has changed. Over the years the custom hoist market has decreased in size with the advent of the more durable serial production hoists. A machine shop or fabricating shop will typically use a serial production hoist, while a steel mill or NASA may typically use a custom hoist to meet durability and performance requirements. Overhead hoists require proper installation, operation, inspection, and maintenance. When selecting an overhead hoist, operators must consider the average operating time per day, load spectrum, starts per hour, operating period and equipment life. These parameters determine the Hoist Duty Service Classification, which helps hoist installers and users better understand the hoist's useful life and duty service application. The American Society of Mechanical Engineers also publishes a number or standards related to overhead hoists, including the “ASME B30.16 Standard for Overhead Hoists (Underhung)", which provides additional guidance for the proper design, installation, operation and maintenance of hoists.

Construction hoist

Also known as a Man-Lift, Buckhoist, temporary elevator, builder hoist, passenger hoist or construction elevator, a construction hoist is commonly used on large scale construction projects, such as high-rise buildings or major hospitals. There are many other uses for the construction elevator. Many other industries use the buckhoist for full-time operations, the purpose being to carry personnel, materials, and equipment quickly between the ground and higher floors, or between floors in the middle of a structure. There are three types: Utility (to move material), personnel (to move personnel), and dual-rated, which can do both. The construction hoist is made up of either one or two cars (cages) which travel vertically along stacked mast tower sections. The mast sections are attached to the structure or building every for added stability. For precisely controlled travel along the mast sections, modern construction hoists use a motorized rack-and-pinion system that climbs the mast sections at various speeds. While hoists have been predominantly produced in Europe and the United States, China is emerging as a manufacturer of hoists to be used in Asia. In the United States and abroad, General Contractors and various other industrial markets rent or lease hoists for a specific projects. Rental or leasing companies provide erection, dismantling, and repair services to their hoists to provide General Contractors with turnkey services. Also, the rental and leasing companies can provide parts and service for the elevators that are under contract.

Mine hoist

A mining hoist (also known simply as a hoist or winder) is used in

underground mining Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the economic v ...

to raise and lower conveyances within the

mine shaft Shaft mining or shaft sinking is the action of excavating a mine shaft from the top down, where there is initially no access to the bottom. Shallow shafts, typically sunk for civil engineering projects, differ greatly in execution method from ...

. It is similar to an elevator, used for raising humans, equipment, and assorted loads. Human, animal and water power were used to power the mine hoists documented in Agricola's De Re Metallica, published in 1556.

Stationary steam engine Stationary steam engines are fixed steam engines used for pumping or driving mills and factories, and for power generation. They are distinct from Steam locomotive, locomotive engines used on Rail transport, railways, traction engines for heavy s ...

s were commonly used to power mine hoists through the 19th century and into the 20th, as at the Quincy Mine, where a 4-cylinder cross-compound corliss engine was used.Quincy No. 2 Mine Hoist (1920)
National Historic Engineering Landmark brochure, The American Society of Mechanical Engineers, 1984. Modern hoists are powered using electric motors, historically with

direct current Direct current (DC) is one-directional flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor such as a wire, but can also flow through semiconductors, insulators, or ev ...

drives utilizing solid-state converters ( thyristors); however, modern large hoists use

alternating current Alternating current (AC) is an electric current which periodically reverses direction and changes its magnitude continuously with time in contrast to direct current (DC) which flows only in one direction. Alternating current is the form in whic ...

drives that are variable-frequency controlled. There are three principal types of hoists used in mining applications, Drum Hoists, Friction (or Kope) hoists and Blair multi-rope hoists. Hoist can be defined as anything that is used to lift any heavy materials.

Chain hoist

Differential pulley

Gallery

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References

External links

OSHA Regs for overhead cranes
{{Authority control Actuators Lifting equipment