conveyor

Table of Contents

Introduction References & Edit History Related Topics

Images

For Students

conveyor belt summary

conveyor

mechanical device

Written and fact-checked by The Editors of Encyclopaedia Britannica

Article History

Related Topics:: pneumatic conveyor; air-float conveyor; tow conveyor; slat conveyor; screw conveyor

See all related content

conveyor, any of various devices that provide mechanized movement of material, as in a factory; they are used principally in industrial applications but also on large farms, in warehousing and freight-handling, and in movement of raw materials. Conveyors may be only a few inches in length, or they may be integrated systems several miles long.

Gravity-roller conveyors consist of a series of parallel rollers fastened to a metal frame supported at intervals. The frame can be inclined slightly for gravity flow, but objects and packages may also be rolled along manually. Gravity-wheel conveyors are similar but consist of skate wheels instead of rollers and are usually used for lighter loads. Live-roller conveyors are gravity-roller conveyors that are power driven by means of a belt snubbed against the underpart of the rolls or by a chain driving sprockets attached to the rolls.

Belt conveyors of fabric, rubber, plastic, leather, or metal are driven by a power-operated roll mounted underneath or at one end of the conveyor. The belt forms a continuous loop and is supported either on rollers, for heavy loads, or on a metal slider pan when the load is light enough to prevent frictional drag on the belt. Electric motors operating through constant- or variable-speed reduction gears usually provide the power.

More From Britannica

coal mining: Conveyors

Floor conveyors use chain, cable, or other linkage mounted in or close to the floor in an endless track. They are usually designed to drag a train of four-wheeled carts around in a loop to carry large products or materials for assembly on the conveying system. Power is furnished to the chain by guiding rollers.

Slat conveyors consist of endless chains, driven by electric motors operating through reduction gears and sprockets, with attached spaced slats to carry objects that would damage a belt because of sharp edges or heavy weights.

Flight conveyors have scrapers, or flights, mounted at intervals perpendicular to the direction of travel on endless power-driven chains operating within a trough. Bulk materials such as sawdust, sand, gravel, coal, and chemicals may be pushed along the trough.

Apron conveyors consist of endless chains with attached overlapping and interlocking plates to provide a continuous-carrying surface that forms a leakproof bed suitable for bulk materials without containers.

Vibrating conveyors consist of troughs or tubes flexibly supported and vibrated by mechanical or electrical means to convey objects or bulk materials; vibration takes place in an inclined, elliptical pattern to cause directional as well as upward movement of the material.

In trolley conveyors an overhead rail carries a series of load-bearing containers (trolleys) that are coupled together on an endless propelling medium such as cable, chain, or other linkage. The trolleys may be hooks, magnets, or various carriers designed for the particular load to be handled. The rails are usually supported by the framework of the plant building.

En masse conveyors use skeletal or solid flights mounted at intervals on a cable or chain power driven within a closely fitting casing. Designed for bulk materials that must be enclosed to prevent leakage or explosion, the conveyors can operate in horizontal, vertical, or inclined positions.

Bucket conveyors consist of endless chains or belts to which are attached buckets to convey bulk material in horizontal, inclined, and vertical paths. The buckets remain in carrying position until they are tipped to discharge the material. Various discharging mechanisms are available.

Screw conveyors consist of revolving shafts with continuous or broken spiral flighting that operates inside a casing. Powered by an electric motor and suitable gearing, the screw conveyor usually operates in one direction only to move fine bulk material such as meal, seed, and coal.

Pneumatic conveyors use air pressure or vacuum to move bulk material in tubes or ducts.

Tow conveyors may be overhead trolley cars or floor conveyors adapted for handling dollies, trucks, and cars, which are locked into the towing chain to be moved from any point in the system to any other point.

Various conveyors may be mounted on mobile supports, particularly gravity roller and wheel conveyors and short belt conveyors, for adaptation to portable use.

During the 1960s, air-float conveyors were introduced consisting of a platform, or pallet, equipped with air jets underneath to provide levitation. Thus supported, the platform can be easily moved in any direction over a flat surface.

This article was most recently revised and updated by Amy Tikkanen.

automation

Table of Contents

References & Edit History Related Topics

Images & Videos

types of mechanical joints used in robot manipulators

See how mechatronics help engineers create high-tech products such as industrial robots

For Students

automation summary

automation

Written by Mikell P. Groover

Fact-checked by The Editors of Encyclopaedia Britannica

Article History

Key People:: Jacques de Vaucanson

Related Topics:: industrial robot; programmable automation; flexible automation; machine programming; feedback control

See all related content

News •

Teenagers' Summer Jobs Under Threat • May 23, 2025, 11:02 PM ET (Newsweek)

automation, application of machines to tasks once performed by human beings or, increasingly, to tasks that would otherwise be impossible. Although the term mechanization is often used to refer to the simple replacement of human labour by machines, automation generally implies the integration of machines into a self-governing system. Automation has revolutionized those areas in which it has been introduced, and there is scarcely an aspect of modern life that has been unaffected by it.

The term automation was coined in the automobile industry about 1946 to describe the increased use of automatic devices and controls in mechanized production lines. The origin of the word is attributed to D.S. Harder, an engineering manager at the Ford Motor Company at the time. The term is used widely in a manufacturing context, but it is also applied outside manufacturing in connection with a variety of systems in which there is a significant substitution of mechanical, electrical, or computerized action for human effort and intelligence.

In general usage, automation can be defined as a technology concerned with performing a process by means of programmed commands combined with automatic feedback control to ensure proper execution of the instructions. The resulting system is capable of operating without human intervention. The development of this technology has become increasingly dependent on the use of computers and computer-related technologies. Consequently, automated systems have become increasingly sophisticated and complex. Advanced systems represent a level of capability and performance that surpass in many ways the abilities of humans to accomplish the same activities.

Automation technology has matured to a point where a number of other technologies have developed from it and have achieved a recognition and status of their own. Robotics is one of these technologies; it is a specialized branch of automation in which the automated machine possesses certain anthropomorphic, or humanlike, characteristics. The most typical humanlike characteristic of a modern industrial robot is its powered mechanical arm. The robot’s arm can be programmed to move through a sequence of motions to perform useful tasks, such as loading and unloading parts at a production machine or making a sequence of spot-welds on the sheet-metal parts of an automobile body during assembly. As these examples suggest, industrial robots are typically used to replace human workers in factory operations.

This article covers the fundamentals of automation, including its historical development, principles and theory of operation, applications in manufacturing and in some of the services and industries important in daily life, and impact on the individual as well as society in general. The article also reviews the development and technology of robotics as a significant topic within automation. For related topics, see computer science and information processing.

White semi truck on the Highway. Truck, lorry, motor vehicle to carry freight or goods or perform special services. Cab, carrier, semis trucks.

Britannica Quiz

Machinery and Manufacturing

Historical development of automation

The technology of automation has evolved from the related field of mechanization, which had its beginnings in the Industrial Revolution. Mechanization refers to the replacement of human (or animal) power with mechanical power of some form. The driving force behind mechanization has been humankind’s propensity to create tools and mechanical devices. Some of the important historical developments in mechanization and automation leading to modern automated systems are described here.

Early developments

The first tools made of stone represented prehistoric man’s attempts to direct his own physical strength under the control of human intelligence. Thousands of years were undoubtedly required for the development of simple mechanical devices and machines such as the wheel, the lever, and the pulley, by which the power of human muscle could be magnified. The next extension was the development of powered machines that did not require human strength to operate. Examples of these machines include waterwheels, windmills, and simple steam-driven devices. More than 2,000 years ago the Chinese developed trip-hammers powered by flowing water and waterwheels. The early Greeks experimented with simple reaction motors powered by steam. The mechanical clock, representing a rather complex assembly with its own built-in power source (a weight), was developed about 1335 in Europe. Windmills, with mechanisms for automatically turning the sails, were developed during the Middle Ages in Europe and the Middle East. The steam engine represented a major advance in the development of powered machines and marked the beginning of the Industrial Revolution. During the two centuries since the introduction of the Watt steam engine, powered engines and machines have been devised that obtain their energy from steam, electricity, and chemical, mechanical, and nuclear sources.

Each new development in the history of powered machines has brought with it an increased requirement for control devices to harness the power of the machine. The earliest steam engines required a person to open and close the valves, first to admit steam into the piston chamber and then to exhaust it. Later a slide valve mechanism was devised to automatically accomplish these functions. The only need of the human operator was then to regulate the amount of steam that controlled the engine’s speed and power. This requirement for human attention in the operation of the steam engine was eliminated by the flying-ball governor. Invented by James Watt in England, this device consisted of a weighted ball on a hinged arm, mechanically coupled to the output shaft of the engine. As the rotational speed of the shaft increased, centrifugal force caused the weighted ball to be moved outward. This motion controlled a valve that reduced the steam being fed to the engine, thus slowing the engine. The flying-ball governor remains an elegant early example of a negative feedback control system, in which the increasing output of the system is used to decrease the activity of the system.

Negative feedback is widely used as a means of automatic control to achieve a constant operating level for a system. A common example of a feedback control system is the thermostat used in modern buildings to control room temperature. In this device, a decrease in room temperature causes an electrical switch to close, thus turning on the heating unit. As room temperature rises, the switch opens and the heat supply is turned off. The thermostat can be set to turn on the heating unit at any particular set point.

Another important development in the history of automation was the Jacquard loom (see photograph ), which demonstrated the concept of a programmable machine. About 1801 the French inventor Joseph-Marie Jacquard devised an automatic loom capable of producing complex patterns in textiles by controlling the motions of many shuttles of different coloured threads. The selection of the different patterns was determined by a program contained in steel cards in which holes were punched. These cards were the ancestors of the paper cards and tapes that control modern automatic machines. The concept of programming a machine was further developed later in the 19th century when Charles Babbage, an English mathematician, proposed a complex, mechanical “analytical engine” that could perform arithmetic and data processing. Although Babbage was never able to complete it, this device was the precursor of the modern digital computer. See computers.