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Rear sprocket of a Leclerc tank

Track of a Leclerc tank

U.S. M60 Patton tank. The rear drive sprocket and return rollers holding up the track are clearly seen.

Caterpillar tracks are large (modular) tracks used on tanks, construction equipment and certain other off-road vehicles. Unlike the Kégresse tracks which use a flexible belt, most caterpillar tracks are made of a number of rigid units that are joined to each other. The tracks help the vehicle to distribute its weight more evenly over a larger surface area than wheels can. Tracks do this because as the tracked vehicle moves forward the segments are laid out flat on the ground at the front and are picked up again at the back. The segments inbetween the front and the back end carry load too as they are supported by rollers. This keeps it from sinking in areas where wheeled vehicles of the same weight would sink. From equilibrium, the ground pressure of a car must be equivalent to the pressure of the air in the tires. For most cars this is approximately 30 psi (207 kPa), whereas the seventy-ton M1 Abrams tank has a ground pressure of just over 15 psi (103 kPa). Image File history File links Metadata Size of this preview: 800 × 600 pixelsFull resolution (2560 × 1920 pixel, file size: 1. ... Image File history File links Metadata Size of this preview: 800 × 600 pixelsFull resolution (2560 × 1920 pixel, file size: 1. ... This article does not cite its references or sources. ... The gunners position, looking down from the turret roof. ... Image File history File linksMetadata Download high-resolution version (2560x1920, 2096 KB) Copyright © 2006 David Monniaux File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): 1904 Caterpillar track Metadata This file contains additional information, probably added from the digital... Image File history File linksMetadata Download high-resolution version (2560x1920, 2096 KB) Copyright © 2006 David Monniaux File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): 1904 Caterpillar track Metadata This file contains additional information, probably added from the digital... The gunners position, looking down from the turret roof. ... Download high resolution version (1744x1035, 325 KB) Wikipedia does not have an article with this exact name. ... Download high resolution version (1744x1035, 325 KB) Wikipedia does not have an article with this exact name. ... M46, M47, M48 and M60 Patton were the U.S armys principal main battle tanks of the Cold War, with models in service from the late 1940s to the 1990s. ... This article does not cite its references or sources. ... An excavator. ... Nicholas II Delaunay-Belleville with Kégresse track A Kégresse track is an unusual kind of caterpillar track which uses a flexible belt rather than interlocking metal segments. ... For other uses, see Wheel (disambiguation). ... Ground pressure is the pressure exerted on the ground by the tires or tracks of a motorized vehicle, and is one measure of its potential mobility,[1] especially over soft ground. ... A pressure gauge reading in PSI (red scale) and kPa (black scale) The pound-force per square inch (symbol: lbf/in²) is a non-SI unit of pressure based on avoirdupois units. ... The pascal (symbol: Pa) is the SI derived unit of pressure or stress (also: Youngs modulus and tensile strength). ... The M1 Abrams main battle tank is the principal combat tank of the United States Army, the United States Marine Corps and the Australian Army, with three main versions being deployed starting in 1980: the M1, M1A1, and M1A2. ...

History

A crude caterpillar track was designed in 1770 by Richard Lovell Edgeworth. The British polymath Sir George Cayley patented a caterpillar track, which he called a "universal railway" (The Mechanics' Magazine, 28 January 1826). In 1837, a Russian inventor Dmitry Zagryazhsky designed a "carriage with mobile tracks" which he patented the same year, but due to a lack of funds he was unable to build a working prototype, and his patent was voided in 1839. Steam powered tractors using a form of caterpillar track were reported in use with the Western Alliance during the Crimean War in the 1850s. An "endless railway wheel" had been patented by the British engineer James Boydell 1846. ^[1] Richard Edgeworth, 1812 Richard Lovell Edgeworth (May 31, 1744-June 13, 1817) was a British writer and inventor. ... “Renaissance man” redirects here. ... Sir George Cayley, 6th Baronet (December 27, 1773 – December 15, 1857) was a prolific English engineer from Brompton-by-Sawdon, near Scarborough in Yorkshire. ... Queen Victoria, Queen of the United Kingdom (1837 - 1901) 1837 (MDCCCXXXVII) was a common year starting on Sunday (see link for calendar). ... // A traction engine (sometimes called a road locomotive) is a wheeled steam engine used to move heavy loads, plough ground or to provide power at a chosen location. ... Combatants Allies: Second French Empire British Empire Ottoman Empire Kingdom of Sardinia Russian Empire Bulgarian volunteers Casualties 90,000 French 35,000 Turkish 17,500 British 2,194 Sardinian killed, wounded and died of disease ~134,000 killed, wounded and died of disease The Crimean War (1853–1856) was fought... // Production of steel revolutionized by invention of the Bessemer process Benjamin Silliman fractionates petroleum by distillation for the first time First transatlantic telegraph cable laid First safety elevator installed by Elisha Otis Railroads begin to supplant canals in the United States as a primary means of transporting goods. ...

An effective caterpillar track was invented and implemented by Alvin Lombard for the Lombard steam log hauler. He was granted a patent in 1901. He built the first steam-powered log hauler at the Waterville Iron Works in Waterville, Maine, the same year. In all, 83 Lombard steam log haulers are known to have been built up to 1917, when production switched entirely to internal combustion engine powered machines, ending with a Fairbanks diesel powered unit in 1934. Undoubtedly, Alvin Lombard was the first commercial manufacturer of the tractor crawler. At least one of Lombard's steam-powered machines apparently remains in working order. A gasoline powered Lombard hauler is on display at the Maine State Museum in Augusta. A tractor crawler is a vehicle with tracks instead of wheels. ...

In addition, there may have been up to twice as many Phoenix Centipeed versions of the steam log hauler built under license from Lombard, with vertical instead of horizontal cylinders. In 1903, the founder of Holt Manufacturing, Benjamin Holt, paid Lombard $60,000 for the right to produce vehicles under his patent. There seems to have been an agreement made after Lombard moved to California, but some discrepancy exists as to how this matter was resolved when previous track patents were studied. Popularly, everyone claimed to have been inspired by the dog treadmill used on farms to power the butter churn, etc. to "invent" the crawler on their own, and the more recent the history, the earlier this supposed date of invention seems to get. Benjamin_Holt. ...

At about the same time a British agricultural company, Hornsby in Grantham, developed a caterpillar track which was patented in 1905. The design differed from modern tracks in that it flexed in only one direction with the effect that the links locked together to form a solid rail on which the road wheels ran. Hornsby's tracked vehicles were used as artillery tractors by the British Army from 1906. The patent was purchased by Holt. The Hornsby tractors featured the track-steer clutch arrangement, which is the basis of the modern crawler operation, and some say an observing British soldier quipped that it crawled like a caterpillar. What is known is that caterpillar became a generic term for this type of machine. The word was shrewdly trademarked and defended by Holt. The company bearing the name of Richard Hornsby (1790-1864), the agricultural engineer, was founded when Richard opened a blacksmithy in Grantham, Lincolnshire in 1815. ... Grantham is a medium sized market town in Lincolnshire, England with about 35,000 inhabitants (40,000 including Great Gonerby), situated on the River Witham. ... 1905 (MCMV) was a common year starting on Sunday (link will display the full calendar). ... The British Army is the land armed forces branch of the British Armed Forces. ...

James B. Hill, working in Bowling Green, Wood County, Ohio, patented what he termed "apron traction"[1] on September 24, 1907. His invention--the Buckeye Traction Ditcher--is held as an historical engineering landmark by the American Society of Mechanical Engineers[2]. James B. Hill was born November 29, 1856, near Fremont, Sandusky County, Ohio. ...

Following a merger and name change, The Holt Manufacturing Company became the Caterpillar Tractor Company in 1925. Caterpillar tracks have since revolutionized construction vehicles and land warfare. Track systems have been developed and improved during. The first tanks to be fielded were developed from Holt tractors which were already in use towing artillery over the difficult terrain of the Western Front of the First World War. Caterpillar Inc. ... Year 1925 (MCMXXV) was a common year starting on Thursday (link will display the full calendar) of the Gregorian calendar. ... War is a state of widespread conflict between states, organisations, or relatively large groups of people, which is characterised by the use of lethal violence between combatants or upon civilians. ... Ypres, 1917, in the vicinity of the Battle of Passchendaele. ...

Perhaps the oldest implementation of something like tracks is to be found in theories of prehistoric erection of large stone monuments, when megaliths may have been slid atop rounded wooden logs. The logs were grooved near their ends to be held in alignment and rotation by belts out past the edge of the megalith and lubricated by some means, probably organic. The logs are carried from the back of the procession to the front in an endless chain, like caterpillar track. Attempts by experimental archaeologists to reconstruct these methods have met with varying success. The system is a precursor to development of the axle, which keeps a rotating cylinder fixed relative to its cargo. Prehistory (Greek words &#960;&#961;&#959; = before and &#953;&#963;&#964;&#959;&#961;&#943;&#945; = history) is the period of human history prior to the advent of writing (which marks the beginning of recorded history). ... Megalithic tomb, Mane Braz, Brittany Bronze age wedge tomb in the Burren area of Ireland For the record label, see Megalith Records. ... Experimental archaeology employs a number of different methods, techniques, analyses, and approaches in order to generate and test hypotheses or an interpretation, based upon archaeological source material, like ancient structures or artifacts. ...

The Israeli Defence Forces have developed an improved suspension system, called Mazkum מזקו"ם , which enables greater mobility than regular tracks. The Mazkum is installed on the Israeli Merkava tank which helps improve mobility and speed, some of the Israeli patents were sold to Caterpillar Tractor Company. The Israel Defense Forces (IDF) (Hebrew: &#1510;&#1489;&#1488; &#1492;&#1492;&#1490;&#1504;&#1492; &#1500;&#1497;&#1513;&#1512;&#1488;&#1500; Tsva Ha-Haganah Le-Yisrael ([Army] Force [for] the Defense of Israel), often abbreviated &#1510;&#1492;&#1500; Tsahal, alternative English spelling Tzahal, is the name of Israels armed forces... // The Merkava (Hebrew:  , Chariot) is the main battle tank of the Israel Defense Forces. ... Caterpillar Inc. ...

Engineering

Soviet T-55 tank with "slack track" and rear drive sprocket.

Tracked vehicles may be put on semitrailers or railway cars for long-distance hauling

The tread of a construction machine's tracks.

Modern tracks are built from modular chain links which compose together a closed chain. These chain links are often broad and made of alloy steel. The links are jointed by a hinge. This allows the track to be flexible and wrap around the set of wheels to make the endless loop. Download high resolution version (1243x690, 149 KB) Wikipedia does not have an article with this exact name. ... Download high resolution version (1243x690, 149 KB) Wikipedia does not have an article with this exact name. ... The T-54 and T-55 tank series was the Soviet Unions front-line main battle tank from 1947 until 1962, and remains in service throughout the world to this day, especially by former client states of the Soviet Union. ... Image File history File links Metadata Size of this preview: 800 × 364 pixelsFull resolution (2148 × 976 pixel, file size: 876 KB, MIME type: image/jpeg) Défilé militaire du 14 juillet 2006 sur les Champs Élysées à Paris, France Military parade of July 14, 2006 on the Champs Élysées... Image File history File links Metadata Size of this preview: 800 × 364 pixelsFull resolution (2148 × 976 pixel, file size: 876 KB, MIME type: image/jpeg) Défilé militaire du 14 juillet 2006 sur les Champs Élysées à Paris, France Military parade of July 14, 2006 on the Champs Élysées... Image File history File linksMetadata Download high-resolution version (3008x2000, 6704 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Caterpillar track Tread Metadata This file contains additional information, probably added from the digital camera or scanner used... Image File history File linksMetadata Download high-resolution version (3008x2000, 6704 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Caterpillar track Tread Metadata This file contains additional information, probably added from the digital camera or scanner used... The tread of a tire or caterpillar track refers to the pattern visible on its circumference that makes contact with the road. ...

The vehicle's weight is transferred to the bottom length of track by a number of road wheels, or sets of wheels called bogies. Road wheels are typically mounted on some form of suspension to cushion the ride over rough ground. Suspension design is a major area of development; the very early designs were often unsprung at all, later- developed road wheel suspension offered only a few inches of travel using springs, whereas modern hydro-pneumatic systems allow several feet of travel and include shock absorbers. A bogie is a wheeled wagon or trolley. ... Gasfilled Shock absorber. ...

Tracks are moved by a toothed drive wheel, or drive sprocket, driven by the motor and engaging with holes in the track links or with pegs on them to drive the track. The drive wheel is typically mounted well above the contact area on the ground, allowing it to be fixed in position. Placing a suspension on the driving wheel is possible, but is mechanically more complicated. A non-powered wheel, an idler, is placed at the opposite end of the track, primarily to angle the front (or rear) of the track to allow it to climb over obstacles, and also to tension (take up the slack of) the track properly - loose track could be easily thrown (slipped) off the wheels. To prevent throwing, the track links usually have the vertical guide tongues engaging the grooves or gaps between the doubled road and idler/sprocket wheels. Some track arrangements, usually called live track, use return rollers to keep the top of the track running straight between the drive sprocket and idler. Others, called slack track, allow the track to droop and run along the tops of large road wheels. A drive wheel is a wheel in an automotive vehicle that receives power from the power train. ... This article does not cite its references or sources. ...

Tracked vehicles have better mobility than pneumatic tires over rough terrain. They smooth out the bumps and glide over small obstacles; riding in a fast tracked vehicle feels like riding in a boat over heavy swells. Tracks are tougher than tires since they cannot be punctured or torn. Tracks are much less likely to get stuck in soft ground, mud, or snow, since they distribute the weight of the vehicle over a larger contact area, decreasing its ground pressure. Bulldozers, which are most often tracked, use this attribute to rescue other vehicles (such as wheel loaders) which have become stuck in or sunk into the ground. Tracks as well give higher maneuverability, as a tracked vehicle can turn on the spot. Firestone tire A tire (U.S. spelling) or tyre (UK spelling) is a roughly toroidal piece of material placed on the circumference of a wheel, either for the purpose of cushioning or to protect the wheel from wear and tear. ... Ground pressure is the pressure exerted on the ground by the tires or tracks of a motorized vehicle, and is one measure of its potential mobility,[1] especially over soft ground. ... A Caterpillar D10N bulldozer at work A bulldozer is a very powerful crawler (caterpillar tracked tractor) equipped with a blade. ... A loader clearing a landslide. ...

The disadvantages of tracks are lower top speed and the damage that their all-steel versions cause to what passes beneath them: they can severely damage hard terrain like asphalt pavement, but deal less damage to lawns and farm fields than wheeled analogs ^{[citation needed]}. A compromise between the all-steel and all-rubber tracks for military vehicles to ensure their smoother, faster, quieter and non-damaging movement on paved surfaces at a slight reduction in cross-country traction has been found in attaching rubber pads to individual track links (first used on German semitracks, then on the US post-war tanks). Prolonged use places enormous strain on the drive transmission and the mechanics of the tracks, which must be overhauled or replaced regularly. It is common to see tracked vehicles such as bulldozers or tanks transported long distances by a wheeled carrier such as a semitrailer or train, though technological advances have made this practice less common among tracked military vehicles than it once was. Additionally, the loss of a single segment in a track immobilises the entire vehicle, which can be a disadvantage in situations where high reliability is important. “Gearbox” redirects here. ... semi-trailer truck with sleeper behind the cab. ... For other uses, see Train (disambiguation). ...

Recently many manufactures use rubber tracks instead of the steel ones, especially for agricultural use. Instead of a track made of linked steel plates, a reinforced rubber belt with chevron treads is used, which improves traction and reduces soil compaction. Having a rubber belt also means that the vehicle can relocate itself on public roads without damaging the road surface. Previous belt-like systems, such as used for half-tracks in World War II, were not so strong, and during military actions were easily damaged. Rubber tracks are Caterpillar tracks which are made of flexible rubber belt instead of rigid units that are joined to each other. ... M3 Half-track A half-track is a civilian or military vehicle with regular wheels on the front for steering, and caterpillar tracks on the back to propel the vehicle and carry most of the load. ...

See also

• Excavator
• Snowmobile
• Snowcat

A tracked excavator by Daewoo. ... A snowmobile tour at Yellowstone National Park, note the mixture of exhaust and snowdust in the air and the required guide. ... Pisten Bully 300 Polar snowcat moving snow A snowcat, is an enclosed-cab, truck sized, fully tracked vehicle designed to move on snow. ...

References

External links

• Scale model of Hornsby Chain Tractor at 2005 Harrogate Model Engineering Show