![Challenger 1 suspension](https://upload.wikimedia.org/wikipedia/commons/7/7e/Challenger_1_suspension.jpg)
Continuous track is a system of
vehicle propulsion
Propulsion is the generation of force by any combination of pushing or pulling to modify the translational motion of an object, which is typically a rigid body (or an articulated rigid body) but may also concern a fluid. The term is derived fro ...
used in tracked vehicles, running on a continuous band of treads or track plates driven by two or more wheels. The large surface area of the tracks distributes the weight of the vehicle better than steel or rubber tires on an equivalent vehicle, enabling continuous tracked vehicles to traverse soft ground with less likelihood of becoming stuck due to sinking.
Modern continuous tracks can be made with soft
belts of
synthetic rubber, reinforced with steel wires, in the case of lighter
agricultural machinery
Agricultural machinery relates to the mechanical structures and devices used in farming or other agriculture. There are many types of such equipment, from hand tools and power tools to tractors and the countless kinds of farm implements that ...
. The more common classical type is a solid chain track made of steel plates (with or without rubber pads), also called caterpillar tread or tank tread,
which is preferred for robust and heavy
construction vehicles and
military vehicles.
The prominent treads of the metal plates are both hard-wearing and damage resistant, especially in comparison to rubber tyres. The aggressive treads of the tracks provide good traction in soft surfaces but can damage paved surfaces, so some metal tracks can have rubber pads installed for use on paved surfaces. Other than soft rubber belts, most chain tracks apply a stiff mechanism to distribute the load equally over the entire space between the
wheels for minimal deformation, so that even the heaviest vehicles can move easily, just like a train on its straight tracks.
The stiff mechanism was first given a physical form by
Hornsby & Sons in 1904 and then made popular by
Caterpillar Tractor Company, with
tank
A tank is an armoured fighting vehicle intended as a primary offensive weapon in front-line ground combat. Tank designs are a balance of heavy firepower, strong armour, and good battlefield mobility provided by tracks and a powerful engi ...
s emerging during
World War I
World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
. Today, they are commonly used on a variety of vehicles, including
snowmobile
A snowmobile, also known as a Ski-Doo, snowmachine, sled, motor sled, motor sledge, skimobile, or snow scooter, is a motorized vehicle designed for winter travel and recreation on snow. It is designed to be operated on snow and ice and does not ...
s,
tractor
A tractor is an engineering vehicle specifically designed to deliver a high tractive effort (or torque) at slow speeds, for the purposes of hauling a trailer or machinery such as that used in agriculture, mining or construction. Most commo ...
s,
bulldozers,
excavators and
tank
A tank is an armoured fighting vehicle intended as a primary offensive weapon in front-line ground combat. Tank designs are a balance of heavy firepower, strong armour, and good battlefield mobility provided by tracks and a powerful engi ...
s.
The idea of continuous tracks can be traced back as far as the 1830s, however.
History
Polish mathematician and inventor
Józef Maria Hoene-Wroński
Józef Maria Hoene-Wroński (; french: Josef Hoëné-Wronski ; 23 August 1776 – 9 August 1853) was a Polish messianist philosopher, mathematician, physicist, inventor, lawyer, occultist and economist. He was born as Hoëné to a municipal archit ...
designed caterpillar vehicles in the 1830s to compete with the railways.
The British
polymath
A polymath ( el, πολυμαθής, , "having learned much"; la, homo universalis, "universal human") is an individual whose knowledge spans a substantial number of subjects, known to draw on complex bodies of knowledge to solve specific pro ...
Sir
George Cayley patented a continuous track, which he called a "universal railway" in 1825. In 1837,
Russia
Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eig ...
n army captain Dmitry Andreevich Zagryazhsky (1807 – after 1860) designed a ''"carriage with mobile tracks"'' which he patented the same year, but due to a lack of funds and interest from manufacturers he was unable to build a working prototype, and his patent was voided in 1839.
Heathcote's Steam Plough
![HeathcotesSteamPlough](https://upload.wikimedia.org/wikipedia/commons/1/1a/HeathcotesSteamPlough.jpg)
Patented in 1832 by
John Heathcoat (also Heathcote) M.P. for Tiverton, the Heathcote steam plough was demonstrated in 1837 and press coverage fortunately provided a wood cut of this unusual tracked vehicle. The continuous tracks were made of sections of wood bolted to continuous iron bands which were driven by the 'drums' at each end. A strong chassis provided the bearings for the drums, carried the steam engine, fuel and winch. The chassis was supported on "numerous small wheels or rollers" which ran upon the lower iron bands, which "thus form a perfectly portable and smooth road for the platform". The drums were in diameter, apart. The tracks were each wide with a gap in-between giving an overall width of . The twin-cylinder steam engine could be used either to drive the plough winch or to drive the vehicle along, at a speed of up to . Although the machine weighed 30 tons complete with 6 tons of fuel, its ground pressure was only , considerably less than a man. The successful demonstration was carried out on
Red Moss at
Bolton-le-Moors on 20 April 1837. The steam plough was lost when it sank into a swamp by accident and was then abandoned as the inventor did not have the funds to continue development.
Dreadnaught wheel by Boydell (1846)
Although not a continuous track in the form encountered today, a
dreadnaught wheel or "endless railway wheel" was patented by the British Engineer
James Boydell in 1846. In Boydell's design, a series of flat feet are attached to the periphery of the wheel, spreading the weight. A number of horse-drawn wagons, carts and gun carriages were successfully deployed in the
Crimean War
The Crimean War, , was fought from October 1853 to February 1856 between Russia and an ultimately victorious alliance of the Ottoman Empire, France, the United Kingdom and Piedmont-Sardinia.
Geopolitical causes of the war included the ...
, waged between October 1853 and February 1856, the Royal Arsenal at Woolwich manufacturing dreadnaught wheels. A letter of recommendation was signed by Sir William Codrington, the General commanding the troops at Sebastopol.
Boydell patented improvements to his wheel in 1854 (No. 431) – the year his dreadnaught wheel was first applied to a steam engine – and 1858 (No. 356), the latter an impracticable palliative measure involving the lifting one or other of the driving wheels to facilitate turning.
A number of manufacturers including Richard Bach,
Richard Garrett & Sons
Richard Garrett & Sons was a manufacturer of agricultural machinery, steam engines and trolleybuses. Their factory was Leiston Works, in Leiston, Suffolk, England. The company was founded by Richard Garrett in 1778.
The company was active ...
,
Charles Burrell & Sons
Charles Burrell & Sons were builders of steam traction engines, agricultural machinery, steam lorries and steam tram engines. The company were based in Thetford, Norfolk and operated from the St Nicholas works on Minstergate and St Nicholas St ...
and
Clayton & Shuttleworth
Clayton & Shuttleworth was an engineering company located at Stamp End Works, Lincoln, Lincolnshire, England. The company was established in 1842 when Nathaniel Clayton (1811–1890) formed a partnership with his brother-in-law, Joseph Shuttlewo ...
applied the Boydell patent under licence. The British military were interested in Boydell's invention from an early date. One of the objectives was to transport
Mallet's Mortar
Mallet's Mortar was a British shell-firing mortar built for the Crimean War, but never used in combat.
The mortar was designed by Robert Mallet and was constructed in separate sections so that it could be transported.
Robert Mallet first made h ...
, a giant 36 inch weapon which was under development, but, by the end of the Crimean War, the
mortar was not ready for service. A detailed report of the tests on steam traction, carried out by a select Committee of the Board of Ordnance, was published in June 1856, by which date the Crimean War was over, consequently the mortar and its transportation became irrelevant. In those tests, a Garrett engine was put through its paces on Plumstead Common. The Garrett engine featured in the Lord Mayor's show in London, and in the following month that engine was shipped to Australia. A
steam tractor
:''This article refers to the steam-powered agricultural tractor; for other types of steam tractor, see: Traction engine''
A steam tractor is a vehicle powered by a steam engine which is used for pulling.
In North America, the term ''steam ...
employing dreadnaught wheels was built at Bach's Birmingham works, and was used between 1856 and 1858 for ploughing in Thetford; and the first generation of Burrell/Boydell engines was built at the St. Nicholas works in 1856, again, after the close of the Crimean War.
Between late 1856 and 1862 Burrell manufactured not less than a score of engines fitted with dreadnaught wheels. In April 1858, the journal ''The Engineer'' gave a brief description of a Clayton & Shuttleworth engine fitted with dreadnaught wheels, which was supplied not to the Western Allies, but to the Russian government for heavy artillery haulage in
Crimea
Crimea, crh, Къырым, Qırım, grc, Κιμμερία / Ταυρική, translit=Kimmería / Taurikḗ ( ) is a peninsula in Ukraine, on the northern coast of the Black Sea, that has been occupied by Russia since 2014. It has a pop ...
in the post-war period. Steam tractors fitted with dreadnaught wheels had a number of shortcomings and, notwithstanding the creations of the late 1850s, were never used extensively.
Endless Railway by John Fowler (1858)
In August 1858, more than two years after the end of the
Crimean War
The Crimean War, , was fought from October 1853 to February 1856 between Russia and an ultimately victorious alliance of the Ottoman Empire, France, the United Kingdom and Piedmont-Sardinia.
Geopolitical causes of the war included the ...
,
John Fowler filed British Patent No. 1948 on another form of "Endless Railway". In his illustration of the invention, Fowler used a pair of wheels of equal diameter on each side of his vehicle, around which pair of toothed wheels ran a 'track' of eight jointed segments, with a smaller jockey/drive wheel between each pair of wheels, to support the 'track'. Comprising only eight sections, the 'track' sections are essentially 'longitudinal', as in Boydell's initial design. Fowler's arrangement is a precursor to the multi-section caterpillar track in which a relatively large number of short 'transverse' treads are used, as proposed by Sir George Caley in 1825, rather than a small number of relatively long 'longitudinal' treads.
Further to Fowler's patent of 1858, in 1877, a Russian,
Fyodor Blinov, created a tracked vehicle called "
wagon
A wagon or waggon is a heavy four-wheeled vehicle pulled by draught animals or on occasion by humans, used for transporting goods, commodities, agricultural materials, supplies and sometimes people.
Wagons are immediately distinguished from ...
moved on endless rails".
It lacked self-propulsion and was pulled by horses. Blinov received a patent for his "wagon" in 1878. From 1881 to 1888 he developed a steam-powered caterpillar-tractor. This self-propelled crawler was successfully tested and featured at a farmers' exhibition in 1896.
[
]
20th century efforts
Steam traction engines were used at the end of the 19th century in the Boer War
The Second Boer War ( af, Tweede Vryheidsoorlog, , 11 October 189931 May 1902), also known as the Boer War, the Anglo–Boer War, or the South African War, was a conflict fought between the British Empire and the two Boer Republics (the Sou ...
s. But neither dreadnaught wheels nor continuous tracks were used, rather "roll-out" wooden plank roads were thrown under the wheels as required.
In short, whilst the development of the continuous track engaged the attention of a number of inventors in the 18th and 19th centuries, the general use and exploitation of the continuous track belonged to the 20th century, mainly in the United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...
and England
England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...
.
A little-known American inventor, Henry Thomas Stith (1839–1916), had developed a continuous track prototype which was, in multiple forms, patented in 1873, 1880, and 1900. The last was for the application of the track to a prototype off-road bicycle built for his son. The 1900 prototype is retained by his surviving family.
Frank Beamond (1870–1941), a less-commonly known but significant British inventor, designed and built caterpillar tracks, and was granted patents for them in a number of countries, in 1900 and 1907.
First commercial success (1901)
A first effective continuous track was not only invented but really implemented by Alvin Orlando Lombard for the Lombard Steam Log Hauler
The term Lombard refers to people or things related to Lombardy, a region in northern Italy.
History and culture
* Lombards, a Germanic tribe
* Lombards of Sicily, a linguistic minority living in Sicily, southern Italy
* Lombard League, a me ...
. He was granted a patent in 1901 and 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. Alvin Lombard may also have been 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. 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
Benjamin Leroy Holt (January 1, 1849 – December 5, 1920) was an American businessman and inventor who patented and manufactured the first practical crawler-type tread tractor. The continuous-type track is used for heavy agricultural and engi ...
, paid Lombard $60,000 for the right to produce vehicles under his patent.
The stiff chain by Hornsby & Sons (1904)
At about the same time a British agricultural company, Hornsby in Grantham
Grantham () is a market and industrial town in the South Kesteven district of Lincolnshire, England, situated on the banks of the River Witham and bounded to the west by the A1 road. It lies some 23 miles (37 km) south of the Lincoln and ...
, developed a continuous 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 given trials as artillery tractor
An artillery tractor, also referred to as a gun tractor, is a specialized heavy-duty form of tractor unit used to tow artillery pieces of varying weights and calibres. It may be wheeled, tracked, or half-tracked.
Traction
There are two ...
s by the British Army
The British Army is the principal land warfare force of the United Kingdom, a part of the British Armed Forces along with the Royal Navy and the Royal Air Force. , the British Army comprises 79,380 regular full-time personnel, 4,090 Gurk ...
on several occasions between 1905 and 1910, but not adopted.
The Hornsby tractors pioneered a track-steer clutch arrangement, which is the basis of the modern crawler operation. The patent was purchased by Holt.
File:Roberts_tracked_steam_tractor.jpg, upright=1.25, First Chain Tracked Tractor
A tractor is an engineering vehicle specifically designed to deliver a high tractive effort (or torque) at slow speeds, for the purposes of hauling a trailer or machinery such as that used in agriculture, mining or construction. Most commo ...
(1905, Richard Hornsby & Sons)
File:Hornsby.jpg, upright=1.3, Hornsby Chain Tracked Tractor
(1907 enhanced Version)
Holt and the Caterpillar
The name ''Caterpillar'' came from a soldier during the tests on the Hornsby crawler, "trials began at Aldershot
Aldershot () is a town in Hampshire, England. It lies on heathland in the extreme northeast corner of the county, southwest of London. The area is administered by Rushmoor Borough Council. The town has a population of 37,131, while the Alder ...
in July 1907. The soldiers immediately christened the 70bhp No.2 machine the 'caterpillar'."
Holt adopted that name for his "crawler" tractors. Holt began moving from steam to gasoline-powered designs, and in 1908 brought out the "Holt Model 40 Caterpillar". Holt incorporated the Holt Caterpillar Company, in early 1910, later that year trademarked the name "Caterpillar" for his continuous tracks.[
]
Caterpillar Tractor Company began in 1925 from a merger of the Holt Manufacturing Company
The Holt Manufacturing Company began with the 1883 founding of Stockton Wheel Service in Stockton, California, United States. Benjamin Holt, later credited with patenting the first workable crawler ("caterpillar") tractor design, incorporated ...
and the C. L. Best Tractor Company, an early successful manufacturer of crawler tractors.
With the Caterpillar D10 in 1977, Caterpillar resurrected a design by Holt and Best, the high-sprocket-drive, since known as the " High Drive", which had the advantage of keeping the main drive shaft away from ground shocks and dirt,
and is still used in their larger dozers.
File:Cat45-mojave.jpg, Two Holt 45 gasoline crawler tractors teamed up to pull a long wagon train in the Mojave Desert
The Mojave Desert ( ; mov, Hayikwiir Mat'aar; es, Desierto de Mojave) is a desert in the rain shadow of the Sierra Nevada mountains in the Southwestern United States. It is named for the indigenous Mojave people. It is located primarily ...
during construction of the Los Angeles Aqueduct in 1909
File:Rear-D9-0002.jpg, Caterpillar D9
The Caterpillar D9 is a large track-type tractor designed and manufactured by Caterpillar Inc. It is usually sold as a bulldozer equipped with a detachable large blade and a rear ripper attachment.
The D9, with 354 kW (474 hp) of gross p ...
High Drive. The elevated drive sprocket offers advantages to large earth-moving machines
Snow vehicles
In a memorandum of 1908, Antarctic explorer Robert Falcon Scott
Captain Robert Falcon Scott, , (6 June 1868 – c. 29 March 1912) was a British Royal Navy officer and explorer who led two expeditions to the Antarctic regions: the ''Discovery'' expedition of 1901–1904 and the ill-fated ''Terra Nov ...
presented his view that man-hauling to the South Pole was impossible and that motor traction was needed. Snow vehicles did not yet exist however, and so his engineer Reginald Skelton
Sir Reginald William Skelton (3 June 1872 – 5 September 1956) was a British vice-admiral and engineer who served as chief engineer and official photographer of the 1901-1904 Discovery Expedition to Antarctica.
Early life
Skelton was born at Lon ...
developed the idea of a caterpillar track for snow surfaces. These tracked motors were built by the Wolseley Tool and Motor Car Company in Birmingham, tested in Switzerland and Norway, and can be seen in action in Herbert Ponting's 1911 documentary film of Scott's Antarctic Terra Nova Expedition
The ''Terra Nova'' Expedition, officially the British Antarctic Expedition, was an expedition to Antarctica which took place between 1910 and 1913. Led by Captain Robert Falcon Scott, the expedition had various scientific and geographical objec ...
. Scott died during the expedition in 1912, but expedition member and biographer Apsley Cherry-Garrard
Apsley George Benet Cherry-Garrard (2 January 1886 – 18 May 1959) was an English explorer of Antarctica. He was a member of the ''Terra Nova'' expedition and is acclaimed for his 1922 account of this expedition, '' The Worst Journey in t ...
credited Scott's "motors" with the inspiration for the British World War I tanks, writing: "Scott never knew their true possibilities; for they were the direct ancestors of the 'tanks' in France."
In time, however, a wide array of vehicles were developed for snow and ice, including ski slope grooming machines, snowmobile
A snowmobile, also known as a Ski-Doo, snowmachine, sled, motor sled, motor sledge, skimobile, or snow scooter, is a motorized vehicle designed for winter travel and recreation on snow. It is designed to be operated on snow and ice and does not ...
s, and countless commercial and military vehicles.
Military application
Continuous track was first applied to a military vehicle on the British prototype tank Little Willie
Little Willie was a prototype in the development of the British Mark I tank. Constructed in the autumn of 1915 at the behest of the Landship Committee, it was the first completed tank prototype in history. ''Little Willie'' is the oldest surv ...
. British Army officers, Colonel Ernest Swinton and Colonel Maurice Hankey, became convinced that it was possible to develop a fighting vehicle that could provide protection from machine gun fire.
During World War I
World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
, Holt tractors were used by the British and Austro-Hungarian armies to tow heavy artillery and stimulated the development of tank
A tank is an armoured fighting vehicle intended as a primary offensive weapon in front-line ground combat. Tank designs are a balance of heavy firepower, strong armour, and good battlefield mobility provided by tracks and a powerful engi ...
s in several countries. The first tanks to go into action, the Mark I, built by Great Britain, were designed from scratch and were inspired by, but not directly based on, the Holt. The slightly later French and German tanks were built on modified Holt running gear.
Patent history
A long line of patents disputes who was the "originator" of continuous tracks. There were a number of designs that attempted to achieve a track laying mechanism, although these designs do not generally resemble modern tracked vehicles.
In 1877 Russian inventor Fyodor Abramovich Blinov created a horse-drawn tracked vehicle called "wagon
A wagon or waggon is a heavy four-wheeled vehicle pulled by draught animals or on occasion by humans, used for transporting goods, commodities, agricultural materials, supplies and sometimes people.
Wagons are immediately distinguished from ...
moved on endless rails",[ which received a patent the next year. In 1881–1888 he created a steam-powered caterpillar-tractor. This self-propelled crawler was successfully tested and showed at a farmers' exhibition in 1896.][
According to '']Scientific American
''Scientific American'', informally abbreviated ''SciAm'' or sometimes ''SA'', is an American popular science magazine. Many famous scientists, including Albert Einstein and Nikola Tesla, have contributed articles to it. In print since 1845, it ...
'', Charles Dinsmoor of Warren, Pennsylvania
Warren is a city in Warren County, Pennsylvania, United States, located along the Allegheny River. The population was 9,404 at the 2020 census. It is the county seat of Warren County. It is home to the headquarters of the Allegheny National Fores ...
invented a "vehicle" on endless tracks, patented as No. 351,749 on November 2, 1886. The article gives a detailed description of the endless tracks.
Alvin O. Lombard of Waterville, Maine was issued a patent in 1901 for the Lombard Steam Log Hauler
The term Lombard refers to people or things related to Lombardy, a region in northern Italy.
History and culture
* Lombards, a Germanic tribe
* Lombards of Sicily, a linguistic minority living in Sicily, southern Italy
* Lombard League, a me ...
that resembles a regular railroad steam locomotive with sled steerage on front and crawlers in rear for hauling logs in the Northeastern United States and Canada. The haulers allowed pulp to be taken to rivers in the winter. Prior to then, horses could be used only until snow depths made hauling impossible. Lombard began commercial production which lasted until around 1917 when focus switched entirely to gasoline
Gasoline (; ) or petrol (; ) (see ) is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignited internal combustion engines (also known as petrol engines). It consists mostly of organi ...
powered machines. A gasoline-powered hauler is on display at the Maine State Museum in Augusta, Maine.
After Lombard began operations, Hornsby in England manufactured at least two full length "track steer" machines, and their patent was later purchased by Holt in 1913, allowing Holt to claim to be the "inventor" of the crawler tractor. Since the "tank" was a British concept it is more likely the Hornsby, which had been built and unsuccessfully pitched to their military, was the inspiration.
In a patent dispute involving rival crawler builder Best, testimony was brought in from people including Lombard, that Holt had inspected a Lombard log hauler shipped out to a western state by people who would later build the Phoenix log hauler in Eau Claire, Wisconsin, under license from Lombard. The Phoenix Centipeed typically had a fancier wood cab, steering wheel tipped forward at a 45 degree angle and vertical instead of horizontal cylinders.
File:Blinov tractor schematic.png, The draft of Blinov's steam-powered continuous track tractor
A tractor is an engineering vehicle specifically designed to deliver a high tractive effort (or torque) at slow speeds, for the purposes of hauling a trailer or machinery such as that used in agriculture, mining or construction. Most commo ...
File:Ruston crawler tractor working model.JPG, A working model of the original Hornsby & Sons tracked tractor
Linn
In the meantime, a gasoline-powered motor home
A motorhome (or motor coach) is a type of self-propelled recreational vehicle (RV) which offers mobile living accommodation.
Features
Motorhomes usually have sleeping spaces for two to eight people. Each sleeping space is either fixed or conv ...
was built by Lombard for Holman Harry (Flannery) Linn of Old Town, Maine
Old Town is a city in Penobscot County, Maine, United States. The population was 7,431 at the 2020 census. The city's developed area is chiefly located on the relatively large Marsh Island, though its boundaries extend beyond that. The island i ...
to pull the equipment wagon of his dog & pony show, resembling a trolley car only with wheels in front and Lombard crawlers in rear. Linn had experimented with gasoline and steam-powered vehicles and six-wheel drive before this, and at some point entered Lombard's employment as a demonstrator, mechanic and sales agent. This resulted in a question of proprietorship of patent rights after a single rear-tracked gasoline-powered road engine of tricycle arrangement was built to replace the larger motor home in 1909 on account of problems with the old picturesque wooden bridges. This dispute resulted in Linn departing Maine and relocating to Morris, New York, to build an improved, contour following flexible lag tread or crawler with independent suspension of halftrack
A half-track is a civilian or military vehicle with regular wheels at the front for steering and continuous tracks at the back to propel the vehicle and carry most of the load. The purpose of this combination is to produce a vehicle with the cro ...
type, gasoline and later diesel powered. Although several were delivered for military use between 1917 and 1946, Linn never received any large military orders. Most of the production between 1917 and 1952, approximately 2500 units, was sold directly to highway departments and contractors. Steel tracks and payload capacity allowed these machines to work in terrain that would typically cause the poorer quality rubber tyres that existed before the mid-1930s to spin uselessly, or shred completely.
Linn was a pioneer in snow removal before the practice was embraced in rural areas, with a nine-foot steel v-plow and sixteen foot adjustable leveling wings on either side. Once the highway system became paved, snowplowing could be done by four wheel drive
Four-wheel drive, also called 4×4 ("four by four") or 4WD, refers to a two-axled vehicle drivetrain capable of providing torque to all of its wheels simultaneously. It may be full-time or on-demand, and is typically linked via a transfer cas ...
trucks equipped by improving tyre designs, and the Linn became an off highway vehicle, for logging, 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 ...
, dam construction, arctic exploration
Arctic exploration is the physical exploration of the Arctic region of the Earth. It refers to the historical period during which mankind has explored the region north of the Arctic Circle. Historical records suggest that humankind have explored ...
, etc.
Engineering
File:Tracks (diagram).png, Diagram of tracked suspension.(1=rear drive wheel (rear wheel drive), 2=track, 3=return rollers, 4=front drive wheel (front wheel drive), 5=road wheels, 6=idler)
File:Leclerc p1040882.jpg, A sprocket
A sprocket, sprocket-wheel or chainwheel is a profiled wheel with teeth that mesh with a roller chain, chain, Caterpillar track, track or other perforated or indented material. The name 'sprocket' applies generally to any wheel upon which radial ...
wheel on a tank
A tank is an armoured fighting vehicle intended as a primary offensive weapon in front-line ground combat. Tank designs are a balance of heavy firepower, strong armour, and good battlefield mobility provided by tracks and a powerful engi ...
Construction and operation
Modern tracks are built from modular chain links which together compose a closed chain. The links are jointed by a hinge, which allows the track to be flexible and wrap around a set of wheels to make an endless loop. The chain links are often broad, and can be made of manganese alloy steel for high strength, hardness, and abrasion resistance.
Track construction and assembly is dictated by the application. Military vehicles use a track shoe that is integral to the structure of the chain in order to reduce track weight. Reduced weight allows the vehicle to move faster and decreases overall vehicle weight to ease transportation. Since track weight is completely unsprung, reducing it improves suspension performance at speeds where the track's momentum is significant. In contrast, agricultural and construction vehicles opt for a track with shoes that attach to the chain with bolts and do not form part of the chain's structure. This allows track shoes to break without compromising the ability of the vehicle to move and decrease productivity but increases the overall weight of the track and vehicle.
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 in military vehicles is a major area of development; the very early designs were often completely unsprung. 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. Torsion-bar suspension has become the most common type of military vehicle suspension. Construction vehicles have smaller road wheels that are designed primarily to prevent track derailment and they are normally contained in a single bogie that includes the idler-wheel
{{refimprove, date=June 2015
An idler-wheel is a wheel which serves only to transmit rotation from one shaft to another, in applications where it is undesirable to connect them directly. For example, connecting a motor to the platter of a phono ...
and sometimes the sprocket.
File:Bundesarchiv Bild 101I-635-3965-28, Panzerfabrik in Deutschland.jpg, Overlapped and interleaved road wheels of a German Tiger I
The Tiger I () was a German heavy tank of World War II that operated beginning in 1942 in Africa and in the Soviet Union, usually in independent heavy tank battalions. It gave the German Army its first armoured fighting vehicle that mounted ...
heavy tank
File:Bundesarchiv Bild 101I-750-0001A-05A, Bau von Zugkraftwagen 3t (Sd.Kfz. 11).jpg, upAn Sd.Kfz. 11
The Sd.Kfz. 11 (''Sonderkraftfahrzeug'' – special motor vehicle) was a German half-track that saw widespread use in World War II. Its main role was as a prime mover for medium towed guns ranging from the 3.7 cm FlaK 43 anti-aircraft gun up t ...
's half-track units, showing the rims of its six ''Schachtellaufwerk'' overlapped/interleaved roadwheel sets for each track unit per side
Overlapping road wheels
Many World War II German military vehicles, initially (starting in the late 1930s) including all vehicles originally designed to be half-tracks and all later tank designs (after the Panzer IV
The ''Panzerkampfwagen'' IV (Pz.Kpfw. IV), commonly known as the ''Panzer'' IV, was a German medium tank developed in the late 1930s and used extensively during the Second World War. Its ordnance inventory designation was Sd.Kfz. 161.
The Pan ...
), had slack-track systems, usually driven by a front-located drive sprocket, the track returning along the tops of a design of overlapping and sometimes interleaved large diameter road wheels, as on the suspension systems of the Tiger I
The Tiger I () was a German heavy tank of World War II that operated beginning in 1942 in Africa and in the Soviet Union, usually in independent heavy tank battalions. It gave the German Army its first armoured fighting vehicle that mounted ...
and Panther
Panther may refer to:
Large cats
*Pantherinae, the cat subfamily that contains the genera ''Panthera'' and ''Neofelis''
**'' Panthera'', the cat genus that contains tigers, lions, jaguars and leopards.
*** Jaguar (''Panthera onca''), found in So ...
tanks, generically known by the term ''Schachtellaufwerk'' (interleaved or overlapping running gear) in German, for both half-track and fully tracked vehicles. There were suspensions with single or sometimes doubled wheels per axle, alternately supporting the inner and outer side of the track, and interleaved suspensions with two or three road wheels per axle, distributing the load over the track.
The choice of overlapping/interleaved road wheels allowed the use of slightly more transverse-orientation torsion bar
A torsion bar suspension, also known as a torsion spring suspension, is any vehicle suspension that uses a torsion bar as its main weight-bearing spring. One end of a long metal bar is attached firmly to the vehicle chassis; the opposite end termi ...
suspension members, allowing any German tracked military vehicle with such a setup to have a noticeably smoother ride over challenging terrain, leading to reduced wear, ensuring greater traction and more accurate fire. However, on the Russian front, mud and snow would become lodged between the overlapping wheels, freeze, and immobilize the vehicle. As a tracked vehicle moves, the load of each wheel moves over the track, pushing down and forward that part of the earth or snow underneath it, similarly to a wheeled vehicle but to a lesser extent because the tread helps distribute the load. On some surfaces, this can consume enough energy to slow the vehicle down significantly. Overlapped and interleaved wheels improve performance (including fuel consumption) by loading the track more evenly. It also must have extended the life of the tracks and possibly of the wheels. The wheels also better protect the vehicle from enemy fire, and mobility is improved when some wheels are missing.
This relatively complicated approach has not been used since World War II ended. This may be related more to maintenance than to original cost. The torsion bars and bearings may stay dry and clean, but the wheels and tread work in mud, sand, rocks, snow, and other surfaces. In addition, the outer wheels (up to nine of them, some double) had to be removed to access the inner ones. In WWII, vehicles typically had to be maintained for a few months before being destroyed or captured, but in peacetime, vehicles must train several crews over a period of decades.
Drive train
Transfer of power to the track is accomplished by a drive wheel
A drive wheel is a wheel of a motor vehicle that transmits force, transforming torque into tractive force from the tires to the road, causing the vehicle to move. The powertrain delivers enough torque to the wheel to overcome stationary for ...
, or ''drive sprocket
A sprocket, sprocket-wheel or chainwheel is a profiled wheel with teeth that mesh with a roller chain, chain, Caterpillar track, track or other perforated or indented material. The name 'sprocket' applies generally to any wheel upon which radial ...
'', driven by the motor and engaging with holes in the track links or with pegs on them to drive the track. In military vehicles, the drive wheel is typically mounted well above the contact area on the ground, allowing it to be fixed in position. In agricultural crawlers it is normally incorporated as part of the bogie. Placing suspension on the sprocket is possible, but is mechanically more complicated. A non-powered wheel, an ''idler'', is placed at the opposite end of the track, primarily to tension the track, since loose track could be easily thrown (slipped) off the wheels. To prevent throwing, the inner surface of the track links usually have vertical guide horns engaging grooves, or gaps between the doubled road and idler/sprocket wheels. In military vehicles with a rear sprocket, the idler wheel is placed higher than the road wheels to allow it to climb over obstacles. Some track arrangements 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. This was a feature of the Christie suspension, leading to occasional misidentification of other slack track-equipped vehicles.
Steering
Continuous track vehicle steer Steer, Steers or Steering may refer to:
Animals
* Steer or bullock, castrated male cattle
* Ox, a steer used as a draft animal
People
* Steer (surname)
* Steers (surname)
Places
* Steer Creek (West Virginia), a tributary of the Little ...
by applying more or less drive torque to one side of the vehicle than the other, and this can be implemented in a variety of ways.
"Live" and "dead" track
Tracks may be broadly categorized as ''live'' or ''dead'' track. ''Dead'' track is a simple design in which each track plate is connected to the rest with hinge-type pins. These dead tracks will lie flat if placed on the ground; the drive sprocket pulls the track around the wheels with no assistance from the track itself. ''Live'' track is slightly more complex, with each link connected to the next by a bushing which causes the track to bend slightly inward. A length of live track left on the ground will curl upward slightly at each end. Although the drive sprocket must still pull the track around the wheels, the track itself tends to bend inward, slightly assisting the sprocket and somewhat conforming to the wheels.
Rubber track pads
Tracks are often equipped with rubber pads to improve travel on paved surfaces more quickly, smoothly and quietly. While these pads slightly reduce a vehicle's cross-country traction, they prevent damage to any pavement. Some pad systems are designed to remove easily for cross-country military combat.
File:Caterpillar Tracks On Seal Machine.jpg, Small tracks on a roadworks machine. Note the rubber pads to reduce wear on the carriageway.
File:USMC-12197.jpg, Worn and new track pads on an M1 Abrams battle tank.
File:CASE_IH_8240_Raupenantrieb.JPG, Rubber tracks (''Case IH
Case IH is an American agricultural machinery manufacturer. It was created in 1985 when Tenneco bought selected assets of the agricultural division from International Harvester and merged it into its J.I. Case Company (IH then became Navistar).T ...
8240'')
File:Armored vehicle on trailer p1040729.jpg, Tracked vehicles long-distance hauling on semi-trailers
A semi-trailer is a trailer without a front axle. In the United States, the term is also used to refer to the combination of a truck and a semi-trailer; a tractor-trailer.
A large proportion of a semi-trailer's weight is supported by a tracto ...
or railway car
A railroad car, railcar ( American and Canadian English), railway wagon, railway carriage, railway truck, railwagon, railcarriage or railtruck (British English and UIC), also called a train car, train wagon, train carriage or train truck, is ...
s
Rubber tracks
Starting from late 1980s, many manufacturers provide rubber tracks instead of steel, especially for agricultural applications. Rather than a track made of linked steel plates, a reinforced rubber belt with chevron
Chevron (often relating to V-shaped patterns) may refer to:
Science and technology
* Chevron (aerospace), sawtooth patterns on some jet engines
* Chevron (anatomy), a bone
* '' Eulithis testata'', a moth
* Chevron (geology), a fold in rock ...
treads is used.
In comparison to steel tracks, rubber tracks are lighter, waste less power on internal friction, make less noise and do not damage paved roads. However, they impose ''more'' ground pressure
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, especially over soft ground. It also applies to the feet of a walking person or machine. Ground pr ...
below the wheels, as they are not able to equalize pressure as well as the stiff mechanism of track plates, especially the spring loaded ''live'' tracks. Another disadvantage is that they are not disassemblable into tracks and therefore cannot be repaired, having to be discarded as whole if once damaged.
Previous belt-like systems, such as those used for half-track
A half-track is a civilian or military vehicle with regular wheels at the front for steering and continuous tracks at the back to propel the vehicle and carry most of the load. The purpose of this combination is to produce a vehicle with the cro ...
s in World War II, were not as strong, and during military actions were easily damaged. The first rubber track was invented and constructed by Adolphe Kégresse and patented in 1913; in historic context rubber tracks are often called Kégresse track
A Kégresse track is a kind of rubber or canvas continuous track which uses a flexible belt rather than interlocking metal segments. It can be fitted to a conventional car or truck to turn it into a half-track, suitable for use over rough or soft ...
s. First rubber-tracked agricultural tracked was Oliver Farm Equipment
The Oliver Farm Equipment Company was an American farm equipment manufacturer from the 20th century. It was formed as a result of a 1929 merger of four companies: the American Seeding Machine Company of Richmond, Indiana; Oliver Chilled Plow ...
HGR in 1945-1948, which was ahead of its time and only seen small-scale production.
Advantages
* 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
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, especially over soft ground. It also applies to the feet of a walking person or machine. Ground pr ...
: The seventy-ton M1 Abrams tank has an average ground pressure of just over . Since tyre air pressure is approximately equal to average ground pressure, a typical car will have an average ground pressure of to .
* Tracked vehicles have better mobility over rough terrain than those with wheels: They smooth out the bumps, glide over small obstacles and are capable of crossing trenches or breaks in the terrain: Riding in a fast tracked vehicle feels just like riding in a boat over heavy swells.
* The larger contact area, coupled with the cleats, or grouser
Grousers are devices intended to increase the traction of continuous tracks, especially in loose material such as soil or snow. This is done by increasing contact with the ground with protrusions, similar to conventional tire treads, and analogo ...
s, on the track shoes, allows vastly ''superior traction'' that results in a much better ability to push or pull large loads where wheeled vehicles would dig in. Bulldozers, which are most often tracked, use this attribute to rescue other vehicles, (such as wheel loader
A loader is a heavy equipment machine used in construction to move or load materials such as soil, rock, sand, demolition debris, etc. into or onto another type of machinery (such as a dump truck, conveyor belt, feed-hopper, or railroad car) ...
s) which have become stuck in, or sunk into, the ground.
* Tracks cannot be punctured or torn and are more resistant in military combat. Should a track be broken, it often can be repaired immediately using some special tools and spare parts, without the need for special facilities, which might be crucial in combat situations.
Disadvantages
The disadvantages of tracks are lower top speed, much greater mechanical complexity, shorter life and the damage that their all-steel versions cause to the surface on which they pass: They often cause damage to less firm terrain such as lawns, gravel roads, and farm fields, as the sharp edges of the track easily rout the turf. Accordingly, vehicle laws and local ordinances often require rubberised tracks or track pads. A compromise between all-steel and all-rubber tracks exists: attaching rubber pads to individual track links ensures that continuous track vehicles can travel more smoothly, quickly, and quietly on paved surfaces. While these pads slightly reduce a vehicle's cross-country traction, in theory they prevent damage to any pavement.
Additionally, the loss of a single segment in a track immobilizes the entire vehicle, which can be a disadvantage in situations where high reliability is important. Tracks can also ride off their guide wheels, idlers or sprockets, which can cause them to jam or to come completely off the guide system (this is called a 'thrown' track). Jammed tracks may become so tight that the track may need to be broken before a repair is possible, which requires either explosives or special tools. Multi-wheeled vehicles, for example, 8 X 8 military vehicles, may often continue driving even after the loss of one or more non-sequential wheels, depending on the base wheel pattern and drive train.
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 tank transporter
A tank transporter is a combination of a heavy tractor unit and a mating full trailer or semi-trailer (typically of the "lowboy" type), used for transporting tanks and other armoured fighting vehicles. Some also function as tank recovery vehi ...
or train
In rail transport, a train (from Old French , from Latin , "to pull, to draw") is a series of connected vehicles that run along a railway track and transport people or freight. Trains are typically pulled or pushed by locomotives (often ...
, though technological advances have made this practice less common among tracked military vehicles than it once was.
Gallery
File:THG Cruser.JPG, ''Komatsu CD-110R''
File:Bundesarchiv Bild 101I-801-0664-37, Berlin, Unter den Linden, Schützenpanzer.jpg, German World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...
-era SdKfz 251
The Sd.Kfz. 251 (''Sonderkraftfahrzeug 251'') half-track was a World War II German armored personnel carrier designed by the Hanomag company, based on its earlier, unarmored Sd.Kfz. 11 vehicle. The Sd.Kfz. 251 was designed to transport the ''Panz ...
military halftrack
A half-track is a civilian or military vehicle with regular wheels at the front for steering and continuous tracks at the back to propel the vehicle and carry most of the load. The purpose of this combination is to produce a vehicle with the cro ...
, with overlapped interleaved wheels and "slack track"
File:279-7.jpg, Experimental four-track tank (Obyekt 279
The Obiekt 279, or Object 279, (Объект 279) was a Soviet experimental heavy tank developed at the end of 1959.
This special purpose tank was intended to fight on cross country terrain, inaccessible to conventional tanks, acting as a heavy b ...
)
File:T-55 skos RB.jpg, Soviet T-55
The T-54 and T-55 tanks are a series of Soviet main battle tanks introduced in the years following the Second World War. The first T-54 prototype was completed at Nizhny Tagil by the end of 1945.Steven Zaloga, T-54 and T-55 Main Battle Tank ...
tank with "slack track" and rear drive sprocket
File:American M60A3 tank Lake Charles, Louisiana April 2005.jpg, U.S. M60 tank
The M60 is an American second-generation main battle tank (MBT). It was officially standardized as the Tank, Combat, Full Tracked: 105-mm Gun, M60 in March 1959. Although developed from the M48 Patton, the M60 tank series was never officially ...
with rear drive sprocket
A sprocket, sprocket-wheel or chainwheel is a profiled wheel with teeth that mesh with a roller chain, chain, Caterpillar track, track or other perforated or indented material. The name 'sprocket' applies generally to any wheel upon which radial ...
and return rollers holding up the track
File:Leclerc p1040868.jpg, Track of a Leclerc tank
The Leclerc is a third generation French main battle tank developed and manufactured by Nexter Systems. It was named in honor of Marshal Philippe Leclerc de Hauteclocque, a commander of the Free French Forces, who led the 2nd Armoured Divisio ...
File:B-36 tracked gear edit.jpg, Experimental tracked landing gear
Landing gear is the undercarriage of an aircraft or spacecraft that is used for takeoff or landing. For aircraft it is generally needed for both. It was also formerly called ''alighting gear'' by some manufacturers, such as the Glenn L. Martin ...
on a B-36 Peacemaker
The Convair B-36 "Peacemaker" is a strategic bomber that was built by Convair and operated by the United States Air Force (USAF) from 1949 to 1959. The B-36 is the largest mass-produced piston-engined aircraft ever built. It had the longest win ...
Current manufacturers
The pioneer manufacturers have been replaced mostly by large tractor companies such as AGCO, Liebherr Group
Liebherr is a German-Swiss multinational equipment manufacturer based in Bulle, Switzerland, with its main production facilities and origins in Germany.
Liebherr consists of over 130 companies organized into 11 divisions: earthmoving, mining, ...
, John Deere, Yanmar
is a Japanese diesel engine, heavy machinery and agricultural machinery manufacturer founded in Osaka, Japan in 1912. Yanmar manufactures and sells engines used in a wide range of applications, including seagoing vessels, pleasure boats, cons ...
, New Holland, Kubota, Case, Caterpillar Inc.
Caterpillar Inc. (stock symbol CAT) is an American ''Fortune'' 500 corporation and the world's largest construction-equipment manufacturer.
In 2018, Caterpillar was ranked number 65 on the ''Fortune'' 500 list and number 238 on the Global ''Fo ...
, CLAAS
}
CLAAS is an agricultural machinery manufacturer based in Harsewinkel, Germany, in the federal state of North Rhine Westphalia. Founded in 1913 by August Claas, CLAAS is a family business and one of the market and technology leaders in harv ...
. Also, there are some crawler tractor companies specialising in niche markets. Examples are Otter Mfg. Co. and Struck Corporation., with many wheeled vehicle conversion kits available from the American Mattracks firm of Minnesota since the mid-1990s.
Russian off-road vehicles are built by companies such as ZZGT and Vityaz.
In nature
* '' Navicula'' diatoms are known for their ability to creep about on each other and on hard surfaces such as microscope slides. It is thought that around the outside of the navicula's shell is a girdle of protoplasm that can flow and thus act as a tank track.
See also
* Excavator
* Half-track
A half-track is a civilian or military vehicle with regular wheels at the front for steering and continuous tracks at the back to propel the vehicle and carry most of the load. The purpose of this combination is to produce a vehicle with the cro ...
* Kégresse track
A Kégresse track is a kind of rubber or canvas continuous track which uses a flexible belt rather than interlocking metal segments. It can be fitted to a conventional car or truck to turn it into a half-track, suitable for use over rough or soft ...
* Pedrail wheel
The pedrail wheel is a type of all-terrain wheel developed in the late 19th and early 20th century by Londoner Bramah Joseph Diplock. It consists of a series of "feet" (''pedes'' in Latin) connected to pivots on a wheel. As the wheel travels, ...
* Recreational products
* Screw-propelled vehicle
A screw-propelled vehicle is a land or amphibious vehicle designed to cope with difficult terrain, such as snow, ice, mud, and swamp. Such vehicles are distinguished by being moved by the rotation of one or more auger-like cylinders fitted ...
* Snowcat
* Snowmobile
A snowmobile, also known as a Ski-Doo, snowmachine, sled, motor sled, motor sledge, skimobile, or snow scooter, is a motorized vehicle designed for winter travel and recreation on snow. It is designed to be operated on snow and ice and does not ...
* Undercarriage
* Airoll
References
External links
Scale model of Hornsby Chain Tractor at 2005 Harrogate Model Engineering Show
Dedication to the only commercially-sold Hornsby caterpillar crawler
Hornsby Steam Chain Tractor website
Video clips
Hornsby Chain Tractor Promotion-Video (6:17, 1908)
(British Film Institute
The British Film Institute (BFI) is a film and television charitable organisation which promotes and preserves film-making and television in the United Kingdom. The BFI uses funds provided by the National Lottery (United Kingdom), National Lot ...
)
Scale Model Hornsby Traktor
(Stapleford Steam, Leicestershire, 2008)
1/3 Scale Hornsby Traktor
{{Robotics
Tractors
Engineering vehicles
Carriages and mountings
Propulsion
Tank subassembly