Grouser

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Grousers on a bulldozer track Caterpillar track shingle.JPG
Grousers on a bulldozer track

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 analogous to athletes' cleated shoes. On tanks and armoured vehicles, grousers are usually pads attached to the tracks; but on construction vehicles they may take the form of flat plates or bars. [1]

Contents

Similar traction-improving patterns have been implemented on the surface of the wheels on tractors. These include strakes, where material is removed from the surface of the wheel to achieve protrusion; cleats, with spikes instead of straight bars; and lugs with raised rubber on a tire tread.

Steam traction engine, with straked wheels, constructed of riveted steel Den otevrenych dveri arealu MHD Reckovice Technickeho muzea v Brne (24).jpg
Steam traction engine, with straked wheels, constructed of riveted steel

Variations

Developed during World War I, external track extensions – often called "grousers" or "duckbills" – were added to the outside edges of the trackshoes on armored fighting vehicles such as tanks, widening the track for improved performance in snow or mud. [2] Track segments (i.e., trackshoes) that incorporate grouser bars are known as grouser shoes, and typically include one to three grousers. [3]

Grousers are commonly used on construction vehicles such as bulldozers, loaders, and excavators. Grousers may be permanently attached to, or formed as a single piece with, the track shoe, or they may be bolted onto the track shoe for ease of replacement as they become worn. While grousers are usually straight, they may have more complex shapes, including spikes [4] and involute curves, depending on the type of terrain and the performance requirements of the vehicle. [5] Grousers are typically made of metal, such as forged steel, and are not designed for use on paved roads. [4] Various devices, with names such as road bands, have been developed to temporarily cover grousers/cleats in order to allow a vehicle to travel on paved roads.

Grousers have been used in such exotic environments as the deep sea floor, and the surfaces of the Moon and Mars. [5] Snowmobiles once used cleated tracks, but racing snowmobiles are banned from using cleated track for safety reasons and instead use rubber tracks. [6]

Protrusions molded into rubber tractor tire treads are known as lugs, as are cleats for round wheels,[ citation needed ] which perform a similar function. Unlike metal grousers, these rubber tire treads or crawler-track shoes/pads may be more suitable for driving on roads. [7]

Grousers on a captured World War I British tank. German photo with English Tank.jpg
Grousers on a captured World War I British tank.

Terramechanics

Grousers function by trapping soil against the contact area of the track. It is the shearing of the soil against itself that generates tractive force. The gross tractive effort, or soil thrust, of a vehicle may be calculated from the equation: [8]

where:

soil thrust
track width
contact length
coefficient of cohesion (a soil property)
grouser height
gross vehicle weight
angle of repose (a soil property)

See also

Related Research Articles

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<span class="mw-page-title-main">Continuous track</span> System of vehicle propulsion

Continuous track or tracked treads are a system of vehicle propulsion 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 tyres on an equivalent vehicle, enabling continuous tracked vehicles to traverse soft ground with less likelihood of becoming stuck due to sinking.

<span class="mw-page-title-main">Tractor</span> Engineering vehicle specifically designed to deliver a high tractive effort

A tractor is an engineering vehicle specifically designed to deliver a high tractive effort at slow speeds, for the purposes of hauling a trailer or machinery such as that used in agriculture, mining or construction. Most commonly, the term is used to describe a farm vehicle that provides the power and traction to mechanize agricultural tasks, especially tillage, and now many more. Agricultural implements may be towed behind or mounted on the tractor, and the tractor may also provide a source of power if the implement is mechanised.

<span class="mw-page-title-main">Bulldozer</span> Mobile machine which uses a frontal blade to push large volumes of material

A bulldozer or dozer is a large, motorized machine equipped with a metal blade to the front for pushing material: soil, sand, snow, rubble, or rock during construction work. It travels most commonly on continuous tracks, though specialized models riding on large off-road tires are also produced. Its most popular accessory is a ripper, a large hook-like device mounted singly or in multiples in the rear to loosen dense materials.

Off-road transport is moving people or articles on land without the use of paved roads, typically using off-road vehicles.

<span class="mw-page-title-main">Slip angle</span> Term or maneuver in vehicle dynamics

In vehicle dynamics, slip angle or sideslip angle is the angle between the direction in which a wheel is pointing and the direction in which it is actually traveling. This slip angle results in a force, the cornering force, which is in the plane of the contact patch and perpendicular to the intersection of the contact patch and the midplane of the wheel. This cornering force increases approximately linearly for the first few degrees of slip angle, then increases non-linearly to a maximum before beginning to decrease.

<span class="mw-page-title-main">Racing slick</span> Type of tire used in auto racing

A racing slick or slick tyre is a type of tyre that has a smooth tread used mostly in auto racing. The first production slick tyre was developed by M&H Tires in the early 1950s for use in drag racing. By eliminating any grooves cut into the tread, such tyres provide the largest possible contact patch to the road, and maximize dry traction for any given tyre dimension; see Performance. Slick tyres are used on race tracks and in road racing, where acceleration, steering and braking require maximum traction from each wheel. Slick tyres are typically used on only the driven (powered) wheels in drag racing, where the only concern is maximum traction to put power to the ground, and are not used in rallying.

<span class="mw-page-title-main">Aquaplaning</span> Loss of traction due to water buildup under tires

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Cleat may refer to:

<span class="mw-page-title-main">Tire tread</span> Rubber on the circumference of a tire that contacts the ground

The tread of a tire or track refers to the rubber on its circumference that makes contact with the road or the ground. As tires are used, the tread is worn off, limiting its effectiveness in providing traction. A worn tire can often be retreaded.

<span class="mw-page-title-main">Paddle tire</span>

Paddle tires are mainly used on off-road vehicles, specifically designed for use in sand and mud. They consist of a smooth tire core which has a series of large rubber cups attached to it. The volume inside of a paddle is much larger than the void of a knobby tire, so it is unlikely to clog up with sand/mud. A street legal mud tire is a more or less normal tire, but with extra large gaps or "voids" between each tread block to allow centrifugal force to "self-clean" or fling the mud out of the gap. Smaller gaps trap the mud in between the tire lugs, which turns the tire into something resembling a "slick" with no tread at all, which will have no traction in mud.

<span class="mw-page-title-main">Rolling resistance</span> Force resisting the motion when a body rolls on a surface

Rolling resistance, sometimes called rolling friction or rolling drag, is the force resisting the motion when a body rolls on a surface. It is mainly caused by non-elastic effects; that is, not all the energy needed for deformation of the wheel, roadbed, etc., is recovered when the pressure is removed. Two forms of this are hysteresis losses, and permanent (plastic) deformation of the object or the surface. Note that the slippage between the wheel and the surface also results in energy dissipation. Although some researchers have included this term in rolling resistance, some suggest that this dissipation term should be treated separately from rolling resistance because it is due to the applied torque to the wheel and the resultant slip between the wheel and ground, which is called slip loss or slip resistance. In addition, only the so-called slip resistance involves friction, therefore the name "rolling friction" is to an extent a misnomer.

<span class="mw-page-title-main">Tucker Sno-Cat</span> Family of tracked vehicles

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<span class="mw-page-title-main">Snow chains</span> Devices fitted to the tires of vehicles to improve traction on snow and ice

Snow chains, or tire chains, are devices fitted to the tires of vehicles to provide increased traction when driving through snow and ice.

Traction, traction force or tractive force is a force used to generate motion between a body and a tangential surface, through the use of either dry friction or shear force. It has important applications in vehicles, as in tractive effort.

<span class="mw-page-title-main">Siping (rubber)</span> Process to improve rubbers traction

Siping is a process of cutting thin slits across a rubber surface to improve traction in wet or icy conditions.

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Uniform Tire Quality Grading, commonly abbreviated as UTQG, is a set of standards for passenger car tires that measures a tire's treadwear, temperature resistance and traction. The UTQG was created by the National Highway Traffic Safety Administration in 1978, a branch of the United States Department of Transportation (DOT). All passenger car tires manufactured for sale in the United States since March 31, 1979 are federally mandated to have the UTQG ratings on their sidewall as part of the DOT approval process, in which non-DOT approved tires are not legal for street use in the United States. Light truck tires are not required to have a UTQG. It is not to be confused with the tire code, a supplemental and global standard measuring tire dimensions, load-bearing ability and maximum speed, maintained by tire industry trade organizations and the International Organization for Standardization.

<span class="mw-page-title-main">Cleat (shoe)</span> Projection on sole of shoe

Cleats or studs are protrusions on the sole of a shoe or on an external attachment to a shoe that provide additional traction on a soft or slippery surface. They can be conical or blade-like in shape and can be made of plastic, rubber or metal. The type worn depends on the environment of play: grass, ice, artificial turf, or other grounds.

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Off-road tires are a category of vehicle tires that use deep tread to provide more traction on unpaved surfaces such as loose dirt, mud, sand, or gravel. Compared to ice or snow tires, they lack studs but contain deeper and wider grooves meant to help the tread sink into mud or gravel surfaces.

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References

  1. Various (2003). "Forum Posts". Axis History Forum. Retrieved 18 Oct 2015.
    Admfisher:"Track pads on a modern bulldozer would have normally a single grouser pad. That is the part of the track that provides traction. Or simpler way of looking at it is, the bar that crosses the pad and is raised.";
    Aufklarung:"On Ex/Winter we put in place of the rubber [pad] a steel plate in the shape of a raised "X". This we here call a "Grouser"."
  2. Fletcher, David (2011). Mark V Tank. Osprey Publishing. p. 5. ISBN   978-1-84908-351-5.
  3. "Track Shoes". Berco of America, Inc. Archived from the original on 2010-01-26. Retrieved 2010-02-27.
  4. 1 2 "Grouser Shoes". RitchieWiki. Ritchie Bros. Auctioneers. 13 October 2009. Retrieved 2010-02-27.
  5. 1 2 Hong, Sup; Jong-Su Choi (2001). "Experimental Study on Grouser Shape Effects on Trafficability of Extremely Soft Seabed" (PDF). Proceedings of the Fourth Ocean Mining Symposium. Szczecin, Poland: The International Society of Offshore and Polar Engineers. pp. 115ff. Retrieved 2010-02-28.
  6. Dave Dunigan (2006). "Forum Posts". American Snowmobiler. Retrieved 18 October 2015. They banned the cleated track the next year.
  7. "Compare & Contrast — Making the Case for Tires vs. Tracks". www.farm-equipment.com. Retrieved 2023-09-15.
  8. Gerhart, Grant; Sean Laughery; Richard Goetz (2006). "Off-Road Vehicle Locomotion Using Bekker's Model". Warren, Michigan: United States Army Tank Automotive Research, Development and Engineering Center. p. 9. Retrieved 2010-02-28.