Grouser
Encyclopedia
A grouser or cleat is a protrusion on the surface of a wheel
or continuous track segment, intended to increase traction
in soil
, snow
, or other loose material, in the same manner as cleated shoes
provide traction to athletes. Track segments which incorporate grouser bars are known as grouser shoes, and typically include one to three grousers. Grousers are commonly used on construction vehicles such as bulldozer
s, loader
s, and excavator
s, as well as tank
s, agricultural vehicles, and snowmobile
s. They have also found use in such extreme environments as the deep sea
floor
, and the surfaces of the Moon
and Mars
.
Grousers may take the form of flat plates or bars, or may take on more complex shapes, including spikes and involute
curves, depending on the type of terrain and the performance requirements of the vehicle. Unlike rubber tire tread
s or track shoe pads, grousers are typically made of metal, such as forged
steel
, and are not designed for use on paved roads.
Grousers may be permanently attached to, or formed as a single piece with, the track shoe, or they may be bolted on to the track shoe for ease of replacement as they become worn.
of the soil against itself that generates tractive force. The gross tractive effort, or soil thrust, of a vehicle may be calculated from equation:
where:
soil thrust
track width
contact length
coefficient of cohesion
(a soil property)
grouser height
gross vehicle weight
angle of repose
(a soil property)
Wheel
A wheel is a device that allows heavy objects to be moved easily through rotating on an axle through its center, facilitating movement or transportation while supporting a load, or performing labor in machines. Common examples found in transport applications. A wheel, together with an axle,...
or continuous track segment, intended to increase traction
Traction (engineering)
Traction refers to the maximum frictional force that can be produced between surfaces without slipping.The units of traction are those of force, or if expressed as a coefficient of traction a ratio.-Traction:...
in soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
, snow
Snow
Snow is a form of precipitation within the Earth's atmosphere in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. Since snow is composed of small ice particles, it is a granular material. It has an open and therefore soft structure, unless packed by...
, or other loose material, in the same manner as cleated shoes
Cleat (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...
provide traction to athletes. Track segments which incorporate grouser bars are known as grouser shoes, and typically include one to three grousers. Grousers are commonly used on construction vehicles such as bulldozer
Bulldozer
A bulldozer is a crawler equipped with a substantial metal plate used to push large quantities of soil, sand, rubble, etc., during construction work and typically equipped at the rear with a claw-like device to loosen densely-compacted materials.Bulldozers can be found on a wide range of sites,...
s, loader
Loader (equipment)
A loader is a heavy equipment machine often used in construction, primarily used to load material into or onto another type of machinery .-Heavy equipment front loaders:A loader A loader is a heavy equipment machine often used in construction, primarily used to load material (such as asphalt,...
s, and excavator
Excavator
Excavators are heavy construction equipment consisting of a boom, stick, bucket and cab on a rotating platform . The house sits atop an undercarriage with tracks or wheels. A cable-operated excavator uses winches and steel ropes to accomplish the movements. They are a natural progression from the...
s, as well as tank
Tank
A tank is a tracked, armoured fighting vehicle designed for front-line combat which combines operational mobility, tactical offensive, and defensive capabilities...
s, agricultural vehicles, and snowmobile
Snowmobile
A snowmobile, also known in some places as a snowmachine, or sled,is a land vehicle for winter travel on snow. Designed to be operated on snow and ice, they require no road or trail. Design variations enable some machines to operate in deep snow or forests; most are used on open terrain, including...
s. They have also found use in such extreme environments as the deep sea
Deep sea
The deep sea, or deep layer, is the lowest layer in the ocean, existing below the thermocline and above the seabed, at a depth of 1000 fathoms or more. Little or no light penetrates this part of the ocean and most of the organisms that live there rely for subsistence on falling organic matter...
floor
Seabed
The seabed is the bottom of the ocean.- Ocean structure :Most of the oceans have a common structure, created by common physical phenomena, mainly from tectonic movement, and sediment from various sources...
, and the surfaces of the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
and Mars
Mars
Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...
.
Grousers may take the form of flat plates or bars, or may take on more complex shapes, including spikes and involute
Involute
In the differential geometry of curves, an involute is a curve obtained from another given curve by attaching an imaginary taut string to the given curve and tracing its free end as it is wound onto that given curve; or in reverse, unwound. It is a roulette wherein the rolling curve is a straight...
curves, depending on the type of terrain and the performance requirements of the vehicle. Unlike rubber tire tread
Tread
The tread of a tire or track refers to the rubber on its circumference that makes contact with the road. As tires are used, the tread is worn off, limiting its effectiveness in providing traction. A worn tire tread can often be retreaded. The word tread is often used incorrectly to refer to the...
s or track shoe pads, grousers are typically made of metal, such as forged
Forging
Forging is a manufacturing process involving the shaping of metal using localized compressive forces. Forging is often classified according to the temperature at which it is performed: '"cold," "warm," or "hot" forging. Forged parts can range in weight from less than a kilogram to 580 metric tons...
steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
, and are not designed for use on paved roads.
Grousers may be permanently attached to, or formed as a single piece with, the track shoe, or they may be bolted on to the track shoe for ease of replacement as they become worn.
Terramechanics
Grousers function by trapping soil against the contact area of the track. It is the shearingShear strength (soil)
Shear strength is a term used in soil mechanics to describe the magnitude of the shear stress that a soil can sustain. The shear resistance of soil is a result of friction and interlocking of particles, and possibly cementation or bonding at particle contacts. Due to interlocking, particulate...
of the soil against itself that generates tractive force. The gross tractive effort, or soil thrust, of a vehicle may be calculated from equation:
where:
soil thrust track width contact length coefficient of cohesionCohesion (geology)
Cohesion is the component of shear strength of a rock or soil that is independent of interparticle friction.In soils, true cohesion is caused by one of three things:# Electrostatic forces in stiff overconsolidated clays...
(a soil property)
grouser height gross vehicle weight angle of reposeAngle of repose
The angle of repose or, more precisely, the critical angle of repose, of a granular material is the steepest angle of descent or dip of the slope relative to the horizontal plane when material on the slope face is on the verge of sliding. This angle is in the range 0°–90°.When bulk granular...
(a soil property)
See also
- Heavy equipment (construction)
- Soil mechanicsSoil mechanicsSoil mechanics is a branch of engineering mechanics that describes the behavior of soils. It differs from fluid mechanics and solid mechanics in the sense that soils consist of a heterogeneous mixture of fluids and particles but soil may also contain organic solids, liquids, and gasses and other...
- TerramechanicsTerramechanicsTerramechanics is the study of soil properties, specifically the interaction of wheeled or tracked vehicles on various surfaces.-External links:**...