A chassis (, ; plural ''chassis'' from French châssis ) is the

load Load or LOAD may refer to: Aeronautics and transportation *Load factor (aeronautics), the ratio of the lift of an aircraft to its weight *Passenger load factor, the ratio of revenue passenger miles to available seat miles of a particular transpo ...

-bearing framework of an artificial object, which structurally supports the object in its construction and function. An example of a chassis is a

vehicle frame A vehicle frame, also historically known as its '' chassis'', is the main supporting structure of a motor vehicle to which all other components are attached, comparable to the skeleton of an organism. Until the 1930s, virtually every car had ...

, the underpart of a

motor vehicle A motor vehicle, also known as motorized vehicle or automotive vehicle, is a self-propelled land vehicle, commonly wheeled, that does not operate on rails (such as trains or trams) and is used for the transportation of people or cargo. The vehi ...

, on which the body is mounted; if the

running gear In railway terminology the term running gear refers to those components of a railway vehicle that run passively on the rails, unlike those of the driving gear. Traditionally these are the wheels, axles, axle boxes, springs and vehicle frame of ...

such as wheels and transmission, and sometimes even the driver's seat, are included, then the assembly is described as a

rolling chassis A rolling chassis is the chassis without bodywork of a motor vehicle (car, truck, bus, or other vehicle), assembled with suspension and wheels. Heavy vehicles Separate chassis remain in use for almost all heavy vehicles ranging from pickup truc ...

Examples of use

Chassis with suspension and exhaust system

Vehicles

In the case of vehicles, the term ''rolling chassis'' means the

frame A frame is often a structural system that supports other components of a physical construction and/or steel frame that limits the construction's extent. Frame and FRAME may also refer to: Physical objects In building construction *Framing (co ...

plus the "running gear" like

engine An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power gene ...

transmission Transmission may refer to: Medicine, science and technology * Power transmission ** Electric power transmission ** Propulsion transmission, technology allowing controlled application of power *** Automatic transmission *** Manual transmission ** ...

drive shaft A drive shaft, driveshaft, driving shaft, tailshaft (Australian English), propeller shaft (prop shaft), or Cardan shaft (after Girolamo Cardano) is a component for transmitting mechanical power and torque and rotation, usually used to connec ...

, differential and

suspension Suspension or suspended may refer to: Science and engineering * Suspension (topology), in mathematics * Suspension (dynamical systems), in mathematics * Suspension of a ring, in mathematics * Suspension (chemistry), small solid particles suspen ...

. An underbody (sometimes referred to as "

coachwork A coachbuilder or body-maker is someone who manufactures bodies for passenger-carrying vehicles.Construction has always been a skilled trade requiring a relatively lightweight product with sufficient strength. The manufacture of necessarily ...

"), which is usually not necessary for integrity of the structure, is built on the chassis to complete the vehicle. For

commercial vehicle A commercial vehicle is any type of motor vehicle used for transporting goods or paying passengers. The United States defines a "commercial motor vehicle" as any self-propelled or towed vehicle used on a public highway in interstate commerce to ...

s, a rolling chassis consists of an assembly of all the essential parts of a truck without the body to be ready for operation on the road. A car chassis will be different from one for commercial vehicles because of the heavier loads and constant work use. Commercial vehicle manufacturers sell "chassis only", "cowl and chassis", as well as "

chassis cab A chassis cab, also called a cab chassis or half truck, is a type of vehicle construction, often found in medium duty truck commercial vehicles. Instead of supplying the customer with a factory pre-assembled flatbed, cargo container, or other eq ...

" versions that can be outfitted with specialized bodies. These include

motor homes A recreational vehicle, often abbreviated as RV, is a motor vehicle or trailer that includes living quarters designed for accommodation. Types of RVs include motorhomes, campervans, coaches, caravans (also known as travel trailers and camper ...

fire engines The Fire Engines were a post-punk band from Edinburgh, Scotland. The Fire Engines were an influence on many bands that followed, including Franz Ferdinand and The Rapture, with Meat Whiplash and The Candyskins both taking their names from Fi ...

ambulance An ambulance is a medically equipped vehicle which transports patients to treatment facilities, such as hospitals. Typically, out-of-hospital medical care is provided to the patient during the transport. Ambulances are used to respond to medi ...

box truck A box truck—also known as a box van, cube van, bob truck or cube truck—is a chassis cab truck with an enclosed cuboid-shaped cargo area. On most box trucks, the cabin is separate to the cargo area; however some box trucks have a door between ...

s, etc. In particular applications, such as

school bus A school bus is any type of bus owned, leased, contracted to, or operated by a school or school district. It is regularly used to transport students to and from school or school-related activities, but not including a charter bus or transit bus ...

es, a government agency like

National Highway Traffic Safety Administration The National Highway Traffic Safety Administration (NHTSA ) is an agency of the U.S. federal government, part of the Department of Transportation. It describes its mission as "Save lives, prevent injuries, reduce vehicle-related crashes" rela ...

(NHTSA) in the U.S. defines the design standards of chassis and body conversions. An

armoured fighting vehicle An armoured fighting vehicle (AFV) is an armed combat vehicle protected by armour, generally combining operational mobility with offensive and defensive capabilities. AFVs can be wheeled or tracked. Examples of AFVs are tanks, armoured cars ...

's hull serves as the chassis and comprises the bottom part of the AFV that includes the tracks, engine, driver's seat, and crew compartment. This describes the lower hull, although common usage might include the upper hull to mean the AFV without the turret. The hull serves as a basis for

platform Platform may refer to: Technology * Computing platform, a framework on which applications may be run * Platform game, a genre of video games * Car platform, a set of components shared by several vehicle models * Weapons platform, a system or ...

s on

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 ...

armoured personnel carrier An armoured personnel carrier (APC) is a broad type of armoured military vehicle designed to transport personnel and equipment in combat zones. Since World War I, APCs have become a very common piece of military equipment around the world. Ac ...

combat engineering vehicle A military engineering vehicle is a vehicle built for construction work or for the transportation of combat engineers on the battlefield. These vehicles may be modified civilian equipment (such as the armoured bulldozers that many nations fiel ...

s, etc. In the intermodal trucking industry, a

chassis A chassis (, ; plural ''chassis'' from French châssis ) is the load-bearing framework of an artificial object, which structurally supports the object in its construction and function. An example of a chassis is a vehicle frame, the underpart ...

is a type of semi-trailer onto which a

cargo container An intermodal container, often called a shipping container, is a large standardized shipping container, designed and built for intermodal freight transport, meaning these containers can be used across different modes of transport – from ship ...

can be mounted for road transport.

Electronics

In an

electronic device The field of electronics is a branch of physics and electrical engineering that deals with the emission, behaviour and effects of electrons using electronic devices. Electronics uses active devices to control electron flow by amplification a ...

(such as a computer), the chassis consists of a frame or other internal supporting structure on which the

circuit board A printed circuit board (PCB; also printed wiring board or PWB) is a medium used in electrical and electronic engineering to connect electronic components to one another in a controlled manner. It takes the form of a laminated sandwich struct ...

s and other electronics are mounted. In some designs, such as older

ENIAC ENIAC (; Electronic Numerical Integrator and Computer) was the first programmable, electronic, general-purpose digital computer, completed in 1945. There were other computers that had these features, but the ENIAC had all of them in one pac ...

sets, the chassis is mounted inside a heavy, rigid cabinet, while in other designs such as modern

computer case A computer case, also known as a computer chassis, is the enclosure that contains most of the hardware of a personal computer. The components housed inside the case (such as the CPU, motherboard, memory, mass storage devices, power supply unit a ...

s, lightweight covers or panels are attached to the chassis. The combination of chassis and outer covering is sometimes called an ''enclosure''.

Firearms

In firearms, the chassis is a

bedding Bedding, also known as bedclothes or bed linen, is the materials laid above the mattress of a bed for hygiene, warmth, protection of the mattress, and decorative effect. Bedding is the removable and washable portion of a human sleeping environme ...

frame on

long gun A long gun is a category of firearms with long barrels. In small arms, a ''long gun'' or longarm is generally designed to be held by both hands and braced against the shoulder, in contrast to a handgun, which can be fired being held with a single ...

s such as

rifle A rifle is a long-barreled firearm designed for accurate shooting, with a barrel that has a helical pattern of grooves (rifling) cut into the bore wall. In keeping with their focus on accuracy, rifles are typically designed to be held with b ...

s to replace the traditionally wooden

stock In finance, stock (also capital stock) consists of all the shares by which ownership of a corporation or company is divided.Longman Business English Dictionary: "stock - ''especially AmE'' one of the shares into which ownership of a company ...

, for the purpose of better

accurizing Accurizing is the process of improving the accuracy and precision of a gun ( firearm or airgun). For firearms, accuracy is the ability to hit exactly what one is aiming at, and precision is the ability to hit the same place over and over again ...

the gun. The chassis is usually made from hard

metal A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typica ...

lic material such as

aluminium alloy An aluminium alloy (or aluminum alloy; see spelling differences) is an alloy in which aluminium (Al) is the predominant metal. The typical alloying elements are copper, magnesium, manganese, silicon, tin, nickel and zinc. There are two principa ...

(and less frequently stainless steel,

titanium alloy Titanium alloys are alloys that contain a mixture of titanium and other chemical elements. Such alloys have very high tensile strength and toughness (even at extreme temperatures). They are light in weight, have extraordinary corrosion resistance ...

or recently

magnesium alloy Magnesium alloys are mixtures of magnesium (the lightest structural metal) with other metals (called an alloy), often aluminium, zinc, manganese, silicon, copper, rare earths and zirconium. Magnesium alloys have a hexagonal lattice structure, w ...

) due to metals having superior

stiffness Stiffness is the extent to which an object resists deformation in response to an applied force. The complementary concept is flexibility or pliability: the more flexible an object is, the less stiff it is. Calculations The stiffness, k, of a bo ...

and

compressive strength In mechanics, compressive strength or compression strength is the capacity of a material or structure to withstand loads tending to reduce size (as opposed to tensile strength which withstands loads tending to elongate). In other words, compre ...

compared with wood or synthetic polymer, which are commonly used in conventional rifle stocks. The chassis essentially functions as a more extensive pillar bedding, providing a metal-on-metal

bearing surface A bearing surface in mechanical engineering is the area of contact between two objects. It usually is used in reference to bolted joints and bearings, but can be applied to a wide variety of engineering applications. On a screw the bearing area ...

that has reduced shifting potential under the stress of

recoil Recoil (often called knockback, kickback or simply kick) is the rearward thrust generated when a gun is being discharged. In technical terms, the recoil is a result of conservation of momentum, as according to Newton's third law the force req ...

. A

barrel A barrel or cask is a hollow cylindrical container with a bulging center, longer than it is wide. They are traditionally made of wooden staves and bound by wooden or metal hoops. The word vat is often used for large containers for liquids, ...

action Action may refer to: * Action (narrative), a literary mode * Action fiction, a type of genre fiction * Action game, a genre of video game Film * Action film, a genre of film * ''Action'' (1921 film), a film by John Ford * ''Action'' (1980 fil ...

bedded into a metal chassis would theoretically operate more consistently during repeated firing, resulting in better

precision Precision, precise or precisely may refer to: Science, and technology, and mathematics Mathematics and computing (general) * Accuracy and precision, measurement deviation from true value and its scatter * Significant figures, the number of digit ...

. With the increasing availability of CNC machining, chassis have become more affordable and sophisticated, and gained increasing popularity as it can also be expanded to accommodate customizable "furnitures" (

buttstock A gunstock or often simply stock, the back portion of which is also known as a shoulder stock, a buttstock or simply a butt, is a part of a long gun that provides structural support, to which the barrel, action, and firing mechanism are attac ...

pistol grip On a firearm or other tools, a pistol grip is a distinctly protruded handle underneath the main mechanism, to be held by the user's hand at a more vertical (and thus more ergonomic) angle, similar to the how one would hold a conventional pis ...

, etc.) and rail interface systems that provide mounting points for various accessories.

References

*Starry, Donn A. GEN. ''Mounted Combat in Vietnam.'' ''Vietnam Studies'';

Department of the Army The United States Department of the Army (DA) is one of the three military departments within the Department of Defense of the U.S. The Department of the Army is the federal government agency within which the United States Army (U.S.) is org ...

Washington, D.C. ) , image_skyline = , image_caption = Clockwise from top left: the Washington Monument and Lincoln Memorial on the National Mall, United States Capitol, Logan Circle, Jefferson Memorial, White House, Adams Morgan, Na ...

1978. {{CarDesign nav Automotive chassis types Vehicle technology Computer enclosure Carriages and mountings

Examples of use

Vehicles

Electronics

Firearms

See also

References