TAK-4

independent suspension Independent suspension is any automobile suspension system that allows each wheel on the same axle to move vertically (i.e. reacting to a bump on the road) independently of the others. This is contrasted with a beam axle or deDion axle system ...

system is a family of independent suspension systems designed and manufactured by

Oshkosh Corporation Oshkosh Corporation, formerly Oshkosh Truck, is an American industrial company that designs and builds specialty trucks, military vehicles, truck bodies, airport fire apparatus, and access equipment. The corporation also owns Pierce Manufac ...

for use on military, severe-duty and

emergency vehicle An emergency vehicle is a vehicle used by emergency services. Emergency vehicles typically have specialized emergency lighting and vehicle equipment that allow emergency services to reach calls for service in a timely manner, transport equipment ...

s. The system was developed from the mid-1990s. In addition to third party usage for

U.S. Army The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cl ...

and

Marines Marines, or naval infantry, are typically a military force trained to operate in littoral zones in support of naval operations. Historically, tasks undertaken by marines have included helping maintain discipline and order aboard the ship (refl ...

Mine Resistant Ambush Protected (

MRAP Mine-Resistant Ambush Protected (MRAP; ) is a term for United States Armed Forces, United States military light tactical vehicles produced as part of the MRAP program that are designed specifically to withstand improvised explosive device (IE ...

) fleet upgrades, TAK-4 independent suspension system is fitted by Oshkosh to a variety of its military vehicles and by its business unit, Oshkosh Airport Products, to its Striker Airport Rescue vehicle and Pierce Manufacturing to its Aircraft Rescue Fire Fighting (ARFF) trucks and other appliances.

Development

In 1999 Oshkosh was awarded a

United States Air Force The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Si ...

(USAF) contract to supply P23 ARFF trucks. These, and the earlier P23 supplied to the Air Force between 1994 and 1996 by Teledyne and Emergency-One (E-One) were fitted with independent suspension designed by Timoney Technology of Ireland. The success of the P23, and subsequent interest in an independent suspension solution for US Army and Marines 5-ton truck upgrade projects led to Oshkosh (and the then Rockwell) approaching Timoney with regard to a licence arrangement for the suspension. Following discussions with both, Timoney opted to enter into a licence arrangement with Rockwell (now

Meritor Meritor, Inc. is an American corporation headquartered in Troy, Michigan, which manufactures automobile components for military suppliers, trucks, and trailers. Meritor is a Fortune 500 company. In 1997, Rockwell International spun off its auto ...

). Oshkosh then developed two, possibly three independent suspension systems, including the set-up that came to be marketed as TAK-4 independent suspension system. JLTV Demo KJ7L2159 8x10 hires-crop

The first use of TAK-4 independent suspension system was on an M939 5-ton truck as part of the Marines’ plan to upgrade its M939 fleet. The upgrade approach was ultimately abandoned, this replaced by a new-build approach for which the Oshkosh

Medium Tactical Vehicle Replacement The Medium Tactical Vehicle Replacement (MTVR) is a series of vehicles used by the U.S. Marines. The first MTVRs were delivered in late 1999. The MTVR is the equivalent of the U.S. Army’s Family of Medium Tactical Vehicles (FMTV); the Marines ...

(MTVR) was selected. The first production contract for the MTVR was awarded in February 1999 and the type remains in production for the US Marines. The MTVR is fitted with TAK-4 independent suspension system independent suspension and was the first mass-produced military truck with fully independent suspension. Oshkosh has since fitted TAK-4 independent suspension system to its

Palletized Load System The Palletized Load System (PLS) is a truck-based logistics system that entered service in the United States Army in 1993. It performs long and short distance freight transport, unit resupply, and other missions in the tactical environment to sup ...

(PLS) trucks, Logistic Vehicle System Replacement (LVSR) trucks and M-ATVs (MRAP – All-Terrain Vehicle), and the system has been retro-fitted to US Army/Marines General Dynamics/Force Protection

Cougar The cougar (''Puma concolor'') is a large cat native to the Americas. Its range spans from the Canadian Yukon to the southern Andes in South America and is the most widespread of any large wild terrestrial mammal in the Western Hemisphere. ...

MRAPs, BAE Systems’

RG-31 The RG-31 Nyala is a 4×4 multi-purpose mine-resistant ambush protected infantry mobility vehicle manufactured in South Africa by Land Systems OMC (the division of Denel SOC LTD, located in Benoni, South Africa) and in Turkey by FNSS Defenc ...

and

RG-33 The RG-33 is a mine-resistant light armored vehicle initially designed by BAE Systems Land Systems South Africa (formerly Land Systems OMC), a South African subsidiary of BAE Systems. BAE Systems in the US extensively modified it with addition ...

MRAPs. Oshkosh business units Pierce Manufacturing and Oshkosh Airport Products fit TAK-4 independent suspension system systems to a large amount of its fire trucks. Most recently the latest TAK-4i intelligent independent suspension system has been fitted to Oshkosh's L-ATV (Light Combat Tactical – All-Terrain Vehicle), this selected to meet the US Army and Marines JLTV (Joint Light Tactical Vehicle) requirement. Oshkosh remains current market leader for independent suspension systems above the 5000 kg threshold for where commercial systems are often used, and excluding Striker and Pierce products has equipped in the region of 30,000 military vehicles with the TAK-4 independent suspension system set-up. This figure will increase as JLTV production ramps up. To date the TAK-4 independent suspension system has accrued in excess of 1,000,000 actual durability test miles, most of these in extreme conditions.

Description

The Oshkosh TAK-4 (and TAK-4i) suspension is known as double wishbone independent suspension. This is an independent suspension design using two wishbone-shaped arms to locate the wheel. Each arm has two mounting points to the

subframe A subframe is a structural component of a vehicle, such as an automobile or an aircraft, that uses a discrete, separate structure within a larger body-on-frame or unit body to carry certain components, such as the engine, drivetrain, or suspen ...

and one joint at the

knuckle The knuckles are the joints of the fingers. The word is cognate to similar words in other Germanic languages, such as the Dutch "knokkel" (knuckle) or German "Knöchel" (ankle), i.e., ''Knöchlein'', the diminutive of the German word for bone ( ...

, and in the case of TAK-4 independent suspension system these arms are of unequal length. The

shock absorber A shock absorber or damper is a mechanical or hydraulic device designed to absorb and damp shock impulses. It does this by converting the kinetic energy of the shock into another form of energy (typically heat) which is then dissipated. Most ...

and

spring Spring(s) may refer to: Common uses * Spring (season), a season of the year * Spring (device), a mechanical device that stores energy * Spring (hydrology), a natural source of water * Spring (mathematics), a geometric surface in the shape of a h ...

mount to the lower arm to control vertical movement. The double-wishbone suspension can also be referred to as ‘double A-arm,’ though the arms themselves can be A-shaped, L-shaped, or even a single bar linkage. The complete TAK-4 independent suspension system set-up also includes a subframe which contains the axle differential, half shafts, and wheel ends with steering attachments and

brakes A brake is a mechanical device that inhibits motion by absorbing energy from a moving system. It is used for slowing or stopping a moving vehicle, wheel, axle, or to prevent its motion, most often accomplished by means of friction. Backgroun ...

. TAK-4 independent suspension system accepts various spring mediums, but the vast majority of systems supplied by Oshkosh to date have been fitted with coil springs. Exceptions are the rear axles on the LVSR and the wrecker variant of the MTVR which are hydro-pneumatic struts with Hendrickson components. The original TAK-4 independent suspension system

coil spring A selection of conical coil springs The most common type of spring is the coil spring, which is made out of a long piece of metal that is wound around itself. Coil springs were in use in Roman times, evidence of this can be found in bronze Fib ...

set-up as fitted to MTVR, LVSR and PLS A1 (front axles), M-ATV and upgraded MRAPs offers around 16-inches of vertical wheel travel and for MTVR, LVSR and PLS-A1, and has an off-road

gross vehicle weight rating Vehicle weight is a measurement of wheeled motor vehicles; either an actual measured weight of the vehicle under defined conditions or a gross weight rating for its weight carrying capacity. Curb or kerb weight Curb weight (U.S. English) or kerb ...

(GVWR) of 12,020 kg. The slighter lighter-capacity version fitted to the M-ATV has an off-road GVWR of 10,433 kg. The light version offered as a potential

HMMWV The High Mobility Multipurpose Wheeled Vehicle (HMMWV; colloquial: Humvee) is a family of light, four-wheel drive, military trucks and utility vehicles produced by AM General. It has largely supplanted the roles previously performed by the ori ...

upgrade has a GVWR of 10,000 kg and offers around 14-inches of vertical wheel travel. In all cases the operating profile of the system is 70% off-road, 30% on-road. The new Oshkosh TAK-4i intelligent independent suspension system suspension provides 20-inches of wheel travel, and again a 70% off-road, 30% on-road operating profile. TAK-4i intelligent independent suspension system suspension is fitted to Oshkosh's JLTV/L-ATV. TAK-4i intelligent independent suspension system suspension is an ‘intelligent’ independent suspension, providing variable ride height through gas springs. To promote TAK-4i intelligent independent suspension system suspension, Oshkosh has stated the following: “In fact, Independent testing proves that the Oshkosh L-ATV provides the same ride quality at speeds 70 percent faster than today’s industry gold standard for off-road mobility, the Oshkosh MRAP All-Terrain Vehicle (M-ATV).”

TAK-4 Applications

(coil springs unless stated) * M939 5-ton: Development for potential upgrade which evolved into MTVR procurement * Oshkosh

(MTVR): 11,350 (est.) US Marines/Navy plus 430 (est.) export sales. Rear axles on the MK36 wrecker variant are

hydropneumatic Hydropneumatic suspension is a type of motor vehicle suspension system, designed by Paul Magès, invented by Citroën, and fitted to Citroën cars, as well as being used under licence by other car manufacturers, notably Rolls-Royce ( Silver Shad ...

struts with Hendrickson International components * Oshkosh Heavy Expanded Mobility Tactical Truck (HEMTT): Very small quantity of early models to Qatar * Oshkosh

(PLS A1): >2150. Front

axle An axle or axletree is a central shaft for a rotating wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In the former case, beari ...

pair only * Oshkosh Logistic Vehicle System Replacement (LVSR): 2022. Rear axles are hydropneumatic struts with Hendrickson International components * Oshkosh M-ATV: 10,000 (est.) * Oshkosh L-ATV/JLTV: TAK-4i intelligent independent gas spring suspension system suspension; total requirement for 49,099 (Army) and 5500 (Marines) * Oshkosh S-ATV: Developmental; TAK-4 independent suspension system *

upgrade proposal: Developmental; light version *

Family of Medium Tactical Vehicles The Family of Medium Tactical Vehicles (FMTV) is a series of military vehicles that are based on a common chassis and vary by payload and mission requirements. The FMTV is derived from the Austrian Steyr 12M18 truck, but substantially m ...

(FMTV) Enhanced Protection & Mobility Demonstrator (EPMD); upgrade proposal: Developmental *

BAE Systems BAE Systems plc (BAE) is a British multinational arms, security, and aerospace company based in London, England. It is the largest defence contractor in Europe, and ranked the seventh-largest in the world based on applicable 2021 revenue ...

RG-31 Mk5 MRAP: 97 TAK-4® independent suspension system upgrade kits supplied from February 2010, 21 new-build vehicles in early 2011 * BAE Systems RG-33 MRAP: 390 (4x4) variants retro-fitted * Force Protection/General Dynamics Cougar: Approx. 2,900 Cougar (in an undisclosed mix of (4x4) and (6x6) were retro-fitted with TAK-4 independent suspension system) * Force Protection/

General Dynamics General Dynamics Corporation (GD) is an American publicly traded, aerospace and defense corporation headquartered in Reston, Virginia. As of 2020, it was the fifth-largest defense contractor in the world by arms sales, and 5th largest in the Uni ...

Ridgback: UK variant of

; single example fitted with TAK-4 independent suspension system for evaluation * Hawk Extreme: A a wildland firefighting water tender based on the MTVR MK23/MK25 and developed in conjunction with Pierce Manufacturing * Oshkosh Airport Products Striker: A range of 4x4, 6x6 and 8x8 specialized Aircraft Rescue and Fire Fighting vehicles built by Oshkosh at the Pierce Manufacturing facilities

Appleton, Wisconsin Appleton ( mez, Ahkōnemeh) is a city in Outagamie, Calumet, and Winnebago counties in the U.S. state of Wisconsin. One of the Fox Cities, it is situated on the Fox River, southwest of Green Bay and north of Milwaukee. Appleton is the c ...

* Pierce Manufacturing: TAK-4 independent suspension system is an option on Pierce Arrow (F), Enforcer (F), Impel (F/R), Dash CF (F/R), Velocity (F/R) and Quantum (F/R) custom chassis * Oshkosh P-19R Aircraft Rescue and Fire Fighting (ARFF)

Gallery

File:M939 with TAK-4.jpg, The first use of TAK-4 independent suspension system was on an M939 5-ton truck as part of the Marines’ plan to upgrade its M939 fleet. File:MTVR TAK-4.jpg, Oshkosh's MTVR is fitted with TAK-4 independent suspension and was the first mass-produced military truck with fully independent suspension. File:Pierce TAK-4.jpg, Oshkosh's TAK-4 independent suspension system is an option on the Pierce Arrow (F), Enforcer (F), Impel (F/R), Dash CF (F/R), Velocity (F/R) and Quantum (F/R) custom chassis. File:U.S. Air Force Staff Sgt. Ryan Vanterpool, an aerial porter with the 455th Expeditionary Aerial Port Squadron, chains down a mine-resistant, ambush-protected vehicle aboard an Air Force C-17 Globemaster III 131002-F-YL744-098.jpg, Oshkosh's MRAP – All-Terrain Vehicle (M-ATV) is fitted with TAK-4 independent suspension. About 10,000 M-ATVs have been built to date File:Five days, two pairs of socks later, Marine convoy operations in Afghanistan 131022-M-ZB219-479.jpg, The front axle pair of Oshkosh's Logistic Vehicle System Replacement (LVSR) 2022 are fitted with TAK-4, the rear axles are hydropneumatic struts with Hendrickson International components File:Stryker (3561270493).jpg, Oshkosh's Striker range of specialized Aircraft Rescue and Fire Fighting vehicles are fitted with TAK-4 independent suspension File:Hillcrest NY 2002 Pierce Dash Midmount Platform.jpg, Oshkosh's TAK-4 independent suspension system is an option on the front or rear axles of the Pierce Dash File:Oshkosh-TAK-4.jpg, Oshkosh's TAK-4 independent suspension system has been retro-fitted to US Army/Marines MRAPs including the General Dynamics/Force Protection

File:Ridgback TAK-4-crop.jpg, A single example of the British Army's Ridgback MRAP (UK-specific version of Cougar) has been fitted with Oshkosh's TAK-4 independent suspension for evaluation

References

External links

{{Commons, Oshkosh TAK-4 Independent Suspension System
Oshkosh TAK-4 Independent Suspension System portal

comparison TAK-4 vs. standard suspension - interesting

TAK-4 on Pierce fire appliances
Oshkosh vehicles Oshkosh Corporation