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Excavator
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A typical modern excavator:a CAT 325C, fitted with quickcoupler and tilting bucket.
Principle of excavator operation. [4]
ExcavatorFrom Wikipedia, the free encyclopedia
For the AMD CPU microarchitecture, see Excavator(microarchitecture).
Excavators are heavy construction equipment consisting of aboom, stick, bucket and cab on a rotating platform known as the"house".[1] The house sits atop an undercarriage with tracks orwheels. A cableoperated excavator uses winches and steel ropesto accomplish the movements.[2] They are a natural progressionfrom the steam shovels and often called power shovels. Allmovement and functions of a hydraulic excavator areaccomplished through the use of hydraulic fluid, with hydrauliccylinders and hydraulic motors.[3] Due to the linear actuation ofhydraulic cylinders, their mode of operation is fundamentallydifferent from cableoperated excavators.
Contents
1 Terminology2 Usage3 Configurations4 Excavator attachments5 Notable manufacturers6 See also7 References8 External links
Terminology
Excavators are also called diggers, JCBs (a proprietary name, in an example of a generic trademark),mechanical shovels, or 360degree excavators (sometimes abbreviated simply to 360). Trackedexcavators are sometimes called "trackhoes" by analogy to the backhoe.[5] In the UK, wheeledexcavators are sometimes known as "rubber ducks."[6]
Usage
Excavators are used in many ways:
Digging of trenches, holes, foundationsMaterial handlingBrush cutting with hydraulic attachmentsForestry workForestry mulchingDemolitionGeneral grading/landscaping
Mining, especially, but not only openpit miningRiver dredgingDriving piles, in conjunction with a pile driverDrilling shafts for footings and rock blasting, by use of an auger or hydraulic drill attachmentSnow removal with snowplow and snow blower attachments
An old excavatorunder the Northwest(now Terex) name atthe Pageant of Steamgrounds
Excavator demolishinga house. Note thehydraulic thumb
LinkBelt excavatortrenching
CAT 5230 in coalmining operation
A L&T Komatsuexcavator seen in India
A New Holland E215in Hamburg, Germany.
Configurations
Modern, hydraulic excavators come in a wide variety of sizes. The smaller ones are called mini orcompact excavators.[7] For example, Caterpillar's smallest miniexcavator weighs 2,060 pounds (930 kg)and has 13 hp; their largest model is the largest excavator available (a record previously held by theOrenstein & Koppel RH400) the CAT 6090, it weighs in excess of 2,160,510 pounds (979,990 kg), has4500 hp and has a bucket size of around 52.0 m³ depending on bucket fitted.
Engines in hydraulic excavators usually just drive hydraulic pumps; there are usually 3 pumps: the twomain pumps are for supplying oil at high pressure (up to 5000 psi) for the arms, swing motor, trackmotors, and accessories, and the third is a lower pressure (700 psi) pump for Pilot Control, this circuitused for the control of the spool valves, this allows for a reduced effort required when operating thecontrols.
The two main sections of an excavator are the undercarriage and the house. The undercarriage includesthe blade (if fitted), tracks, track frame, and final drives, which have a hydraulic motor and gearingproviding the drive to the individual tracks, and the house includes the operator cab, counterweight,
Unimog backhoe loader withexcavator attachment
engine, fuel and hydraulic oil tanks. The house attaches to the undercarriage by way of a center pin.High pressure oil is supplied to the tracks' hydraulic motors through a hydraulic swivel at the axis of thepin, allowing the machine to slew 360° unhindered.[8]
The main boom attaches to the house, and can be one of several different configurations:
Most are mono booms: these have no movement apart from straight up and down.Some others have a knuckle boom which can also move left and right in line with the machine.Another option is a hinge at the base of the boom allowing it to hydraulically pivot up to 180°independent to the house; however, this is generally available only to compact excavators.There are also triplearticulated booms (TAB).
Attached to the end of the boom is the stick (or dipper arm). The stick provides the digging force neededto pull the bucket through the ground. The stick length is optional depending whether reach (longerstick) or breakout power (shorter stick) is required.
On the end of the stick is usually a bucket. A wide, large capacity (mud) bucket with a straight cuttingedge is used for cleanup and levelling or where the material to be dug is soft, and teeth are not required.A general purpose (GP) bucket is generally smaller, stronger, and has hardened side cutters and teethused to break through hard ground and rocks. Buckets have numerous shapes and sizes for variousapplications. There are also many other attachments which are available to be attached to the excavatorfor boring, ripping, crushing, cutting, lifting, etc.
Before the 1990s, all excavators had a long or conventional counterweight that hung off the rear of themachine to provide more digging force and lifting capacity. This became a nuisance when working inconfined areas. In 1993 Yanmar launched the world's first Zero Tail Swing excavator,[9] which allowsthe counterweight to stay inside the width of the tracks as it slews, thus being safer and more userfriendly when used in a confined space. This type of machine is now widely used throughout the world.
There are two main types of "Control" configuration generally use in excavators to control the boom andbucket, both of which spread the four main digging controls between two xy joysticks. This allows askilled operator to control all four functions simultaneously. The most popular configuration in the US isthe SAE controls configuration while in other parts of the world, the ISO control configuration is morecommon. Some manufacturers such as Takeuchi have switches that allow the operator to select whichcontrol configuration to use.
Excavator attachments
Hydraulic excavator capabilities have expanded far beyondexcavation tasks with buckets. With the advent of hydraulicpowered attachments such as a breaker, a grapple or an auger, theexcavator is frequently used in many applications other thanexcavation. Many excavators feature a quick coupler forsimplified attachment mounting, increasing the machine'sutilization on the jobsite. Excavators are usually employedtogether with loaders and bulldozers. Most wheeled, compact andsome mediumsized (11 to 18tonne) excavators have a backfill(or dozer) blade. This is a horizontal bulldozerlike bladeattached to the undercarriage and is used for levelling andpushing removed material back into a hole.
Notable manufacturers
See also
Types of excavator
Compact excavatorDragline excavatorLong reach excavatorAmphibious excavatorPower shovelSteam shovelSuction excavatorWalking ExcavatorBucketwheel excavator
Other
Bobcat CompanyBucyrus InternationalCase CECaterpillar Inc.CNH GlobalDoosan Infracore (formerly Daewoo Heavy Industries & Machinery) including Solar brandENMTPHitachi Construction MachineryHydremaHyundai Heavy IndustriesJohn DeereJ. C. Bamford (JCB)Kanga LoadersKomatsu LimitedLBX (LinkBelt) ExcavatorsThyssenKruppKobelcoKubotaLiebherrLiuGongL&TMitsubishi Heavy IndustriesNew HollandOrenstein & Koppel (O&K)PoclainSamsung GroupSandvik Mining and ConstructionSanyST KineticsTerex CorporationVolvo Construction EquipmentWacker NeusonXCMGYanmar
Wikimedia Commons hasmedia related to Excavators.
Look up excavator inWiktionary, the freedictionary.
BulldozerCivil engineeringHeavy equipmentLoader (equipment)Mining simulationTractorSkid Steer LoaderMini Loader
References1. "Use Powerful Excavator Building Tamiami Trail" (http://news.google.com/newspapers?
nid=2456&dat=19160915&id=NdxWAAAAIBAJ&sjid=IUMNAAAAIBAJ&pg=3734,2088410). The WeeklyMiami Metropolis. September 15, 1916. Retrieved 29 December 2013.
2. "First Wind Farm In Nh To Begin Operation" (http://news.google.com/newspapers?nid=2457&dat=20060109&id=SsA8AAAAIBAJ&sjid=Ey4MAAAAIBAJ&pg=1480,1690624). Bangor DailyNews. Jan 9, 2006. Retrieved 29 December 2013.
3. "Industrial Expe ..Lasso Gives More Power To The HyMac Elbow" (http://news.google.com/newspapers?nid=2507&dat=19620609&id=QOA9AAAAIBAJ&sjid=QkgMAAAAIBAJ&pg=3615,1603500). TheGlasgow Herald. June 9, 1962. Retrieved 29 December 2013.
4. Simionescu, P.A. (2014). Computer Aided Graphing and Simulation Tools for AutoCAD users (1st ed.).Boca Raton, FL: CRC Press. ISBN 9781482252903.
5. F, Kevin. "Types of Excavators and Their Uses" (http://www.brighthubengineering.com/buildingconstructiondesign/44424typesofexcavatorsandtheiruses/). Retrieved 29 December 2013.
6. "Komatsu PW1307" (http://www.heservices.co.uk/plant/komatsupw130.php). H.E. Services. Retrieved13 April 2010.
7. "Tips to Help You Operate Your Mini Excavator" (http://natparts.com/tipstohelpyouoperateyourminiexcavator/). Retrieved 29 December 2013.
8. How it works: The track motor spool in an Excavator (https://www.youtube.com/watch?v=oUVE2PIV5_k)9. http://www.yanmar.com/construction/products/excavators/
External links
Hydraulic Crawler Excavators Product Reviews, Specs andBuying Files(http://www.constructionequipment.com/crawlerexcavators)NIOSH Publication: Preventing Injuries When WorkingWith Hydraulic Excavators and Backhoe Loaders(http://www.cdc.gov/niosh/docs/wpsolutions/2004107/default.html)Excavators Used as Cranes (http://www.adapttraining.co.uk/pdfs/cpa.pdf)Safety Alert: Excavators Used as Cranes (http://www.operc.com/SafetyAlert/ALT_017_A4.pdf)"Big Shovels and Why" Popular Mechanics, March 1930, pp 466470(http://books.google.com/books?id=cOIDAAAAMBAJ&pg=PA466&dq=Popular+Science+1930+plane+%22Popular+Mechanics%22&hl=en&ei=WhNjTqPcEcnm0QGisoX1CQ&sa=X&oi=book_result&ct=result&resnum=7&sqi=2&ved=0CEMQ6AEwBg#v=onepage&q&f=true)
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Categories: Tracked vehicles Excavators
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