Reoort Backhoe

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  • 8/9/2019 Reoort Backhoe




    Department of Mechanical Engineering

    CerticateThis is to certify that the work in Seminar

    entite! "#ackhoe Loa!ers$%mitte!

    %y s$ni K$mar %earin& Re&! no

    '(')**++,-. is a recor! of work !one in

    Partia /$0ment Of The Re1$irement /or

    Awar! #acheor Of Technoo&y in

    2echanica En&ineerin&

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    s s pati PROF A.K. BEHERA



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    6Pick the !ate75IKAS3 KU2AR


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    PR"#C"P'E OF (ORK"#)

    H*DRO&'"C +A'+E!

    H*DRO&'"C! "# BACKHOE

    H*DRO&'"C! "# 'OADER



    A%%ACH"#) D"FFERE#% %OO'!

    %HE REA!O# %HA% (E &!E A BACKHOE



  • 8/9/2019 Reoort Backhoe



    A %ackhoe oa!er is an interestin& in9ention %eca$se it is act$ay three:ieces of constr$ction e1$i:ment com%ine! into one $nit; A %ackhoeoa!er isa steerin& whee. %rakes.

    etc;?; #ackhoe ca%s are either com:etey encose! or ha9e an o:en cano:y

    str$ct$re to &i9e the o:erator :rotection;


    The oa!er can !o se9era !i@erent thin&s; In many a::ications. yo$ $se itike a %i&. :owerf$ !$st:an or co@ee scoo:; o$ $s$ay !onBt !i& with ityo$ mosty $se it to :ick $: an! carry ar&e amo$nts of oose materia; ItBsaso $se! to smooth thin&s o9er ike a %$tter knife. or to :$sh !irt ike a:ow; The o:erator contros the oa!er whie !ri9in& the tractor;


    The -achoeis the main too of the %ackhoe oa!er; ItBs $se! to !i& $: har!.

    com:act materia. $s$ay earth. or to ift hea9y oa!s. s$ch as a sewer%oD; It

    can ift this materia an! !ro: it in a :ie to the si!e of the hoe;

    #asicay. the %ackhoe is a %i&. eDtremey :owerf$ 9ersion of yo$r arm or0n&er; It has three se&ments

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    The -oom The stic

    The -/cet

    This arran&ement is 9ery simiar to yo$r arm; o$r arm has threese&ments yo$r $::er arm. forearm an! han!;

    The %ackhoe se&ments are connecte! %y three 0oints. com:ara%e toyo$r wrist. e%ow an! sho$!er; The %ackhoe mo9es in :retty m$ch thesame way as yo$r arm; In a Cater:iarF %ackhoe. the %oom is %ent$:war! to make it easier to !i& with o%staces in the way; This !esi&n aso:ro9i!es eDtra s:ace for the %$cket when the o:erator c$rs it in with a f$oa!;

    The %ackhoe can !i& a sorts of hoes. %$t is es:eciay s$ite! for !i&&in&

    ,itches; To $se the %ackhoe. the o:erator has to :ark the tractor an! t$rnthe seat aro$n!;

    So what !o the tractor. oa!er an! %ackhoe ha9e to !o with each otherThe tractor com:onent is for mo9in& the other two com:onents from:ace to :ace. an! the o:erator aso mane$9ers it when $sin& the oa!er;The oa!er an! %ackhoe com:onents are a nat$ra com%ination for asorts of =o%s; Hhen yo$ !i& $: a ot of !irt to make a !itch or any othersort of hoe. yo$ &eneray nee! a oa!er to either mo9e the !irt o$t of thearea or to 0 the !irt %ack in once yo$B9e &ot the :i:es. :ower ines. etc;

    in :osition; The most common a::ication for a %ackhoe oa!er is this%asic =o% !i&&in& a trench with the %ackhoe an! then -ac$lling itwith the oa!er;

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    %HE !%AB"'"1ER 'E)

    The other a::en!a&es yo$B ty:icay notice on a %ackhoe oa!er are the

    two sta-ili2er legs=$st %ehin! the rear whees; These e&s are cr$cia to%ackhoe o:eration %eca$se they take the %r$nt of the wei&ht when a%ackhoe is !i&&in&; Hitho$t the sta%iier e&s. the wei&ht of a hea9y oa!or the !ownwar! force of !i&&in& into the &ro$n! wo$! strain the wheesan! tires. an! the whoe tractor wo$! %o$nce constanty; The sta%iierskee: the tractor stea!y. minimiin& the =ostin& e@ect of !i&&in& with the%ackhoe; They aso sec$re the tractor so that it wonBt si: into the !itch orhoe;

    The sta%iier e&s ha9e two ty:es of shoes. so that they can %e :ante!sec$rey on %oth !irt an! :a9ement; The gro/ser shoesi!e !i&s into the

    !irt for a %etter &ri:. %$t wo$! tear $: the :a9ement if yo$ were to $se iton a roa!; /or a &oo! &ri: on as:hat. the o:erator sim:y i:s ther/--er$pa,,e, shoeinto :osition;

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    PR"#C"P'E OF (ORK"#)

    If yo$B9e e9er watche! a %ackhoe at work. yo$ know that it is an

    eDtraor!inariy :owerf$ too; An eD:erience! o:erator can !i& a -foot!ee:. )'footon& !itch in ess than )- min$tes; J$st think how on& itwo$! take yo$ to !o that with ony a sho9e Amain&y. a of this work is!one with h3,ra/lics :$m:in& i1$i! to mo9e :istons;

    The conce:t of hy!ra$ic machinery may seem :retty %iarre how can:$m:in& i1$i! &i9e yo$ s$ch :ower %$t itBs act$ay 9ery sim:e; /irst.etBs ook at the %asic i!ea of a hy!ra$ic system. an! then weB see how a%ackhoe $ses these systems to !i& an! oa! s$ch h$&e amo$nts of !irt;

    3y!ra$ic systems sim:y transmit forces from :oint to :oint thro$&h $i!;2ost systems $se an incompressi-le$i!. a $i! that is as !ense as itcan &et; This sort of $i! transmits neary a of the ori&ina force instea!of a%sor%in& some of it; The most commony $se! incom:ressi%e $i! inhy!ra$ic machinery is oil;

    In the 9ery sim:e hy!ra$ic machine shown %eow. the o:erator :$sheson the oi with one :iston so that the oi :$shes on another :iston. raisin&it $:;

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    #eca$se the secon! :iston has a ar&er ,iameterthan the 0rst :iston.

    the secon! :iston mo9es a shorter !istance %$t :$shes $: with &reaterforce;

    The %asic conce:t at work is a tra!e %etween !istance an! force; Thework yo$ !o in :ressin& !own on the :iston on the eft has twocom:onents the amo/nt of forceyo$ a::y an! ho4 faryo$ :$sh the:iston; This :$shes !own a certain amo$nt of $i!; Since the $i! isincom:ressi%e. it canBt a%sor% the force yo$ a::y. so it :$shes $: on the:iston on the ri&ht; The $i! has the same press/re>:o$n!s :er s1$areinch? at e9ery :oint in the system; Since the :ress$re at the :iston on theri&ht is workin& on a ar&er area. that :iston :$shes $:war! with a &reaterforce;

    ItBs :retty easy to 0&$re o$t the eDact m/ltiplication factor; Ass$methat the :iston on the eft has a *inch !iameter >)inch ra!i$s?. whie the:iston on the ri&ht has a Minch !iameter >+inch ra!i$s?; The area of each:iston is Pi 5 r6; The area of the eft :iston is therefore +;), >+;), )*?.whie the area of the :iston on the ri&ht is *8;*M >+;), D +*?; The :iston onthe ri&ht is nine times ar&er than the :iston on the eft; This means thatany force a::ie! to the efthan! :iston wi %e nine times &reater on theri&hthan! :iston; So. in the i$stration a%o9e. the )'':o$n! !ownwar!

    force a::ie! to the eft :iston creates a '':o$n! $:war! force on theri&ht :iston; #$t. in kee:in& with the force!istance tra!eo@. yo$B9emo9e! the efthan! :iston inches an! raise! the ri&hthan! :iston ony) inch;

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  • 8/9/2019 Reoort Backhoe


    H*DRO&'"C +A'+E!

    Hith o$r 9ery sim:e hy!ra$ic machine. we :$she! !own on some oi withone :iston an! that oi :$she! $: a ar&er :iston. there%y m$ti:yin& the

    force of o$r e@ort; This sort of hy!ra$ic mechanism is &reat for systemswhere yo$ nee! to a::y a force 9ery %riey. e9ery once in a whie a%rake system. for eDam:e; #$t in a :iece of e1$i:ment s$ch as a%ackhoe. yo$Bre aways mo9in& :istons. so yo$ nee! constant oilpress/re;

    In a %ackhoe. this :ress$re comes from an oi :$m: that is :owere! %y a!iese en&ine;The :$m: !oes the same sort of thin& as the narrow :istonwe saw in the earier eDam:e; It a::ies a esser force to the oi at a hi&hrate of s:ee!. &eneratin& eno$&h :ress$re to mo9e another :iston moresowy %$t with &reater force; The :$m: kee:s a stea!y s$::y of hi&h

    :ress$re oi owin& to a 9a9e %ock system. which !irects the :ress$reBsforce;

    So. the :owerf$ :istons in a %ackhoe are act$ay mo9e! %y the same forcesthat we saw workin& in the sim:e hy!ra$ic !esi&n; There are some si&ni0cant!i@erences in how the two systems o:erate. howe9er; The sim:e :iston weooke! at co$! ony a::y m$ti:ie! force in one !irection; If yo$ :$she! !ownon the narrower :iston. the wi!er :iston mo9e! $: with &reater force; #$t for a%ackhoe to !i&. its arms ha9e to %e a%e to mo9e in ,i7erent ,irections; To

    mo9e this way. the :istons m$st %e a%e to :$sh and:$If we were to c$t o:enone of the :iston cyin!ers from a %ackhoe. yo$ wo$! see somethin& ike this*.8+'k&? stick ift ca:acity an! a+.,'% >).(8(k&? %oom ift ca:acity;

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    H*DRO&'"C! "# %HE 'OADER

    HeB9e mosty foc$se! on the %ackhoe here. %$t the oa!er is aso !ri9en

    %y hy!ra$ics; Its hy!ra$ic rams are con0&$re! in a si&hty !i@erent way they work as pairs; The rams ift the %$cket in eDacty the same wayyo$ wo$! ift a hea9y %oD yo$ &ra% %oth si!es an! ift with %oth arms;The 9a9e system :$m:s the same amo$nt of oi to each ram in the :airso that they mo9e in $nison; This sta%iies the oa!er %$cket;

    Cater:iar has two ty:es of oa!ers on its %ackhoes a single tilt>yeow? an! a parallel lift>%ack?; #oth ty:es $se a :iston :air to ift theoa!er arms; This :iston :air is attache! to the tractor an! the armsho!in& the %$cket; The :istons eDten! to raise the arms an! retract toower them; Paraeift oa!ers $se a secon! :air of rams attache! to theoa!er arms an! the %$cket itsef; These rams eDten! to !$m: the %$cketan! retract to tit it %ack $:; Sin&etit oa!ers !o this with ony onecentra ram;

    Paraeift oa!ers ha9e an eight$-ar$linage !esi&n that im:ro9esoa!in& :erformance; In this system. !i@erent sets of %ars in the oa!erare connecte! in s$ch a way that the %$cket !oesnBt ti: as it rises;#asicay. the two main sets of :arae %ars that ho! the %$cket mo9eto&ether so that they kee: the %$cket e9e with the &ro$n!; Hitho$t:arae ift. the oa!er wo$! %e somethin& ike a seesaw with a crate

    naie! to one en!; If yo$ 0e! the crate with oran&es when the seesawwas e9e. a ot of them wo$! fa o$t when yo$ tite! the seesaw $:; A:araeift system aows for more ecient oa!in& %eca$se it kee:s moreof the materia in the %$cket as it ifts;

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  • 8/9/2019 Reoort Backhoe



    As yo$B9e seen. %ackhoe oa!ers are 0e! with hy!ra$ic 9a9es an!cyin!ers; In a!!ition. %ackhoe oa!ers ha9e a sorts of thin&s yo$ wo$!

    0n! in any tractor. car or tr$ck; In this section. weB ook at some of thecom:onents that make a %ackhoe work;

    The c$taway !rawin& %eow shows many of the ma=or com:onents of aCater:iar %ackhoe oa!er

    A %ackhoe oa!ers ha9e a set of stan!ar! com:onents;

    An engine In a ty:ica %ackhoe oa!er. the tractor. oa!er an! %ackhoe

    are a :owere! %y a !iese en&ine; The Cater:iar 8'horse:ower +'-,

    en&ine %eow has a ,cyin!er. ,stroke. !irectin=ection !esi&n; It aso

    feat$res a ,r3$t3pe9 ra,ial$seal t4o$stage air lter an! a thermal

    starting ai, that aows the en&ine to start $: e9en at *' !e&rees

    /ahrenheit >* C?; The %asic !e is nat/rall3 aspirate,. %$t some

    Cater:iar %ackhoes ha9e a t$r%ochar&e!
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    A transmission To a::y the en&ine :ower to the tractor an! the

    %ackhoe an! oa!er hy!ra$ic systems. yo$ nee! a transmission; A

    %ackhoe transmission !oes the same %asic =o% as the transmission in yo$r

    car it ets the o:erator switch %etween &ears. &o forwar! or in re9erse

    an! $se en&ine :ower ecienty; #ackhoe oa!ers come with eithera$tomatic or man$a transmissions; The Caterpillar po4er$sh/ttle

    transmission %eow :ro9i!es fo$r s:ee!s. as we as forwar! an!

    %ackwar!; It has forwar! an! re9erse hy!ra$icay shifte! sh$tte c$tches.

    which et the o:erator chan&e !irection an! tra9e s:ee! on the &o; It aso

    has a tor1$econ9erterthat ena%es maDim$m :ower eciency;

    A:les The whees in a %ackhoe oa!er are t$rne! %y aDes; The

    Cater:iar stan!ar! rear aDe shown %eow has a s:ecia encose! !esi&n

    that :rotects it from the eements; This ets the %ackhoe o:erate reia%y.

    e9en in eDtremey harsh en9ironments; Braes J$st ike yo$r car. %ackhoe oa!ers nee! %rakesin or!er to sto:

    mo9in&; Cater:iar %ackhoes $se hy!ra$icayact$ate!. sefa!=$stin&

    !isc %rakesto sto: the tractor; They ha9e a se:arate :arkin& %rake that

    the o:erator a::ies with a han! e9er;
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    These com:onents. as we as a the other %ackhoe :arts weB9e ooke! at

    in this artice. are a assem%e! on a st$r!y steeframe



    Hhen yo$ sto: an! think a%o$t a the !i@erent mo9in& :arts in a %ackhoe

    oa!er. it seems $n%eie9a%e that yo$ nee! ony one :erson at the contros; Aswe saw in the ast two sections. the %ackhoe arm swi9es on fo$r !i@erent hin&es

    >some %$cket !esi&ns ha9e 09e? an! the oa!er mo9es on two to three hin&es;

    A!!itionay. the o:erator contros the sta%iier arms an! mo9es the tractor

    aro$n! whie oa!in&; 3ow !oes one :erson !o a of this

    The main contros for a Cater:iar %ackhoe are two com:$terstye=oysticks; 3ere are the f$nctions of the =oysticks+.(' k&? an! can ho! );(- c$%ic yar!s >);+ c$%icmeters? of !irt in its stan!ar! %$cket; The %ackhoe an! oa!ercom:onents !onBt ha9e 1$ite as m$ch :ower as ar&er e1$i:ment. %$tthey !o 9ery we. e9en with fairy !ic$t =o%s;

    A constr$ction crew that !oes a sorts of !i@erent work wi $s$ay %$y a%ackhoe rather than more ecient s:eciaie! e1$i:ment %eca$se the%ackhoe :erforms we in a wi!e 9ariety of sit$ations; /or sma to me!i$m!i&&in& =o%s. a %ackhoe is certainy s$cient; An! as weB see ater on.

    some %ackhoe mo!es !o a ot more than =$st !i&&in& an! oa!in&;

  • 8/9/2019 Reoort Backhoe


  • 8/9/2019 Reoort Backhoe





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