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Page 1: Concepts and Techniques of Machine Safeguarding

8/12/2019 Concepts and Techniques of Machine Safeguarding

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Page 2: Concepts and Techniques of Machine Safeguarding

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Adapted from the U.S. Department of Labor,

Occupational Safety and Health Administration OSHA 306, !""# $%e&ised'

 

CONCEPTS AND TECHNIQUES OFMACHINE SAFEGUARDING

 

Table of Contents 

Introduction • Chapter 1 - Basics of Machine Safeguarding

• Chapter 2 - Methods of Machine Safeguarding• Chapter 3 - Guard Construction

• Chapter 4 - Machinery Maintenance and Repair

• Chapter 5 - ti!i"ation of Industry Consensus Standards• Chapter # - Ro$otics in the %or&p!ace

• Chapter ' - Ce!!u!ar Manufacturing Syste(s

Chapter ) - *rgono(ic Considerations of Machine Safeguarding• Chapter + - Cooperation and ,ssistance

• Machine Guarding Chec&!ist

• %or&er Rights and Responsi$i!ities• Bi$!iography

• States ith ,ppro.ed /!ans

• 0S, Consu!tation /roect irectory• Re!ated /u$!ications

his (ateria! as adapted fro( origina! docu(ents found at the Sa!t a&e

City 0S, e$ site6 7o guarantee of the accuracy of this infor(ation is (adeor i(p!ied8 for the !atest regu!ations and infor(ation9 contact 0S, :6S6epart(ent of a$or; direct!y6

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Adapted from the U.S. Department of Labor,

Occupational Safety and Health Administration OSHA 306, !""# $%e&ised'

 

CHAPTER 1Basics of Machine Safeguarding

Basics of Machine Safeguarding 

Crushed hands and ar(s9 se.ered fingers9 $!indness -- the !ist of possi$!e(achinery-re!ated inuries is as !ong as it is horrifying6 here see( to $e as(any ha"ards created $y (o.ing (achine parts as there are types of(achines6 Safeguards are essentia! for protecting or&ers fro( need!ess andpre.enta$!e inuries6

 , good ru!e to re(e($er is< ,ny (achine part9 function9 or process hich(any cause inury (ust $e safeguarded6 %hen the operation of a (achine oraccidenta! contact ith it can inure the operator or others in the .icinity9 the

ha"ards (ust $e either contro!!ed or e!i(inated6

his (anua! descri$es the .arious ha"ards of (echanica! (otion andpresents so(e techni=ues for protecting or&ers fro( these ha"ards6 Genera!infor(ation co.ered in this chapter inc!udes -- here (echanica! ha"ardsoccur9 the ha"ards created $y different &inds of (otions and the re=uire(entsfor effecti.e safeguards9 as e!! as a $rief discussion of non(echanica!ha"ards6

Where Mechanical Hazards Occur  

angerous (o.ing parts in three $asic areas re=uire safeguarding<

he point of operation< that point here or& is perfor(ed on the (ateria!9such as cutting9 shaping9 $oring9 or for(ing of stoc&6

/oer trans(ission apparatus< a!! co(ponents of the (echanica! syste(hich trans(it energy to the part of the (achine perfor(ing the or&6 heseco(ponents inc!ude f!yhee!s9 pu!!eys9 $e!ts9 connecting rods9 coup!ings9ca(s9 spind!es9 chains9 cran&s9 and gears6

0ther (o.ing parts< a!! parts of the (achine hich (o.e hi!e the (achine isor&ing6 hese can inc!ude reciprocating9 rotating9 and trans.erse (o.ingparts9 as e!! as feed (echanis(s and au>i!iary parts of the (achine6

Hazardous Mechanical Motions and Actions 

 , ide .ariety of (echanica! (otions and actions (ay present ha"ards to theor&er6 hese can inc!ude the (o.e(ent of rotating (e($ers9 reciprocatingar(s9 (o.ing $e!ts9 (eshing gears9 cutting teeth9 and any parts that i(pact orshear6 hese different types of ha"ardous (echanica! (otions and actionsare $asic in .arying co($inations to near!y a!! (achines9 and recogni"ing

the( is the first step toard protecting or&ers fro( the danger they present6

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Adapted from the U.S. Department of Labor,

Occupational Safety and Health Administration OSHA 306, !""# $%e&ised'

 

he $asic types of ha"ardous (echanica! (otions and actions are<

Motions

rotating :inc!uding in-running nip points;• reciprocating

• trans.ersing

 ,ctions

• cutting• punching

• shearing• $ending

Motions 

Rotating (otion can $e dangerous8 e.en s(ooth9 s!o!y rotating shafts cangrip c!othing9 and through (ere s&in contact force an ar( or hand into adangerous position6 Inuries due to contact ith rotating parts can $e se.ere6

Co!!ars9 coup!ings9 ca(s9 c!utches9 f!yhee!s9 shaft ends9 spind!es9 (eshinggears9 and hori"onta! or .ertica! shafting are so(e e>a(p!es of co((onrotating (echanis(s hich (ay $e ha"ardous6 he danger increases henproections such as set scres9 $o!ts9 nic&s9 a$rasions9 and proecting &eys orset scres are e>posed on rotating parts9 as shon in ?igure 16

In-running nip point ha"ards are caused $y the rotating parts on (achinery6here are three (ain types of in-running nips6

/arts can rotate in opposite directions hi!e their a>es are para!!e! to eachother6 hese parts (ay $e in contact :producing a nip point; or in c!osepro>i(ity6 In the !atter case the stoc& fed $eteen the ro!!s produces the nippoints6 his danger is co((on on (achines ith inter(eshing gears9 ro!!ing(i!!s9 and ca!enders6 See ?igure 26

7ip points are a!so created $eteen rotating and tangentia!!y (o.ing parts6So(e e>a(p!es ou!d $e< the point of contact $eteen a poer trans(ission$e!t and its pu!!ey9 a chain and a sproc&et9 and a rac& and pinion6 See ?igure 36

7ip points can occur $eteen rotating and fi>ed parts hich create ashearing9 crushing9 or a$rading action6 *>a(p!es are< spo&ed handhee!s orf!yhee!s9 scre con.eyors9 or the periphery of an a$rasi.e hee! and anincorrect!y adusted or& rest6 See ?igure 46

Reciprocating (otions (ay $e ha"ardous $ecause9 during the $ac&-and-forth

or up-and-don (otion9 a or&er (ay $e struc& $y or caught $eteen a

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Adapted from the U.S. Department of Labor,

Occupational Safety and Health Administration OSHA 306, !""# $%e&ised'

 

(o.ing and a stationary part6 See ?igure 5 for an e>a(p!e of a reciprocating(otion6

rans.erse (otion :(o.e(ent in a straight9 continuous !ine; creates a ha"ard

$ecause a or&er (ay $e struc& or caught in a pinch or shear point $y the(o.ing part6 See ?igure #6

Actions 

Cutting action (ay in.o!.e rotating9 reciprocating9 or trans.erse (otion6 hedanger of cutting action e>ists at the point of operation here finger9 ar( and$ody inuries can occur and here f!ying chips or scrap (ateria! can stri&e thehead9 particu!ar!y in the area of the eyes or face6 Such ha"ards are present at

the point of operation in cutting ood9 (eta!9 or other (ateria!s6

*>a(p!es of (echanis(s in.o!.ing cutting ha"ards inc!ude $andsas9circu!ar sas9 $oring or dri!!ing (achines9 turning (achines :!athes;9 or (i!!ing(achines6 See ?igure '6

/unching action resu!ts hen poer is app!ied to a s!ide :ra(; for the purposeof $!an&ing9 draing9 or sta(ping (eta! or other (ateria!s6 he danger of thistype of action occurs at the point of operation here stoc& is inserted9 he!d9and ithdran $y hand6

ypica! (achines used for punching operations are poer presses and ironor&ers6 See ?igure )6

Shearing action in.o!.es app!ying poer to a s!ide or &nife in order to tri( orshear (eta! or other (ateria!s6 , ha"ard occurs at the point of operationhere stoc& is actua!!y inserted9 he!d9 and ithdran6

*>a(p!es of (achines used for shearing operations are (echanica!!y9hydrau!ica!!y9 or pneu(atica!!y poered shears6 See ?igure +6

Bending action resu!ts hen poer is app!ied to a s!ide in order to dra orsta(p (eta! or other (ateria!s6 , ha"ard occurs at the point of operationhere stoc& is inserted9 he!d9 and ithdran6

*=uip(ent that uses $ending action inc!udes poer presses9 press $ra&es9and tu$ing $enders6 See ?igure 1@6

Reuire!ents for Safeguards 

%hat (ust a safeguard do to protect or&ers against (echanica! ha"ardsASafeguards (ust (eet these (ini(u( genera! re=uire(ents<

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Adapted from the U.S. Department of Labor,

Occupational Safety and Health Administration OSHA 306, !""# $%e&ised'

 

/re.ent contact< he safeguard (ust pre.ent hands9 ar(s9 and any other partof a or&ers $ody fro( (a&ing contact ith dangerous (o.ing parts6 , goodsafeguarding syste( e!i(inates the possi$i!ity of the operator or anotheror&er p!acing parts of their $odies near ha"ardous (o.ing parts6

Secure< %or&ers shou!d not $e a$!e to easi!y re(o.e or ta(per ith thesafeguard9 $ecause a safeguard that can easi!y $e (ade ineffecti.e is nosafeguard at a!!6 Guards and safety de.ices shou!d $e (ade of dura$!e(ateria! that i!! ithstand the conditions of nor(a! use6 hey (ust $e fir(!ysecured to the (achine6

/rotect fro( fa!!ing o$ects< he safeguard shou!d ensure that no o$ects canfa!! into (o.ing parts6 , s(a!! too! hich is dropped into a cyc!ing (achinecou!d easi!y $eco(e a proecti!e that cou!d stri&e and inure so(eone6

Create no ne ha"ards< , safeguard defeats its on purpose if it creates aha"ard of its on such as a shear point9 a agged edge9 or an unfinishedsurface hich can cause a !aceration6 he edges of guards9 for instance9shou!d $e ro!!ed or $o!ted in such a ay that they e!i(inate sharp edges6

Create no interference< ,ny safeguard hich i(pedes a or&er fro(perfor(ing the o$ =uic&!y and co(forta$!y (ight soon $e o.erridden ordisregarded6 /roper safeguarding can actua!!y enhance efficiency since it canre!ie.e the or&ers apprehensions a$out inury6

 ,!!o safe !u$rication< If possi$!e9 one shou!d $e a$!e to !u$ricate the (achine

ithout re(o.ing the safeguards6 ocating oi! reser.oirs outside the guard9ith a !ine !eading to the !u$rication point9 i!! reduce the need for the operatoror (aintenance or&er to enter the ha"ardous area6

"on!echanical Hazards 

%hi!e this (anua! concentrates attention on concepts and techni=ues forsafeguarding (echanica! (otion9 (achines o$.ious!y present a .ariety ofother ha"ards hich cannot $e ignored6 ?u!! discussion of these (atters is$eyond the scope of this pu$!ication9 $ut so(e non(echanica! ha"ards are$rief!y (entioned $e!o to re(ind the reader of things other thansafeguarding (o.ing parts that can affect the safe operation of (achines6

 ,!! poer sources for (achines are potentia! sources of danger6 %hen usinge!ectrica!!y poered or contro!!ed (achines9 for instance9 the e=uip(ent ase!! as the e!ectrica! syste( itse!f (ust $e proper!y grounded6 Rep!acingfrayed9 e>posed9 or o!d iring i!! a!so he!p to protect the operator and othersfro( e!ectrica! shoc&s or e!ectrocution6 igh pressure syste(s9 too9 needcarefu! inspection and (aintenance to pre.ent possi$!e fai!ure fro( pu!sation9.i$ration9 or !ea&s6 Such a fai!ure cou!d cause9 a(ong other things9 e>p!osionsor f!ying o$ects6

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Adapted from the U.S. Department of Labor,

Occupational Safety and Health Administration OSHA 306, !""# $%e&ised'

 

Machines often produce noise :unanted sound; hich can resu!t in anu($er of ha"ards to or&ers6 7oise can start!e and disrupt concentration9and can interfere ith co((unications9 thus hindering the or&ers safe o$perfor(ance6 Research has !in&ed noise to a ho!e range of har(fu! hea!th

effects9 fro( hearing !oss and aura! pain to nausea9 fatigue9 reduced (usc!econtro!9 and e(otiona! distur$ance6 *ngineering contro!s such as the use ofsound-da(pening (ateria!s9 and persona! protecti.e e=uip(ent9 such as earp!ugs and (uffs9 can he!p contro! the har(fu! effects of noise6 ,!so9ad(inistrati.e contro!s that in.o!.e re(o.ing the or&er fro( the noise sourcecan $e an effecti.e (easure hen feasi$!e6

Because so(e (achines re=uire the use of cutting f!uids9 coo!ants9 and otherpotentia!!y har(fu! su$stances9 operators9 (aintenance or&ers9 and othersin the .icinity (ay need protection6 hese su$stances can cause ai!(entsranging fro( der(atitis to serious i!!nesses and disease6 Specia!!y

constructed safeguards9 .enti!ation9 and protecti.e e=uip(ent and c!othingare possi$!e te(porary so!utions to the pro$!e( of (achinery-re!atedche(ica! ha"ards unti! these ha"ards can $e $etter contro!!ed or e!i(inatedfro( the or&p!ace6

Training 

*.en the (ost e!a$orate safeguarding syste( cannot offer effecti.e protectionun!ess the or&er &nos ho to use it and hy6 Specific and detai!ed trainingis therefore a crucia! part of any effort to pro.ide safeguarding against(achine-re!ated ha"ards6 horough operator training shou!d in.o!.e

instruction or hands-on training in the fo!!oing<

16 a description and identification of the ha"ards associated ith particu!ar(achines8

26 the safeguards the(se!.es9 ho they pro.ide protection9 and theha"ards for hich they are intended8

36 ho to use the safeguards and hy846 ho and under hat circu(stances safeguards can $e re(o.ed9 and

$y ho( :in (ost cases9 repair or (aintenance personne! on!y;8 and56 hat to do :e6g69 contact the super.isor; if a safeguard is da(aged9

(issing9 or una$!e to pro.ide ade=uate protection6

his &ind of safety training is necessary for ne operators and (aintenanceor setup personne!9 hen any ne or a!tered safeguards are put in ser.ice9 orhen or&ers are assigned to a ne (achine or operation6

Protecti#e Clothing and Personal Protecti#e Eui$!ent 

*ngineering contro!s9 that e!i(inate the ha"ard at the source and do not re!yon the or&ers $eha.ior for their effecti.eness offer the $est and (ostre!ia$!e (eans of safeguarding6 herefore9 engineering contro!s (ust $e the

e(p!oyers first choice for e!i(inating (achine ha"ards6 But hene.erengineering contro!s are not a.ai!a$!e or are not fu!!y capa$!e of protecting the

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Adapted from the U.S. Department of Labor,

Occupational Safety and Health Administration OSHA 306, !""# $%e&ised'

 

e(p!oyee :an e>tra (easure of protection is necessary;9 operators (ust earprotecti.e c!othing or persona! protecti.e e=uip(ent6

If it is to pro.ide ade=uate protection9 the protecti.e c!othing and e=uip(ent

se!ected (ust a!ays $e<

16 appropriate for the particu!ar ha"ards826 (aintained in good condition836 proper!y stored hen not in use9 to pre.ent da(age or !oss8 and46 &ept c!ean9 fu!!y functiona!9 and sanitary6

/rotecti.e c!othing is9 of course9 a.ai!a$!e for different parts of the $ody6 ardhats can protect the head fro( the i(pact of $u(ps and fa!!ing o$ects henthe or&er is hand!ing stoc&8 caps and hair nets can he!p &eep the or&ershair fro( $eing caught in (achinery6 If (achine coo!ants cou!d sp!ash or

partic!es cou!d f!y into the operators eyes or face9 then face shie!ds9 safetygogg!es9 g!asses9 or si(i!ar &inds of protection (ight $e necessary6 earingprotection (ay $e needed hen or&ers operate noisy (achines6 o guardthe trun& of the $ody fro( cuts or i(pacts fro( hea.y or rough-edged stoc&9there are certain protecti.e co.era!!s9 ac&ets9 .ests9 aprons9 and fu!!-$odysuits6 %or&ers can protect their hands and ar(s fro( the sa(e &inds of inuryith specia! s!ee.es and g!o.es6 Safety shoes and $oots9 or other accepta$!efoot guards9 can shie!d the feet against inury in case the or&er needs tohand!e hea.y stoc& hich (ight drop6

It is i(portant to note that protecti.e c!othing and e=uip(ent can create

ha"ards6 , protecti.e g!o.e hich can $eco(e caught $eteen rotating parts9or a respirator facepiece hich hinders the earers .ision9 for e>a(p!e9re=uire a!ertness and continued attenti.eness hene.er they are used6

0ther parts of the or&ers c!othing (ay present additiona! safety ha"ards6?or e>a(p!e9 !oose-fitting shirts (ight possi$!y $eco(e entang!ed in rotatingspind!es or other &inds of (o.ing (achinery6 ee!ry9 such as $race!ets andrings9 can catch on (achine parts or stoc& and !ead to serious inury $ypu!!ing a hand into the danger area6

)

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Adapted from the U.S. Department of Labor,

Occupational Safety and Health Administration OSHA 306, !""# $%e&ised'

 

+

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Adapted from the U.S. Department of Labor,

Occupational Safety and Health Administration OSHA 306, !""# $%e&ised'

 

1@

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Adapted from the U.S. Department of Labor,

Occupational Safety and Health Administration OSHA 306, !""# $%e&ised'

 

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Adapted from the U.S. Department of Labor,

Occupational Safety and Health Administration OSHA 306, !""# $%e&ised'

 

CHAPTER 2Methods of Machine Safe!a"din

Methods of Machine Safeguarding 

here are (any ays to safeguard (achines6 he type of operation9 the si"eor shape of stoc&9 the (ethod of hand!ing9 the physica! !ayout of the or&area9 the type of (ateria!9 and production re=uire(ents or !i(itations i!! he!pto deter(ine the appropriate safeguarding (ethod for the indi.idua! (achine6

 ,s a genera! ru!e9 poer trans(ission apparatus is $est protected $y fi>edguards that enc!ose the danger areas6 ?or ha"ards at the point of operation9here (o.ing parts actua!!y perfor( or& on stoc&9 se.era! &inds ofsafeguarding (ay $e possi$!e6 0ne (ust a!ays choose the (ost effecti.eand practica! (eans a.ai!a$!e6

%e can group safeguards under fi.e genera! c!assifications6

16 Guards  ,6 ?i>ed  B6 Inter!oc&ed  C6 ,dusta$!e  6 Se!f-adusting

  26 e.ices  ,6 /resence Sensing  :1; /hotoe!ectrica! :optica!;  :2; Radiofre=uency :capacitance;  :3; *!ectro(echanica!  B6 /u!!$ac&  C6 Restraint  6 Safety Contro!s  :1; Safety trip contro!  :a; /ressure-sensiti.e $ody $ar 

  :$; Safety tripod  :c; Safety tripire ca$!e  :2; o-hand contro!  :3; o-hand trip  *6 Gates  :1; Inter!oc&ed  :2; 0ther 

  36 ocationDistance

  46 /otentia! ?eeding and *ection Methods to I(pro.e Safety for the

0perator   ,6 ,uto(atic feed

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Adapted from the U.S. Department of Labor,

Occupational Safety and Health Administration OSHA 306, !""# $%e&ised'

 

B6 Se(i-auto(atic feed  C6 ,uto(atic eection  6 Se(i-auto(atic eection  *6 Ro$ot

  56 Misce!!aneous ,ids  ,6 ,areness $arriers  B6 Misce!!aneous protecti.e shie!ds  C6 and-feeding too!s and ho!ding fi>tures

%uards 

Guards are $arriers hich pre.ent access to danger areas6 here are fourgenera! types of guards<

?i>ed< ,s its na(e i(p!ies9 a fi>ed guard is a per(anent part of the (achine6It is not dependent upon (o.ing parts to perfor( its intended function6 It (ay$e constructed of sheet (eta!9 screen9 ire c!oth9 $ars9 p!astic9 or any other(ateria! that is su$stantia! enough to ithstand hate.er i(pact it (ayrecei.e and to endure pro!onged use6 his guard is usua!!y prefera$!e to a!!other types $ecause of its re!ati.e si(p!icity and per(anence6

*>a(p!es of fi>ed guards666

In ?igure 119 a fi>ed guard on a poer press co(p!ete!y enc!oses the point of

operation6 he stoc& is fed through the side of the guard into the die area9 iththe scrap stoc& e>iting on the opposite side6

?igure 12 shos a fi>ed guard that protects the operator fro( a (echanis(that fo!ds cartons6 his guard ou!d not nor(a!!y $e re(o.ed e>cept toperfor( (aintenance on the (achine6 ?igure 13  shos a fi>ed enc!osureguard shie!ding the $e!t and pu!!ey of a poer trans(ission unit6 ,n inspectionpane! is pro.ided on top in order to (ini(i"e the need for re(o.ing the guard6o re(ain effecti.e9 the inspection pane! cannot $e re(o.ed hi!e the(echanis( is in operation6 In ?igure 149 fi>ed enc!osure guards are shon ona $andsa6 hese guards protect the operator fro( the turning hee!s and(o.ing sa $!ade6 7or(a!!y9 the on!y ti(e for the guards to $e opened orre(o.ed ou!d $e for a $!ade change or (aintenance6 It is .ery i(portant thatthey $e secure!y fastened hi!e the sa is in use6

 , fi>ed guard is shon on a .eneer c!ipper in ?igure 156 his guard acts as a$arrier9 protecting fingers fro( e>posure to the $!ade6 7ote the side .ie ofthe cur.ed portion of the guard6

?igure 1# shos $oth a fi>ed $!ade guard and a throat and gap guard on apoer s=uaring shear6 hese guards shou!d $e re(o.ed on!y for

(aintenance or $!ade changes6

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Adapted from the U.S. Department of Labor,

Occupational Safety and Health Administration OSHA 306, !""# $%e&ised'

 

In ?igure 1'9 a transparent9 fi>ed $arrier guard is $eing used on a press $ra&eto protect the operator fro( the unused portions of the die6 his guard is easyto insta!! or re(o.e6

Inter!oc&ed< %hen this type of guard is opened or re(o.ed9 the tripping(echanis( andDor poer auto(atica!!y shuts off or disengages9 and the(achine cannot cyc!e or $e started unti! the guard is $ac& in p!ace6

 ,n inter!oc&ed guard (ay use e!ectrica!9 (echanica!9 hydrau!ic9 or pneu(aticpoer or any co($ination of these6 Inter!oc&s shou!d not pre.ent EinchingE $yre(ote contro! if re=uired6 Rep!acing the guard shou!d not auto(atica!!yrestart the (achine6 o $e effecti.e9 a!! (o.a$!e guards shou!d $e inter!oc&edto pre.ent occupationa! ha"ards6 :See a!so ?igure 136;

?igure 1) shos an inter!oc&ed $arrier guard (ounted on an auto(atic $read

$agging (achine6 %hen the guard is re(o.ed9 the (achine i!! not function6

In ?igure 1+9 the $eater (echanis( of a pic&er (achine :used in the te>ti!eindustry; is co.ered $y an inter!oc&ed $arrier guard6 his guard cannot $eraised hi!e the (achine is running9 nor can the (achine $e restarted ith theguard in the raised position6

In ?igure 2@9 an inter!oc&ed guard co.ers the rotating cy!inder of the di.idinghead of a ro!! (a&e-up (achine used for (a&ing ha($urger and hot-dog ro!!s6

 ,dusta$!e< ,dusta$!e guards are usefu! $ecause they a!!o f!e>i$i!ity in

acco((odating .arious si"es of stoc&6

?igure 21 shos a $andsa ith an adusta$!e guard to protect the operatorfro( the unused portion of the $!ade6 his guard can $e adusted according tothe si"e of stoc&6

In ?igure 229 the $ars adust to acco((odate the si"e and shape of the stoc&6?igures 23  and 24  sho guards that can $e adusted according to thethic&ness of the stoc&6

In ?igure 259 the guard adusts to pro.ide a $arrier $eteen the operator andthe $!ade6

?igure 2# shos an adusta$!e enc!osure guard on a $andsa6

Se!f-,dusting< he openings of these $arriers are deter(ined $y the(o.e(ent of the stoc&6 ,s the operator (o.es the stoc& into the danger area9the guard is pushed aay9 pro.iding an opening hich is on!y !arge enough toad(it the stoc&6 ,fter the stoc& is re(o.ed9 the guard returns to the restposition6 his guard protects the operator $y p!acing a $arrier $eteen thedanger area and the operator6 he guards (ay $e constructed of p!astic9

(eta!9 or other su$stantia! (ateria!6 Se!f-adusting guards offer differentdegrees of protection6

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*>a(p!es of se!f-adusting guards666

?igure 2' shos a radia! ar( sa ith a se!f-adusting guard6 ,s the $!ade ispu!!ed across the stoc&9 the guard (o.es up9 staying in contact ith the stoc&6

?igure 2)  shos a tin-action9 transparent9 se!f-adusting guard6 he firstguard rises as the stoc& enters9 then returns to its rest position as the stoc&(o.es ahead to raise the second guard6

 , se!f-adusting guard is shon in ?igure 2+6 ,s the $!ade (o.es through thestoc&9 the guard rises up to the stoc& surface6

?igure 3@ shos a se!f-adusting enc!osure guard (ounted on a ointer6 hisguard is (o.ed fro( the cutting head $y the stoc&6 ,fter the stoc& is re(o.ed9the guard i!! return9 under spring tension9 to the rest position6

 ,nother type of se!f-adusting guard (ounted on a ointer is i!!ustrated in?igure 316 he guard (o.es to ays6 ,n edging operation causes the guardto (o.e hori"onta!!y6 If the stoc& is ide enough during a surfacing operation9the stoc& (ay $e fed under the guard9 causing it to (o.e .ertica!!y6

%&AR'S

Method Safeguarding Action Ad#antages (i!itations

?i>ed /ro.ides a $arrier  

--Can $econstructed to suit

(any specificapp!ications6--In-p!antconstruction isoften possi$!e6--Can pro.ide(a>i(u(protection6--sua!!y re=uires(ini(u((aintenance6

--Can $e suita$!eto high production9repetiti.eoperations6

--May interfere ith.isi$i!ity6--Can $e !i(ited tospecific operations6--Machine adust(entand repaird oftenre=uire its re(o.a!9there$y necessitatingother (eans ofprotection for(aintenancepersonne!6

Inter!oc&ed Shuts off or disengagespoer and pre.entsstarting of (achinehen guad is open8shou!d re=uire the(achine to $e stopped$efore the or&er canreach into the danger

--Can pro.ide(a>i(u(protection6--,!!os access to(achine forere(o.ing a(sithout ti(econsu(ing re(o.a!

--Re=uires carefu!adust(ent and(aintenance6--May $e easy todisengage a(s6

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area of fi>ed guards6

 ,dusta$!e

/ro.ides a $arrier that(ay $e adusted tofaci!itate a .ariety ofproduction operations

--Can $econstructed to suit(any specificapp!ications6--Can $e adustedto ad(it .aryingsi"es of stoc&6

--ands (ay enterdanger area -protection (ay not $e

co(p!ete at a!! ti(es6--May re=uire fre=uent(aintenance andDoradust(ent6--he guard (ay $e(ade ineffecti.e $ythe operator6--May interfere ith.isi$i!ity6

Se!f-adusting

/ro.ides a $arrier that(o.es according to thesi"e of the stoc&entering the danger area

0ff-the-she!fguards are oftenco((ercia!!ya.ai!a$!e

--oes not a!ays

pro.ide (a>i(u(protection6--May interfere ith.isi$i!ity6--May re=uire fre=uent(aintenance andadust(ent6

'e#ices 

 , safety de.ice (ay perfor( one of se.era! functions6 It (ay stop the

(achine if a hand or any part of the $ody is inad.ertent!y p!aced in the dangerarea8 restrain or ithdra the operators hands fro( the danger area duringoperation8 re=uire the operator to use $oth hands on (achine contro!s9 thus&eeping $oth hands and $ody out of danger8 or pro.ide a $arrier hich issynchroni"ed ith the operating cyc!e of the (achine in order to pre.ent entryto the danger area during the ha"ardous part of the cyc!e6

Presence)Sensing 

he photoe!ectric :optica!; presence-sensing de.ice uses a syste( of !ightsources and contro!s hich can interrupt the (achines operating cyc!e6 If the!ight fie!d is $ro&en9 the (achine stops and i!! not cyc!e6 his de.ice (ust $eused on!y on (achines hich can $e stopped $efore the or&er can reach thedanger area6 he design and p!ace(ent of the guard depends upon the ti(e itta&es to stop the (echanis( and the speed at hich the e(p!oyees handcan reach across the distance fro( the guard to the danger "one6

?igure 32 shos a photoe!ectric presence-sending de.ice on a part-re.o!utionpoer press6 %hen the !ight $ea( is $ro&en9 either the ra( i!! not start to

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cyc!e9 or9 if the cyc!e has $egun9 the stopping (echanis( i!! $e acti.ated sothat the press stops $efore the operators hand can enter the danger "one6

 , photoe!ectric presence-sending de.ice used ith a press $ra&e is i!!ustrated

in ?igure 336 he de.ice (ay $e sung up or don to acco((odate differentproduction re=uire(ents6

he radiofre=uency :capacitance; presence-sending de.ice uses a radio$ea( that is part of the (achine contro! circuit6 %hen the capacitance fie!d is$ro&en9 the (achine i!! stop or i!! not acti.ate6 i&e the photoe!ectric de.ice9this de.ice sha!! on!y $e used on (achines hich can $e stopped $efore theor&er can reach the danger area6 his re=uires the (achine to ha.e afriction c!utch or other re!ia$!e (eans for stopping6

?igure 34 shos a radiofre=uency presence-sensing de.ice (ounted on a

part-re.o!ution poer press6

he e!ectro(echanica! sensing de.ice has a pro$e or contact $ar hichdescends to a predeter(ined distance hen the operator initiates the(achine cyc!e6 If there is an o$struction pre.enting it fro( descending its fu!!predeter(ined distance9 the contro! circuit does not actuate the (achinecyc!e6

?igure 35 shos an e!ectro(echanica! sensing de.ice on an eye!etter6 hesensing pro$e in contact ith the operators finger is a!so shon6

Pullbac* 

/u!!$ac& de.ices uti!i"e a series of ca$!es attached to the operators hands9rists9 andDor ar(s6 his type of de.ice is pri(ari!y used on (achines ithstro&ing action6 %hen the s!ideDra( is up $eteen cyc!es9 the operator isa!!oed access to the point of operation6 %hen the s!ideDra( $egins to cyc!e$y starting its descent9 a (echanica! !in&age auto(atica!!y assures ithdraa!of the hands fro( the point of operation6

?igure 3# shos a pu!!$ac& de.ice on a straight-side poer press6 %hen thes!ideDra( is in the EupE position9 the operator can feed (ateria! $y hand intothe point of operation6 %hen the press cyc!e is actuated9 the operators handsand ar(s are auto(atica!!y ithdran6 ?igure 3' shos a pu!!$ac& de.ice ona s(a!!er press6

 , pu!!$ac& de.ice on a press $ra&e is i!!ustrated in ?igure 3)6

Restraint 

he restraint :ho!dout; de.ice in ?igure 3+ uti!i"es ca$!es or straps that areattached to the operators hands at a fi>ed point6 he ca$!es or straps (ust $e

adusted to !et the operators hands tra.e! ithin a predeter(ined safe area6here is no e>tending or retracting action in.o!.ed6 Conse=uent!y9 hand-

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feeding too!s are often necessary if the operation in.o!.es p!acing (ateria!into the danger area6

his (ateria! as adapted fro( origina! docu(ents found at the Sa!t a&e

City 0S, e$ site6 7o guarantee of the accuracy of this infor(ation is (adeor i(p!ied8 for the !atest regu!ations and infor(ation9 contact 0S, :6S6epart(ent of a$or; direct!y6

1)

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CHAPTER 2 #PART 2$Methods of Machine Safe!a"din

Safet+ Tri$ Controls 

Safety trip contro!s pro.ide a =uic& (eans for deacti.ating the (achine in ane(ergency situation6

 , pressure-sensiti.e $ody $ar9 hen depressed9 i!! deacti.ate the (achine6If the operator or anyone trips9 !oses $a!ance9 or is dran toard the (achine9app!ying pressure to the $ar i!! stop the operation6 he positioning of the $ar9therefore9 is critica!6 It (ust stop the (achine $efore a part of the e(p!oyees$ody reaches the danger area6 ?igure 4@ shos a pressure-sensiti.e $ody$ar !ocated on the front of a ru$$er (i!!6

%hen pressed $y hand9 the safety deacti.ates the (achine6 Because thetriprod has to $e actuated $y the operator during an e(ergency situation9 itsproper position is a!so critica!6 ?igure 41 shos a triprod !ocated a$o.e theru$$er (i!!6 ?igure 42 shos another app!ication of a triprod6

Safety tripire ca$!es are !ocated around the peri(eter of or near the dangerarea6 he operator (ust $e a$!e to reach the ca$!e ith either hand to stopthe (achine6 ?igure 43 shos a ca!ender e=uipped ith this type of contro!9hi!e ?igure 44 shos a to(ato sorter ith a safety tripire ca$!e6

 ,!! of these tripire rods or other safety de.ices (ust $e (anua!!y reset torestart the (achine6 Si(p!y re!easing the tripire to restart the (achine i!!not ensure that the e(p!oyee is out of danger hen the (achine restarts6

T,o)Hand Control 

he to-hand contro! re=uires constant9 concurrent pressure $y the operatorto acti.ate the (achine6 his &ind of contro! re=uires a part-re.o!ution c!utch9$ra&e9 and a $ra&e (onitor if used on a poer press as shon in ?igure 456%ith this type of de.ice9 the operators hands are re=uired to $e at a safe

!ocation :on contro! $uttons; and at a safe distance fro( the danger area hi!ethe (achine co(p!etes its c!osing cyc!e6

DEVICES 

Method Safeguarding Action Ad#antages (i!itations

/hotoe!ectricMachine i!! not startcyc!ing hen the !ightfie!d is interrupted6

Can a!!o freer(o.e(ent foroperator6

oes not protectagainst (echanica!fai!ure6

6 %hen the !ight fie!d is$ro&en $y any part of

the operators $odyduring the cyc!ing

-Si(p!icity ofuse

--sed $y(u!tip!e

i(ited to (achinesthat can $e stopped6

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process9 i((ediate(achine $ra&ing isacti.ated6

operators--/ro.idepasser$yprotection

--7o adust(entre=uired

Radiofre=uency:optica!;

--Machine cyc!yingi!! not start hen thecapacitance fie!d isinterrupted--%hen thecapacitance fie!d isdistur$ed $y any partof the operators $odyduring the cyc!ingprocess9 i((ediate(achine $ra&ing isacti.ated6

Can a!!o freer(o.e(ent foroperator6

--oes not protectagainst (echanica!fai!ure--,tennae sensiti.ity(ust $e proper!yadusted8 thisadust(ent (ust $e(aintained proper!y

--i(ited to(achines that can$e stopped

*!ectro(echanica!

--Contact $ar or pro$etra.e!s apredeter(ineddistance $eteen theoperator and thedanger area6--Interruption of this

(o.e(ent pre.entsthe starting of(achine cyc!ing6

Can a!!oaccess at thepoint ofoperation

Contact $ar orpro$e (ust $eproper!y adusted foreach app!ication8this adust(ent(ust $e (aintainedproper!y

/u!!$ac&

 ,s the (achine$egins to cyc!e9 theoperators hands arepu!!ed out of thedanger area

*!i(inates theneed forau>i!iary$arriers or otherinterference atthe dangerarea6

--i(its (o.e(entof operator6May o$struct or&space aroundoperator6

Restraint:ho!d$ac&; /re.ents the operatorfro( reaching into thedanger area

itt!e ris& of(echanica!fai!ure

--,dust(ents (ust$e (ade for specificoperations and foreach indi.idua!6--Re=uires fre=uentinspections andregu!ar(aintenance6--Re=uires c!osesuper.ision of theoperators use of the

e=uip(ent6--i(its (o.e(ent

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of operator6--May o$struct or&space6

Safety trip contro!s<-/ressure-sensiti.e$ody $ar  -Safety triprod-Safety tripire

Stops (achine hentripped

Si(p!icity of use

--,!! contro!s (ust

$e (anua!!yacti.ated--May $e difficu!t toacti.ate contro!s$ecause of their!ocation6--0n!y protects theoperator6--May re=uirespecia! fi>tures toho!d or&6--May re=uire a(achine $ra&e6

o-hand contro!

Concurrent use of$oth hands isre=uired9 pre.entingthe operator fro(entering the danger

area

--0peratorshands are at apre-deter(ined!ocation--0peratorshands are freeto pic& up a ne

part after firstha!f of cyc!e isco(!eted

--Re=uires a partia!cyc!e (achine itha $ra&e6--So(e to-handedcontro!s can $erendered unsafe $yho!ding ith ar( or$!oc&ing9 there$y

per(itting one-handoperation6--/rotects on!y theoperator6

o-hand trip

Concurrent use of tohands on separatecontro!s pre.entshands fro( $eing indanger area hen(achine cyc!e starts

--0peratorshands are aayfro( dangerarea--Can $eadapted to(u!tip!eoperations--7o o$structionto hand feeding--oes notre=uireadust(ent foreach operation

--0perator (ay tryto reach into dangerarea after tripping(achine6--So(e trips can $erendered unsafe $yho!ding ith ar( or$!oc&ing9 there$yper(itting one-handoperation6--/rotects on!y theoperator6--May re=uirespecia! fi>tures

Gate /ro.ides a $arrier$eteen danger areaand operator or other

personne!

Can pre.entreaching into ora!&ing into the

danger area

--May re=uirefre=uent inspectionand regu!ar

(aintenance6--May interfere ith

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operators a$i!ity tosee the or&6

T,o)Hand Tri$ 

he to-hand trip in ?igure 4#  re=uires concurrent app!ication of $oth theoperators contro! $uttons to acti.ate the (achine cyc!e9 after hich the handsare free6 his de.ice is usua!!y used ith (achines e=uipped ith fu!!-re.o!ution c!utches6 he trips (ust $e p!aced far enough fro( the point ofoperation to (a&e it i(possi$!e for the operator to (o.e his or her hands fro(the trip $uttons or hand!es into the point of operation $efore the first ha!f of thecyc!e is co(p!eted6 he distance fro( the trip $utton depends upon the speedof the cyc!e and the $and speed constant6 hus the operators hands are &eptfar enough aay to pre.ent the( fro( $eing p!aced in the danger area priorto the s!ideDra( or $!ade reaching the fu!! EdonE position6

o $e effecti.e9 $oth to-hand contro!s and trips (ust $e !ocated so that theoperator cannot use to hands or one hand and another part of hisDher $odyto trip the (achine6

%ate 

 , gate is a (o.a$!e $arrier that protects the operator at the point of operation$efore the (achine cyc!e can $e started6 Gates are9 in (any instances9

designed to $e operated ith each (achine cyc!e6

?igure 4' shos a hori"onta! inection (o!ding (achine ith a gate6 o $eeffecti.e9 the gate (ust $e inter!oc&ed so that the (achine i!! not $egin acyc!e un!ess the gate guard is in p!ace6 It (ust $e in the c!osed position $eforethe (achine can function6

?igure 4) shos a gate on a poer press6 If the gate is not per(itted todescend to the fu!!y c!osed position9 the press i!! not function6

 ,nother potentia! app!ication of this type of guard is here the gate is a

co(ponent of a peri(eter safeguarding syste(6 ere the gate (ay pro.ideprotection not on!y to the operator $ut to pedestrian traffic as e!!6

Safeguarding b+ (ocation-'istance 

he e>a(p!es (entioned $e!o are a fe of the nu(erous app!ications of theprincip!e of safeguarding $y !ocationDdistance6 , thorough ha"ard ana!ysis ofeach (achine and particu!ar situation is a$so!ute!y essentia! $eforeatte(pting this safeguarding techni=ue6

o consider a part of a (achine to $e safeguarded $y !ocation9 the dangerous

(o.ing part of a (achine (ust $e so positioned that those areas are notaccessi$!e or do not present a ha"ard to a or&er during the nor(a! operation

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of the (achine6 his (ay $e acco(p!ished $y !ocating a (achine so that theha"ardous parts of the (achine are !ocated aay fro( operator or& stationsor other areas here e(p!oyees a!& or or&6 his can $e acco(p!ished $ypositioning a (achine ith its poer trans(ission apparatus against a a!!

and !ea.ing a!! routine operations conducted on the other side of the (achine6 ,dditiona!!y9 enc!osure a!!s or fences can restrict access to (achines6 ,nother possi$!e so!ution is to ha.e dangerous parts !ocated high enough to$e out of the nor(a! reach of any or&er6

he feeding process can $e safeguarded $y !ocation if a safe distance can $e(aintained to protect the or&ers hands6 he di(ensions of the stoc& $eingor&ed on (ay pro.ide ade=uate safety6

?or instance9 if the stoc& is se.era! feet !ong and on!y one end of the stoc& is$eing or&ed on9 the operator (ay $e a$!e to ho!d the opposite end hi!e the

or& is $eing perfor(ed6 ,n e>a(p!e ou!d $e a sing!e-end punching(achine6 oe.er9 depending upon the (achine9 protection (ight sti!! $ere=uired for another personne!6

he positioning of the operators contro! station pro.ides another potentia!approach to safeguarding $y !ocation6 0perator contro!s (ay $e !ocated at asafe distance fro( the (achine if there is no reason for the operator to tend it6

.eeding the E/ection Methods to 0!$ro#e O$erator Safet+ 

Many feeding and eection (ethods do not re=uire the operator to p!ace his or

her hands in the danger area6 In so(e cases9 no operator in.o!.e(ent isnecessary after the (achine is set up6 In other situations9 operators can(anua!!y feed the stoc& ith the assistance of a feeding (echanis(6 /roper!ydesigned eection (ethods do not re=uire any operator in.o!.e(ent after the(achine starts to function6

So(e feeding and eection (ethods (ay e.en create ha"ards the(se!.es6?or instance9 a ro$ot (ay e!i(inate the need for an operator to $e near the(achine $ut (ay create a ne ha"ard itse!f $y the (o.e(ent of its ar(6

sing these feeding and eection (ethods does not e!i(inate the need forguards and de.ices6 Guards and de.ices (ust $e used here.er they arenecessary and possi$!e in order to pro.ide protection fro( e>posure toha"ards6

ypes of feeding and eection (ethods666

 ,uto(atic feeds reduce the e>posure of the operator during the or& process9and so(eti(es do not re=uire any effort $y the operator after the (achine isset up and running6

In ?igure 4+9 the poer press has an auto(atic feeding (echanis(6 7oticethe transparent fi>ed enc!osure guard at the danger area6

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Adapted from the U.S. Department of Labor,

Occupational Safety and Health Administration OSHA 306, !""# $%e&ised'

 

?igure 5@ shos a sa ith an auto(atic inde>ing (echanis( that (o.es thestoc& a predeter(ined distance for each cut6 he tra.e!ing head auto(atica!!yrecyc!es for each cut6

%ith se(iauto(atic feeding9 as in the case of a poer press9 the operatoruses a (echanis( to p!ace the piece $eing processed under the ra( at eachstro&e6 he operator does not need to reach into the danger area9 and thedanger area is co(p!ete!y enc!osed6

?igure 51 shos a chute feed6 It (ay $e either a hori"onta! or an inc!inedchute into hich each piece is p!aced $y hand6 sing a chute feed on aninc!ined press not on!y he!ps center the piece as it s!ides into the die9 $ut (aya!so si(p!ify the pro$!e( of eection6

 , p!unger feed is shon in ?igure 526 he $!an&s or pieces are p!aced in the

nest one at a ti(e $y the p!unger ith pushes the( under the s!ide6 /!ungerfeeds are usefu! for operations on irregu!ar!y shaped or&pieces hich i!! notstac& in a (aga"ine or i!! not s!ide easi!y don a gra.ity chute6 he(echanis( shon is (echanica!!y connected to the press tripping(echanis(6 %hen the p!unger is pushed in9 pin EBE is a!!oed to rise up intoho!e E,9E a!!oing yo&e ECE to re!ease so the press can $e tripped6

?igure 53 shos a p!unger and (aga"ine feed6 S!ot E,E (ust $e in a!ign(entith inter!oc& EBE $efore the press can $e tripped6

he s!iding die in ?igure 54 is pu!!ed toard the operator for safe feeding and

then pushed into position under the s!ide prior to the donard stro&e6 hedie (o.es in and out $y hand or $y a foot !e.er6 he die shou!d $e inter!oc&edith the press to pre.ent tripping hen the die is out of a!ign(ent ith thes!ide6 /ro.iding EstopsE i!! pre.ent the die fro( $eing inad.ertent!y pu!!ed outof the s!ides6

?igure 55  shos a s!iding $o!ster6 he press $ed is (odified ith ahydrau!ica!!y or pneu(atica!!y contro!!ed $o!ster that s!ides in hen EstartE$uttons are depressed9 and out hen the stro&e is co(p!eted6

?igure 5# shos a dou$!e-dia! feed6 he dia!s re.o!.e ith each stro&e of thepress6 he operator p!aces the part to $e processed in a nest on the dia!hich is positioned in front of the die6 he dia! is inde>ed ith each upstro&eof the press to de!i.er the nested part into the die6

 ,uto(atic eection (ay e(p!oy either an air-pressure or a (echanica!apparatus to re(o.e the co(p!eted part fro( a press6 It (ay $e inter!oc&edith the operating contro!s to pre.ent operation unti! part eection isco(p!eted6 his (ethod re=uires additiona! safeguards for fu!! protection ofthe operator

 ,s shon in ?igure 5'9 the pan shutt!e (echanis( (o.es under the finishedpart as the s!ide (o.es toard the EupE position6 he shutt!e then catches the

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Adapted from the U.S. Department of Labor,

Occupational Safety and Health Administration OSHA 306, !""# $%e&ised'

 

part stripped fro( the s!ide $y the &noc&out pins and def!ects it into a chute6%hen the ra( (o.es don toard the ne>t $!an&9 the pan shutt!e (o.esaay fro( the die area6

?igures 5)  and 5+ sho air eection and (echanica! eection (echanis(s9respecti.e!y6 7ote< ,ir eection (ethods often present a noise ha"ard tooperators6

?igure #@  shos a se(iauto(atic eection (echanis( used on a poerpress6 %hen the p!unger is ithdran fro( the die area9 the eector !eg9 hichis (echanica!!y coup!ed to the p!unger9 &ic&s the co(p!eted or& out6

*ssentia!!y9 ro$ots perfor( or& that ou!d otherise ha.e to $e done $y anoperator6 hey are $est used in high-production processes re=uiring repeatedroutines here they pre.ent other ha"ards to e(p!oyees6 oe.er9 they (ay

create ha"ards the(se!.es9 and if they do9 appropriate guards (ust $e used6

?igures #19  #29 and #39 respecti.e!y9 sho a type of ro$ot in operation9 thedanger areas it can create9 and an e>a(p!e of the &ind of tas& :feeding apress; it can perfor(6

.EE'0"% A"' EECT0O" METHO'S 

MethodSafeguardingAction

Ad#antages (i!itations

 ,uto(atic ?eed

Stoc& is fed fro(ro!!s9 inde>ed $y(achine(echanis(9 etc6

*!i(inates the needfor operatorin.o!.e(ent in thedanger area

--0ther guards are

a!so re=uired foroperator protection -usua!!y fi>ed $arrierguards6--Re=uires fre=uent(aintenance6--May not $e a$!e tostoc& .ariation6

Se(iauto(atic

?eed

Stoc& is fed $ychutes9 (o.a$!edies9 dia! feed9

p!ungers or s!iding$o!ster6

6 6

 ,uto(atic*ection

%or& pieces areeected $y air or(echanica! (eans

6

--May create aha"ard of $!oingchips or de$ris6--Si"e of stoc& !i(itsuse of this (ethod6--,ir eection (aypresent a noiseha"ard6

Se(iauto(atic*ection

%or& pieces areeected $y

0perator does notha.e to enter

--0ther guards arere=uired for operator

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Adapted from the U.S. Department of Labor,

Occupational Safety and Health Administration OSHA 306, !""# $%e&ised'

 

(echanica! (eanshich are initiated$y the operator 

danger area tore(o.e finishedor&

protection6--May not $eadapta$!e to stoc&.ariation6

Ro$otshey perfor( or&usua!!y done $yoperator 

--0perator does notha.e to enterdanger area6--,re suita$!e foroperations herehigh stress factorsare present9 suchas heat and noise6

--Can create ha"ardsthe(se!.es6--Re=uire (a>i(u((aintenance6--,re suita$!e on!y tospecific operations6

Miscellaneous Aids 

%hi!e these aids do not gi.e co(p!ete protection fro( (achine ha"ards9 they(ay pro.ide the operator ith an e>tra (argin of safety6 Sound udg(ent isneeded in their app!ication and usage6 Be!o are se.era! e>a(p!es ofpossi$!e app!ications6

 ,n aareness $arrier does not pro.ide physica! protection9 $ut ser.es on!y tore(ind a person that he or she is approaching the danger area6 Genera!!y9aareness $arriers are not considered ade=uate hen continua! e>posure tothe ha"ard e>ists6

?igure #4 shos a rope used as an aareness $arrier on the rear of a poers=uaring shear6 ,!though the $arrier does not physica!!y pre.ent a personfro( entering the danger area9 it ca!!s attention to it6 ?or an e(p!oyee to enterthe danger area9 it ca!!s attention to it6 ?or an e(p!oyee to enter the dangerarea9 an o.ert act (ust ta&e p!ace9 that is9 the e(p!oyee (ust either reach orstep o.er9 under or through the $arrier6

Shie!ds9 another aid9 (ay $e used to pro.ide protection fro( f!ying partic!es9sp!ashing cutting oi!s9 or coo!ants6 ?igure ##  shos se.era! potentia!app!ications6

Specia! hand too!s (ay $e used to p!ace or re(o.e stoc&9 particu!ar!y fro( orinto the point of operation of a (achine6 , typica! use ou!d $e for reachinginto the danger area of a press or press $ra&e6 ?igure #'  shos anassort(ent of too!s for this purpose6 o!ding too!s shou!d not $e used insteadof other (achine safeguards8 they are (ere!y a supp!e(ent to the protectionthat other guards pro.ide6

 , push stic& or $!oc&9 such as those in ?igure #)9 (ay $e used hen feedingstoc& into a sa $!ade6 %hen it $eco(es necessary for hands to $e in c!osepro>i(ity to the $!ade9 the push stic& or $!oc& (ay pro.ide a fe inches ofsafety and pre.ent a se.ere inury6 In the i!!ustration the push $!oc& fits o.erthe fence6

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Adapted from the U.S. Department of Labor,

Occupational Safety and Health Administration OSHA 306, !""# $%e&ised'

 

his (ateria! as adapted fro( origina! docu(ents found at the Sa!t a&eCity 0S, e$ site6 7o guarantee of the accuracy of this infor(ation is (adeor i(p!ied8 for the !atest regu!ations and infor(ation9 contact 0S, :6S6epart(ent of a$or; direct!y6

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Adapted from the U.S. Department of Labor,

Occupational Safety and Health Administration OSHA 306, !""# $%e&ised'