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What is BF?

Tubes

Sprockets

Grooves

Coatings & Platings

Axles

Axle Machining

Bearings

Roller Assembly

Tapers

Formed Tubes

Special Features

Applications

Questions to Ask

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Table of ConTenTs

2

n Thedistancebetweenthesideframesofaconveyoristhe“BetweenFrame”dimensionor“BF”.

WhaT is bf?

n Thelengthoftherollerfrombearingtiptobearingtipisthe“OverallCone”or“OAC”.

n TheOACis1/8"shorterthantheBFforrollersupto3.5"diameter.Forrollersover3.5"diametertheOAC is3/16"shorterthantheBF.

bf and oaC are more important than Tube length.

n Tubelengthisnotanaccuratewaytomeasurethelengthofarollerbecauseitisdependentonhowfarthe bearingsprotrudefromthetubeandthereforechangeswithdifferentbearings.

Between Frame Width (BF)

Overall Cone (OAC)

3

n TubesarespecifiedbytheOuterDiameter(OD)andthethicknessofthetubewall.

n Themostcommonrollertubesizesare1.9"ODx16ga.and2.5"ODx11ga.

n Omniofferstubediametersizesrangingfrom1"to8".

n Omniofferstubesmadefromthesematerials:

– Mild(low-carbon)Steel – GalvanizedSteel – StainlessSteel – Aluminum – PVC – IndustrialSteelPipe

n Steeltubescanbeheattreatedwhichincreasesthesurfacehardnessandmakesthetubemoreresistant toabrasionsandsmallimpacts.

There is a difference between tube and pipe.

n PipeisspecifiedbyInnerDiameter(ID)andaSchedulenumberthatrepresentswallthickness.

n Themostcommonpipesizeforrollersis1-1/2SCH40whichhasanouterdiameterof1.9".

n Pipeisindustrialgradeandcanhaveaveryroughfinish.

Tubes

Wall Thickness

Outer Diameter

4

n Sprocketsareweldedtotubesfor usewithchains.

n TypicallyusedinChainDrivenLive Rollerconveyor.

sproCkeTs

n SprocketsarespecifiedbytheChainPitchandNumberofTeeth.

n Thechainpitchspecifiesthedistancebetweentheteeth.

n Sprocketlocationsaremeasuredfromtheinsidefaceofthesideframe tothecenterlineofthesprocket.

n Eachadditionalsprocketismeasuredfromcenterlinetocenterline.

n Locationofsprockets,chainsize,andnumberofteethmustbespecified.

Grooves

n GroovescanbeformedintocertaintubesforusewithO-rings.

n TypicallyusedinLineShaftConveyors.

n Locationandsizeofgroovesmustbespecified.

CL CL

5/32" RAD 1/4" RAD

1/4"3/16"

Narrow Groove

WideGroove

n Omnihastwostandardgroovessizes, narrowandwide.

n NarrowGroovesare5/16”wideandmade for3/16”dia.belt.

n WideGroovesare½”wideandmade for¼”dia.belt.

5CoaTinGs & plaTinGs

n Coatingsreduceimpacttoproduct,reduce scuffingtoproduct,createmorefriction betweenrollerandproduct,andprotect thetubefromabrasion

n Materialtype,durometer,andthickness mustbespecified.

n Omnioffersrollerscoatedwiththese materials:

– Urethane – Plastisol – Neoprene – Teflon – Vinyl – Other

n Platingsprotectthesurfaceofthetubefromcorrosionandabrasionwhileenhancingappearance.

n Omnioffersrollersplatedwiththesematerials:

– Zinc – Chrome – Nickel

n Galvanizedtubeissteeltubewithathinlayerofzincplatingthatisappliedduringthefabricationprocess ofthetube.Itisthinnerthanhot-dippedzincplatingwhichisappliedafterthetubeismade.

6

A B C D E

n Axlesaregenerallyroundorhexshaped.

– Hexaxlesarespecifiedbythelengthacrosstheflats. – Roundaxlesarespecifiedbytheirdiameter.

n Themostcommonaxlesizesare7/16"hexand11/16"hex.

n OmnioffersaxlesmadefromeitherMildSteelorStainlessSteel.

n Axlesaregenerallyretainedbyaspring(A)orcotterpins(C).

n Springsareheldinplacewithdimplesstampedintothematerial(E). CotterPinsareputintoholesdrilledthrutheaxle(B).

n Otheraxleretentionmethodsinclude:

– HogRings(axleD) – SpringBothEnds – FixedorStaked

axles

axle MaChininG

n AxleMachiningoffersotheroptionsforretainingtheaxle.

n Someaxlemachiningoperationsinclude,butarenotlimitedto:

Drilled and Tapped Threaded Milled Slot for Keeping Bar

Milled Flat Turned Snap Ring Groove

DiameterFlats

7

n Bearingsarethemostcomplexandcriticalpartofaroller.

n Bearingscomeinawidevarietyofsizes,shapes,andfeaturesthatallofferdifferentperformance characteristics.

n Omnihasalargeofferingofstandardbearingsbutiscapableofutilizingmosttypesofbearings forcustomapplications.

n Somecommonbearingfeaturesareshownbelow.

Bearing capacity does not dictate roller capacity.

n Rollerloadcapacityisusuallydictatedbyaxleortubedeflection.

n Highercapacitybearingsinalongrollerwillnotnecessarilychangetheloadcapacityoftheroller.

n BearingcapacityisusuallythelimitingfactorofrollercapacityonlyatshortBF’s.

bearinGs

n Flangedbearingshavealiparoundthebodywhich preventsthebearingfrombeingpressedtoofarintoatube.

n Stampedbearings(left)arehousedwithsheetmetalthatis stampedorformedaroundthecomponents.

n Machinedbearings(right)arehousedwithsolidmachined steelwhichholdsmuchtightertolerancesthanstamped bearings.

n Unflangedbearingshaveacylindricalbodythatcanbepressed completelyintoatube.Thesebearingscanberecessedfully intothetube.

�bearinGsn Sealedbearings(left)havesoftsealscoveringthe ballsthatprotectthemfromcontaminationand preventgreasefromleaking.

n Sealscanbemadefrom:

– Rubber – Nylatron – Teflon – Felt – Other

n Shieldedbearings(right)havehardmetalshields thatcovertheballsandprotectthemfrom contamination.

n Regreasablebearingshaveaholethroughthe innerracethatallowsgreasetobedirectedinto thebearingthroughspeciallydrilledchannels andagreasezerkintheaxle.

n Unground(Non-precision)bearingsaremadeofastampedmetal housingwithveryloosetolerances.Theyincludeafullcomplementof ballswhicharenotseparated.Theyarenotintendedforveryhigh loadsorhighspeeds.

n Semi-Precisionbearingshavemachinedmetalhousingswithtighter tolerancesthanungroundbearings.Theyalsoincludeaballretainer tokeeptheballsseparatedandevenlyspacedaroundthebearing. Thismakesthemcapableofhigherspeedsandhigherloadcapacities thanungroundbearings.

�bearinGs

n RadialBearingshaveaverybasicshape.Theyhavenoflanges andbothracesarethesamewidth.RadialABECbearingsare usuallymetricwitharoundborethatismeanttopressontoashaft. Theyaredifficulttofitintoatubecorrectly.Makingarollerwithradial ABECbearingscanbeverylaborintensiveandimpractical.

n Omni’sAllMetalABECbearingsarecustomradial ABECbearings.Theyaremodifiedwithlargerbody diameters,hexbores,extendedinnerraces,and flanges.Theyofferallthebenefitsofpolyhoused ABECbearingsbutaremoredurableanddonot requireacrimp,whichmeanstheyarereplaceable.

n PolypropyleneHousedBearingsconsistofaradialABEC bearinginsideapolypropylenehousingassembly.The outerhousingismucheasiertofitintotubeswithout damagingtheradialbearing.Theinneradapterallowsthe bearingtofitontodifferentaxles,usuallyhexshaped. The“poly”housingmustbecrimpedintotubesandisnot replaceable.

n ABEC(Precision)bearingsaremadefromhighqualitysteel,heat treatedtouniformhardnessandgroundtoamicrofinish. Thetolerancesaremuchtighterthansemi-precisionbearings. Thismakesthemcapableofevenhigherspeedsandhigherload capacitiesbutsensitivetodeflectionandmisalignment.

�0bearinGs

n InsertbearingsareABECbearingsdesignedforusein housingunitslikepillowblocks.Theyarecharacterizedby set-screws,orsomeothermechanism,onanextended innerracethatlockstheinnerracetotheaxle.Theycan onlybepressedintorollertubesiftheyhaveacylindrical body.

n SphericalSleevedBearingsarelargeinsertbearingswithspherical bodiesthatmustbefitintomachinedsleevestobeinstalledin rollertubes.Thebearingscanrotatewithinthesleevewhich allowsformoremisalignmentoftheaxleshaft.

n Agricultural(AG)bearingsaresimilartoinsertbearingsbutlack theabilitytolocktoanaxleshaft.TheyareABECbearingsthat canalsobeusedinhousingunitsandmusthaveacylindrical bodytobepressedintoarollertube.UnlikeotherABEC bearingstheyareavailablewithhexboresandsquarebores.

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n Plasticbearingshavemoldedplasticbodiesandstainless steelballs.UsuallythebodiesareDelrin,theballsare420 stainlesssteel,andthereisaballretainer.Theyareusedfor highlycorrosiveenvironmentsandcanbetotallysubmerged. Theydonotrequirelubrication,duetothesoftnessofthe plastic,buthaveverylimitedloadcapacity.

n FramesavercartridgescontaintworadialABEC bearingsandastubshaftinapolypropylene housing.Thestubshaftishexshaped,spring loaded,andslightlytaperedtoensureasnugfitin theframe.Thispreventstherollerfrombouncingin theframeandcausingwear.

bearinGs

n Bushings(RollEndBearings)aresolidpiecesofmaterialwithnorollingelementsormovingparts. Theyfitdirectlyintotubesandsimplyslideovertheaxleastheyrotate.Dependingonthematerial, theycanbeusedforextremetemperatures,dirtyenvironments,corrosiveenvironments,orsanitary conditions.Anadapterisrequiredforusewithhexaxles.Blindboreversionscanbeusedwithstub shaftstomaketherollerwater-tight.

�2roller asseMblY

n Apressfitrollerhasatubewhichis counterboredtothecorrectinside diameterforthebearingtobepressfitinto placeorslipfitforlargediameterrollers.

n Arollerwithbosseshassteelslugsweldedinsidetheendsofthetube.Bearingsthataretoosmalltofit intothetubecanbepressfitintothebosses.Thisallowsforawidervarietyofbearingstobeusedinthe tube.

n Rollerswithweldedaxleshavebossesthatareweldeddirectlytotheaxle.Theserollersdonotuseinternal bearings.Insteadtherollerwouldbesupportedbyexternallymountedbearings.

n Acrimpedrollerhasatubewhichiscrimped downoverthebearingtoholditinplace. Bearingsinstalledinthismannerare non-replaceable.

�3Tapers

n Taperedrollersarespecifiedbyalargeandsmalldiameter.

n TheanglethatthediameterchangesoveracertainlengthiscalledtheTaperRate. (similartothepitchofaroof)

n Thereareaboutadozentaperratesthatarestandardthroughouttheindustry.

n Omnihastheabilitytocreateatruetaperbasedonthedimensionsofthecurve.

n Omnicancreatetaperswithspecialtaperratesaswellasallindustrystandards.

Center of Curve

Center of Curve

n Whenthetaperrateistrueforagivencurve theproductwillmaintainitsorientation aroundthecurve.

n Ifthetaperrateisnottrueforagivencurve thentheproductwillbecomeskewedaround thecurve.

�4forMed Tubes

n Tubescanbeformedintomanyshapesforspecificapplications.

n Typicallyformedtubesareusedtoguidespecialproductsortofit intospecialmachinery.

n Therearenostandardformedtubessoeachtubeiscustombuilt forthespecificapplication.

n Somebasictubeshapesinclude,butarenotlimitedto:(right)

Concave Rollers

Bow-Tie Rollers

Turned-Down Rollers

Dog-Bone Rollers

Bubble Roller

speCial feaTures

n Manydifferentfeaturescanbeweldedontoormachinedintoarollertube.

n Typicallythefeaturesshownbelowhavenostandardsandarecustombuiltforeachapplication.

n Someoptionsinclude,butarenotlimitedto:

Sprocketed hubs allow the use of small sprockets with large

tubes.

V-groove hubs have different groove profiles for use with

v-groove belts.

Trapezoidal Crowns are machined into tubes to assist in

centering the drive belt.

Flanges are welded to tubes to

guide product.

�5

Omnihasthecapabilitytomanufacturerollersforalmostanycondition.Belowarelistedsomecommonsituationsandthewaysinwhichrollersarespecializedtobesthandletheseconditions.Keepinmindthataparticularapplicationmayincludeseveralofthefollowingscenarios.

Gravity applicationsRollersarenotdirectlydrivenandonlyrotatewhenproductpassesoverthem.Forlightproductsrollersarelight-weightandbearingsarelightlyoiledtoreducerotationalfriction.Bearingsmaybegreasepackedforheavierproductsthatcaneasilyovercomerotationalfriction.

powered applicationsRollersaredirectlydrivenbybelts,chains,orothermeans.Rollersmayberotatingevenwhenproductisnotpresent.Bearingsaregreasepackedtomaintainlubricationthroughmorecontinuoususe.

high speedsRollersaresubjectedtooperatingspeedsabove250RPM.Rollersarebuiltwithlightweighttubesthatarestraightenedtotighttolerancestoreduceimbalancesandpreventbouncing.Bearingsaresemi-precisionorprecisionforprolongedservicelife.Whenoperatingspeedsexceed400RPMrollersarebuiltusingonlyprecisionbearings.

heavy loadsRollersaresubjectedtolargeliveloadsduringnormaluse.Forsmall,light-dutyrollers,aheavyloadmaybelessthan100lbs.Forlarge,heavy-dutyrollers,aheavyloadmaybemorethan1000lbs.Rollersarebuiltwithcomponentsthatarelargeenoughtoresistdeflection.AtlongBF’sacenterpuckmaybeaddedtotheaxletopreventtheaxlefromdeflectingtoofarandrubbingalongtheinsideofthetube.

stationary loadsRollersaresubjectedtolongperiodsofbeingloadedbutnotrotating.Rollersarebuiltwiththickertubestopreventdentingfromprolongedloadingonjustonesideofthetube.Bearingsfeaturehardenedracewaystoresistdentingandcages,orretainers,thatkeeptheballsevenlyspacedaroundthebearingtoevenlydistributetheload.Bushingsmayalsobeusedduetotheirhighstaticloadcapacities.

impact loads (shock loading)Rollersaresubjectedtoobjectscollidingwiththem.Productsmayhaveunevenbottomsthatcausethemtobouncealongtherollersorproductsmaybedroppedorthrownwhilebeingloadedontotherollers.Rollersarebuiltwithheavywalledtubestoresistdenting.Bearingsarehighcapacitytoreducetheriskofdamage.Bushingsmaybeusedduetotheirlackofmoving(breakable)parts.

dirty/Gritty environmentRollersaresubjectedtosmallparticlesofdirtordustthatcancontaminatebearinglubricationandpreventthebearingsfromrotating.Bearingsfeaturecontactsealsandshieldsthatpreventparticlesfromentering.Bearingsmayalsoberegreaseablesothatlubricationcanberegularlyflushed.Bushingsmayalsobeusedduetotheirlackofmovingpartsorneedforlubrication.

appliCaTions

�6appliCaTions

abrasive productsRollersaresubjectedtoproductsthatcanscratchthetubesurfaceandcauseunevenweartothetube.Productsmayhaveanabrasivebottom,therollersmaybespinningunderastationaryproduct,ortheremaysimplybedirtbetweentheproductandtherollers.Rollersarebuiltwithtubesthatareheattreatedtoincreasethetubesurfacehardnessandresistscratching.Rollersmayalsobecoatedwithdifferentmaterialsthatareresistanttoscratching.

Wash-down ConditionsRollersaresubjectedtohighpressurespraywashesandpossiblystrongdetergents.Rollersarebuiltfrommaterialsthatwillnotrust.Bearingsfeaturesealsthatpreventlubricationfrombeingwashedaway.Bushingsmaybeusedbecausetheyrequirenolubrication.

Corrosive environmentRollersaresubjectedtochemicalsthatpromotecorrosion.Rollersarebuiltwithmaterialsthatareresistanttocorrosionfromthespecificchemicalsinvolved.Therollersmaybecoatedorplatedwithresistantmaterialsforadditionalprotection.

low TemperatureRollersaresubjectedtosub-zeroambienttemperaturesorproducttemperatures.Rollersarebuiltwithbearingscontaininglowtemperaturegreaseorlightoilthatwillnotfreezeandreducesstart-upfriction.

high TemperatureRollersaresubjectedtoambienttemperaturesorproducttemperaturesabove200°F.Rollersarebuiltwiththickwalledtubestodissipateheatandpreventwarping.Bearingsfeaturehightemperaturegreaseandhavenorubbersealsthatcanmelt.Bushingsmaybeusedthataremadefromhightemperaturematerialsandrequirenolubrication.

�7QuesTions To ask

ThemoreinformationthatcanbegatheredfromthecustomeraboutarollerthebetterOmnicanhelpprovidearollerthatwillmeetthecustomer’sneeds.Belowaresomeexamplequestionsthatmightbeaskedofthecustomerinordertohelpgatherasmuchinformationaspossible.

Is the roller being used in a conveyor?

What kind of conveyor is the roller being used in?

What is the product being conveyed?

What is the size of the product and how much does it weight?

How close together are the rollers in the conveyor?

How fast is the roller rotating?

How many hours per day is the roller being used?

noTes