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RO
LLE
Rm
AN
UA
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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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7-��
�2
�3
�4
�4
�5-�6
�7
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.
��
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