conveyor pulleys

bulk materials handling technology

Each JND pulley isindividually computerdesigned to meet theclient's duty requirements.Design is based on thepre-determined tolerancesof stress loading and thedistribution of load throughthe individual componentsof the pulley, within thecritical calculation offatigue factors.Bending and shearstresses are limited in thedesign of drive and non-drive shafts together withthe deflection of the shaftat the pulley hub.JND have a deepunderstanding of theprecise calculation of allstress potential and thematching performance ofcomponents andconstituent materials. Enddisc design calculation isbased on the ability ofeach end disc to give100% support of direct andbending stress.Internal diaphragms helpsupport the rims of widerpulleys. The skills andexperience of JND areassisted by the latest incomputer aidedtechnology andmanufacturing techniquesemployed with the highlevel of control availableonly to a complete in-house production unit.

conveyor pulleys

Long established market leaders Jenkins Newell Dunford (JND)have unrivalled abilities in conveyor pulley design and engineeringand are internationally acknowledged as a premier supplier to theWorld industries of coal, civil construction, engineering steel,quarrying and mining. JND conveyor pulleys are the product ofdecades of dedicated research, development and perception ofclients needs, producing the most proficient quality assured, highintegrity manufactured pulley available today.

JND pulleys aremanufactured andassembled in accordancewith ISO standards withwelding toASME 9/BS4870. Specialpurpose fixtures areemployed in pulleyassembly to ensureconcentricity is maintained.Stage inspection andquality control is inherentin every process andselected welds aresubjected to the MPImethod of non-destructivetesting, a process whichcan be further extended toinclude 100% ultrasonic orradiography testing whererequired.

Design Philosophy Manufacturing and Assembly Pulley RangeThe ShellJND pulley shells are onepiece rolled with a singleseam weld. The partlyformed shell is squeezedin a special machinearound the machined enddiscs to ensure accurateconcentricity and to keepconsistent weldpreparations between thediscs and the shell. Theresulting fabrication isaccurate in concentricity,has even load distributionbetween the rim and theend discs and althoughstatic and dynamicbalancing is not necessaryfor most applications, itcan be added if required.

The JND standard rangeof conveyor pulleys isavailable in sizes up to 2min diameter and up to2.2m face width.Special pulleys areavailable for larger drives.End discs, shells andshafts, can be assembledin different combinationsto fit customer needs andthe shaft fastener, theindividual factoridentifying different pulleytypes, can becompression, keyed bossor shrink fit.Whilst the majority ofpulleys produced by JNDare fitted with thepatented Dick single taper

shaft fastener, JND'sapplication specialists willadvise the most suitablefastening for anyapplication.

A JND conveyor pulley is a unique rotatingfabrication, in which the integrity of designproduces a component, fully engineered buteconomically priced.

Single TaperedCompression

Incorporating the DickBush� Interchangeable shafts� Shaft sizes 60 to 250mm� Ideal for rationalisation� Easy to install and

removeThe Dick bush, as adaptedby JND is the bestexample of this uniquefastening. It features asteep taper in acompression type couplingwhich has the significantadvantage of eliminatingthe need for fitted keysand allows for easierremoval. A side-fitting key

‘...the most proficient quality assured, high integrity manufactured

pulley available today...’

Fabricated End Disc Keyed Hub Solid End Disc Fabricated End Disc Cast Steel End Disc

can be specified for thedrive pulley assemblies.Good tolerances tobending and deflectionresult in an exceptionallycost effective design andeach bush can bemachined to suit a rangeof shaft diameters. Thebush is manufactured inclose grain cast iron andmachining standards ofthe matching tapers of thebush and hub ensureminimal assemblystresses, fretting andcorrosion.

Double TaperedCompression� High load capacity

(best achieved with caststeel end disc)

� Interchangeable shaft� High torque carrying

ability� Low surface pressure

compression� Designed specifically

for handlingexceptionally heavyloads.

Keyed Boss

A low cost pulley withcaptive or removableshafts. Parallel keys canbe supplied at one end ofthe pulley for non-driveand single drive and atboth ends for doubledrive.

Shrink Fit

JND "shrink fit" pulleys aredesigned specifically totransmit high torque,making them especiallyeffective in heavy loadapplications. Captive shaftpulleys with "shrink fit" typehubs, do not require keysalthough they can be fittedto customer specification.

End Discs

The load distribution isdetermined at the designstage and is a decidingfactor in the choice of enddisc.Three basic designs areused, all machined on theouter rim and bores.

Fabricated End Discs arethe most common, theyare individually designengineered in two types -flexing discs and rigiddiscs. They employ eitherkeyed hub or compressionfasteners for replaceableshaft pulleys.

Solid End Discs aredesigned to carry thefastening directly,satisfying the demand forextending the originalpulley design toaccommodate increasedloads.Cast Steel End Discs area further development forvery high horsepowersthat exceed the designloads on the moreconventional disc to shellwelds.Standard designs,machined, butt welded tothe ends of the shells andthermally stress relievedare available up to5,000h.p.

AssemblyFinal assembly is ameticulous operation andpulleys are prepared fordelivery with a laggedspecification, using rubberor neoprene, or unlaggedwith paint finish andprotected machinedsurfaces. Bearings can besupplied and fitted orcustomers' free issuebearings fitted togetherwith couplings and drivecomponents.

Cast Steel End DiscWeldingThe cast steel end discsare welded to the pulleyshell by MIG andsubmerged arc weldingusing special tools andfixtures to weld the insideand outside of the disc tothe shell, in a low stressarea.

MachiningWell equipped workshopswith advanced CNCfacilities ensure highcalibre finishing of allcomponents.

JND Manufacturing Ltd Thrumpton Lane, RetfordNottinghamshire, DN22 7AN, EnglandTel +44 (0)1 777 706 777Fax +44 (0)1 777 710 604www.jnd.co.uk

A member of The Jenkins Newell Dunford Group Ltd

Issue: JND 0029/05/03/1

A Langley Holdings Company

Welding toASME/BS4870JND pulley designs havebeen developed specificallyto eliminate all stress con-centration from machinedcomponents and fixturesbetween shafts and hubs.The designs are based ontheoretical and practicaltests carried out with theWelding Institute for fatigueanalysis of weldedconstruction and sincethere are no establishedrecommendations forstress levels on somewelds-fillet and one sidepenetration welds, JND'sdesign calculations arederived from their ownfatigue tests.

Pulley RationalisationThe flexibility of the Dick bush design removes the needto carry a complete pulley for each location.The resulting rationalising effects the whole range ofinterchangeable shafts, bushes and pulleys andsignificantly reduces the spares stockholding. As anexample, a recent survey of a major site with 34conveyors and a total of 158 pulleys has greatlyreduced the spares holding to only:4 pulley shells4 non-drive shafts4 drive shafts5 Dick bushes7 pairs of bearingsJND offer a service to both new and existing plants tosurvey and submit rationalisation proposals.

Seam WeldingAll JND shells are seamwelded by MIG andsubmerged arc processand all welds are finishedto a smooth profile withthe completed pulley.The accuracy ofconstruction eliminatesthe need for themachining of standard flatpulleys.

End Disc Welding Both discs are weldedsimultaneously to theshells by a speciallydeveloped double-endedwelding machine toensure consistent,economically efficientmanufacture.

The information contained within this brochure is deemed to be correct at the time of goingto press. Due to the policy of continued improvement, we reserve the right to change anyspecification without prior notice. ERRORS & OMISSIONS EXCEPTED