Glossary Correia

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Glossary of Industrial Terms

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Glossary of Industrial Terms

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A

Abraded: Worn away by friction.

Abrasion: Wearing away by friction.

Abrasion test: Determination of the rate ofwearing away by friction.

Abrasion tester: Accelerated aging:Intensive exposure to operatingconditions to obtain an earlychange in physical propertiesof an elastomer.

Accelerated life test: A method designed to approxi-mate in a short time the dete-riorating effects obtained undernormal service conditions.

Across the line starting tension:Tension developed in a beltwhen full electrical power isapplied to the drive system.

Adhesion: Basically, the adhering, cling-ing, bonding or sticking of twomaterial surfaces to one an-other, such as rubber to rubber,rubber to metal, rubber towood, rubber to fabric.

Adhesion failure:The separation of two adjoiningsurfaces due to service condi-tions.

Adhesive: A material which, when applied,will cause two surfaces incontact with each other to sticktogether.

Adhesive coating: A coating applied to a surfaceto increase its bond to anadjoining surface.

Adhesive fabric: A fabric with a surface treat-ment which will bond twosurfaces together when inter-

posed between them.

Aftercure: A continuation of the process ofvulcanization after the cure hasbeen carried to the desireddegree and the source of heatremoved.

Afterglow: In fire resistance testing, thered glow persisting after extinc-tion of the flame.

Aging: To undergo changes in physicalproperties with age or lapse oftime.

Air bomb aging: A means of acceleratingchanges in the physical proper-ties of material by exposingthem to the action of air atelevated temperature andpressure.

Air checks: The surface markings or de-pressions which occur due toair trapped between the mate-rial and the mold or presssurface.

Air curing: The vulcanization of a rubberproduct in air as distinguishedfrom vulcanizing in a press orsteam vulcanizer.

Air oven aging: A means of accelerating achange in the physical proper-ties of rubber compounds byexposing them to the action ofair at an elevated temperatureat atmospheric pressure.

Air trap: See air checks.

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Ambient temperature:The environment temperaturesurrounding the object under

consideration.

Angle of repose:The angle to the horizontalwhich a material will naturallyassume when dropped in apile.

Angle of slide: The angle at which materialbegins to slide down an in-clined surface.

ANSI: American National StandardsInstitute

Anti-backdrop: See backstop.

Anti-static: See static conductive.

Antioxidant: A compounding ingredientused to retard deteriorationcaused by oxygen.

Antiozonant: A compounding ingredientused to retard deteriorationcaused by ozone.

Antislip surface: A specially treated surface toobtain greater than normaltraction.

Apron feed: An intermediate feed system.

Arc of contact: (1) The portion of a curved

surface which is engaged. (2)In belts, it refers to the portionof a pulley which is engaged bythe belt and is usually ex-pressed in degrees.

Armored belt: A conveyor belt with crosswiseinsertions in the cover such assteel cables to minimize goug-

ing or tearing of the cover bysharp objects.

Army duck: See duck.

Artificial weathering:Exposure to cyclic laboratoryconditions involving changes intemperature, relative humidity,and radiant energy, with orwithout direct water spray,attempting to produce changesin the material similar to thatobserved after long-termcontinuous outdoor exposure.

ASME: American Society of Mechani-cal Engineers.

ASTM: American Society for Testingand Materials.

Atmospheric cracking:Small fissures in the surface ofa belt cover caused by expo-sure to atmospheric conditions.

Automatic take-up: A mechanical device to main-tain proper tension in a beltautomatically compensating forbelt stretch or shrinkage inservice.

Average modulus:

The total change of stressdivided by the total change ofstrain.

B

Back cover: See bottom cover.

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Backstop: A mechanical device for pre-venting a loaded, inclinedconveyor or elevator belt fromrunning backwards after thebelt has been stopped.

Banbury mixer: A specific type of internal mixerused to incorporate filler andother ingredients in rubber orplastic operations.

Bare back: The textile face of an articlewhich is free of any treatmentor covering.

Bare duck: The duck surface of a fabri-cated article wherein theexposed duck surface is free ofany covering.

Bare duck belt: A belt in which at least oneside has the exposed ducksurface free of any covering.

Bare pulley: A pulley whose face surface isnot covered or lagged.

Bareback surface: A belt surface where the textilesurface is without any coating.

Base belt: The portion of a closed belt ina closed belt conveyor whichremains flat and provides thenecessary tensile strength.

Basic tension bearing yarns:One of the two warp systems in

a straight warp fabric where thewarp yarns are substantiallywithout crimp and provide thetensile strength for the belt.

Basket weave: A fabric with ends of yarn sideby side in both the warp andfilling in a plain weave con-struction.

Bead rubber: An extruded polymeric com-pound used to fill the voidbetween butted joint of twopieces of fabric.

Bed: A continuous surface overwhich a conveyor belt mayslide.

Belt: A flexible reinforced bandplaced around two or morepulleys to carry materials fromone place to another.

Belt carcass: See carcass.

Belt clamp: Beams or metal plates securedtransversely on both sides ofbelt ends to hold the ends in adesired position.

Belt cleaning device: A scraper or rotating devicepressed against the belt sur-face to remove material stuckto the belt.

Belt conveyor: A mechanical system com-posed of suitable head, tail,bend pulleys and belt idlers ora slider bed to handle bulkmaterials, packages, or otherobjects placed directly upon it.

Belt drive: An assembly of power-drivenpulley(s) used to transmitmotion to a conveyor or eleva-tor belt.

Belt duck: An open weave duck madefrom plied yarns with strengthpredominately in the warpdirection. Used primarily in themanufacture of belts.

Belt fastener: A device for holding the ends ofbelt together.

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Belt fleet: The lateral movement of aconveyor belt to either side ofits intended path.

Belt grade: A classification of beltingaccording to the quality andproperties of the belt cover.

Belt modulus: The ratio of stress to strain.

Belt pitch line: See pitch line.

Belt sag: The amount of vertical deflec-tion of a conveyor belt from astraight line between idlers,usually expressed as a per-centage of the center to centerspacing of the idlers.

Belt slip: The action that takes place,causing a differential move-ment between the pulleysurface and the belt.

Belt slope tension: See tension, slope.

Belt surface finish:Final surface condition of belt.

Belt tracking switch: A limit switch actuated by theedge of a conveyor belt whenthe belt moves abnormally toeither side of its centered path.

Belt training idler: An idler having a belt-actuated

swivel mechanism to controlthe side runout of a conveyorbelt.

Belt turnover: A system of pulleys arranged toturn a belt over. Frequentlyused to prevent building-up onreturn idlers by turning the dirtyside (carrying side) up. Seealso twist.

Belting deflector: A mechanism which deflects theconveyed material off of the belt

at specific points along theconveyor.

Belting, flat conveyor:See flat belt.

Bench test: A modified service test in whichthe service conditions areapproximated in the laboratory.

Bend pulley: A pulley used to change direc-tion of belt run.

Bending force: The force required to bend abelt under prescribed condi-tions.

Bending modulus:That force required to inducebending around a specifiedradius and, hence, a measureof stiffness.

Bias angle: The smaller included anglebetween the warp yarns of afabric and the diagonal lineacross the warp yarns.

Bias cut: A cut of a textile material madediagonally at an angle less than90 degrees to the longitudinalaxis.

Bias laid: Material laid on or wrappedaround so the warp yarns are at

an angle less than 90 degreesto the longitudinal direction.

Bias seam: The seam at which bias cutfabrics are joined together.

Binder warp yarn:One of the warp systems in astraight warp fabric interlacedwith the filling yarn to providethe strength to hold mechanicalfasteners.

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Bite: See nip

Bleeding: Migration to the surface ofplasticizer, waxes or similarmaterials to form a film orbeads. See also Bloom.

Blemish: A mark, deformity, or injurywhich impairs the appearance.

Blisters: A raised spot on the surface ora separation between layersusually forming a void or air-filled space in the vulcanizedarticle.

Bloom: A discoloration or change inappearance of the surface of arubber product caused by themigration of a liquid or solid tothe surface. Examples: sulfurbloom, wax bloom. Not to beconfused with dust on thesurface from external sources.

Blow-up: A blister between plies of an

article.Bolted plate hinge fastener:

Steel plates both sides andboth ends of two belt ends tobe fastened together (securedto the belt with bolts with theends of the plates constructedinto a circular hole for accept-ing a hinge pin to secure thetwo ends of the belt(s) together.

Bond: See Adhesion.

Boot: Enclosure for the loading endof a bucket elevator belt.

Bootlegging: (1) Progressive ply delamina-tion. (2) The separation of pliesin belting due to flexing.

Bottom cover: The protective rubber cover onthe surface contacting thedriving mechanism of a con-

veyor belt.

Bow: (1) Curvature from flat plane inthe surface. (2) The deviationfrom the straight line of the fillyarn in a fabric. (3) The devia-tion from the straight line of aproduct when unrolled and laidon a flat surface.

Brand: A mark or symbol identifying ordescribing a product and/ormanufacturer: may be eitherembossed, inlaid, or printed.

Breaker ply: An open weave fabric usednext to the carcass fabric and/ or in the cover to improve theattachment of the cover to thecarcass and to improve covercut and gouge resistance.

Breaking strength:The tensile which a textile yarnor cable, a steel cord, or a beltis at rupture.

Brushed finish: The mechanical removal of anysurface impregnation or coatingfrom the belt fabric.

Bucket: One of the cups on an elevatorbelt.

Bucket cover: The cover of an elevator belt

next to the carrying buckets.

Bucket elevator: Belt with buckets attached.

Bucket projection:The distance the bucket pro-trudes beyond an elevator belt.

Buckled ply: A deformed ply, usually theresult of a fold or wrinkle, whichdistorts it from its normal plane.

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Calendered rubber sheets:Continuous film of uncuredelastomer produced from acalendar.

Camber: The curvature of a belt relativeto the center line (see bow).

Capacity: The maximum number ofpieces, volume, or weight ofmaterial a belt conveyor canhandle in a given time intervaland belt speed.

Capped edge: A rubber protective edge placedaround a product internallyreinforced with textile or othermaterial.

Capped end: A belt end covered with anelastomer to protect the car-cass end.

Carcass: The fabric, cord and/or metalreinforcing section of anyrubber product such as a belt,

as distinguished from therubber cover.

Carcass break: A ply or plies of fabric rupturedby impact or gouging.

Carcass tear strength: The resistance of a beltagainst tearing.

Carcass tear test: The determination of thetension at which a belt may betorn.

Carrier: See idler (2).

Carry (or carrying) side cover: See top cover.

Carrying roller: See carrying idler.

Carrying run: The portion of a conveyor thatcarries the load between theloading and discharge points.

Buffing marks: The characteristic surfacecondition after a buffing opera-tion.

Bumping: In the operation of a flat press,the alternative application andrelease of ram pressure to venttrapped air and gases.

Butt seam: A seam made by placing thetwo pieces to be joined edge toedge.

Butt strap joint: The connection of elevator beltends with a piece of belting thewidth of the elevator beltplaced over the butted beltends, usually extending underat least two buckets and se-cured with bolts to the belt.

C

Cable yarn: Two or more plied yarnstwisted together.

Calculated center distance:In belt drives, the distancebetween two shaft centerscalculated from pulley diam-eters and belt length beingused.

Calender: A machine with three or moreinternally heated or cooledcylinders used to (1) continu-

ously sheet out polymericcompound or fused PVC (2) towipe polymeric compound intothe interstices of a fabricleaving a small portion of it onthe surface of the fabric, or (3)to lay a continuous sheet ofcompound on a fabric.

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Carrying surface:The outward face or side of thebelt which carries the conveyed

material.

Castfilm: A film made by depositing alayer of plastic, either molten,in solution, or in a dispersiononto a surface, solidifying andremoving the film from thesurface.

Catenary idler: A type of flexible belt-carryingidler with ends supported inpivoted stands. The tube orrollers sag under the weight ofthe load to form trough.

CEMA: Conveyor Equipment Manufac-turers Association.

Cement: A mixture of polymeric com-pound or elastomer used as anadhesive or sealant.

Cemented edge: An application of cementaround the edge of a fabricatedproduct with or without internalreinforcement for protection oradhesion. (A form of CappedEdge.)

Cemented end: A belt end sealed with theapplication of elastomericcement.

Center roll: The horizontal roll between the

side troughing rolls.

Center-to-center:The distance between thecenter of two pulleys or idlers.

Also called centers or centerdistance.

Centrifugal bucket elevator: A type of bucket elevatorhaving a belt which travels atsufficient speed to dischargematerial from the buckets bycentrifugal force.

Chafer duck: A relatively open weave duck ofapproximately square wovenconstruction made with singleor ply yarn.

Chalking: Formation of a powdery sur-face condition due to disinte-gration of surface binder orelastomer due in turn to weath-ering or other destructiveenvironments.

Checking: Short shallow cracks on thesurface generally due to effectof destructive action of environ-mental conditions.

Chevron: A ridge or profile arranged in a Vee shaped configuration on abelt carrying cover to stabilize

material carried up an incline.Chute lining: Highly abrasion resistant

elastomeric lining in a chute toprotect the metal chute fromabrasion wear.

Chute slope: Angle relative to the horizontala chute is inclined.

Cleated belt: Transverse raised sections on aconveyor belt to stabilize

material carried up an incline.

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Cord: Several strands of yarn twistedtogether.

Cord belt: A belt with textile or steel cordsfor the longitudinal tension-bearing member.

Cord fabric: A fabric with plied or cabledyarns in the warp direction anda light weight filling yarnspaced only sufficiently toprocess the fabric.

Cotton: A natural fiber of high cellulosiccontent.

Count: In fabric, the number of warpends, the number of fillingpicks, or both in a square inchof fabric.

Counter weight:In conveyor belting, the weightapplied to the take-up assem-bly to maintain proper belttension.

Cover: The outer component of a belt.

Cover seam: See cover splice.

Cover splice: The transverse joint formed byconnecting two lengths of coverstock.

Cover surface profile: A cross-sectional view of thecover surface.

Cover wear: The loss of material during usedue to abrasion, cutting, orgouging.

Cracking: A sharp break or fissure in thesurface. Generally due toexcessive strain.

Crater: A small shallow surface imper-fection.

Continuous bucket elevator: A bucket elevator belt thatdischarges by gravity over the

inverted bottom of the preced-ing bucket on the descendingside of the elevator.

Control: A material or a product ofknown characteristics includedin a series of tests to provide abasis for evaluation of otherproducts.

Conveyor: A system for the continuousmovement or transport of bulkmaterials, packages or objectsalong a predetermined path.

Conveyor belt: A belt that carries materialsfrom one place to another

Conveyor belt package deflector: A mechanical diverter placed atan angle across the belt todeflect packages off the belt atspecific locations.

Conveyor belt stretch:The increase in belt lengthwhich takes place when tensionis imposed. Stretch is eitherelastic or permanent. Elasticstretch is a temporary changein length which varies directlywith the pull. Permanent stretchis the residual change in lengthafter tension has been re-moved; it generally accumu-

lates over a period of time.

Conveyor width:In belt conveyors, the width of abelt.

Copolymer: A substance consisting ofmolecules characterized by therepetition of two or more typesof monomeric units.

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Crystallization: A change in physical propertiesresulting from the crystallinereorientation caused by tem-

perature.

Cure: The act of vulcanization.

Cure time: Time required, at a giventemperature, to produce opti-mum physical properties in anelastomer.

Curing temperature:The temperature at which therubber product is vulcanized.

Curl: The action of the edges of abelt bending upward on thecarrying run and downward onthe return run. Also calledcupping.

Cushion breaker: A leno or cord breaker imbed-ded in a belt cover.

Cut belts: See cut edge.

Cut edge: The uncovered edge of alaminated product, such a belt,created by cutting after vulcani-zation.

Cut resistance: The ability of a belt cover towithstand the cutting action ofsharp objects.

DData code: Any combination of numbers,

letters, symbols, or other meth-ods used by a manufacturer toidentify the date of manufac-ture.

Decking: A protective covering over thereturn run of a belt conveyor.

Crazing: A cover surface with manyfissures.

Creep: (1) The deformation occurringwith the lapse of time in bothcured and uncured rubber, in abody under stress in addition tothe immediate elastic deforma-tion. Some related terms andproperties are stress-relax-ation, hysteresis, damping,flow, compression set andviscosity. See Cold Flow. (2) Inbelts, the action of a beltalternately losing speed on thedriving pulley and gainingspeed on the driven pulley.

Creeper drive: An auxiliary drive, usuallyconsisting of a small motor andspeed reducer, used to keep abelt conveyor in motion at avery low speed during non-operating periods in extremelycold weather. It is used toprevent freezing of a belt andother components.

Crimp: (1) The waviness of the yarn ina woven fabric. (2) The differ-ence in distance between twopoints on a yarn as it lies in afabric and the same two pointswhen the yarn has been re-moved and straightened.Expressed as a percentage ofthe distance between the twopoints as the yarn lies in the

fabric.

Crown: The difference between thediameter at the center and atthe edges of a pulley or a roll.

Crowned pulley: A pulley with a greater diameterat the center, or other points,than at the edges.

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Deflector: A board or plate at an angleacross the path of a belttraveling over a flat surface to

transfer material off the belt.

Deformation: Any change of form or shapeproduced in a body by a stress.

Degradation: A deleterious change in thechemical structure of a mate-rial.

Delamination: The separation of layers ofmaterial in a laminate.

Denier: A yarn sizing system for con-tinuous filament syntheticfibers on the basis of theweight in grams of 9000meters of the yarn.

Density: The ratio of the mass of a bodyto its volume or the mass perunit volume of the substance.For ordinary practical pur-poses, density and specificgravity may be regarded asequivalent.

Diameter: The length of a straight linepassing through the geometriccenter to the periphery of anobject.

Dielectric strength:The measure of electric poten-tial strength of a rubber prod-uct. Measure of its ability as an

insulating compound to resistpassage of a disruptive dis-charge produced by an electricstress. Measured as volts permil of thickness.

Dip coat: A thin coat on a surface ob-tained by dipping the materialto be coated into the coatingmaterials.

Dipped fabric: Coated with rubber compoundby passing through a rubbersolution and drying.

Discharge: Removal of material from abelt.

Dog leg: A bending from a straight line.

Double plate bolt fastener:Two ends of belting joinedtogether with a plate on bothsides across both ends of the

joint.

Drive: An assembly of electrical andmechanical parts that providemotive power to a belt.

Drive, dual: See dual drive.

Drive factor: A numerical factor used forcalculating the belt minimumslack side tension required fora given driving condition and orconfiguration.

Drive, head-tail: See head-tail drive.

Drive pulley: A pulley mounted on a driveshaft which transmits power tothe belt.

Drive, single: A one-pulley drive.

Drive snubbed pulley: An undriven pulley locatedclose to the drive pulley to

provide a greater arc of contactaround the drive pulley.

Drive, tandem: See tandem drive.

Drive-on hinged fastener:Two ends of belting joinedtogether with a pre-packagedfastener assembly havingprongs for driving through thebelt end.

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Dutchman: A short section of beltingmechanically spliced into alength of belting and removed

when the take-up allowance isexceeded.

Dynamic fatigue:Loss in properties of a materialwhen continually subjected toflexing and or cyclic stress.

Dynamometer: An apparatus capable ofinducing various loads forevaluation of dynamic beltingproperties.

E

Edge wear: Damage to the edge of a beltby abrasion.

Effective tension:Difference between the tightside and the slack side tensionat the drive pulley providing thenecessary pull to move theload.

Elastic limit: The limiting extent to which amaterial may be deformed andyet return to approximately itsoriginal shape after removal ofthe deforming force.

Elasticity: The property of an article whichtends to return it to its original

shape after deformation.

Elastomer: An elastic rubber-like sub-stance, such as natural orsynthetic rubber.

Elastomeric properties:The chemical and physicalproperties of an elastomer.

Drive-on plate fastener:Two ends of belting joined witha single plate, across the top

cover joint, with rivets or sharpteeth clinched over on thebottom cover side of the belt-ing.

Drop ply: The omission of a reinforcingply for a specified distancefrom each edge. Usually thebottom or next to bottom ply inflat conveyor belting.

Dry blend: A free-flowering dry compoundprepared without fluxing.

Dual drive: A belt driving system employingtwo adjacent pulleys eachpowered with its own motor.

Duck: A term applied to a wide rangeof medium and heavyweightfabrics, commonly made ofcotton, including the heaviestand strongest of all single-woven fabrics. There are threemain types: number duck,army-type duck and flat duck.

Dumbbell: A test specimen with lesserwidth at the middle of its lengththan at its ends.

Durometer: An instrument for measuringthe hardness of rubber. Mea-sures the resistance to thepenetration of an indentor point

into the surface of rubber.

Durometer hardness: An arbitrary numerical valuewhich measures the resistanceto penetration of the indentorpoint of the durometer. Valuemay be taken immediately orafter a very short specifiedtime.

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Elevator belt: A belt that raises materialvertically in buckets attached tothe belt.

Elongation: Increase in length expressednumerically as a fraction orpercentage of initial length.

Embossing: Operation of transferring adesign to a rubber or rubber-like surface.

Endless belt: A belt made endless without a joint.

Ends: See fabric count.

Equivalent free fall:The calculated vertical distancematerial falls from the dis-charge point to end of a belt.

Exposed fabric: An area of a belt where thefabric reinforcement shows dueto lack of cover.

Extensibility: The capability of increasedcenter distance in a belt con-veyor.

Extensible conveyor: An adjustable conveyor systemwith a loop of belting betweenthe carrying idlers and thereturn idlers for changing thecenter distance.

Extraction test: A test in which certain compo-

nents are separated from asolid by dissolving them in aliquid solvent under suitableconditions.

Extruded: Forced through die of tubingmachine in either solid orhollow cross section.

Extrusion: A process whereby heated orunheated plastic forced througha shaping orifice becomes a

continuously formed piece.

F

Fabric: A planar structure produced bynonwoven or interwoven yarns,fibers, or filaments.

Fabric count: The number of warp ends perinch and the number of fillingpicks per inch.

Fabric design: The combination of size andnumbers of fibers or yarns, inboth warp and filling, and themanner in which they ar pro-cessed.

Fabric finish: See fabric impression.

Fabric impression: A pattern in the cover of a beltformed by contact with a fabricduring processing.

Fabric picks/inch:The number of filling (weft)yarns per inch.

Fabric rating: The maximum tension per plyof fabric a belt should beoperated under ideal condi-tions.

Face: The outer surface of a pulley orbelt.

Face cover: See top cover.

Fastener: See belt fastener.

Fatigue: The weakening or deteriorationof a material caused by arepetition of stress or strain.

Index Pa


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Flame performance:The manner in which beltingafter being ignited will burn and/

or self extinguish.

Flame retardance:Intensity of flame diminished byfire retardant ingredient(s) inthe plastic compound.

Flame test: A means, under specific condi-tion, for establishing the flameperformance of a belt. This willnot indicate the performance ofthe belt in any fire in which thebelt may be involved.

Flange: A raised edge on a plasticarticle.

Flanged edge: In conveyor belting, an edgebuilt up to prevent spillage.

Flanged pulley: A pulley with a raised rim at theedges for the purpose of keep-ing the belt on the pulley.

Flash: Material protruding from thesurface of a molded part,appearing at the mold partingline or mold vent points.

Flat belt: (1) A belt the cross section ofwhich is in the general form of arectangle; (2) A belt whichoperates on a smooth flat bedor straight idlers or rollers.

Flat press: A belt finishing press with flatplatens, between which the beltis heated and compressed.

Flat spots: Thin spots on a conveyor beltsurface stored on a flat surfacefor a long time.

Flat wire braid: Flattened braided wire, fre-quently used for armoring thebelt.

Feeder belt: A belt that discharges materialonto another conveyor belt.

Fiber: A unit of matter having a lengthat least 100 times its diameterand which can be spun into ayarn.

Filament: A continuous fiber of extremelength.

Filler: A material mixed with a poly-mer to improve quality or lowercost of a compound.

Filler seam: Extruded polymeric compoundused to fill the void betweentwo pieces of belt cover orfabric.

Filling threads: The yarns in a fabric running atright angle to the warp.

Filling yarns: The transverse yarns in afabric.

Film: A sheet of plastic not greaterthen 0.010" in thickness.

Finger splice: Belt ends cut into matingfingers.

Finish, fabric: See fabric impression.

Finish, plate: See plate finish.

Finish, platen: See platen finish.

Fire resistance: See flame retardance.

Fire resistant: Retards the burning action offire or flame.

Fisheye: A small globule that has notblended completely into thesurrounding material.

Index Pa


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Folded-edge: (1) A belt construction whereinthe inner carcass is enclosed inan envelope ply or plies. (2) An

edge where an outer coveringhas been wrapped around acarcass and folded over theedge so that the carcass isclosed on the edges.

FPM: Abbreviation for Feet perMinute.

Frequency factor:The duration of time in minutesrequired for one complete cycleof a conveyor belt.

Friction: (1) The resistance to motion ofa belt due to the contact be-tween two surfaces.(2) Improperly used to indicatethe bond between two sur-faces.

Friction coat: An impregnation of rubbermaterial calendered by frictionmotion to a fabric so that thematerial is forced into theweave of the fabric.

Friction, coefficient of:The ration between the forcepressing the surfaces togetherand the force required to moveit.

Friction, kinetic:The force which is required to

keep a body sliding at a uni-form rate. Also called frictionof motion.

Friction pull: See adhesion.

Friction, static: The force which is required tostart a body sliding.

Fleet: The lateral movement of aconveyor belt to either side ofits intended path.

Flex cracking: A surface cracking induced byrepeated bending or flexing.

Flex life: The relative ability of a rubberarticle to withstand dynamicbending stresses.

Flex life test: A laboratory method used todetermine the life of a plasticproduct when subjected todynamic bending stresses.

Flexibility: The ability to be bent repeat-edly without cracking.

Flexing: The bending of a belt.

Flight: (1) One of a series of beltconveyors discharging one toanother. (2) A series of cleatsor profiles on a belt.

Floating breaker: A leno or cord breaker embed-ded in a belt cover with adistinct layer of elastomerseparating the breaker from thecarcass.

Floating idler pulley:See take-up pulley.

Flow crack: A surface imperfection causedby improper flow and failure of

a compound to blend with itselfduring the molding operation.

Flow line: See flow mark.

Flow mark: A surface imperfection similarto a flow crack, but with a minordepression.

Index Pa


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Friction surface:The exposed portion of a beltfinished with a layer of impreg-

nated plastic as distinguishedfrom being completely coveredwith a layer of plastic.

Frictioned fabric:Coated with rubber compoundon a friction (uneven speed)calender.

Frosting: Light scattering surface resem-bling fine crystals.

Full rated tension:See rating.

Fungicide: An agent that destroys fungi orinhibits their growth.

Fusion: An irreversible process duringwhich a PVC compound orplatisol undergoes a physicalchange and becomes a homo-geneous mixture by the mutualsolvation of the PVC resin andthe plasticizer in the com-pound, as result of heating toan appropriate temperature.

G

Gauge: The measure of thickness ofthe individual elements makingup a rubber product.

Gel: The initial semi-solid stage thatdevelops during the solvationof a resin by a plasticizer.

Gel point: The stage at which a liquidbegins to exhibit pseudo-elasticproperties.

Glass fiber: Glass extruded through a diewith many fine holes intocontinuous filaments.

Gouging: The effect of sharp heavymaterial falling onto a conveyorbelt cover to loosen or tear out

pieces of the cover.

Grab test: A tensile test for woven fabricusing specimens considerablywider than the jaws holding theends of the test specimen.

Grade: The ration of incline or declineof a conveyor expressed a spercent of the vertical height tothe horizontal distance.

Grade of belting:The quality of belting cover onthe basis or gouge, cut, andabrasion resistance.

Gravity take-up: A mechanical system thatadjusts for the stretch or shrink-ing of a conveyor belt automati-cally by a weighted pulley in thesystem.

Grooved lagging:Lagging with round or angulargrooves to minimize materialbuildup on the pulley.

Ground finish: Surface produced by grindingor buffing. See Buffing.

H

Hammock belt idler:See catenary idler.

Hank: A length of 840 yards of a yarn.

Hardening: An increase in resistance toindentation.

Index Pa


19/4119

Hinge pin: A cable or rod to join togetherhinged fasteners.

Hinged fastener: A fastener attached indepen-dently to each of the belt endsdesigned with an opening inthe end of the fastener toaccept a pin through the open-ing to complete the joint.

Hold back: See backstop.

Holland cloth: A filled sheeting (usually starchfilled) with a smooth, glossyfinish on both sides, used asseparating medium.

Homogenous: Of uniform compositionthroughout.

Horizontal belt curve:The portion of a conveyorsystem which deviates from astraight line in the same hori-zontal plane as the rest of thesystem.

Horsepower: A unit of power equal to 33,000foot-pounds per minute (746watts).

Horseshoe: A fold in a surface in a definiteU-shaped pattern. Particularlyused in describing squeezed-out blisters in a belt cover. Alsocalled ring blisters, dog earsand pig ears. Colloquial.

Hot air cure: Vulcanization by using heatedair, with or without pressure.

Hugger belt conveyor:Two belt conveyors whoseconveying surfaces combine toconvey loads up steep inclinesor vertically.

Hardness: Property or extent of beinghard. Measured by extent offailure of the indentor point of

any one of a number of stan-dard hardness testing instru-ments to penetrate the product.

Haze: The cloudy appearance of anotherwise transparent film.

Hazing: A dull finish.

Head: The delivery end of a conveyorbelt.

Head pulley: The terminal pulley at thedischarge end of the conveyor.

Head-tail drive: A belt driving system using oneor more powered pulleys at ornear both the head and tailpulleys with each pulley inde-pendently driven.

Heat degradation:Change in chemical and/orphysical properties due toexcessive exposure to heat.

Heat mark: Extremely shallow depressionor groove in the surface of aplastic visible because of asharply defined rim or rough-ened surface.

Heavy weight belt: A belt with a rated maximumworking tension equal to or

greater than 160 pounds perinch width, when operatingunder ideal conditions.

Herringbone weave:The longitudinal appearance ofa row of parallel lines slantingat an angle in the oppositedirection to another row ofslanting parallel lines.

Index Pa


20/4120

Impact energy: The effective combination offorce (weight of the body andheight) when one body falls on

another.

Impact force: The energy power of impact.

Impact idler: A belt idler having a resilient rollcovering, resilient moldedelastomer rings, pneumatictires, springs or other means ofabsorbing impact energy at orclose to the place where mate-rial contacts the belt.

Impact rating: The maximum rating of a beltconstruction based on thefabric, impact rolls, design ofloading, size of material fallingon the belt, relative speed ofthe material and the belt, etc. towithstand the energy of impactloading.

Impact resistance:The relative ability of a con-veyor belt assembly to absorbimpact loading without damageto the belt.

Impregnated: Fabric interstices filled and/oryarns saturated with plasticcompound.

Impregnation: To fill the interstices of an articlewith a rubber compound.Generally applies to treatmentof textile fabrics, yarns and

cords.

Impression: Design formed during vulcani-zation in the surface of anyrubber article by a method oftransfer, such as fabric impres-sion or molded impression.

Impulse: An application of force in amanner to produce suddenstrain or motion.

Hysteresis: A loss of energy due to succes-sive deformation and relax-ation. A measurement of the

area between the deformationand relaxation stress-straincurves.

Hysteresis loop: The configuration of thegraphical plot of stress andstrain from the initial applicationof stress to some reducedstress. The measure of hyster-esis is the area under stress-strain curves of increasing anddecreasing stress.

Hysteresis loss A loss of mechanical energydue to successive deformationand relaxation. It is measuredby the area between the defor-mation and relaxation stress-strain curves.

I

Idler: (1) A nonpowered pulleyaround which a belt travels (2)a nonpowered roll or rollssupporting a belt.

Idler pulley: See idler.

Idler stand: The mechanical system thatsupports an idler pulley.

Immediate set: The amount of deformation

measured immediately afterremoval of the load causing thedeformation.

Impact: The single instantaneousstroke or contact of a movingbody with another either mov-ing or at rest, such as a largelump of material dropping on aconveyor belt.

Index Pa


21/4121

J

Jaws: Clamps to hold a specimenwhen applying stress to thespecimen for certain tests.

Joint: The area where two ends of abelt are fastened together,either by heat and pressure ormechanical means. See alsosplice.

K

Kinking: A temporary or permanentdistortion of belting caused bydoubling the belt on itself.

Knitted Ply: Spirally interlaced loops of yarnforming a continuous tubularstructure.

Knuckles: Raised loops of a woven textilestructure.

L

Lagged drive pulley:See lagged pulley.

Lagged pulley: A pulley having its surfacecovered with lagging.

Lagging: A smooth or embossed cover-ing on a pulley to increasefriction between belt and pulley.

Laminate: A product made by bondingtogether two or more layers ofmaterial.

Laminated: Build up from thinner layers.

Indentation: (1) The extent of deformationby the indentor point of any oneof a number of standard hard-

ness testing instruments; (2) A recess in the surface of a beltcover.

Inside length: A belt length measured alongits inside circumference.

Installation allowance:The amount by which thecenter distance can be ad-

justed so a belt can be installedwithout damaging.

Instantaneous modulus:The ratio of stress to strain at asingle point on the stress-straincurve.

Interstice: A small opening, such asbetween fibers in a cord orthreads in a woven or braidedfabric.

Interstice of fabric:Spaces between the yarns orcord of a woven fabric.

Interwoven conveyor belt: A type of conveyor belt con-struction similar to that of asolid woven belt, with pliesinterwoven such that it isimpossible to separate them.

Irons: Strips of metal at the edges of

a belt in a flat press to confinethe edge elastomer for makinga molded edge or to obtainuniform thickness of the edgesof a slit edge belt near itsedges.

ISO: The abbreviation for the Inter-national Organization forStandardization.

Index Pa


22/4122

Light weight belt: A belt with a rated maximumworking tension of less than

160 pounds per inch width.

Lined bolt holes:Bolt holes which have beengiven a protective coating tocover the exposed carcass.

Liner: A separator, usually cloth,plastic film, or paper, used toprevent adjacent layers ofmaterial from sticking together.

Live roller conveyor: A roller bed conveyor systemwith frequently placed rollersabove and in contact with thebelt so the powered belt turns-makes alive-the rollers abovethe belt. The packages, etc.are conveyed on the rollersabove the belt.

Live rolls: A series of rolls over whichobjects are moved by applica-tion of power to all or some ofthe rolls.

Live storage: (1) The storage of objects on aconveyor belt having a lowcoefficient of friction surface oron live rollers so the objectscan accumulate while they areadded to or removed at differentrates (2) The storage of mate-rial in a silo while material is

being discharged or poured inat the same time (3) An exten-sible conveyor with a loop ofbelting between the carryingand return idlers where thelength of the loop is continu-ously decreased as the equip-ment at the mining face isadvanced.

Lap joint: An elevator joint where one endof the belt laps over the otherend with the leading edge on

the bucket side.

Lap: A part that extends over itself ora like part.

Lap seam: A seam made by placing theedge of one piece of materialextending flat over the edge ofthe second piece of material.

Lateral: Coming from the side.

Lateral misalignment:Offset of pulleys, idlers, orstructure from a design longitu-dinal reference line.

Leno breaker: An open-mesh fabric madefrom coarse ply yarns, with aleno weave. A leno weave isone in which certain warpthreads-termed doup or cross-ing threads-are passed fromside to side of one or moreends-termed standard threadsand are found in by the filling inthis position. Where thecrossed interlacing occurs anopen, perforated structure isformed.

Leno weave: An open mesh fabric in whichthe warp yarns are held by thefilling yarns with the filling yarnstwisted around alternating warp

yarns in opposite direction.

Life test: A laboratory procedure used todetermine the resistance ofrubber article to a specific set ofdestructive forces or conditions.

Lift: The net vertical distance mate-rial is moved by a conveyor orbucket elevator.

Index Pa


23/4123

Load support: The ability of a fully loadedconveyor belt to bridge the idlergap without creasing into the

idler gap and carry materialwithout excessive sag betweenthe carrying idler pulleys.

Load weight: The weight of material per unitof time.

Loading angle: The angle to the horizontal atwhich material is loaded onto aconveyor belt.

Loading impact:The energy with which materialis loaded onto a conveyor belt.

Longitudinal: A lengthwise direction.

Longitudinal seam: A seam joining two materials inthe length of the finishedproduct.

Loop edge: A selvage formed by having thefilling loop around a catch cordor wire, which is later with-drawn, leaving small loopsalong the edge of the cloth.

Loose cover: A separation of the cover fromthe carcass or textile reinforce-ment.

Loose edge: An edge which has separatedfrom a textile carcass.

Loose ply: A separation between adjacentplies of fabric.

Low spot: A depression below the generalsurface of an object.

Low temperature flexibility:The ability of belting to be bentor flexed at low temperatureswithout loss of serviceability.

Low temperature flexing:The act of bending a productunder conditions of a cold

environment.

Lump size: The size of larger material on aconveyor belt.

M

Masterbatch: A preliminary mixture of two ormore compound ingredients forpurposes of more thoroughdispersion or better processing,and which will later becomepart of the final compound in asubsequent mixing operation.

Maximum horsepower:The highest power requirement.

Maximum ply: (1) The maximum number ofplies permissible that will permitfor satisfactory troughability; (2)The maximum number of pliespermissible to satisfactorilyoperate around a pulley of agiven diameter.

Maximum safe working stress:The greatest tension at which abelt should be operated.

Maximum tension:See tension, maximum.

Mechanical fastener: Any mechanical device used to join the ends of belting.

Migration: The transfer of an ingredient ina rubber compound from onelayer to an adjacent layer or tothe surface.

Index Pa


24/4124

Migration stain: When staining occurs on thearea of an object adjacent tothe rubber article it is known as

migration stain.

Mildew: Growth on organic matterproduced by fungi, generally intextile components of rubberarticles. Usually causes deterio-ration.

Mildew inhibited:The article contains material toprevent or retard mildew.

Mill: A machine with two horizontalrolls revolving in oppositedirections used for the mastica-tion or mixing of rubber.

Minimum accelerating time:The least time allowed toaccelerate a conveyor belt fromrest to normal speed withoutexceeding its maximum safeworking stress.

Minimum braking time:The least time allowed todecelerate a conveyor belt fromnormal speed to rest withoutexceeding the maximum safeworking stress or causing thebelt to double up on itself.

Minimum ply: The least number of plies thatwill support the load on a beltwithout damaging deformation.

Minimum pulley diameter:The smallest pulley diameteraround which a belt is recom-mended to operate.

Minimum tension:See tension, minimum.

Mirror finish: A bright, polished surfaceappearance.

Mix: See compound

Modified grab test:

A tensile test for woven fabricusing specimens wider than the

jaws holding the specimen cutmidway between the jaws tothe warp yarns held by the

jaws. Minimizes warp yarnpopout experienced by raveledspecimen test.

Modulus: (1) A coefficient or numericalmeasure of some property.(2) In rubber, modulus usuallyrefers to one of several mea-surements of stiffness or resis-tance to deformation. The useof the word without modifyingterms may be confusing andsuch use should not be encour-aged. Modulus in rubber maybe either static or dynamic;static moduli are subdividedinto tagent, chord, andcompounders. Compoundersmodulus is always in tension,but all the others may be inshear, compression or tension.Other terms used in connectionwith modulus are elasticity,rigidity, Youngs tangent, andelongation.(3) All elastic moduli in rubber(except compounders) areratios of stress to the strainproduced by that stress, thestress, usually p.s.i.

Modulus, belt: The force per unit width of beltrequired to produce a statedpercentage of elongation.

Modulus of elasticity:The force divided by the per-cent elongation (divided by100) to cause the elongation.

Index Pa


25/4125

Moisture regain:The reabsorption of water by atextile.

Mold edge: A belt edge formed duringvulcanization by curing in amold or against edge irons.

Mold lubricant: The material used to coat thesurfaces of a mold to preventthe rubber adhering to themetal during vulcanization.

Mold mark: An indentation or embossmenton the surface of a moldedproduct caused by irregularitiesin the mold surface.

Mold register: The means used to align theparts of a mold.

Mold release: See mold lubricant.

Monofilament: A single extruded strand ofmaterial.

Monomer: A relatively simple compoundwhich can react to form apolymer.

Mooney viscosity: A measure of the plasticity of apolymeric compound deter-mined in a Mooney shearingdisc viscometer.

MSHA: Abbreviation for Mine Safetyand Health Administration.

MSHA flame retardant test:Flame procedure for under-ground conveyor belting pre-scribed by the Mine Safety & Health Administration of theU.S. Department of Labor.

Mulitifilament: Many extruded fine strands ofmaterial grouped together.

N

Narrow disc idler: A flat pulley with discs attachedaround the pulley at certainintervals across the pulley.

Necking down: A localized decrease in thecross-sectional area of aproduct.

Needle punched:Nonwoven fabric punched witha hack latched needle toimprove its strength and stabil-ity.

Net endless length:The manufactured lengthnecessary to provide properinitial fit and tensioning of a belton a specified drive.

Nicks: Cuts in the surface or edge ofbelting.

Nip: The clearance between tworolls of a calender.

Nitrile: Common name for nitrile-butadiene polymer.

Nominal: An approximate amount.

Nonblooming: The absence of bloom.

Nonwoven fabric:

A mat of nonaligned fiberbonded together.

Norway type elevator bolt:Flat top, squared shoulder boltfor attaching elevator bucketsto elevator belts.

NR: Abbreviation for isoprenepolymer.

Index Pa


26/4126

Numbered duck:Fabric weight designated bynumbers based on linear yard

of cloth 22" in width.

Nylon: Common name for polyamidefiber.

O

Offset idler: The center carrying roller whichis offset and transverselylapping the troughing idlers.

Oil proof: Not adversely affected byexposure to oil.

Oil resistant: Withstands the deteriorationeffect of oil (generally refers topetroleum) on the physicalproperties.

Oil swell: The change in volume of arubber article due to absorptionof oil.

Oil well splice: Two ends of a belt each bent90 degrees around a steel formand bolted together through thebelt and steel form.

Oligomer: A polymer consisting of only afew monomer units such as indimer, a trimer, a tetramer etc.& their mixtures.

One side: Pertains to one of the twooutward faces or surfaces of aconveyor belt (not the edges ofthe belt).

Open seam: A seam whose edges do notmeet creating a void.

Operating tensions:The tension of longitudinalsections of a belt system (tight

side and slack side) whenmoving material, as distin-guished from tension when thebelt is running empty.

Optimum cure: The time, temperature andcompression of vulcanization orof fusion at which a desiredcombination of properties isattained in an elastomer.

Organosol: A suspension of a finely dividedplastic in a plasticizer with avolatile organic solvent.

Outside diameter eccentricity:The degree a pulley is out-of-round with respect to is centralaxis.

Oven: A low pressure hot air chamberused for the purpose of heat-ing, drying, baking or vulcaniz-ing rubber products. See Aging.

Oxidation: The reaction of oxygen on arubber product, usually de-tected by a change in theappearance or feel of thesurface or by a change inphysical properties.

Oxygen bomb: A chamber capable of holdingoxygen at an elevated pressurewhich can be heated to an

elevated temperature. Usedfor an accelerated aging test.

Oxygen bomb aging: A means of acceleratingchange in the physical proper-ties of rubber compounds byexposing them to the action ofoxygen at an elevated tem-perature and pressure.

Index Pa


27/4127

Picking idler: A short-sided troughing idler forreadily removing material byhand from a belt.

Pierce tape: A woven mesh of steel wire orcord.

Pimple: A small sharp or conical eleva-tion on the surface of a prod-uct.

Pit: A small crater in the surface ofa product with width about thesame as its depth.

Pitch line: The plane within a belt whichundergoes neither stretchingnor compression when the beltrounds the pulley, i.e., theneutral plane of the belt struc-ture.

Plain weave: The simplest type of weavewith both adjacent warp andfilling yarns crossing over andunder each other.

Planished cover: An irregular coated surfacetransformed into a smoothsurface by some means.

Planished finish:See planished cover.

Plastic: A material that contains as anessential ingredient one ormore organic polymeric sub-

stances of large molecularweight, is solid in its finishedstate, can be shaped by flow.

Plasticity: (1) A measure of the resistanceto shear of an unvulcanizedelastomer;(2) a measurement of resis-tance to shear with heat his-tory.

Ozone cracking:Belt cover cracks or crazingcaused by exposure to ozone

in the atmosphere.

Ozone resistant:Withstands the deterioratingeffects of ozone (generallycracking).

P

Package conveyor: A conveyor which transportspackaged, boxed, or baggedmaterial.

Package deflector:See conveyor belt packagedeflector.

Packed material:Material on belting compactedas the belting moves along thesystem.

Performance test:See service test.

Permanent set: The amount by which an elasticmaterial fails to return to itsoriginal form after deformation.

Permanent stretch:Elongation permanently re-moved from belting when it is

first used.

Permeability: The quality or condition ofallowing passage of liquids orgases through a rubber layer.

Physical properties: A measure of mechanicalcharacteristics of a material.

Pick: An individual filling yarn of afabric.

Index Pa


28/4128

Porosity: The condition of containingnumerous small holes or voids.

Portable conveyor: A conveyor system readilymoved from one place toanother.

Portable vulcanizer: A vulcanizer readily movedfrom one place to another,usually used for making fieldsplices and repairs.

Pot life: The period of time during whicha reacting polymeric compoundremains suitable for its in-tended use after having beenmixed with a reaction-initiatingagent.

Powered roller conveyor: A term used by the U.S. PostalService to mean a live rollerconveyor. See live rollerconveyor.

Press: A machine consisting of two ormore heated plates which canbe brought together and sepa-rated by hydraulic pressure ormechanical action.

Press cold ends:The area of reduced tempera-ture at the press platen end.

Press lap: The area of overlap of one

press cure length on the next.

Press length: The length of a belt which canbe pressed at one time.

Press marks: Irregularities in the surface of avulcanized product caused bythe press ends or by corre-sponding irregularities in thepress surface.

Plasticizer: A compounding ingredientwhich can change the physicaland chemical properties and

processibility of a polymericcompound.

Plastisol: A despersion of a powderouspolymer in a plasticizer.

Plate finish: A finish resulting from contactwith commercially smooth butnot polished press platens.

Plied yarn: A yarn made by twisting to-gether two or more singleyarns.

Plows: Plates across a belt to removematerial lying on or sticking tothe belt.

Ply: A layer of rubberized fabric.

Ply adhesion: The force required to separatetwo adjoining strength reinforc-ing members in a rubberproduct.

Ply separation: Lack of adhesion betweenplies.

Ply tensile: The ultimate breaking strengthof a belt expressed in force perinch width per ply.

Polymer: A macromolecular materialformed by the chemical combi-nation of monomers having

either the same or differentchemical composition.

Polymerization: The process that convertsmonomers into polymers.

Polyvinyl chloride: A polymer prepared by thepolymerization of vinyl chlorideas the sole monomer.

Index Pa


29/4129

Press, rotary: See rotary press.

Pricker marks: Small marks in the cover of a

vulcanized belt where a rollwith sharp needles had pen-etrated the uncured belt toallow trapped air in the uncuredbelt composite to escape.

Processing: The operations in the manufac-ture of a belt.

Profile top cover:Belt surface having a series ofcontinuous or interrupted,straight or curved ridges,across the belt at regularintervals to enhance the beltsability to move materials upinclines or down declines.

Prong: The sharp point of a mechani-cal fastener that penetrates thebelt.

Pulley: A cylinder, mounted on acentral axis rod.

Pulley cover: See bottom cover.

Pulley lagging: See lagging.

Pulley projection:The amount a pulley face widthextends beyond belt edge.

Pulley wear cover:(1) Elastomeric material at-

tached to the pulley to minimizepulley surface wear (2) Addi-tional belt bottom cover thick-ness where extraordinary wearis anticipated.

Pulley wrap: See arc of contact.

Pure gum compound: A natural rubber or isoprenecompound containing only the

ingredients necessary toprocess it, to protect it fromaging, and to cause vulcaniza-tion.

PVC cover: Cover using a PVC compound.

PVC impregnated:Impregnated with PVC com-pound.

Qualification conformance inspection:The examination of samplesfrom a production run to deter-mine conformance to a givenspecification.

Q

Qualification inspection test:The examination of samplesfrom a typical production run todetermine conformance to agiven specification for approvalto become a supplier.

Quarter turn drive: A belt system in which the axesof the adjacent pulleys are atright angles to each other tocause a 90 degree twist in thebelt about its longitudinal axis.

R

RAC: Abbreviation for The Rubber Association of Canada.

Raised cover center: A belt cover with increasedthickness along the centerportion of the belt.

Index Pa


30/4130

Raised edge: A flanged edge conveyor belt tominimize spillage.

Raised rib belt: A belt with transverse or diago-nal bars or cleats on the topcover.

Rated conveyor belt:The manufacturers recom-mended maximum workingtension for a conveyor belt.

Rated working tension:See rating.

Rating: The normal working tensionrecommended for a belt.

Raw edge: The uncovered square edge ofa belt created by cutting aftervulcanization.

Recovery: The degree an elastomericmaterial returns to its originaldimensions after beingstressed.

Reefed: A belt folded back and forth onitself.

Reinforcement: The textile strengtheningmember of a belt. See alsocarcass.

Reinforcement agent: An ingredient in a polymericcompound not basic to itsvulcanization used to increase

its chemical and physicalproperties.

Reinforcing element:The strengthening members ofa belt.

Repair: The area of new materialreplacing damaged material ina belt.

Repose angle: See angle of repose.

Resin: Certain materials produced by

chemical synthesis.

Resistance: The property or ability of matterto withstand the effects offorce, pressure, heat or chemi-cal action.

Return idler: A roll(s) that supports a belt onits return run.

Return run: The part of a conveyor systemwhere the belt returns to thetail.

Reversion: (1) The change which occurs invulcanized rubber as the resultof aging or overcuring in thepresence of air or oxygenusually resulting in a semi-plastic mass. (2) It is the basisof rubber reclaiming processesand is aided by the use ofswelling solvents, chemicalplasticizer and mechanicaldisintegration to obtain aworkable mass.

Ribbon blender: A type of internal mixer used tomix powders and liquids into adry powderous viscous or liquidmass.

Ribs: Transverse configurations onthe carrying side of a belt tofacilitate carrying material on

an incline.

Riveted plate joint: A mechanical fastener withrivets projecting through a plateon both sides of the belt.

RMA: Abbreviation for The RubberManufacturers Association, Inc.

Index Pa


31/4131

RMBT: Abbreviation for Rated Manu-facturers Belt Tension.

Roll belting: Belting made to ordered widthbut of nominal lengths forcutting later into shorterlengths.

Roller bed conveyor: A conveyor belt operating overa series of steel support rollers.

Rosin: The hard amber-colored mate-rial of the residue from thedistillation of oil of turpentine.

Rotary press: A vulcanizing machine consist-ing of a rotating, heated drumwith a flexible steel bandpartially encircling the drum,which continuously advances amaterial while under pressureand heat between drum andband.

Rotocure: See rotary press.

Rough top: A belt made with projections inthe carrying surface to improvethe ability of the belt to carrymaterial on inclines.

Rubber cement: A mixture of polymeric com-pound or elastomer used as anadhesive or sealant.

Rubberized: Coated with rubber compound.

Run: The distance or route coveredby a conveyor.

S

Saddle: An additional short length ofbelting added to an existingbelt. See butt strap.

Safety factor: The ratio of the maximumstress that a belt or a beltsplice can withstand to the

maximum stress recommendedfor it by the manufacturer. Theratio of breaking strength torated working tension.

Safe working strength:The manufacturers recom-mended maximum workingtension for a conveyor beltoperating in ideal conditions.

Sag : The amount of vertical deflec-tion of a conveyor belt from astraight line between idlers,usually expressed as a per-centage of the spacing be-tween idlers.

Sag belt tension:The minimum tension in anyportion of the carrying run of abelt necessary to preventexcessive sag of the beltbetween idlers.

Sample: A piece of material removed forevaluation.

Scraper: A device for cleaning thesurface of belting.

Screw take-up : A take-up for a conveyorsystem in which movement of apulley-bearing block is accom-plished by means of a screw.

See also take-up.

Seam: The place where two edges offabric or elastomer are adja-cent to each other to form asingle ply or layer.

Seaming strip: A strip of polymeric materiallaid over and/or in a seam to fillany voids between the adjacentplies of material.

Index Pa


32/4132

Simulated service test:See bench test.

Singles yarn: The product from aligning andtwisting together fibers ortwisting together filament fibers.

Sink: A collapsed blister or bubbleleaving a depression in aproduct.

Skew: Amount by which the ends of asingle pick yarn in a fabric areoffset longitudinally.

Skim: A thin layer of polymeric com-pound applied to a fabric.

Skim or skim coat: A layer of rubber material laidon a fabric but not forced intothe weave. Normally laid on africtioned fabric.

Skirt board: In a conveyor system, thevertical or inclined plates lo-cated longitudinally and closelyabove the belt to confine theconveyed material.

Skive: A cut made on an angle to thesurface to produce a tapered orfeathered cut.

Slab belting: Belting made in wide widthsand long lengths for later slittinginto narrower widths and cuttinginto shorter lengths.

Slack side tension:The lessor of the tensions in abelt on an operating conveyor.Usually immediately followingthe drive pulley.

Slider bed: A stationary surface on which abelt slides.

Self-aligning idler: An idler having a belt-activatedswivel mechanism to control

the side movement of anoperating conveyor belt.

Selvage: The lengthwise woven edge ofa fabric. Also called selvedge.

Semi-cure: A partial or incomplete cure.

Service condition: All the conditions of operationto which a conveyor or elevatorbelt is exposed.

Service factor: The amount by which thenormal rating of a unit is alteredto compensate for specificservice requirements.

Service test: A test in which the product ismade to operate under serviceconditions in the actual equip-ment.

Set: The amount of deformationremaining after completerelease of the load producingthe deformation.

Shadowing: A bas-relief or outline of areinforcement which appearson a cover after vulcanization.

Sheeting: A form of plastic in which thethickness is very small inproportion to length and width

and in which the plastic ispresent as a continuous phasethroughout.

Shelf storage life:The period of time prior to useduring which a product retainsits intended performancecapability.

Index Pa


33/41


34/4134

Stamped metal: Perforated metal sheet used formaking a rough top design on aconveyor belt.

Standard: A quality level set for theresults from a belt test.

Staple: A textile fiber of relatively short(1" to 3") length which whenspun and twisted forms a yarn.

Staple fiber: The short fibers from which aspun yarn is made.

Starting tension:The tension necessary toaccelerate a belt from rest tonormal operating speed.

Static conductive:Capability to conduct staticelectricity.

Static electricity:Electrical potential resultingfrom two surfaces rubbingtogether or parting one fromthe other.

Static friction: The resistance which must beovercome to start a bodysliding down a belt surface.

Steel cable: Several steel cords twistedtogether.

Steel cord: Several steel wires twistedtogether.

Steel cord belt: A conveyor belt having atension bearing member ofsteel cords lying in the sameplane with a definite spacingbetween the cords, elastomerbetween the cords and anelastomeric cover on bothsides of the belt.

Step ply: A conveyor belt having a pliedtextile carcass in which theupper ply or plies are set back

toward the edges to increasethe cover gauge in loadingarea.

Stepped splice: The joint of one end of multi-plybelting with plies of fabricremoved so respective plyends will butt together andoverlap adjacent plies of fabric.

Stiffness: Resistance to flexing.

Stitched belt: (1) A belt made from plies ofnon-rubberized fabric sewedtogether to make a unit struc-ture. (2) A rubberized belt inwhich the plies have beesewed.

Stitching: A method of butting or joiningtwo pieces of material together,usually by means of a stitcherroller.

Stock roll: A belt made to some nominallength and width for subse-quent cutting to required lengthand width.

Straight face pulley: A pulley without any crown.

Straight warp weave:Two warp yarn systems and a

filling yarn system where onewarp system is essentiallywithout crimp and is the tensionbearing member, while theother warp system is interlacedwith the filling yarn and pro-vides mechanical fastenerholding capability.

Index Pa


35/4135

Strain: Deformation resulting from aforce applied to a body.

Stress: Force applied to a body thatresults in the body beingdeformed.

Stress-strain: The relationship of force anddeformation in a body duringcompression, extension, orshear. In a belt this is therelationship of tension (stress)and resulting elongation(strain).

Stretch: An increase in length.

Striated cover: A cover having grooved orchanneled lines, due to transferof irregularities from contactwith surfaces of forming orfinishing equipment.

Strike through: Penetration of plastic com-pound through the fabric.

Strip test: In fabric testing, a tensilestrength test made on a strip offabric with cut edge or raveleddown to a specified number ofthreads or width of fabric, all ofwhich are firmly held in gripping

jaws wider than the test piece.

Sun check: Fine cracks and crazing of anelastomeric surface primarilydue to the suns ultravioletrays.

Surface finish: See belt surface finish.

Swelling: An increase in volume of anelastomer or belt.

T

Tack: Having a property of temporaryadhesion.

Tail end: The end of a conveyor, usuallynear its loading points.

Tail pulley: The belt pulley near the loadingend of the conveyor system.

Take-up (1) Removal of slack or stretchin a belt (2) An assembly ofstructural and mechanical partsto maintain proper belt tension.

Take-up, automatic:See automatic take-up.

Take-up, gravity: See gravity take-up.

Take-up pulley: A pulley which can move inspace due to gravity, a spring,or other forces in order tomaintain relatively constanttension in a specific strand of abelt.

Take-up, screw: See screw take-up.

Take-up tension: See tension, take-up.

Take-up travel: The distance the take-up canmove during the belt operation.

Tandem drive: A belt driving system employingtwo adjacent powered pulleys.

Tape line measurement-maximum length:The inside circumference of abelt measured around thepulley surfaces when the take-up idler(s) are moved out to

where they take up all the beltslack their movement permits.

Tape line measurement-minimum length:The inside circumference of abelt measured around thepulley surfaces when the take-up idler(s) are moved in for theinstallation of the shortest beltpossible.

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Tension member: See carcass.

Tension minimum:

The lowest tension occurring ina belt in a conveyor or elevatorsystem under operating condi-tions.

Tension rating: Maximum safe working tensionrecommended by a belt manu-facturer.

Tension ratio: In an operating belt system, theratio of the larger to the smallertension as the belt approachesand leaves a driving or drivenpulley.

Tension, slack side:In a belt system, where the twoportions of the length of a belton either side of a driving ordriven pulley have differenttensions, the slack side tensionis the smallest of the two.

Tension, slope: The tension in an inclined beltcaused by the weight of thematerial being elevated inaddition to the belt weight andindependent of friction andother sources of tension.

Tension, take-up:The amount of tension in eachof the runs of belting approach-ing and leaving the take-up

pulley, the total of which is theforce exerted by the take-updevice.

Tension, tight side:In an operating conveyorsystem, the greater of thetensions as the belt ap-proaches and leaves the drivepulley.

Tear down: The removal of a ply of fabric ina multi-ply fabric belt to preparethe stepped down configuration

for a stepped splice.

Tear Propagation: Continuation of tear.

Telescoped roll: At the outside end of a roll ofbelting, turns of the beltingprogressively loosened andmoved outward from the re-mainder of the evenly woundturns of the belting.

Template: A pattern to guide the punchingof holes or cuts in belt ends.

Tensile member: See carcass.

Tensile strength: The maximum force,stress, applied to a specimenat rupture.

Tensile stress: The force applied to stretch atest piece (specimen).

Tension: Stress on a material tending tocause extension of the mate-rial.

Tension, effective:In a belt drive, it is the differ-ence between the two tensionsin a belt as it approaches andleaves a driving or drivenpulley. In a two-pulley drive, itis the difference between tightand slack side tensions. Being

a measure of power require-ment, it is sometimes referredto as horsepower pull.

Tension, maximum:(1) The highest tension occur-ring in any portion of a beltdrive. In a two-pulley drive it isthe tight side tension. (2) Inconveyors, the maximumtension may occur at a pointother than the drive pulley.

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Tension, working:The maximum working tensionfor a fabric or belt recom-

mended by the manufacturer.

Terminal position:The maximum working tensionfor a fabric or belt recom-mended by the manufacturer.

Terminal pulley: The pulley at or near thedischarge end of a conveyorbelt system.

Tex: A yarn size system defined asthe weight in grams of 1000meters of yarn.

Textile: A general term applied to yarn,cord, nonwoven, or wovenfabric made from a fibrousmaterial.

Thermoplastic: Capable of being repeatedlysoftened by heating and hard-ened by cooling and in thesoftened state can be shapedby flow.

Tie cloth breaker: A leno or other open weavefabric breaker between a beltcover and the carcass.

Tie gum: A thin sheet of unvulcanizedrubber inserted between pliesin vulcanized repairs of splices.

Tight side tension: See tension, tight side.

Tilted troughing idlers:Used for belt training.

Time cycle: The duration of time, in min-utes, required for one completecycle of a conveyor belt.

Tire bead wire: Steel wire placed in or beneaththe top cover to minimize ripsin the belt by objects that

penetrate the belt.

Tolerances: The limiting values for a dimen-sion.

Top cover: Loss of the elastomer due toabrasion.

Top cover wear:The protective rubber cover onthe material conveying surfaceor surfaces of a conveyor belt.

Tracking alignment:See training.

Traction: The friction between a drivepulley and the conveyor belt.

Traction top: See rough top.

Training: The process of adjusting idlers,pulleys, and loading conditionsto insure the belt runs straight.

Training idler: An idler mounted on a me-chanical device, actuated bythe belt moving against it tomake the belt run straight.

Trajectory: The arc made by materialfreely discharged from a con-veyor system.

Transfer system: A combination of mecha-

nisms to move objects or bulkmaterial to or from a conveyor.

Transition distance:The distance between the lastfully troughed idler and the flatdriving or discharge pulley.

Transition idler: A troughed belt idler having alesser degree of trough thanthe previous carrying idlers.

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Transverse: A crosswise direction of a belt.

Transverse cord breaker:

A cord fabric laid in the topcover at right angles to the beltedges.

Transverse rigidity:Resistance to belt deformationin the belt crosswise direction.

Transverse seam:The joint, across the belt, oftwo ends of a fabric ply in thebelt or cover material.

Trapped air: Air which is enclosed in aproduct or between a productand a mold surface duringcure.

Traveling deflector: A mechanism which movesover the carrying surface of thebelt and deflects the conveyedmaterial off of the belt.

Tripper: A fixed or moveable mecha-nism at some intermediateplace in the conveyor system todischarge material from thebelt.

Troughability: The property of a belt thatpermits it to conform to thecontour of troughing idlers.

Troughability index:

The ratio of the deflection of afreely supported transversesection of a belt to the distancebetween the freely supportedends.

Troughed belt: A belt operating in a conveyorsystem with inclined side idlersto cause the belt edges to turn

up and increase the amount ofmaterial carried while minimiz-ing side spillage of the material.

Troughing angle:The angle troughing idlers areto the horizontal extension ofthe flat carrying idler.

Troughing idlers: An idler system which supportsa belt in a troughed configura-tion. Usually it consists of acenter horizontal roll with aninclined roll on each side. Seealso catenary idler.

Twill weave: A fabric woven with the appear-ance of diagonal lines.

Twist: The rotation of a belt on itslongitudinal axis. A 180 degreetwist is used as a means ofinverting a belt through thezone of the twist.

U

Ultimate elongation:Elongation at rupture.

Ultimate strength:The force required to rupture aspecimen.

Ultimate tensile:Tensile stress at rupture.

Undercure: A less than optimal state ofvulcanization which may beevidenced by tackiness orinferior physical properties.

Uncured: Not vulcanized.

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V

Vanner edge: See flanged edge.

Vertical curve: The portion of a conveyor beltwhere the angle of inclineincreases.

Viscosity: The flow property of a material.

Void: The absence of material or anarea devoid of materials wherenot intended. See also blisterand sink.

Volume swell: See swelling.

Vulcanization: A process over a range intemperature during which apolymeric compound, through achange in molecular structure(e.g., crosslinking) becomesless plastic and causeschanges in the physical andchemical properties of theresulting elastomer.

Vulcanized splice: A joint in a belt made by meansof vulcanization.

Vulcanized splice step length:The longitudinal distancebetween steps in the splice.

W

Warp: (1) The yarns that run length-wise in a woven fabric or jacket. (2) The total deviationfrom a straight line of a hosewhen subjected to internalpressure.

Warp-yarn: (1) A longitudinal yarn in afabric. (2) A corner yarn in abraid.

Weathering: Surface deterioration, evi-denced by cracks and crazingof an elastomer, during outdoor

exposure.

Weave: A fabric pattern descriptiondenoting a specific relationshipof warp and filling yarns atspecific locations in the fabric.

Weft: The crosswise threads in afabric; filling threads. Thetreads or yarns running at rightangle to the warp.

Weftless cord: A cord ply without filling yarns.

Winged pulley: A pulley with radial vanesextending from a supportingstructure to the center shaft tominimize trapping material thatotherwise would build up anddamage the belt.

Wire hook fastener: A mechanical fastener consist-ing of wires capable of beingdriven through the belt end andbent back into the belt by aspecial tool device.

Wires: Metal in the form of a fineflexible rod.

Working load: See working tension.

Working tension:Stress on the belt when the belt

is loaded with conveyed mate-rial and moving.

Woven fabric: A flat structure composed oftwo series of interlacing yarnsof filaments, one parallel to thefabric and the other transverse.

Woven wire carcass: A belt with woven wire fabric.

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Wrinkled ply: See buckled ply.

Y

Yarn: A generic term for continuousstrands of textile fibers orfilaments in a form suitable forknitting, weaving, or otherwiseintertwining to form a textilefabric. It may comprise (1) anumber of fibers twisted to-gether (2) a number of fila-ments laid together without atwist (a zero-twist yarn) (3) anumber of filaments laid to-gether with more or less twistor (4) a single filament with orwithout twist (a mono-filament).

Yarn number: The number of hanks in apound of spun yarn.

Yield point: The stress in a material atwhich a substantial increase instrain occurs with a minimumincrease in stress.

Yield strength: The stress at which a materialexhibits a specified limitingpermanent set. Determined bya measurable value of plasticyielding of the material, abovewhich the material is consid-ered to be damaged and belowwhich the damaging effects areconsidered to be negligible.

Youngs modulus:

Stress per unit strain for per-fectly elastic material.

Z

Zero load: A reference load applied intaking an initial reading andprior to determining compress-ibility or extensibility.

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21 Laredo Drive

C O N V E Y O R B E L T I N G A M E R I C A S

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Glossary Correia

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