Belting Terms

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  • 7/31/2019 Belting Terms




    Abraded: Worn away by friction.

    Abrasion: Wearing away by friction.

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

    Abrasion tester: A machine for determiningrelative abrasion resistance.

    Accelerated aging: Intensive exposure tooperating conditions to obtain an early change inphysical properties of an elastomer.

    Accelerated life test: A method designed toapproximate in a short time the deterioratingeffects obtained under normal serviceconditions.

    Across the line starting tension: Tensiondeveloped in a belt when full electrical power isapplied to the drive system.

    Adhesion: Basically, the adhering, clinging,bonding or sticking of two material surfaces toone another, such as rubber to rubber, rubber tometal, rubber to wood, rubber to fabric.

    Adhesion failure: The separation of twoadjoining surfaces due to service conditions.

    Adhesive: A material which, when applied, willcause two surfaces in contact with each other tostick together.

    Adhesive coating: A coating applied to asurface to increase its bond to an adjoiningsurface.

    Adhesive fabric: A fabric with a surfacetreatment which will bond two surfaces togetherwhen interposed between them.

    Aftercure: A continuation of the process ofvulcanization after the cure has been carried tothe desired degree and the source of heatremoved.

    Afterglow: In fire resistance testing, the redglow persisting after extinction of the flame.

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

    Air bomb aging: A means of acceleratingchanges in the physical properties of material byexposing them to the action of air at elevatedtemperature and pressure.

    Air checks: The surface markings ordepressions which occur due to air trappedbetween the material and the mold or presssurface.

    Air curing: The vulcanization of a rubberproduct in air as distinguished from vulcanizingin a press or steam vulcanizer.

    Air oven aging: A means of accelerating achange in the physical properties of rubbercompounds by exposing them to the action of airat an elevated temperature at atmosphericpressure.

    Air trap: See air checks.

    Ambient temperature: The environmenttemperature surrounding the object underconsideration.

    Angle of repose: The angle to the horizontalwhich a material will naturally assume whendropped in a pile.

    Angle of slide: The angle at which materialbegins to slide down an inclined surface.

    ANSI: American National Standards Institute

    Anti-backdrop: See backstop.

    Anti-static: See static conductive.

    Antioxidant: A compounding ingredient used toretard deterioration caused by oxygen.

    Antiozonant: A compounding ingredient usedto retard deterioration caused by ozone.

    Antislip surface: A specially treated surface toobtain greater than normal traction.

    Apron feed: An intermediate feed system.

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    Arc of contact: (1) The portion of a curvedsurface which is engaged. (2) In belts, it refers tothe portion of a pulley which is engaged by thebelt and is usually expressed in degrees.

    Armored belt: A conveyor belt with crosswiseinsertions in the cover such as steel cables tominimize gouging or tearing of the cover bysharp objects.

    Army duck: See duck.

    Artificial weathering: Exposure to cycliclaboratory conditions involving changes intemperature, relative humidity, and radiantenergy, with or without direct water spray,attempting to produce changes in the materialsimilar to that observed after long-termcontinuous outdoor exposure.

    ASME: American Society of MechanicalEngineers.

    ASTM: American Society for Testing andMaterials.

    Atmospheric cracking: Small fissures in thesurface of a belt cover caused by exposure toatmospheric conditions.

    Automatic take-up: A mechanical device tomaintain proper tension in a belt automaticallycompensating for belt stretch or shrinkage inservice.

    Average modulus: The total change of stress

    divided by the total change of strain.


    Back cover: See bottom cover.

    Backstop: A mechanical device for preventinga loaded, inclined conveyor or elevator belt fromrunning backwards after the belt has beenstopped.

    Banbury mixer: A specific type of internalmixer used to incorporate filler and otheringredients in rubber or plastic operations.

    Bare back: The textile face of an article whichis free of any treatment or covering.

    Bare duck: The duck surface of a fabricatedarticle wherein the exposed duck surface is freeof any covering.

    Bare duck belt: A belt in which at least oneside has the exposed duck surface free of anycovering.

    Bare pulley: A pulley whose face surface is notcovered or lagged.

    Bareback surface: A belt surface where thetextile surface is without any coating.

    Base belt: The portion of a closed belt in aclosed belt conveyor which remains flat and

    provides the necessary tensile strength.

    Basic tension bearing yarns: One of the twowarp systems in a straight warp fabric where thewarp yarns are substantially without crimp andprovide the tensile strength for the belt.

    Basket weave: A fabric with ends of yarn sideby side in both the warp and filling in a plainweave construction.

    Bead rubber: An extruded polymericcompound used to fill the void between butted

    joint of two pieces of fabric.

    Bed: A continuous surface over which aconveyor belt may slide.

    Belt: A flexible reinforced band placed aroundtwo or more pulleys to carry materials from oneplace to another.

    Belt carcass: See carcass.

    Belt clamp: Beams or metal plates securedtransversely on both sides of belt ends to holdthe ends in a desired position.

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    Belt cleaning device: A scraper or rotatingdevice pressed against the belt surface toremove material stuck to the belt.

    Belt conveyor: A mechanical systemcomposed of suitable head, tail, bend pulleysand belt idlers or a slider bed to handle bulkmaterials, packages, or other objects placeddirectly upon it.

    Belt drive: An assembly of power-drivenpulley(s) used to transmit motion to a conveyoror elevator belt.

    Belt duck: An open weave duck made fromplied yarns with strength predominately in thewarp direction. Used primarily in themanufacture of belts.

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

    Belt fleet: The lateral movement of a conveyor

    belt to either side of its intended path.

    Belt grade: A classification of belting accordingto the quality and properties of the belt cover.

    Belt modulus: The ratio of stress to strain.

    Belt pitch line: See pitch line.

    Belt sag: The amount of vertical deflection of aconveyor belt from a straight line between idlers,usually expressed as a percentage of the centerto center spacing of the idlers.

    Belt slip: The action that takes place, causing adifferential movement between the pulleysurface and the belt.

    Belt slope tension: See tension, slope.

    Belt surface finish: Final surface condition ofbelt.

    Belt tracking switch: A limit switch actuated bythe edge of a conveyor belt when the belt movesabnormally to either side of its centered path.

    Belt training idler: An idler having a belt-actuated swivel mechanism to control the siderunout of a conveyor belt.

    Belt turnover: A system of pulleys arranged toturn a belt over. Frequently used to preventbuilding-up on return idlers by turning the dirtyside (carrying side) up. See also twist.

    Belting deflector: A mechanism which deflectsthe conveyed material off of the belt at specificpoints along the conveyor.

    Belting, flat conveyor: See flat belt.

    Bench test: A modified service test in whichthe service conditions are approximated in thelaboratory.

    Bend pulley: A pulley used to change directionof belt run.

    Bending force: The force required to bend abelt under prescribed conditions.

    Bending modulus: That force required toinduce bending around a specified radius and,

    hence, a measure of stiffness.

    Bias angle: The smaller included anglebetween the warp yarns of a fabric and thediagonal line across the warp yarns.

    Bias cut: A cut of a textile material madediagonally at an angle less than 90 degrees tothe longitudinal axis.

    Bias laid: Material laid on or wrapped aroundso the warp yarns are at an angle less than 90degrees to the longitudinal direction.

    Bias seam: The seam at which bias cut fabricsare joined together.

    Binder warp yarn: One of the warp systems ina straight warp fabric interlaced with the fillingyarn to provide the strength to hold mechanicalfasteners.

    Bite: See nip

    Bleeding: Migration to the surface ofplasticizer, waxes or similar materials to form afilm or beads. See also Bloom.

    Blemish: A mark, deformity, or injury whichimpairs the appearance.

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    Blisters: A raised spot on the surface or aseparation between layers usually forming avoid or air-filled space in the vulcanized article.

    Bloom: A discoloration or change inappearance of the surface of a rubber productcaused by the migration of a liquid or solid to thesurface. Examples: sulfur bloom, wax bloom.Not to be confused with dust on the surface fromexternal sources.

    Blow-up: A blister between plies of an article.

    Bolted plate hinge fastener: Steel plates bothsides and both ends of two belt ends to befastened together (secured to the belt with boltswith the ends of the plates constructed into acircular hole for accepting a hinge pin to securethe two ends of the belt(s) together.

    Bond: See Adhesion.

    Boot: Enclosure for the loading end of a bucket

    elevator belt.

    Bootlegging: (1) Progressive ply delamination.(2) The separation of plies in belting due toflexing.

    Bottom cover: The protective rubber cover onthe surface contacting the driving mechanism ofa conveyor belt.

    Bow: (1) Curvature from flat plane in thesurface. (2) The deviation from the straight lineof the fill yarn in a fabric. (3) The deviation from

    the straight line of a product when unrolled andlaid on a flat surface.

    Brand: A mark or symbol identifying ordescribing a product and/or manufacturer: maybe either embossed, inlaid, or printed.

    Breaker ply: An open weave fabric used nextto the carcass fabric and/or in the cover toimprove the attachment of the cover to thecarcass and to improve cover cut and gougeresistance.

    Breaking strength: The tensile which a textileyarn or cable, a steel cord, or a belt is at rupture.

    Brushed finish: The mechanical removal ofany surface impregnation or coating from thebelt fabric.

    Bucket: One of the cups on an elevator belt.

    Bucket cover: The cover of an elevator beltnext to the carrying buckets.

    Bucket elevator: Belt with buckets attached.

    Bucket projection: The distance the bucketprotrudes beyond an elevator belt.

    Buckled ply: A deformed ply, usually the resultof a fold or wrinkle, which distorts it from itsnormal plane.

    Buffing marks: The characteristic surfacecondition after a buffing operation.

    Bumping: In the operation of a flat press, thealternative application and release of rampressure to vent trapped air and gases.

    Butt seam: A seam made by placing the twopieces to be joined edge to edge.

    Butt strap joint: The connection of elevator

    belt ends with a piece of belting the width of theelevator belt placed over the butted belt ends,usually extending under at least two buckets andsecured with bolts to the belt.


    Cable yarn: Two or more plied yarns twistedtogether.

    Calculated center distance: In belt drives, the

    distance between two shaft centers calculatedfrom pulley diameters and belt length beingused.

    Calender: A machine with three or moreinternally heated or cooled cylinders used to (1)continuously sheet out polymeric compound orfused PVC (2) to wipe polymeric compound intothe interstices of a fabric leaving a small portionof it on the surface of the fabric, or (3) to lay acontinuous sheet of compound on a fabric.

    Calendered "rubber" sheets: Continuous filmof uncured elastomer produced from a calendar.

    Camber: The curvature of a belt relative to thecenter line (see bow).

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    Capacity: The maximum number of pieces,volume, or weight of material a belt conveyorcan handle in a given time interval and beltspeed.

    Capped edge: A rubber protective edge placedaround a product internally reinforced with textileor other material.

    Capped end: A belt end covered with anelastomer to protect the carcass end.

    Carcass: The fabric, cord and/or metalreinforcing section of any rubber product suchas a belt, as distinguished from the rubbercover.

    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 be torn.

    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 the loading anddischarge points.

    Carrying surface: The outward face or side ofthe belt which carries the conveyed material.

    Castfilm: A film made by depositing a layer ofplastic, either molten, in solution, or in adispersion onto a surface, solidifying andremoving the film from the surface.

    Catenary idler: A type of flexible belt-carryingidler with ends supported in pivoted stands. Thetube or rollers sag under the weight of the loadto form trough.

    CEMA: Conveyor Equipment ManufacturersAssociation.

    Cement: A mixture of polymeric compound orelastomer used as an adhesive or sealant.

    Cemented edge: An application of cementaround the edge of a fabricated product with orwithout internal reinforcement for protection oradhesion. (A form of Capped Edge.)

    Cemented end: A belt end sealed with theapplication of elastomeric cement.

    Center roll: The horizontal roll between theside troughing rolls.

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

    Centrifugal bucket elevator: A type of bucketelevator having a belt which travels at sufficientspeed to discharge material from the buckets bycentrifugal force.

    Chafer duck: A relatively open weave duck ofapproximately square woven construction madewith single or ply yarn.

    Chalking: Formation of a powdery surfacecondition due to disintegration of surface binderor elastomer due in turn to weathering or other

    destructive environments.

    Checking: Short shallow cracks on the surfacegenerally due to effect of destructive action ofenvironmental conditions.

    Chevron: A ridge or profile arranged in a Veeshaped configuration on a belt carrying cover tostabilize material carried up an incline.

    Chute lining: Highly abrasion resistantelastomeric lining in a chute to protect the metalchute from abrasion wear.

    Chute slope: Angle relative to the horizontal achute is inclined.

    Cleated belt: Transverse raised sections on aconveyor belt to stabilize material carried up anincline.

    Closed belt conveyor: A moving, endlessconveyor belt formed into a tubular shape by

    joining its edges while carrying material, andopening the edges while in motion to receiveand discharge material.

    Cloth impression: See fabric impression.

    Cluster end: A flat disc idler with several discsadjacent to each other at the ends of the idler.

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    Coefficient of friction: The ratio of the forcerequired to move a package across a beltsurface to the weight of the package.

    Cog: A tooth on the rim of a wheel or rubberproduct.

    Cogged V-belt: A V-belt cut or produced with aseries of evenly spaced V-shaped indentationsin the inner face.

    Cohesive: Tendency of a material to stick toitself.

    Cold feed: The introduction of plastic pelletsinto processing equipment without milling.

    Cold flex: See low temperature flexing.

    Cold flexibility: The relative ease of bendingfollowing exposure to low temperature.

    Cold flow: Continued deformation under stress.

    See Creep.

    Cold splice/bond: Usually the joining of two ormore sub-straits together, using a two-partcement that is chemically cured without usingsupplemental heat from an external source.

    "Cold bond cement" usually is an uncuredmixture of varied elastomers, chemicals, andsolvents that will not self-cure or vulcanize untilmixed with an activator to create a chemicalvulcanization (usually exo-thermic).

    Commercially smooth: A degree ofsmoothness of an article which is acceptable inaccordance with industry practice.

    Compound: A mixture of a polymer(s) andother materials to give the desired chemical andphysical properties in the elastomericcomponents of a belt.

    Compression member: The portion of a beltbeneath the pitch line as the belt bends arounda pulley.

    Compression set: The deformation in amaterial remaining after it has been subjected toand released from a compressive force.

    Conductivity: Quality of power of conducting ortransmitting heat or electricity.

    Contact stain: When staining occurs on thearea of an object directly in contact with therubber article it is known as "contact stain".

    Continuous bucket elevator: A bucketelevator belt that discharges by gravity over theinverted bottom of the preceding bucket on thedescending side of the elevator.

    Control: A material or a product of knowncharacteristics included in a series of tests toprovide a basis for evaluation of other products.

    Conveyor: A system for the continuousmovement or transport of bulk materials,packages or objects along a predeterminedpath.

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

    Conveyor belt package deflector: Amechanical diverter placed at an angle acrossthe belt to deflect packages off the belt atspecific locations.

    Conveyor belt stretch: The increase in belt

    length which takes place when tension isimposed. Stretch is either elastic or permanent.Elastic stretch is a temporary change in lengthwhich varies directly with the pull. Permanentstretch is the residual change in length aftertension has been removed; it generallyaccumulates over a period of time.

    Conveyor width: In belt conveyors, the widthof a belt.

    Copolymer: A substance consisting ofmolecules characterized by the repetition of two

    or more types of monomeric units.

    Cord: Several strands of yarn twisted together.

    Cord belt: A belt with textile or steel cords forthe longitudinal tension-bearing member.

    Cord fabric: A fabric with plied or cabled yarnsin the warp direction and a light weight fillingyarn spaced only sufficiently to process thefabric.

    Cotton: A natural fiber of high cellulosiccontent.

    Count: In fabric, the number of warp ends, thenumber of filling picks, or both in a square inchof fabric.

    Counter weight: In conveyor belting, theweight applied to the take-up assembly tomaintain proper belt tension.

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    Cover: The outer component of a belt.

    Cover seam: See cover splice.

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

    Cover surface profile: A cross-sectional viewof the cover surface.

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

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

    Crater: A small shallow surface imperfection.

    Crazing: A cover surface with many fissures.

    Creep: (1) The deformation occurring with thelapse of time in both cured and uncured rubber,in a body under stress in addition to the

    immediate elastic deformation. Some relatedterms and properties are stress-relaxation,hysteresis, damping, flow, compression set andviscosity. See Cold Flow. (2) In belts, the actionof a belt alternately losing speed on the drivingpulley and gaining speed on the driven pulley.

    Creeper drive: An auxiliary drive, usuallyconsisting of a small motor and speed reducer,used to keep a belt conveyor in motion at a verylow speed during non-operating periods inextremely cold weather. It is used to preventfreezing of a belt and other components.

    Crimp: (1) The waviness of the yarn in a wovenfabric. (2) The difference in distance betweentwo points on a yarn as it lies in a fabric and thesame two points when the yarn has beenremoved and straightened. Expressed as apercentage of the distance between the twopoints as the yarn lies in the fabric.

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

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

    Crystallization: A change in physicalproperties resulting from the crystallinereorientation caused by temperature.

    Cure: The act of vulcanization.

    Cure time: Time required, at a giventemperature, to produce optimum physicalproperties in an elastomer.

    Curing temperature: The temperature at whichthe rubber product is vulcanized.

    Curl: The action of the edges of a belt bendingupward on the carrying run and downward onthe return run. Also called cupping.

    Cushion breaker: A leno or cord breakerimbedded in a belt cover.

    Cut belts: See cut edge.

    Cut edge: The uncovered edge of a laminatedproduct, such a belt, created by cutting aftervulcanization.

    Cut resistance: The ability of a belt cover to

    withstand the cutting action of sharp objects.


    Data code: Any combination of numbers,letters, symbols, or other methods used by amanufacturer to identify the date of manufacture.

    Decking: A protective covering over the returnrun of a belt conveyor.

    Deflector: A board or plate at an angle across

    the path of a belt traveling over a flat surface totransfer 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 material.

    Delamination: The separation of layers ofmaterial in a laminate.

    Denier: A yarn sizing system for continuousfilament synthetic fibers on the basis of theweight in grams of 9000 meters of the yarn.

    Density: The ratio of the mass of a body to itsvolume or the mass per unit volume of thesubstance. For ordinary practical purposes,density and specific gravity may be regarded asequivalent.

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    Diameter: The length of a straight line passingthrough the geometric center to the periphery ofan object.

    Dielectric strength: The measure of electricpotential strength of a rubber product. Measureof its ability as an insulating compound to resistpassage of a disruptive discharge produced byan electric stress. Measured as volts per mil ofthickness.

    Dip coat: A thin coat on a surface obtained bydipping the material to be coated into the coatingmaterials.

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

    Discharge: Removal of material from a belt.

    Dog leg: A bending from a straight line.

    Double plate bolt fastener: Two ends of

    belting joined together with a plate on both sidesacross both ends of the joint.

    Drive: An assembly of electrical andmechanical parts that provide motive power to abelt.Drive, dual: See dual drive.

    Drive factor: A numerical factor used forcalculating the belt minimum slack side tensionrequired for a given driving condition and orconfiguration.

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

    Drive pulley: A pulley mounted on a drive shaftwhich transmits power to the belt.D

    Drive, single: A one-pulley drive.

    Drive snubbed pulley: An undriven pulleylocated close to the drive pulley to provide agreater arc of contact around the drive pulley.

    Drive, tandem: See tandem drive.

    Drive-on hinged fastener: Two ends of beltingjoined together with a pre-packaged fastenerassembly having prongs for driving through thebelt end.

    Drive-on plate fastener: Two ends of beltingjoined with a single plate, across the top coverjoint, with rivets or sharp teeth clinched over onthe bottom cover side of the belting.

    Drop ply: The omission of a reinforcing ply fora specified distance from each edge. Usuallythe bottom or next to bottom ply in flat conveyorbelting.

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

    Dual drive: A belt driving system employingtwo adjacent pulleys each powered with its ownmotor.

    Duck: A term applied to a wide range ofmedium and heavyweight fabrics, commonlymade of cotton, including the heaviest andstrongest of all single-woven fabrics. There arethree main types: number duck, army-type duckand flat duck.

    Dumbbell: A test specimen with lesser width atthe middle of its length than at its ends.

    Durometer: An instrument for measuring the

    hardness of rubber. Measures the resistance tothe penetration of an indentor point into thesurface of rubber.

    Durometer hardness: An arbitrary numericalvalue which measures the resistance topenetration of the indentor point of thedurometer. Value may be taken immediately orafter a very short specified time.

    Dutchman: A short section of beltingmechanically spliced into a length of belting andremoved when the take-up allowance is


    Dynamic fatigue: Loss in properties of amaterial when continually subjected to flexingand or cyclic stress.

    Dynamometer: An apparatus capable ofinducing various loads for evaluation of dynamicbelting properties.


    Edge wear: Damage to the edge of a belt byabrasion.

    Effective tension: Difference between the tightside and the slack side tension at the drivepulley providing the necessary pull to move theload.

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    Elastic limit: The limiting extent to which amaterial may be deformed and yet return toapproximately its original shape after removal ofthe deforming force.

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

    Elastomer: An elastic rubber-like substance,such as natural or synthetic rubber.

    Elastomeric properties: The chemical andphysical properties of an elastomer.

    Elevator belt: A belt that raises materialvertically in buckets attached to the belt.

    Elongation: Increase in length expressednumerically as a fraction or percentage of initiallength.

    Embossing: Operation of transferring a design

    to a rubber or rubber-like surface.

    Endless belt: A belt made endless without ajoint.

    Ends: See fabric count.

    Equivalent free fall: The calculated verticaldistance material falls from the discharge pointto end of a belt.

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

    Extensibility: The capability of increasedcenter distance in a belt conveyor.

    Extensible conveyor: An adjustable conveyorsystem with a loop of belting between thecarrying idlers and the return idlers for changingthe center distance.

    Extraction test: A test in which certaincomponents are separated from a solid bydissolving them in a liquid solvent under suitableconditions.

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

    Extrusion: A process whereby heated orunheated plastic forced through a shaping orificebecomes a continuously formed piece.


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

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

    Fabric design: The combination of size andnumbers of fibers or yarns, in both warp andfilling, and the manner in which they areprocessed.

    Fabric finish: See fabric impression.

    Fabric impression: A pattern in the cover of abelt formed by contact with a fabric duringprocessing.

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

    yarns per inch.

    Fabric rating: The maximum tension per ply offabric a belt should be operated under idealconditions.

    Face: The outer surface of a pulley or belt.

    Face cover: See top cover.

    Fastener: See belt fastener.

    Fatigue: The weakening or deterioration of a

    material caused by a repetition of stress orstrain.

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

    Fiber: A unit of matter having a length at least100 times its diameter and which can be spuninto a yarn.

    Filament: A continuous fiber of extreme length.

    Filler: A material mixed with a polymer toimprove quality or lower cost of a compound.

    Filler seam: Extruded polymeric compoundused to fill the void between two pieces of beltcover or fabric.

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

    Filling yarns: The transverse yarns in a fabric.

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

    Finger splice: Belt ends cut into mating fingers.

    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 not blendedcompletely into the surrounding material.

    Flame performance: The manner in whichbelting after being ignited will burn and/or selfextinguish.

    Flame retardance: Intensity of flamediminished by fire retardant ingredient(s) in theplastic compound.

    Flame test: A means, under specific condition,for establishing the flame performance of a belt.This will not indicate the performance of the beltin any fire in which the belt may be involved.

    Flange: A raised edge on a plastic article.

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

    Flanged pulley: A pulley with a raised rim atthe edges for the purpose of keeping the belt onthe pulley.

    Flash: Material protruding from the surface of amolded part, appearing at the mold parting lineor mold vent points.

    Flat belt: (1) A belt the cross section of which isin the general form of a rectangle; (2) A beltwhich operates on a smooth flat bed or straightidlers or rollers.

    Flat press: A belt finishing press with flatplatens, between which the belt is heated andcompressed.

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

    Flat wire braid: Flattened braided wire,frequently used for armoring the belt.

    Fleet: The lateral movement of a conveyor beltto either side of its intended path.

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

    Flex life: The relative ability of a rubber articleto withstand dynamic bending stresses.

    Flex life test: A laboratory method used todetermine the life of a plastic product whensubjected to dynamic bending stresses.

    Flexibility: The ability to be bent repeatedlywithout cracking.

    Flexing: The bending of a belt.

    Flight: (1) One of a series of belt conveyorsdischarging one to another. (2) A series of cleatsor profiles on a belt.

    Floating breaker: A leno or cord breaker

    embedded in a belt cover with a distinct layer ofelastomer separating the breaker from thecarcass.

    Floating idler pulley: See take-up pulley.

    Flow crack: A surface imperfection caused byimproper flow and failure of a compound toblend with itself during the molding operation.

    Flow line: See flow mark.

    Flow mark: A surface imperfection similar to a

    flow crack, but with a minor depression.

    Folded-edge: (1) A belt construction whereinthe inner carcass is enclosed in an envelope plyor plies. (2) An edge where an outer coveringhas been wrapped around a carcass and foldedover the edge so that the carcass is closed onthe edges.

    FPM: Abbreviation for "Feet per Minute".

    Frequency factor: The duration of time inminutes required for one complete cycle of aconveyor belt.

    Friction: (1) The resistance to motion of a beltdue to the contact between two surfaces. (2)Improperly used to indicate the bond betweentwo surfaces.

    Friction coat: An impregnation of rubbermaterial calendered by friction motion to a fabricso that the material is forced into the weave ofthe fabric.

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    Friction, coefficient of: The ration between theforce pressing the surfaces together and theforce required to move it.

    Friction, kinetic: The force which is required tokeep a body sliding at a uniform rate. Alsocalled "friction of motion".

    Friction pull: See adhesion.

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

    Friction surface: The exposed portion of a beltfinished with a layer of impregnated plastic asdistinguished from being completely coveredwith a layer of plastic.

    Frictioned fabric: Coated with rubbercompound on a friction (uneven speed)calender.

    Frosting: Light scattering surface resembling

    fine crystals.

    Full rated tension: See rating.

    Fungicide: An agent that destroys fungi orinhibits their growth.

    Fusion: An irreversible process during which aPVC compound or platisol undergoes a physicalchange and becomes a homogeneous mixtureby the mutual solvation of the PVC resin and theplasticizer in the compound, as result of heatingto an appropriate temperature.


    Gauge: The measure of thickness of theindividual elements making up a rubber product.

    Gel: The initial semi-solid stage that developsduring the solvation of a resin by a plasticizer.

    Gel point: The stage at which a liquid begins toexhibit pseudo-elastic properties.

    Glass fiber: Glass extruded through a die withmany fine holes into continuous filaments.

    Gouging: The effect of sharp heavy materialfalling onto a conveyor belt cover to loosen ortear out pieces of the cover.

    Grab test: A tensile test for woven fabric usingspecimens considerably wider than the jawsholding the ends of the test specimen.

    Grade: The ration of incline or decline of aconveyor expressed a s percent of the verticalheight to the horizontal distance.

    Grade of belting: The quality of belting coveron the basis or gouge, cut, and abrasionresistance.

    Gravity take-up: A mechanical system thatadjusts for the stretch or shrinking of a conveyorbelt automatically by a weighted pulley in thesystem.

    Grooved lagging: Lagging with round or

    angular grooves to minimize material buildup onthe pulley.

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


    Hammock belt idler: See catenary idler.

    Hank: A length of 840 yards of a yarn.

    Hardening: An increase in resistance toindentation.

    Hardness: Property or extent of being hard.Measured by extent of failure of the indentorpoint of any one of a number of standardhardness testing instruments to penetrate theproduct.

    Haze: The cloudy appearance of an otherwisetransparent film.

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    Hazing: A dull finish.

    Head: The delivery end of a conveyor belt.

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

    Head-tail drive: A belt driving system usingone or more powered pulleys at or near both thehead and tail pulleys with each pulleyindependently driven.

    Heat degradation: Change in chemical and/orphysical properties due to excessive exposure toheat.

    Heat mark: Extremely shallow depression orgroove in the surface of a plastic visible becauseof a sharply defined rim or roughened surface.

    Heavy weight belt: A belt with a ratedmaximum working tension equal to or greaterthan 160 pounds per inch width, when operating

    under ideal conditions.

    Herringbone weave: The longitudinalappearance of a row of parallel lines slanting atan angle in the opposite direction to another rowof slanting parallel lines.

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

    Hinged fastener: A fastener attachedindependently to each of the belt ends designedwith an opening in the end of the fastener to

    accept a pin through the opening to completethe joint.

    Hold back: See backstop.

    Holland cloth: A filled sheeting (usually starchfilled) with a smooth, glossy finish on both sides,used as separating medium.

    Homogenous: Of uniform compositionthroughout.

    Horizontal belt curve: The portion of aconveyor system which deviates from a straightline in the same horizontal plane as the rest ofthe system.

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

    Horseshoe: A fold in a surface in a definite U-shaped pattern. Particularly used in describingsqueezed-out blisters in a belt cover. Alsocalled ring blisters, dog ears and pig ears.Colloquial.

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

    Hugger belt conveyor: Two belt conveyorswhose conveying surfaces combine to conveyloads up steep inclines or vertically.

    Hysteresis: A loss of energy due to successivedeformation and relaxation. A measurement ofthe area between the deformation and relaxationstress-strain curves.

    Hysteresis loop: The configuration of thegraphical plot of stress and strain from the initialapplication of stress to some reduced stress.The measure of hysteresis is the area under

    stress-strain curves of increasing anddecreasing stress.

    Hysteresis loss: A loss of mechanical energydue to successive deformation and relaxation. Itis measured by the area between thedeformation and relaxation stress-strain curves.


    Idler: (1) A nonpowered pulley around 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 deformationmeasured immediately after removal of the loadcausing the deformation.

    Impact: The single instantaneous stroke orcontact of a moving body with another eithermoving or at rest, such as a large lump ofmaterial dropping on a conveyor belt.

    Impact energy: The effective combination offorce (weight of the body and height) when onebody falls on another.

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    Impact force: The energy power of impact.

    Impact idler: A belt idler having a resilient rollcovering, resilient molded elastomer rings,pneumatic tires, springs or other means ofabsorbing impact energy at or close to the placewhere material contacts the belt.

    Impact rating: The maximum rating of a beltconstruction based on the fabric, impact rolls,design of loading, size of material falling on thebelt, relative speed of the material and the belt,etc. to withstand the energy of impact loading.

    Impact resistance: The relative ability of aconveyor belt assembly to absorb impactloading without damage to the belt.

    Impregnated: Fabric interstices filled and/oryarns saturated with plastic compound.

    Impregnation: To fill the interstices of an articlewith a rubber compound. Generally applies to

    treatment of textile fabrics, yarns and cords.

    Impression: Design formed duringvulcanization in the surface of any rubber articleby a method of transfer, such as fabricimpression or molded impression.

    Impulse: An application of force in a manner toproduce sudden strain or motion.

    Indentation: (1) The extent of deformation bythe indentor point of any one of a number ofstandard hardness testing instruments; (2) A

    recess in the surface of a belt cover.

    Inside length: A belt length measured along itsinside circumference.

    Installation allowance: The amount by whichthe center distance can be adjusted so a beltcan be installed without damaging.

    Instantaneous modulus: The ratio of stress tostrain at a single point on the stress-strain curve.

    Interstice: A small opening, such as betweenfibers in a cord or threads in a woven or braidedfabric.

    Interstice of fabric: Spaces between the yarnsor cord of a woven fabric.

    Interwoven conveyor belt: A type of conveyorbelt construction similar to that of a solid wovenbelt, with plies interwoven such that it isimpossible to separate them.

    Irons: Strips of metal at the edges of a belt in aflat press to confine the edge elastomer formaking a molded edge or to obtain uniformthickness of the edges of a slit edge belt near itsedges.

    ISO: The abbreviation for the InternationalOrganization for Standardization.


    Jaws: Clamps to hold a specimen whenapplying stress to the specimen for certain tests.

    Joint: The area where two ends of a belt arefastened together, either by heat and pressureor mechanical means. See also splice.


    Kinking: A temporary or permanent distortionof belting caused by doubling the belt on itself.

    Knitted Ply: Spirally interlaced loops of yarnforming a continuous tubular structure.

    Knuckles: Raised loops of a woven textilestructure.


    Lagged drive pulley: See lagged pulley.

    Lagged pulley: A pulley having its surfacecovered with lagging.

    Lagging: A smooth or embossed covering on apulley to increase friction between belt andpulley.

    Laminate: A product made by bonding togethertwo or more layers of material.

    Laminated: Build up from thinner layers.

    Lap joint: An elevator joint where one end ofthe belt laps over the other end with the leadingedge on the bucket side.

    Lap: A part that extends over itself or a likepart.

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    Lap seam: A seam made by placing the edgeof one piece of material extending flat over theedge of the second piece of material.

    Lateral: Coming from the side.

    Lateral misalignment: Offset of pulleys, idlers,or structure from a design longitudinal referenceline.

    Leno breaker: An open-mesh fabric made fromcoarse ply yarns, with a leno weave. A lenoweave is one in which certain warp threads-termed doup or crossing threads-are passedfrom side to side of one or more ends-termedstandard threads and are found in by the fillingin this position. Where the crossed interlacingoccurs an open, perforated structure is formed.

    Leno weave: An open mesh fabric in which thewarp yarns are held by the filling yarns with thefilling yarns twisted around alternating warpyarns in opposite direction.

    Life test: A laboratory procedure used todetermine the resistance of rubber article to aspecific set of destructive forces or conditions.

    Lift: The net vertical distance material is movedby a conveyor or bucket elevator.

    Light weight belt: A belt with a rated maximumworking tension of less than 160 pounds perinch width.

    Lined bolt holes: Bolt holes which have been

    given a protective coating to cover the exposedcarcass.

    Liner: A separator, usually cloth, plastic film, orpaper, used to prevent adjacent layers ofmaterial from sticking together.

    Live roller conveyor: A roller bed conveyorsystem with frequently placed rollers above andin contact with the belt so the powered beltturns-makes "alive"-the rollers above the belt.The packages, etc. are conveyed on the rollersabove the belt.

    Live rolls: A series of rolls over which objectsare moved by application of power to all or someof the rolls.

    Live storage: (1) The storage of objects on aconveyor belt having a low coefficient of frictionsurface or on live rollers so the objects canaccumulate while they are added to or removedat different rates (2) The storage of material in asilo while material is being discharged or pouredin at the same time (3) An extensible conveyorwith a loop of belting between the carrying andreturn idlers where the length of the loop iscontinuously decreased as the equipment at themining face is advanced.

    Load support: The ability of a fully loadedconveyor belt to bridge the idler gap withoutcreasing into the idler gap and carry materialwithout excessive sag between the carrying idlerpulleys.

    Load weight: The weight of material per unit oftime.

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

    Loading impact: The energy with whichmaterial is loaded onto a conveyor belt.

    Longitudinal: A lengthwise direction.

    Longitudinal seam: A seam joining twomaterials in the length of the finished product.

    Loop edge: A selvage formed by having thefilling loop around a catch cord or wire, which islater withdrawn, leaving small loops along theedge of the cloth.

    Loose cover: A separation of the cover fromthe carcass or textile reinforcement.

    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 ofbelting to be bent or flexed at low temperatureswithout loss of serviceability.

    Low temperature flexing: The act of bending aproduct under conditions of a cold environment.

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

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    Masterbatch: A preliminary mixture of two ormore compound ingredients for purposes ofmore thorough dispersion or better processing,and which will later become part of the finalcompound in a subsequent mixing operation.

    Maximum horsepower: The highest powerrequirement.

    Maximum ply: (1) The maximum number ofplies permissible that will permit for satisfactorytroughability; (2) The maximum number of pliespermissible to satisfactorily operate around apulley of a given diameter.

    Maximum safe working stress: The greatesttension at which a belt should be operated.

    Maximum tension: See tension, maximum.

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

    Migration: The transfer of an ingredient in arubber compound from one layer to an adjacentlayer or to the surface.

    Migration stain: When staining occurs on thearea of an object adjacent to the rubber article itis known as "migration stain".

    Mildew: Growth on organic matter produced by

    fungi, generally in textile components of rubberarticles. Usually causes deterioration.

    Mildew inhibited: The article contains materialto prevent or retard mildew.

    Mill: A machine with two horizontal rollsrevolving in opposite directions used for themastication or mixing of rubber.

    Minimum accelerating time: The least timeallowed to accelerate a conveyor belt from restto normal speed without exceeding its maximumsafe working stress.

    Minimum braking time: The least time allowedto decelerate a conveyor belt from normal speedto rest without exceeding the maximum safeworking stress or causing the belt to double upon itself.

    Minimum ply: The least number of plies thatwill support the load on a belt without damagingdeformation.

    Minimum pulley diameter: The smallest pulleydiameter around which a belt is recommendedto operate.

    Minimum tension: See tension, minimum.

    Mirror finish: A bright, polished surfaceappearance.

    Mix: See compound

    Modified grab test: A tensile test for wovenfabric using specimens wider than the jawsholding the specimen cut midway between the

    jaws to the warp yarns held by the jaws.Minimizes warp yarn popout experienced byraveled specimen test.

    Modulus: (1) A coefficient or numerical

    measure of some property. (2) In rubber,modulus usually refers to one of severalmeasurements of stiffness or resistance todeformation. The use of the word withoutmodifying terms may be confusing and such useshould not be encouraged. Modulus in rubbermay be either static or dynamic; static moduliare subdivided into tangent, chord, andcompounder's. Compounder's modulus isalways in tension, but all the others may be inshear, compression or tension. Other termsused in connection with "modulus" are elasticity,rigidity, Young's tangent, and elongation. (3) All

    elastic moduli in rubber (except compounder's)are ratios of stress to the strain produced by thatstress, the stress, usually p.s.i.

    Modulus, belt: The force per unit width of beltrequired to produce a stated percentage ofelongation.

    Modulus of elasticity: The force divided by thepercent elongation (divided by 100) to cause theelongation.

    Moisture regain: The reabsorption of water bya textile.

    Mold edge: A belt edge formed duringvulcanization by curing in a mold or againstedge irons.

    Mold lubricant: The material used to coat thesurfaces of a mold to prevent the rubberadhering to the metal during vulcanization.

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    Mold mark: An indentation or embossment onthe surface of a molded product caused byirregularities in 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 compound whichcan react to form a polymer.

    Mooney viscosity: A measure of the plasticityof a polymeric compound determined in aMooney shearing disc viscometer.

    MSHA: Abbreviation for Mine Safety and HealthAdministration.MSHA flame retardant test: Flame testprocedure for underground conveyor belting

    prescribed by the Mine Safety & HealthAdministration of the U.S. Department of Labor.

    MSHA flame retardant test:Flame procedure for underground conveyorbelting prescribed by the Mine Safety & HealthAdministration of the U.S. Department of Labor.

    Multifilament: Many extruded fine strands ofmaterial grouped together.


    Narrow disc idler: A flat pulley with discsattached around the pulley at certain intervalsacross the pulley.

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

    Needle punched: Nonwoven fabric punchedwith a hack latched needle to improve itsstrength and stability.

    Net endless length: The manufactured lengthnecessary to provide proper initial fit andtensioning of a belt on a specified drive.

    Nicks: Cuts in the surface or edge of belting.

    Nip: The clearance between two rolls of acalender.

    Nitrile: Common name for nitrile-butadienepolymer.

    Nominal: An approximate amount.

    Nonblooming: The absence of bloom.

    Nonwoven fabric: A mat of nonaligned fiberbonded together.

    Norway type elevator bolt: Flat top, squaredshoulder bolt for attaching elevator buckets toelevator belts.

    NR: Abbreviation for isoprene polymer.

    Numbered duck: Fabric weight designated bynumbers based on linear yard of cloth 22" in


    Nylon: Common name for polyamide fiber.


    Offset idler: The center carrying roller which isoffset and transversely lapping the troughingidlers.

    Oil proof: Not adversely affected by exposure

    to oil.

    Oil resistant: Withstands the deteriorationeffect of oil(generally refers to petroleum) on thephysical properties.

    Oil swell: The change in volume of a rubberarticle due to absorption of oil.

    Oil well splice: Two ends of a belt each bent90 degrees around a steel form and boltedtogether through the belt and steel form.

    Oligomer: A polymer consisting of only a fewmonomer units such as in dimer, a trimer, atetramer etc. & their mixtures.

    One side: Pertains to one of the two outwardfaces or surfaces of a conveyor belt (not theedges of the belt).

    Open seam: A seam whose edges do not meetcreating a void.

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    Operating tensions: The tension oflongitudinal sections of a belt system (tight sideand slack side) when moving material, asdistinguished from tension when the belt isrunning empty.

    Optimum cure: The time, temperature andcompression of vulcanization or of fusion atwhich a desired combination of properties isattained in an elastomer.

    Organosol: A suspension of a finely dividedplastic in a plasticizer with a volatile organicsolvent.

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

    Oven: A low pressure hot air chamber used forthe purpose of heating, drying, baking orvulcanizing rubber products. See Aging.

    Oxidation: The reaction of oxygen on a rubberproduct, usually detected by a change in theappearance or feel of the surface or by a changein physical properties.

    Oxygen bomb: A chamber capable of holdingoxygen at an elevated pressure which can beheated to an elevated temperature. Used for anaccelerated aging test.

    Oxygen bomb aging: A means of acceleratingchange in the physical properties of rubbercompounds by exposing them to the action of

    oxygen at an elevated temperature andpressure.

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

    Ozone resistant: Withstands the deterioratingeffects of ozone (generally cracking).


    Package conveyor: A conveyor whichtransports packaged, boxed, or bagged material.

    Package deflector: See conveyor belt packagedeflector.

    Packed material: Material on beltingcompacted as the belting moves along thesystem.

    Performance test: See service test.

    Permanent set: The amount by which anelastic material fails to return to its original formafter deformation.

    Permanent stretch: Elongation permanentlyremoved from belting when it is first used.

    Permeability: The quality or condition ofallowing passage of liquids or gases through arubber layer.

    Physical properties: A measure of mechanicalcharacteristics of a material.

    Pick: An individual filling yarn of a fabric.

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

    Pierce tape: A woven mesh of steel wire orcord.

    Pimple: A small sharp or conical elevation onthe surface of a product.

    Pit: A small crater in the surface of a productwith width about the same as its depth.

    Pitch line: The plane within a belt whichundergoes neither stretching nor compressionwhen the belt rounds the pulley, i.e., the neutralplane of the belt structure.

    Plain weave: The simplest type of weave withboth adjacent warp and filling yarns crossingover and under each other.

    Planished cover: An irregular coated surfacetransformed into a smooth surface by somemeans.

    Planished finish: See planished cover.

    Plastic: A material that contains as an essentialingredient one or more organic polymericsubstances of large molecular weight, is solid inits finished state, can be shaped by flow.

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    Plasticity: (1) A measure of the resistance toshear of an unvulcanized elastomer; (2) ameasurement of resistance to shear with heathistory.

    Plasticizer: A compounding ingredient whichcan change the physical and chemicalproperties and processibility of a polymericcompound.

    Plastisol: A dispersion of a powderous polymerin a plasticizer.

    Plate finish: A finish resulting from contact withcommercially smooth but not polished pressplatens.

    Plied yarn: A yarn made by twisting togethertwo or more single yarns.

    Plows: Plates across a belt to remove materiallying on or sticking to the belt.

    Ply: A layer of rubberized fabric.

    Ply adhesion: The force required to separatetwo adjoining strength reinforcing members in arubber product.

    Ply separation: Lack of adhesion betweenplies.

    Ply tensile: The ultimate breaking strength of abelt expressed in force per inch width per ply.

    Polymer: A macromolecular material formed by

    the chemical combination of monomers havingeither the same or different chemicalcomposition.

    Polymerization: The process that convertsmonomers into polymers.

    Polyvinyl chloride: A polymer prepared by thepolymerization of vinyl chloride as the solemonomer.

    Porosity: The condition of containing numeroussmall holes or voids.

    Portable conveyor: A conveyor system readilymoved from one place to another.

    Portable vulcanizer: A vulcanizer readilymoved from one place to another, usually usedfor making field splices and repairs.

    Pot life: The period of time during which areacting polymeric compound remains suitable

    for its intended use after having been mixed witha reaction-initiating agent.

    Powered roller conveyor: A term used by theU.S. Postal Service to mean a live rollerconveyor. See live roller conveyor.

    Press: A machine consisting of two or moreheated plates which can be brought togetherand separated by hydraulic pressure ormechanical action.

    Press cold ends: The area of reducedtemperature at the press platen end.

    Press lap: The area of overlap of one presscure length on the next.

    Press length: The length of a belt which can bepressed at one time.

    Press marks: Irregularities in the surface of avulcanized product caused by the press ends or

    by corresponding irregularities in the presssurface.

    Press, rotary: See rotary press.

    Pricker marks: Small marks in the cover of avulcanized belt where a roll with sharp needleshad penetrated the uncured belt to allow trappedair in the uncured belt composite to escape.

    Processing: The operations in the manufactureof a belt.

    Profile top cover: Belt surface having a seriesof continuous or interrupted, straight or curvedridges, across the belt at regular intervals toenhance the belts ability to move materials upinclines or down declines.

    Prong: The sharp point of a mechanicalfastener that penetrates the belt.

    Pulley: A cylinder, mounted on a central axisrod.

    Pulley cover: See bottom cover.

    Pulley lagging: See lagging.

    Pulley projection: The amount a pulley facewidth extends beyond belt edge.

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    Pulley wear cover: (1) Elastomeric materialattached to the pulley to minimize pulley surfacewear (2) Additional belt bottom cover thicknesswhere extraordinary wear is anticipated.

    Pulley wrap: See arc of contact.

    Pure gum compound: A natural rubber orisoprene compound containing only theingredients necessary to process it, to protect itfrom aging, and to cause vulcanization.

    PVC cover: Cover using a PVC compound.

    PVC impregnated: Impregnated with PVCcompound.


    Qualification conformance inspection: Theexamination of samples from a production run to

    determine conformance to a given specification.

    Qualification inspection test: Theexamination of samples from a typicalproduction run to determine conformance to agiven specification for approval to become asupplier.

    Quarter turn drive: A belt system in which theaxes of the adjacent pulleys are at right anglesto each other to cause a 90 degree twist in thebelt about its longitudinal axis.


    RAC: Abbreviation for The Rubber Associationof Canada.

    Raised cover center: A belt cover withincreased thickness along the center portion ofthe belt.

    Raised edge: A flanged edge conveyor belt tominimize spillage.

    Raised rib belt: A belt with transverse ordiagonal bars or cleats on the top cover.

    Rated conveyor belt: The manufacturer'srecommended maximum working tension for aconveyor belt.

    Rated working tension: See rating.

    Rating: The normal working tensionrecommended for a belt.

    Raw edge: The uncovered square edge of abelt created by cutting after vulcanization.

    Recovery: The degree an elastomeric materialreturns to its original dimensions after beingstressed.

    Reefed: A belt folded back and forth on itself.

    Reinforcement: The textile strengtheningmember of a belt. See also carcass.

    Reinforcement agent: An ingredient in apolymeric compound not basic to itsvulcanization used to increase its chemical andphysical properties.

    Reinforcing element: The strengtheningmembers of a belt.

    Repair: The area of new material replacingdamaged material in a belt.

    Repose angle: See angle of repose.

    Resin: Certain materials produced by chemicalsynthesis.

    Resistance: The property or ability of matter towithstand the effects of force, pressure, heat orchemical action.

    Return idler: A roll(s) that supports a belt on its

    return run.

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

    Reversion: (1) The change which occurs invulcanized rubber as the result of aging orovercuring in the presence of air or oxygenusually resulting in a semi-plastic mass. (2) It isthe basis of rubber reclaiming processes and isaided by the use of swelling solvents, chemicalplasticizer and mechanical disintegration toobtain a workable mass.

    Ribbon blender: A type of internal mixer usedto mix powders and liquids into a dry powderousviscous or liquid mass.

    Ribs: Transverse configurations on the carryingside of a belt to facilitate carrying material on anincline.

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    Riveted plate joint: A mechanical fastener withrivets projecting through a plate on both sides ofthe belt.

    RMA: Abbreviation for The RubberManufacturers Association, Inc.

    RMBT: Abbreviation for Rated ManufacturersBelt Tension.

    Roll belting: Belting made to ordered width butof nominal lengths for cutting later into shorterlengths.

    Roller bed conveyor: A conveyor beltoperating over a series of steel support rollers.

    Rosin: The hard amber-colored material of theresidue from the distillation of oil of turpentine.

    Rotary press: A vulcanizing machineconsisting of a rotating, heated drum with aflexible steel band partially encircling the drum,

    which continuously advances a material whileunder pressure and heat between drum andband.

    Rotocure: See rotary press.

    Rough top: A belt made with projections in thecarrying surface to improve the ability of the beltto carry material on inclines.

    Rubber cement: A mixture of polymericcompound or elastomer used as an adhesive orsealant.

    Rubberized: Coated with rubber compound.

    Run: The distance or route covered by aconveyor.


    Saddle: An additional short length of beltingadded to an existing belt. See butt strap.

    Safety factor: The ratio of the maximum stressthat a belt or a belt splice can withstand to themaximum stress recommended for it by themanufacturer. The ratio of breaking strength torated working tension.

    Safe working strength: The manufacturer'srecommended maximum working tension for aconveyor belt operating in ideal conditions.

    Sag: The amount of vertical deflection of aconveyor belt from a straight line between idlers,usually expressed as a percentage of thespacing between idlers.

    Sag belt tension: The minimum tension in anyportion of the carrying run of a belt necessary toprevent excessive sag of the belt between idlers.

    Sample: A piece of material removed forevaluation.

    Scraper: A device for cleaning the surface ofbelting.

    Screw take-up: A take-up for a conveyorsystem in which movement of a pulley-bearingblock is accomplished by means of a screw.See also take-up.

    Seam: The place where two edges of fabric orelastomer are adjacent to each other to form asingle ply or layer.

    Seaming strip: A strip of polymeric materiallaid over and/or in a seam to fill any voidsbetween the adjacent plies of material.

    Self-aligning idler: An idler having a belt-activated swivel mechanism to control the sidemovement of an operating conveyor belt.

    Selvage: The lengthwise woven edge of afabric. Also called selvedge.

    Semi-cure: A partial or incomplete cure.

    Service condition: All the conditions ofoperation to which a conveyor or elevator belt isexposed.

    Service factor: The amount by which thenormal rating of a unit is altered to compensatefor specific service requirements.

    Service test: A test in which the product ismade to operate under service conditions in theactual equipment.

    Set: The amount of deformation remaining aftercomplete release of the load producing thedeformation.

    Shadowing: A bas-relief or outline of areinforcement which appears on a cover aftervulcanization.

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    Sheeting: A form of plastic in which thethickness is very small in proportion to lengthand width and in which the plastic is present asa continuous phase throughout.

    Shelf storage life: The period of time prior touse during which a product retains its intendedperformance capability.

    Simulated service test: See bench test.

    Singles yarn: The product from aligning andtwisting together fibers or twisting togetherfilament fibers.

    Sink: A collapsed blister or bubble leaving adepression in a product.

    Skew: Amount by which the ends of a singlepick yarn in a fabric are offset longitudinally.

    Skim: A thin layer of polymeric compoundapplied to a fabric.

    Skim or skim coat: A layer of rubber materiallaid on a fabric but not forced into the weave.Normally laid on a frictioned fabric.

    Skirt board: In a conveyor system, the verticalor inclined plates located longitudinally andclosely above the belt to confine the conveyedmaterial.

    Skive: A cut made on an angle to the surface toproduce a tapered or feathered cut.

    Slab belting: Belting made in wide widths andlong lengths for later slitting into narrower widthsand cutting into shorter lengths.

    Slack side tension: The lessor of the tensionsin a belt on an operating conveyor. Usuallyimmediately following the drive pulley.

    Slider bed: A stationary surface on which a beltslides.

    Slider bed conveyor: A conveyor beltoperating all, or in part of its length, over a flatsupport surface as opposed to being supportedby a series of rollers.

    Slip: The action that takes place, causing adifferential movement between the pulleysurface and the belt.

    Slip and sequence system: An interlockingbelt conveyor system that stops the systemwhen the speed of the conveyor belt drive pulleyexceeds a certain speed of the conveyor belt.

    Slit belt: A belt cut to lesser width.

    Slit edge: The square finished edge of a beltafter trimming to width.

    Slit edge belt: See cut edge.

    Slope belt: A conveyor belt used to carrymaterial along an inclined flight.

    Slope tension: See tension, slope.

    Snub pulley: A pulley adjacent to a drive pulley

    that increases the arc of contact on the drivepulley to increase the effectiveness of the drive.

    Solid woven belt: A type of conveyor beltwherein the carcass is a single ply consisting ofmultiple layers of warp and filling yarnsinterwoven. The carcass usually is impregnatedand/or coated with polymeric compound.

    Specification: Detail description of specificrequirements.

    Specimen: A piece cut from a sample of belting

    to test.

    Splice angle: The angle at which belting isspliced.

    Splice: Methods for joining the ends of beltingtogether without using a mechanical fastener.

    Spread: To apply a thin coat of liquid materialover a surface by means of a knife, bar, ordoctor blade.

    Spread coat: To apply a thin coat of materialover a surface determined by means of a knife,bar, or doctor blade.

    Spread coated fabric: A fabric coated with aliquid plastic by a spreading process and thenheated to fuse the coating.

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    Spring take-up: A mechanical device on bothsides of the conveyor system where a variableforce spring is secured to the conveyor structureand to the tail pulley block for the purpose ofmaintaining a uniform tension in the belt.

    Spun yarn: A yarn produced from short fibersby aligning and twisting them together.

    Square edge: An edge of plastic-coveredbelting finished against rectangular irons.

    Stacker: A conveyor adapted to piling orstacking bulk material, packages, or objects.

    Stamped metal: Perforated metal sheet usedfor making a rough top design on a conveyorbelt.

    Standard: A quality level set for the resultsfrom a belt test.

    Staple: A textile fiber of relatively short (1" to

    3") length which when spun and twisted forms ayarn.

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

    Starting tension: The tension necessary toaccelerate a belt from rest to normal operatingspeed.

    Static conductive: Capability to conduct staticelectricity.

    Static electricity: Electrical potential resultingfrom two surfaces rubbing together or partingone from the other.

    Static friction: The resistance which must beovercome to start a body sliding down a beltsurface.

    Steel cable: Several steel cords twistedtogether.

    Steel cord: Several steel wires twistedtogether.

    Steel cord belt: A conveyor belt having atension bearing member of steel cords lying inthe same plane with a definite spacing betweenthe cords, elastomer between the cords and anelastomeric cover on both sides of the belt.

    Step ply: A conveyor belt having a plied textilecarcass in which the upper ply or plies are setback toward the edges to increase the covergauge in loading area.

    Stepped splice: The joint of one end of multi-ply belting with plies of fabric removed sorespective ply ends will butt together andoverlap adjacent plies of fabric.

    Stiffness: Resistance to flexing.

    Stitched belt: (1) A belt made from plies ofnon-rubberized fabric sewed together to make aunit structure. (2) A rubberized belt in which theplies have bee sewed.

    Stitching: A method of butting or joining twopieces of material together, usually by means ofa stitcher roller.

    Stock roll: A belt made to some nominal lengthand width for subsequent cutting to required

    length and width.

    Straight face pulley: A pulley without anycrown.

    Straight warp weave: Two warp yarn systemsand a filling yarn system where one warp systemis essentially without crimp and is the tensionbearing member, while the other warp system isinterlaced with the filling yarn and providesmechanical fastener holding capability.

    Strain: Deformation resulting from a force

    applied to a body.

    Stress: Force applied to a body that results inthe body being deformed.

    Stress-strain: The relationship of force anddeformation in a body during compression,extension, or shear. In a belt this is therelationship of tension (stress) and resultingelongation (strain).

    Stretch: An increase in length.

    Striated cover: A cover having grooved orchanneled lines, due to transfer of irregularitiesfrom contact with surfaces of forming or finishingequipment.

    Strike through: Penetration of plasticcompound through the fabric.

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    Strip test: In fabric testing, a tensile strengthtest made on a strip of fabric with cut edge orraveled down to a specified number of threadsor width of fabric, all of which are firmly held ingripping jaws wider than the test piece.

    Sun check: Fine cracks and crazing of anelastomeric surface primarily due to the sun'sultraviolet rays.

    Surface finish: See belt surface finish.

    Swelling: An increase in volume of anelastomer or belt.


    Tack: Having a property of temporary adhesion.

    Tail end: The end of a conveyor, usually nearits loading points.

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

    Take-up: (1) Removal of slack or stretch in abelt (2) An assembly of structural andmechanical parts to 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 in

    space due to gravity, a spring, or other forces inorder to maintain relatively constant tension in aspecific strand of a belt.

    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 a belt measuredaround the pulley surfaces when the take-upidler(s) are moved out to where they take up allthe belt slack their movement permits.

    Tape line measurement-minimum length:The inside circumference of a belt measuredaround the pulley surfaces when the take-upidler(s) are moved in for the installation of theshortest belt possible.

    Tear down: The removal of a ply of fabric in amulti-ply fabric belt to prepare the stepped downconfiguration for a stepped splice.

    Tear Propagation: Continuation of tear.

    Telescoped roll: At the outside end of a roll ofbelting, turns of the belting progressivelyloosened and moved outward from theremainder of the evenly wound turns of thebelting.

    Template: A pattern to guide the punching ofholes or cuts in belt ends.

    Tensile member: See carcass.

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

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

    Tension: Stress on a material tending to cause

    extension of the material.

    Tension, effective: In a belt drive, it is thedifference between the two tensions in a belt asit approaches and leaves a driving or drivenpulley. In a two-pulley drive, it is the differencebetween tight and slack side tensions. Being ameasure of power requirement, it is sometimesreferred to as horsepower pull.

    Tension, maximum: (1) The highest tensionoccurring in any portion of a belt drive. In a two-pulley drive it is the tight side tension. (2) Inconveyors, the maximum tension may occur at apoint other than the drive pulley.

    Tension member: See carcass.

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    Tension minimum: The lowest tensionoccurring in a belt in a conveyor or elevatorsystem under operating conditions.

    Tension rating: Maximum safe working tensionrecommended by a belt manufacturer.

    Tension ratio: In an operating belt system, theratio of the larger to the smaller tension as thebelt approaches and leaves a driving or drivenpulley.

    Tension, slack side: In a belt system, wherethe two portions of the length of a belt on eitherside of a driving or driven pulley have differenttensions, the slack side tension is the smallest ofthe two.

    Tension, slope: The tension in an inclined beltcaused by the weight of the material beingelevated in addition to the belt weight andindependent of friction and other sources oftension.

    Tension, take-up: The amount of tension ineach of the runs of belting approaching andleaving the take-up pulley, the total of which isthe force exerted by the take-up device.

    Tension, tight side: In an operating conveyorsystem, the greater of the tensions as the beltapproaches and leaves the drive pulley.

    Tension, working: The maximum workingtension for a fabric or belt recommended by themanufacturer.

    Terminal position: The maximum workingtension for a fabric or belt recommended by themanufacturer.

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

    Tex: A yarn size system defined as the weightin grams of 1000 meters of yarn.

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

    Thermoplastic: Capable of being repeatedlysoftened by heating and hardened by coolingand in the softened state can be shaped by flow.

    Tie cloth breaker: A leno or other open weavefabric breaker between a belt cover and thecarcass.

    Tie gum: A thin sheet of unvulcanized rubberinserted between plies in vulcanized repairs ofsplices.

    Tight side tension: See tension, tight side.

    Tilted troughing idlers: Used for belt training.

    Time cycle: The duration of time, in minutes,required for one complete cycle of a conveyorbelt.

    Tire bead wire: Steel wire placed in or beneaththe top cover to minimize rips in the belt byobjects that penetrate the belt.

    Tolerances: The limiting values for adimension.

    Top cover: Loss of the elastomer due toabrasion.

    Top cover wear: The protective rubber cover

    on the material conveying surface or surfaces ofa conveyor belt.

    Tracking alignment: See training.

    Traction: The friction between a drive pulleyand the conveyor belt.

    Traction top: See rough top.

    Training: The process of adjusting idlers,pulleys, and loading conditions to insure the beltruns straight.

    Training idler: An idler mounted on amechanical device, actuated by the belt movingagainst it to make the belt run straight.

    Trajectory: The arc made by material freelydischarged from a conveyor system.

    Transfer system: A combination ofmechanisms to move objects or bulk material toor from a conveyor.

    Transition distance: The distance between thelast fully troughed idler and the flat driving ordischarge pulley.

    Transition idler: A troughed belt idler having alesser degree of trough than the previouscarrying idlers.

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    Transverse: A crosswise direction of a belt.

    Transverse cord breaker: A cord fabric laid inthe top cover at right angles to the belt edges.

    Transverse rigidity: Resistance to beltdeformation in the belt crosswise direction.

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

    Trapped air: Air which is enclosed in a productor between a product and a mold surface duringcure.

    Traveling deflector: A mechanism whichmoves over the carrying surface of the belt anddeflects the conveyed material off of the belt.

    Tripper: A fixed or moveable mechanism atsome intermediate place in the conveyor systemto discharge material from the belt.

    Troughability: The property of a belt thatpermits it to conform to the contour of troughingidlers.

    Troughability index: The ratio of the deflectionof a freely supported transverse section of a beltto the distance between the freely supportedends.

    Troughed belt: A belt operating in a conveyorsystem with inclined side idlers to cause the beltedges to turn up and increase the amount of

    material carried while minimizing side spillage ofthe material.

    Troughing angle: The angle troughing idlersare to the horizontal extension of the flatcarrying idler.

    Troughing idlers: An idler system whichsupports a belt in a troughed configuration.Usually it consists of a center horizontal roll withan inclined roll on each side. See also catenaryidler.

    Twill weave: A fabric woven with theappearance of diagonal lines.

    Twist: The rotation of a belt on its longitudinalaxis. A 180 degree twist is used as a means ofinverting a belt through the zone of the twist.


    Ultimate elongation: Elongation at rupture.

    Ultimate strength: The force required torupture a specimen.

    Ultimate tensile: Tensile stress at rupture.

    Undercure: A less than optimal state ofvulcanization which may be evidenced bytackiness or inferior physical properties.

    Uncured: Not vulcanized.


    Vanner edge: See flanged edge.

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

    Viscosity: The flow property of a material.

    Void: The absence of material or an areadevoid of materials where not intended. Seealso blister and sink.

    Volume swell: See swelling.

    Vulcanization: A process over a range intemperature during which a polymeric

    compound, through a change in molecularstructure (e.g., crosslinking) becomes lessplastic and causes changes in the physical andchemical properties of the resulting elastomer.

    Vulcanized splice: A joint in a belt made bymeans of vulcanization.

    Vulcanized splice step length: Thelongitudinal distance between steps in thesplice.


    Warp: (1) The yarns that run lengthwise in awoven fabric or jacket. (2) The total deviationfrom a straight line of a hose when subjected tointernal pressure.

    Warp-yarn: (1) A longitudinal yarn in a fabric.(2) A corner yarn in a braid.

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    Weathering: Surface deterioration, evidencedby cracks and crazing of an elastomer, duringoutdoor exposure.

    Weave: A fabric pattern description denoting aspecific relationship of warp and filling yarns atspecific locations in the fabric.

    Weft: The crosswise threads in a fabric; fillingthreads. The treads 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 supporting structure to thecenter shaft to minimize trapping material thatotherwise would build up and damage the belt.

    Wire hook fastener: A mechanical fastenerconsisting of wires capable of being driventhrough the belt end and bent back into the beltby a special tool device.

    Wires: Metal in the form of a fine flexible rod.

    Working load: See working tension.

    Working tension: Stress on the belt when thebelt is loaded with conveyed material andmoving.

    Woven fabric: A flat structure composed of twoseries of interlacing yarns of filaments, oneparallel to the fabric and the other transverse.

    Woven wire carcass: A belt with woven wirefabric.

    Wrinkled ply: See buckled ply.


    Yarn: A generic term for continuous strands oftextile fibers or filaments in a form suitable forknitting, weaving, or otherwise intertwining toform a textile fabric. It may comprise (1) anumber of fibers twisted together (2) a numberof filaments laid together without a twist (a zero-twist yarn) (3) a number of filaments laidtogether with more or less twist or (4) a singlefilament with or without twist (a mono-filament).

    Yarn number: The number of hanks in a poundof spun yarn.

    Yield point: The stress in a material at which asubstantial increase in strain occurs with aminimum increase in stress.

    Yield strength: The stress at which a materialexhibits a specified limiting permanent set.Determined by a measurable value of plasticyielding of the material, above which thematerial is considered to be damaged and belowwhich the damaging effects are considered to benegligible.

    Young's modulus: Stress per unit strain forperfectly elastic material.


    Zero load: A reference load applied in takingan initial reading and prior to determiningcompressibility or extensibility.

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    Industry Terms

    for the

    Conveyor and Elevator

    Belting Industry


    Waukesha, WI 53188

    (262) 523-9090

    FAX (262) 523-9091

    Web site:

    Price: $5.00 per copy05/01 - MRA

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