Glossary of Terms

Abrasion Wearing away by rubbing, scraping.
Adhesion The bonding strength between two materials.
Ageing The exposure to an environment for a period of time.
Arc of contact The circumferential portion of a pulley which is engaged by a belt.
Belt clamp Beams or metal plates secured transversely on both sides of belt end(s) to hold ends in a desired position.
Belt cleaning device A scraper or rotating or washing device pressed against the belt surface to remove material stuck to the belt.
Belt fastener A device for holding two ends of a conveyor belt together.
Belt modulus The force per unit width of belt required to produce a stated percentage of elongation.
Belt sag The amount of vertical deflection of a conveyor belt from a straight line between idlers, usually expressed as a percentage of the center to center spacing of the idlers.
Belt slip The speed differential between the belt and the pulley surface.
Belt training idler An idler having a belt-actuated swivel mechanism to automatically control side drifting of a conveyor belt.
Belt turnover

A system of idlers to turn a belt over.

Bending modulus The force required to induce bending around a specified radius and, hence, a measure of stiffness.
Bend pulley A pulley used to change the direction of a belt.
Bias cut A cut of a textile material or belt ends made diagonally at an angle less than 90 degrees - usually 30° - to the longitudinal axis.
Binder warp yarn One of the warp systems in a straight warp fabric interlaced with the filling yarn to provide the strength to hold mechanical fasteners.
Bleeding Migration to the surface of plasticizer, waxes or similar materials to form a film or beads. See also Bloom.
Blister A raised spot on the surface or a separation between layers usually forming a void or air-filled space in the vulcanized conveyor belt.
Booster drive Used in some long conveyors to reduce the power/tension at the drive pulley.
Bottom cover The non-carrying belt side towards the pulleys.
Breaker An extra ply for shock absorption to minimize gouging.
Bucket elevator belt A transversely rigid belt with buckets attached, for vertical conveying.
Calender A machine equipped with three or more heavy drums revolving in opposite directions.
Capacity The material load on the belt, given in tons per hour (t/h).
Carcass The fabric, cord and/or metal reinforcing section of a belt, as distinguished from the rubber cover.
Catenary idler A type of flexible belt-carrying idler with ends supported in pivoted stands.  The tube or rollers sag under the weight of the load to form trough.
Center-to-center The distance between the center of two pulleys or idlers.  Sometimes also called centers or center distance or conveyor length.
Cleaner A device for removing adherent material from the belt
Cleat Transverse raised sections on a conveyor belt to stabilize material carried up an incline.
Cord fabric The fabric elongation is adjusted by means of the weft yarn twist.
Compression set The deformation in a material remaining after it has been subjected to and released from a compressive force.
Counter weight The weight applied to the take-up assembly to maintain proper belt tension.
Cover The outer rubber (or PVC) components of a belt.
Cracking A sharp break or fissure in the surface. See also "Wrinkle".
Creep The action of a belt alternately losing speed on the driving pulley and gaining speed on the driven pulley.
Crimp The waviness of the yarn in a woven fabric or the difference in distance between two points on a yarn as it lies in a fabric and the same two points when the yarn has been removed and straightened.  Expressed as a percentage of the distance between the two points as the yarn lies in the fabric.
Crowned pulley A pulley with a greater diameter at the center, or other points, than at the edges.
Cut edge The uncovered edge of a belt, created by cutting after vulcanization.
Degradation A deleterious change in the chemical structure of a material.
Delamination The separation of layers of material.
Denier A yarn sizing system for continuous filament synthetic fibers on the basis of the weight in grams of 9000 meters of the yarn.
Density The ratio of the mass of a body to its volume or the mass per unit volume of the substance. For ordinary practical purposes, density and specific gravity may be regarded as equivalent.
Dipped fabric Coated with rubber compound by passing through a rubber solution and drying.
Dutchman A short section of belting mechanically spliced into a length of belting and removed when the take-up allowance is exceeded.
Dynamometer An apparatus capable of inducing various loads for evaluation of dynamic belting properties.
Electrical conductivity A measure of how well a material accommodates the transport of electric charge, measured in Ohm (Ω).
Endless length The length of a closed belt (without splice allowances).
EOB Energy optimized belt
Extrusion A process whereby rubber is forced through a shaping orifice.
Eytelwein's equation Determines the optimum difference between the forces F1 and F2 without belt slip.
Fatigue The weakening of a material occurring when repeated application of stress causes permanent strain.
Feeder belt A belt that discharges material onto another conveyor belt.
Filament A continuous fiber of very high length.
Fire resistance Retards the burning action of fire or flame. Achieved by adding fire retardents to the compound.
Friction The resistance to motion due to the contact of surfaces
Gauge The thickness of a belt or its individual elements.
Gouging The effect of sharp heavy material falling onto a conveyor belt cover to loosen or tear out pieces of the cover.
Gravity take-up A mechanical system that adjusts for the stretch or shrinking of a conveyor belt automatically by a weighted pulley in the system.
Hardness Degree of resistance to indentation
Head pulley The pulley at the discharge end of the conveyor
Hooke's Law Hooke's law of elasticity states that if a force (F) is applied to an elastic spring, its extension is linearly proportional to its tensile stress σ and modulus of elasticity (E): ΔL = 1/E × F × L/A = 1/E × L × σ
Hysteresis loss A loss of mechanical energy due to successive deformation and relaxation, measured by the area between the deformation and relaxation stress-strain curves.
Idler A nonpowered roller supporting the belt
Impact A stroke of a body dropping on the belt
Impact idler A belt idler having a resilient roll covering, resilient molded elastomer rings, springs or other means of absorbing impact energy at the place where material falls onto the belt.
Impact resistance The relative ability of a conveyor belt assembly to absorb impact loading without damage to the belt. See also "transverse reinforcement".
Joint The connection of two belt ends
Kevlar A trademark for aramid
Lagging A smooth or embossed covering on a pulley to increase friction between belt and pulley.
LRR Low rolling resistance
Maximum tension The highest tension occurring in any portion of the belt under operating conditions
Mechanical fastener Any mechanical device used to join the ends of belting.
Modulus of elasticity The force divided by the percent elongation to cause the elongation.
Molded edge A solid rubber belt edge formed in a mold.
Nylon A trademark for polyamide.
Ozone cracking Cracks caused by exposure to an atmosphere containing ozone.
Overend discharge A discharge over the head of the conveyor
Payne effect Is observed under cyclic loading conditions with small strain amplitudes, and is manifest as a dependence of the viscoelastic storage modulus on the amplitude of the applied strain.
Permanent elongation Elongation permanently removed from belting when it is first used
Permeability Usually the quality or condition of allowing passage of air through a steel cord to identify the degree of rubberization.
Plastisol A suspension of a finely divided polymer (PVC) in a plasticizer.
Ply A layer of fabric in a belt.
Rating The minimum belt breaking strength (DIN) of a belt in Newtons per millimeter of belt width.
In the USA sometimes used as a term for the working tension.
Regenerative conveyor A conveyor for which the head is at a substantially lower altitude than the tail (downhill conveying), generating power.
Return idler Part of a conveyor's return run.
Safety factor A multiplier applied to the calculated maximum force to which a conveyor belt splice (as the weakest link in a conveyor belt) will be subjected. A factor of safety accounts for imperfections in materials, flaws in assembly, material degradation, and uncertainty in load estimates.
Note: In the USA usually the safety factor is related to the belt but not to the splice.
Screw take-up A take-up for a conveyor system in which movement of a pulley-bearing block is accomplished by means of a screw.
Self-extinguishing If set under fire the belt will generate gases that extinguish the fire.
Shelf storage life The period of time prior to use during which a product retains its intended performance capability. Important for (uncured) splicing material.
Shuttle conveyor A belt conveyor having overend discharge, the whole being mounted on a travelling carriage capable of being shuttled backwards and forwards.
Skim coat A layer of rubber material laid on a fabric but not forced into the weave. Normally laid on a frictioned fabric.
Skirt board In a conveyor system, the vertical or inclined plates located longitudinally and closely above the belt to confine the conveyed material.
Skiver Grinding equipment to bevel belt ends for an overlap splice.  There are sanding belt, drum and disk skivers in use.
Slab belting Belting made in wide widths and long lengths for later slitting into narrower widths and cutting into shorter lengths.
Slope belt A conveyor belt used to carry material along an inclined flight.
Snub pulley A non-driven pulley located close to the drive pulley to provide a greater arc of contact around the drive pulley.
Solid woven A single ply ("monoply") interwoven fabric.
Splice allowance Additional length required to make a splice.
Splicer A field splicing engineer.
Straight warp Made of high tenacy polyester fibres for the warp and weft polyamide yarns, both held together by a polyamide composite yarn.
Tail pulley The pulley near the loading end of the conveyor system
Take-up pulley A pulley which can move in space in order to maintain relatively constant tension.
Tensile member The fabric, cord and/or metal reinforcing section of a belt, as distinguished from the rubber cover.
Tension Stress on the belt tending to cause extension.
Tie gum A thin sheet of unvulcanized rubber inserted between plies in vulcanized repairs of splices.
Training idler An idler mounted on a mechanical device, actuated by the belt moving against it to make the belt run straight.
Transition distance The distance between the last fully troughed idler and the flat driving or discharge pulley.
Transverse reinforcement An additional layer of single polyamide cords in custom-made pitch and diameter for increased rip and impact resistance.
Tripper A device for discharging material from a belt.
Troughability The property of a belt that permits it to conform to the contour of troughing idlers.
Viscoelasticity The property of materials that exhibit both viscous and elastic characteristics when being deformed. Viscoelasticity is the result of the diffusion of atoms or molecules inside of an amorphous material.
Viscosity The resistance of a material to flow under stress.
Vulcanization An irreversible process during which a rubber compound, through a change in its chemical structure, becomes elastic. See more.
Vulcanizer A mobile curing machine for field splicing (also called press).
Warp The lengthwise yarns in a woven fabric.
Weft The crosswise yarns in a woven fabric.
Wrinkle An appearance usually resulting from curing with separation paper or cloth.
Young's modulus The stress per unit strain for elastic materials.