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GLOSSARY OF TERMS Home | Maintenance | Safety | Tips | Glossary -A- | -B- | -C- | -D- | -E- | -F- | -G- | -H- | -I- | -L- | -M- | -P- | -R- | -S- | -T- | -U- | -V- | -X,Y,Z- |
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The technical terms used in this manual should be familiar to experienced conveyor maintenance personnel. However, in order to clarify terminology used and to ensure that technical terms have the same meaning for all concerned, the following glossary is provided for convenient reference. It covers that terminology used throughout the Material Handling Industry as it relates to conveyor systems and equipment, and their application, operation and maintenance.
Accumulation Conveyor: A powered roller conveyor that transports product and is capable of product accumulation in predetermined zones. The power to selected rollers in a zone is engaged or disengaged through sensing of product position and utilization of air or electronic logic.
Air Cylinder: A device for converting air pressure to linear motion.
Anti-Friction Bearings: A bearing that uses rolling elements, such as balls, rollers or needles as a carrying/load supporting surface.
BACK TO TOP Bare Faced Pulley: A pulley that directly contacts a surface of the conveyor belt with its metal face.
Bearing Block: The block or housing that contains or supports a bearing. Three types of bearing blocks are found in this system: pillow block, flange block and take-up.
Bed Section: The conveyor frame that supports the conveyor's belt, drive, end units, carrying surface/rollers, etc.
Belt, Conveyor: A power transmission and commodity carrying device consisting of a woven carcass of cotton, duck, fiber, or PVC bonded and coated with rubber or PVC. Belt is made endless by means of mechanical splice.
Belt Cover: A rubber or PVC coating applied to a conveyor belt to protect the belt carcass and/or provide special carrying capacities for the belt.
Belt Lacing: Any type of mechanical device for joining the two ends to a conveyor belt.
Belt Sag: Lack of tension or tautness in the conveyor belt that causes it to droop in areas between supporting members.
Belt Tension: The result of force applied to the conveyor belt that causes or tends to cause stress or stretching of the belt. All belt must be tensioned to some extent to provide proper driving force and tracking. Belt tension is also created in the operating conveyor as the result of pulling the product along the conveyor bed.
Belt Tracking: The path followed by the belt as it runs on the conveyor and around the conveyor pulleys. It also refers to the act of causing the belt to run centrally on the conveyor through the manipulation of tracking rollers (return rollers/idlers).
Belt Wrap: The amount of contact between a belt and a pulley, or roller, measured in degrees.
Brake: A friction device used to bring conveyor components to a controlled stop and/or prevent them from moving once stopped.
BACK TO TOP Center to Center Distance: The distance between two rotating devices that are connected by chain or belt.
Chain Pull: The force necessary to maintain the desired operating speed of a conveyor under a rated capacity load.
Chain Tension: The result of force applied to a chain that causes or tends to cause stress or tautness in the chain.
Chain Wrap: That portion of the chain that is in contact with a sprocket or idler wheel. Chain wrap is measured in degrees.
Clutch: A device used to engage or disengage a load from a power source. This typically enables output control of a power source (such as a motor) without having to turn the motor on and off.
Clutch/Brake: A coupling device normally mounted between a motor and a gearbox providing the benefits of a clutch as well as braking capabilities. This arrangement allows a conveyor to be stopped without having to stop its motor which will improve the life of the motor.
Coefficient of Friction: A number expressing the amount of resistance to relative motion between two bodies in contact and dependent upon the physical characteristics of the contact surfaces of those bodies.
Controls: An arrangement of devices for starting, stopping or actuating conveyor components in a desired manner. These controls could be manual, electrical, hydraulic or pneumatic.
Crown Pulley: A pulley having a face that is slightly tapered from the center to the ends, so that its diameter at the center is greater than at its ends. Used to assist in belt tracking.
BACK TO TOP Diverter: A device used to change direction of an object. This device could be a pusher, deflector arm or wheel type device. Pushers and wheel type devices are used to sort commodity into desired lines from a main line, while deflectors are used to both sort and merge commodity.
Drive: A device consisting of a motor, gearbox, pulley and power transmission components used to provide the motive power to the conveyor.
Drive Chain: The chain used to transmit power from the motor/gearbox to the drive pulley or rollers.
Drive Pulley: The pulley that is connected to the drive gearbox by the drive chain and sprockets transmitting the rotational force provided by the arrangement to the conveyor belt. Driving force to the conveyor belt is provided by the amount of belt wrap on the drive pulley and the vulcanized lagging provided on the pulley.
Drive Sprocket: The sprockets used in the power transmission arrangement found in the conveyor drive unit. The sprocket sizes are selected to provide some mechanical advantage and give the desired conveyor speed from a given out-put RPM of the gear box.
BACK TO TOP Effective Belt Tension: The amount of force, expressed in pounds, transmitted to the conveyor belt by the drive pulley as related directly to the amount of live and dead load on the belt.
Flow Control: An air metering device used to control the speed of an air cylinder. Usually metering the air in one direction only, allowing full flow in the opposite direction.
FPM: Feet Per Minute. Use in reference to conveyor speed.
Frame: A structure supporting the machinery components of a conveyor.
Friction: Resistance to relative motion between two bodies in contact caused by the surface characteristics of the bodies at the point or area of contact, and the contact pressure.
Friction Surface: An anti-slip surface. The carrying surface of a conveyor belt that is specially prepared to give increased traction.
BACK TO TOP Gearbox: A mechanical device used to change the rotational velocity and/or direction of a mechanical power supply. This is usually accomplished through some type of gear train or enclosed in a single housing.
Gearmotor: An arrangement of an electric motor and a gearbox in one housing or connected by means of a "C" face mounting or other coupling method to form a single unit.
Gravity Roller Conveyor: A series of rollers supported in a frame over which objects are advanced by gravity. Rollers are not powered by an outside force.
Head Pulley: A pulley used at the terminal end of the conveyor toward which the commodity is being conveyed.
Head End: The end of the conveyor toward which the commodity is being conveyed.
Horsepower (HP): A standard unit of power equal to a rate of 33,000 foot-pounds of work per minute. Used to rate motors and gearmotors used on conveyor drives.
Idler Sprocket: An unpowered sprocket that supports, guides and/or changes the direction of a chain. Usually mounted on a shaft that in turn is supported by a bearing. In some cases the idler sprocket has internal bearings or bushings of its own.
Incline/Decline Belt Conveyor: A belt conveyor that transports commodity up a slope. Belting is usually special with a rough surface to increase friction preventing the commodity from sliding back down the conveyor. When angle becomes excessive a cleated belt is used.
BACK TO TOP Labyrinth Seal: An intricate combination of metal discs and cups designed to prevent foreign matter from entering balls, rollers or needles of a bearing unit and to retain lubricant in that unit.
Lagged Pulley: A pulley to which a rubber or other similar surface has been attached to increase the friction between a drive pulley and the conveyor belt.
Level Belt Conveyor: A belt conveyor where the carrying surface is level or nearly level (horizontal).
Limit Switch: An electrical device with a lever arm, plunger or other mechanical means of actuating an electrical switch by which the movement of conveyor components or commodity is being controlled or sensed.
Link, Chain: A chain unit of one pitch length.
Magnetic Brake: A brake usually mounted on the motor shaft which is disengaged by applying current to it and engaged when the electric current is cut off or fails. Used as a fail safe device where the movement of the conveyor or device after it is suppose to stop could cause damage to the commodity being handled, to the conveyor itself or danger to personnel around the conveyor.
BACK TO TOP Pitch: In chain, the distance between the centers of two successive chain pins.
Pitch Diameter: The effective diameter of a sheave, pulley or sprocket. The length of a chord passing through the center of the circle formed by the working circumference.
Power Transmission Belt: A belt that transmits power or motion from one rotating part to another.
Power Transmission Parts: Those parts or components by which power produced by the motor or gearmotor is conducted and applied to run the drive pulley of a conveyor.
Pulley: Consist of a steel tube with end plates, taper lock mounting hubs and bushings, and a steel shaft. Used for drive pulleys, end pulleys and take-up pulleys. Note that only the drive pulleys are lagged.
BACK TO TOP Reduction Ratio: With respect to gearboxes it is the relationship between the number of RPM's applied to the input shaft and the number of RPM's transmitted to the output shaft. Usually the output RPM is assigned the value of 1 and the input RPM is expressed in relation to that value.
Right Angle Reducer (Gearbox): A gear reduction unit in which the output shaft is arranged at an angle of 90 degrees with respect to the input shaft. Power transmission within the unit is accomplished through a set of worm gears.
Roller: Consists of a steel tube with bearing pressed or swaged in at both ends, and a spring loaded steel hex shaft passing through the inter race of the bearing. Size of the roller, shaft and the type of bearing used is dependent upon the type of application.
Roller, Carrying: A roller with a minimum diameter of 1.9 inches used to support the commodity being conveyed or the belt carrying the commodity. For powered conveyors these rollers have grease packed bearings. For gravity conveyors these rollers have a bearing that is lightly oiled.
Roller, Return/Idler: A roller with a minimum diameter of 1.9 inches used to support the conveyor belt on the underside of the conveyor. Can be used as a snub roller to change belt direction up to 10 degrees.
Roller, Snub: A roller with a minimum diameter of 2.12 inches used to support conveyor belt at points where a change in the direction of that belt is made. These rollers have a higher load rating than return/idler rollers.
Roller, Take-up: A roller with a minimum diameter of 2.5 inches and mounted in adjustable clips to allow take-up of belt sag. Roller has a belt pull capacity of 1,000 pounds and usually has a belt wrap of 180 degrees.
RPM: Revolutions per minute. The number of complete revolutions accomplished by a shaft or other rotating component in the period of one minute.
Run Out: A condition evidenced by the failure of the conveyor belt to run centrally on the conveyor structure.
BACK TO TOP Screw Take-up: A device that utilizes a pulley or roller in contact with the conveyor belt to apply tension or stress to the belt. The position of the take-up pulley or roller, that determines the degree of the tension imparted, is controlled by means of screws.
Slider Bed: A type of belt conveyor that utilizes a smooth sheet metal surface to support the conveyor belt and the commodity on it.
Snub Pulley: A pulley that is used to change the direction of the return belt or guide the conveyor belt to increase the amount of belt wrap on a drive or end pulley. Usually used when the capacity of a snub roll is exceeded by the belt pull at the location.
Solenoid Valve: A pneumatic valve operated by an electrical solenoid. It may be a single solenoid that requires a constant electrical signal to operate and returns to a home position when that signal is removed. Or, it can be a double solenoid that requires a momentary electrical signal each time the valve position is to be changed.
Stator: A stationary part about which a rotor revolves. The stationary member of an AC electric motor.
BACK TO TOP Tail Pulley: A pulley used at the terminal end of the conveyor that the commodity is being conveyed away from.
Tail End Section: The end of the conveyor that receives commodity from adjacent conveyors that the commodity is being conveyed away from.
Take-up Device: The arrangement of parts that applies tension to the conveyor belt, consisting of a take-up pulley or roller and a means for adjusting its position to create longitudinal stress in the belt.
Torque: The force applied to produce rotation.
Ultimate Strength: As applied to chain, the total tensile force, in pounds, that must be applied to cause failure under stress.
V-Belt: A drive belt having a trapezoidal cross section for operation degrees over grooved sheaves. Its shape permits wedging contact between belt sides and grooves walls for transmission of power.
Zones: Refers to the individual areas of an accumulation conveyor where the driving power is engaged and disengaged.
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