Glossary of Crane and Rigging Terms

Crane Industry TermsMany terms are used by crane operators which refer to crane function, assembly, operation andmaintenance. The following glossary provides a list and brief definition of fundamental terms used in thecrane industry.AccumulatorA container in which fluid is stored under pressure as a source of hydraulicenergy.AnnuallyOnce a year.Anti-Two BlockSystemA system of electromechanical devices used to prevent the crane operatorfrom two blocking the crane. See Two Block.Audio/VisualWarning System1. Alarm device that signals the operator of low engine oil pressure, highengine coolant temperature and high hydraulic oil and transmission oiltemperature.2. Device utilizing buzzer and/or lights as a signal of approaching two blockand/ or overload condition. See Rated Capacity Indicator.Auxiliary LiftingSheaveA unit which connects to the boom head and is used for reeving winch rope fora second hoist line. Also know as an Auxiliary Boom Head or Rooster Sheave.Backward StabilityResistance to overturning of the crane in rearward direction.BailA frame equipped with sheaves and connected to the gantry. The bail is usedin conjunction with the boom hoist drum and bridle to alter the crane's boomangle.Base SectionThe lower most section of a lattice boom or luffing jib.Basic BoomLattice boom attachment made up of only the base and top sections of theboom.Basic JibJib attachment made up of only the base and top section of the jib.Boom AngleThe angle above or below horizontal of the longitudinal axis of the boom.Boom AngleIndicatorAn accessory which measures the angle of the boom relative to horizontal.Boom ChordA main corner structural member of a boom.Boom FootBase of boom where it attaches to the upper revolving frame.v1.0 March 8, 20172

Boom HoistRope drum and its drive, or other mechanism, for controlling the angle of alattice boom crane.Boom LengthThe distance along a straight line through the centreline of the boom foot pinto the centreline of the boom head sheave shaft, measured along thelongitudinal axis of the boom.Boom SectionIndividual lattice structures which are pinned together to form the boomattachment. Crane lattice booms are usually in two basic sections, tip andbase. Such booms may be lengthened by insertion of one or more additionalextension sections.BridleA frame equipped with sheaves and connected to the boom by stationaryropes called pendants. The bridle is used in conjunction with the boom hoistdrum and bail to alter the crane's boom angle.CantileverAny unsupported boom or jib section that projects beyond the supportingpoint.Capacity ChartA chart for the crane which gives rated lifting capacities for the crane underdifferent load conditions and setups. Capacity charts are found on the crane orin the Crane Rating Manual.CarbodyThe crawler carrier upon which the revolving upper frame is mounted.CarrierThe portion of the crane located below the turntable bearing.CavitationA condition where air is induced into a cavity, line, or chamber normally filledwith oil. This condition can cause damage to pumps, cylinders, valves, etc.Check ValveA valve which permits flow in one direction only.ChordA main corner structural member of a lattice boom section.Clamshell BucketA device consisting of two or more similar scoops hinged together and usedfor digging and moving material.Closing LineThe rope reeved from hoist drum to control closing of clamshell bucket.ClutchA friction, electromagnetic, hydraulic, or pneumatic device for engagement ordisengagement of power.Concrete BucketBucket for handling wet concrete, usually handled on lifting crane for hoistingto dumping location.CounterweightWeight used to supplement the weight of the crane in providing stability forlifting loads.Cracking PressureThe pressure at which a pressure actuated valve begins to open to allow flow.v1.0 March 8, 20173

CylinderA device which converts fluid power into mechanical force and motion. Itusually consists of a moveable element such as a piston and a piston rod,which operates within a cylindrical bore.CylinderA device which converts fluid power into mechanical force and motion. Itusually consists of a moveable element such as a piston and piston rod, whichoperates within a cylindrical bore.DerrickingOperation of changing boom angle in a vertical plane. See Boom Hoist.DraglineMachines with dragline attachments are generally used to excavate materialfrom below the grade on which the machine is placed. A dragline bucket isloaded by the drag rope pulling it toward the machine, it is lifted and carriedby the hoist rope reeved over the boom point sheave, and is balanced by thedump rope interconnecting the drag and hoist ropes.Drum RotationIndicatorA device that is used to indicate winch drum motion and can also be used tomonitor speed.Extension (Boom orJib)Sections of the boom or jib which come in various lengths and are used toincrease the overall length of the basic boom or jib.FilterA device which functions to remove insoluble contaminants from a fluid by aporous media.ForceAny cause which tends to produce or modify motion. In hydraulics, total forceis expressed by the product of pressure (P) and the area of the surface (A) onwhich the pressure acts (Force P X A).FrameStructure on which either upper or carrier machinery is attached.Free-FallLowering of the hook and or load without using power. The motion is causedby gravity and must be controlled by a brake.FrictionThe property which tends to resist the relative motion of one surface incontact with another surface. It always exerts a "Drag" in the directionopposite of the motion, thus consumes power.Function Limiter(Function Lockout,Hydraulic Cutouts)Devices incorporated into the anti—two block system or rated capacityindicator system which will disable the crane function of winch up, telescopeout and or boom down (as applicable) as two block or overload situationsapproach.GradeablityThe slope which a machine can climb expressed as a percentage (45 equals100% slope).Ground PressureWeight of machine divided by the area of the surface directly supporting themachine.v1.0 March 8, 20174

HoistFunction of lifting and lowering the loads.Hoist DrumA rotating cylindrical spool with side flanges used to wrap the winch ropeduring the raising and lowering of the load with the winch.Hoist RopeThe wire rope used to reeve the winch and the attachments for lifting loads.Hook BlockBlock with hook attached used in lifting service. It may have a single sheave fortwo or three part line, or multiple sheaves for four or more parts of line.House AssemblyThe housing which covers the machinery mounted on the upper revolvingframe.Hydraulic Reservoir(Sump Tank)The storage tank for hydraulic fluid.Idler RollerRollers of track mechanism which are not power driven but are used tomaintain proper tension on the track.JibA pendant supported extension attached to the boom or fly head to provideadded boom length for handling specified loads. The jib may be in line with theboom or offset.Lattice BoomLattice structure consisting of multiple sections, pinned together to a specificlength and their support system.Lattice BoomBoom of open construction with angle or tubular lacing between main cornermembers (chords) in the form of a truss.Lifting CapacityThe rated load for any given load radius and boom angle under specifiedoperating conditions and machine configurations.Line PullThe rope pull generated off a rope drum or lagging at a specified pitchdiameter.Line SpeedThe feet per minute that a load can be raised or lowered.Live MastFrame hinged at or near the boom foot and extending above the cab for use inconnection with supporting a boom. Head of mast is usually supported andraised or lowered by the boom hoist ropes.Load IndicatorA device for measuring and displaying the net load being lifted.Load LineAnother term for "Hoist Rope". In lifting crane service it refers to the mainhoist. The secondary hoist is referred to as a "Whip Line".Load MomentIndicatorSee Rated Load Indicator.v1.0 March 8, 20175

Load MomentLimiter (LML)A device which aids the operator by automatically sensing the overturningmoment on the crane, i.e. load X radius. It compares this lifting condition tothe crane's rated capacity, provides an audible visual signal when the loadingconditions approach the rated capacity, and when the rated capacity isreached and/or exceeded, it limits crane functions that would result in anoverload condition.Load radiusThe horizontal distance from the centreline of rotation of the upper to thecentre of gravity of the suspended load.Luffing JibA crane attachment adaptable to a crane boom. The luffing jib can be raised orlowered from the operator’s cab while the main boom is stationary. Theluffing jib allows the crane to be set up close to a high building or structureand place an object on the roof of a building while maintaining close proximityto the building.MatSupport, usually of timber or wire construction, for supporting pontoons ortracks on soft surfaces to add stability and or distribute machine loads (reduceground pressure).MidpointSuspensionWire rope pendants used to support the centre portion of a long lattice boomwhen it is being raised from a horizontal position.Motor (Hydraulic)A rotary motion device which changes hydraulic energy into mechanicalenergy.Offset FlyA hydraulic crane fly section that is capable of being pinned at different angles.Oil CoolerA heat exchanger used to remove heat from the hydraulic or transmissionfluid.Operational AidAn accessory that provides information to facilitate operation of a crane orthat takes control of particular crane functions without action of the operatorwhen a limiting condition is sensed.Operator's Cab(Upper Cab)A housing which covers the operator's station.OutriggerAn extendable supporting device used to level the crane and increase stability.Outrigger BeamThe part of the outrigger which extends horizontally and acts as the supportfor the outrigger jack.Outrigger JackThe hydraulic cylinder on the outrigger beam which extends vertically to raiseand lower the crane for leveling.v1.0 March 8, 20176

Pawl (dog)A pivoting locking lever which will permit movement in only one direction.Movement in the opposite direction can be achieved only by manuallyreleasing the mechanism.PendantA supporting rope, which maintains a constant distance between its points ofattachment.PeriodicTime intervals usually determined by crane manufacturer when craneinspections are required.Pick and CarryThe crane operation of lifting a load and traveling with it suspended.Pilot PressureHydraulic pressure used to actuate or control hydraulic components.PinionThe small gear in a gear train which drives the other gears.Pitch DiameterRoot diameter of drum, lagging, or sheave, plus the diameter of the rope.PlanetaryA set of gears used to either speed up or slow down the input or the output togain speed or power whichever is applicable.PontoonThe support which attaches to the outrigger jack to increase the supportingarea.Power Take-Off(PTO)Device used for the transfer or transmission of engine power to the operatingfunctions of the crane.PressureForce per unit of area usually expressed in pounds per square inch (psi) orKilopascals (kPa).Pump (Hydraulic)A device which converts mechanical force and motion into hydraulic fluid flow.RadiusThe horizontal distance from the centerline of rotation of the crane, with noload, to the centre of gravity of the hook or suspended load.Rated CapacityIndicator (RatedLoad Indicator)A device that automatically monitors radius, load weight, and load rating andwarns the crane operator of an overload condition.Rated CapacityLimiter (RCL)A device that automatically monitors radius, load weight, and load rating andprevents movements of the crane that would result in an overload condition.ReevingPassing of ropes over pulleys and or sheaves.Relief ValveA pressure operated valve which by—passes pump delivery to the reservoir,limiting system pressure to a predetermined maximum value.ReservoirA container for storage of fluid in a fluid power system.v1.0 March 8, 20177

ShallThe word shall is to be understood as mandatory.Side FrameSupporting structure of the track mechanism. Side frames are attached to thecrawler carbody and may be extendable.SprocketThe driving element of the track mechanism. Receiving power through thedrive mechanism, the sprocket meshes with the track to travel the crawler.Swing (Slew)The rotation of the upper portion of the crane.Swing BrakeA brake which is used to resist the rotation of the upper during normal,stationary crane operations.Swing LockA mechanical lock that engages the upper with the lower of the crane. Theswing lock is used during a pick & carry operation (moving loads on site).Swing MotorHydraulic device which uses a planetary to rotate the upper on the carrier.TailswingThe distance from the centerline of rotation of the upper frame to theextreme rear swing arc of the counterweight.Third DrumA third hoist drum, in addition to two main hoist drums, often used in piledriving.Tip SectionThe outermost section of a boom. This section contains the sheave/sheavesfor reeving hoist lines.TorqueTurning or twisting force usually measured in foot-pounds (ft-lb) or Newtonmeters (Nm).Track RollerRollers of track mechanism which are not power driven, but are used tosupport the tread member and guide the track along the ground.Tubular JibMultiple section lattice extensions supported by pendants and attached to themain boom head.Turntable BearingA large bearing which attaches the upper to the carrier allowing the upper torotate on the carrier.Two BlockThe situation when the crane's hook block or hook ball contacts theattachment's head machinery.Two Block WarningSystemA system of electromechanical devices used to warn the crane operator ofimpending two block condition, also known as an Anti-two block system.UpperThe portion