Glossary of Crane and Rigging Industry Terms

Crane Industry Terms

The crane and rigging industry is a complex and technical field that requires a thorough understanding of specialized terminology. To help professionals and enthusiasts navigate this language, we have put together an extensive crane and rigging industry terms glossary. This comprehensive resource is designed to provide a clear and concise explanation of the most important terms and concepts in the industry, from basic definitions to more advanced technical jargon.

Anti Two-Block System

Also: ATB
A safety device that detects when the hook of a crane is about to come into contact with the boom tip.

Assist Crane

A secondary crane that is used in the assembly/disassembly of a crane.

Attachment

A unit that is attached to a crane to perform specialized tasks. Some common types of crane attachments include booms, jibs, hoists, hooks, spreaders, counterweights, and more. Crane attachments are essential for the safe and efficient operation of cranes.

All-Terrain Crane

A type of mobile crane designed to be used on various terrains, including highways and rough terrains. All-terrain cranes typically have four-wheel drive and a hydraulically powered telescopic boom.

Auxiliary Lifting Sheave

Also: Auxiliary Boom Head, Rooster Sheave
A unit that connects to the boom head and is used for reeving winch rope for a second hoist line.

Bail

A piece of equipment that helps to control the angle of the crane's boom. It is an important part of the crane's safety system and helps to prevent accidents.

Base Section

Also: Butt Section, Boom Foot Section
The lowermost section of a lattice boom or luffing jib.

Basic Jib

A jib attachment that is made up of only the base and top sections of the jib.

Balance Arm

A large assembly that is mounted on the boom of the crane to help balance the weight of the load being lifted. When the load is lifted, the balance arm helps to keep the crane from tipping over.

Blocking

Also: Cribbing, Mat
Wood or other material used to support equipment and distribute the load to the ground.

Boom

A long arm that attaches to the crane’s cab and is the most basic part of a configuration used to lift heavy objects.

Boom Angle

The angle above or below the horizontal of the boom.

Boom Angle Indicator

An accessory that measures the angle of the boom relative to the horizontal.

Boom Chord

A main corner structural member of a lattice boom section.

Boom Hoist

Rope drum and its drive for controlling the angle of a lattice boom crane.

Boom Mast

Also: Live Mast
A frame hinged at or near the boom foot for use in connection with supporting a boom. The head of the mast is usually supported and raised or lowered by the boom hoist ropes.

Boom Section

Also: Boom Insert, Boom Extension
A segment of a crane boom used to extend the total length of the boom. Boom sections are typically made of steel and are connected to each other by pins or bolts.

Boom Tip

Also: Tip Section, Boom Head, Boom Point
The outermost end of the crane boom that holds the lifting sheave.

Boom Truck Crane

A type of crane featuring a rotating hydraulic boom crane mounted on a large flatbed. Boom truck cranes can be driven on most roads and therefore do not require transport. These cranes often have a lower max load capacity but are a highly versatile piece of equipment.

Bridle Assembly

A part of the boom suspension system used alongside a boom hoist drum to alter the crane’s boom angle. The bridle assembly is the connection point for the pendant lines and the boom hoist wire rope.

Cab

Also: Cage
The enclosure used to house the operator and controls used for controlling a crane.

Cantilever

Any unsupported boom or jib section that projects beyond the supporting point.

Carbody

Also: Lower Frame
The crawler carrier upon which the revolving upper frame is mounted.

Carrier

The portion of the crane located below the turntable bearing.

Clearance

The distance from any part of a crane to the nearest point of an obstruction.

Counterweight

Additional weight added to a crane to provide balance and stability for lifting loads. The use of counterweights increases the overall lifting capacity of a crane.

Crawler Crane

A type of crane that has a cab mounted onto a crawler track undercarriage. These cranes are best suited for long-term work on jobsites demanding heavy load lifts and long reaches.

Drum Rotation Indicator

A device that is used by an operator to monitor drum winch rotation and the rate of movement.

Fall Zone

The area wherein hoisted materials could reasonably fall in the event of an accident.

Fixed Jib

A type of jib that is added to the end of a boom to extend its total reach. A fixed jib is manually configured during assembly with a static (or fixed) working angle based on lifting requirements.

Free-Fall

Lowering of the hook and or load without using power. The motion is caused by gravity and must be controlled by a brake.

Gradeability

The measure of incline a crane has the ability to climb up or down. A 45° angle represents 100% gradeability.

Ground Bearing Capacity

A pressure measurement reflecting the ability of the supporting soil below a crane to bear its load without producing a failure.

Ground Bearing Pressure

The amount of force exerted by a crane at its points of contact with the ground divided by the total surface area of those contact points.

Hoisting

The function of lifting and lowering a load.

Hoist Drum

A rotating cylindrical spool that extra winch rope is wrapped around during the raising of a load with the winch. Winch rope is released from the hoist drum during the lowering of a load.

Hook Ball

Also: Headache Ball
A type of lifting hook with a spherical or hemispherical head that is designed to prevent the load from swinging. The hook ball is attached to the crane's hoist line.

Hook Block

Also: Crane Block
A type of lifting hook with a varying number of sheaves that allows the hoist rope to reeve through it and multiply the total lifting force of the wire rope while staying with its lift rating.

Hydraulic Crane

A type of crane that uses hydraulics to raise and extend its boom as opposed to winches and hoist rope.

Hydraulic Truck Crane

A type of crane that uses a telescoping hydraulic boom to hoist loads. These cranes are set on wheels which gives them great mobility. HTCs are similar to a Boom Truck Crane but provide great stability and lifting capacity.

Idler Roller

Rollers used on the track system of a crane to maintain proper tensioning of the track.

Jib

A jib is used to increase the length of the boom of a mobile crane. Certain types of jibs can be used to simplify or make a specific lift scenario possible. On a tower crane, the jib is the horizontal arm that extends from the mast along which the trolly runs to position the hook block for lifting.

Lattice Boom

A type of boom that uses steel cross-member supports (typically in a W or V formation) to provide rigidity and strength for lifting heavy loads.

Lifting Capacity

The maximum weight that can be safely lifted. This capacity is calculated using a load chart and is affected by the load's radius, boom angle, and other operating and machine configurations.

Line Pull

The lesser of the winch's pulling force or the wire rope's maximum permissible load.

Line Speed

The pace, in feet per minute, at which a load is raised or lowered.

Load

The object being hoisted

Load Chart

Also: Capacity Chart
A chart for a crane which gives rated lifting capacities for the crane under different load conditions and setups. Load charts are often found on the crane or in the Crane Rating Manual.

Load Moment

The product of a load's force its load radius.

Load Moment Indicator (LMI)

Also: Rated Capacity Indicator (RCI)
A system that measures the length of the crane’s boom, the weight of the load, and the angle of the boom. This data is sent to the crane’s computer to calculate the crane’s load moment.

Load Moment Limiter (LML)

Also: Rated Capacity Limiter (RCL)
A device that notifies a crane operator and limits crane functionality when a crane's lifting conditions have reached or exceeded its rated capacity.

Load Radius

The distance between the load's center of gravity and the center of rotation of the crane.

Outrigger

An extendable supporting device used to level the crane and increase stability.

Pendant Line

A fixed length of wire rope or strand used to support the boom.

Pick and Carry

A crane operation involving lifting a load and traveling with it suspended.

Reeving

Passing of ropes over pulleys and/or sheaves.

Rough Terrain Crane

A type of mobile crane designed to be used in off-road conditions. It is typically mounted on a four-wheel drive chassis with oversized tires, which allows it to travel over uneven ground. Rough terrain cranes are also equipped with outriggers that can be extended to provide stability during lifts.

Side Pull

Lifting a load that is not located directly under the hoist. This is potentially dangerous lifting condition which may result in unexpected damage or dangerous results.

Spreader Bar

A device, often made of steel or aluminum, that is used to distribute the load of a lifted object over a wider area. Spreader bars are often used when lifting objects that are too wide, fragile, or require added stability over a single sling.

Swinging

Also: Slewing
The rotation of the upper portion of the crane.

Swing Brake

A brake used to resist the rotation of the upper during normal, stationary crane operations.

Swing Lock

A mechanical lock that engages the upper with the lower of the crane. The swing lock is used during a pick & carry operations.

Tailswing

The distance from the center of rotation of the upper frame to the extreme read swing arc of the counterweight.

Tagline

A rope or wire that is used to stabilize a load during lifting and lowering operations.

Telescopic Crawler Crane

Also: Telecrawler Crane
A type of crane that combines the strengths of a typical telescopic boom crane (extendable boom and good maneuverability) with the benefits of a crawler crane (superior stability and mobility).

Third Drum

A drum hoist added to a crawler crane, typically for the purpose of dragline or pile driving work.

Tower Crane

A type of stationary crane that is typically used in building construction. It consists of a vertical tower mast with a horizontal arm that can rotate. The arm is equipped with a hoist, which is used to lift and move loads.

Track Roller

Rollers for a crawler track that are used to support the track shoes and guide the track along the ground.

Track Shoe

A curved metal plate that is attached to the underside of a crane's crawler track. The track shoe helps distribute the crane's weight evenly and provides stability.

Travel

Moving of a crane from one location to another on a jobsite.

Wire Rope

Also: Hoist Rope, Load Line, Cable
The woven steel line used to reeve the winch and various attachments for the purpose of lifting loads.

Whipline

An auxiliary hoist rope system with a lower load capacity than is provided by the main hoist.