Key Terms

Boom

A boom is a long structure that supports an upper hoisting tackle of a crane or derrick. In general, the boom's length and angle can vary; this allows for increased height and reach while lifting loads. There are several categories of booms, such as cantilevered and articulating.

Please note that if a tower crane's boom is fixed, then it is called a jib. If it can move up and down, then it is a boom.

Brake

A brake is a device used for slowing or stopping motion by use of friction or power. Cranes, cranes, derricks, and hoists typically use the following types of brakes:

• Drag brake: Provides a slowing force without external control
• Holding brake: Prevents motion when the equipment's power is off
• Control brake: Controls crane motor speed when in an overhauling condition

Bridge

A bridge is the part of the crane that carries the trolley. It consists of girders, trucks, end ties and footwalks. "Bridge travel" is the term used to describe crane movement.

Cab

The cab is the operator's compartment on a crane.

Crane

A crane lifts and lowers a load and moves it horizontally, with the hoisting mechanism an integral part of the machine. Cranes can be fixed or mobile. They can be driven manually or by power. There are many types of cranes, many of which will be mentioned in this course.

Derrick

A derrick consists of a mast (or similar structure) held at the head by guys or braces, with or without a boom, for use with a hoisting mechanism and operating ropes. There are many types of derricks.

Consult 29 CFR §1910 for a list of derrick types.

Gantry

A gantry is a bridge-like, overhead structure with a platform that supports equipment (such as a crane).

Hoist

A hoist is part of a crane that exerts a force for lifting or lowering. It can lift and lower loads by winding a line onto or off a drum.

Load

A load is what is hoisted. It also refers to the load-attaching equipment (for example, the ropes and slings).

Lockout/Tagout

"Lockout-tagout" or "lock and tag" is a safety procedure used to ensure that dangerous machines are properly shut off and locked prior to maintenance or repair work. The machines cannot be used until the lock and tag are removed.

Outriggers

Outriggers suspend a working platform above work, storage, or rigging locations.

Rated Capacity

Rated capacity (also called "working load limit") is the maximum working load permitted for the equipment. A rated capacity limiter is a system to help the operator recognize signs of equipment overturn. A rated capacity indicator may have bells, lights, or buzzers.

Switches and Stops

• A stop is a device that limits the travel of a trolley or crane bridge. It typically attaches to a fixed structure.
• An emergency stop switch either manually or automatically stops power to the regular operating controls.
• A limit switch is operated by some part or motion of a power-driven machine or equipment. It changes the electric circuit of the machine or equipment.
• A main switch is a switch that controls the entire power supply to the crane.
• A master switch is a switch that controls the operations of remotely operated devices such as contactors or relays.

To learn more about Crane, Derrick & Hoist visit our Crane, Derrick & Hoist Safety Online Training web page.