Crane Types, Components, and Terminology
Crane Types, Components, and Terminology
This domain tests whether you can identify crane configurations and name the parts that affect capacity and control. Expect questions that pair a component with its function and distinguish gross capacity from allowable load.
Core rules
- Mobile crane families: lattice-boom crawler (high capacity, needs a prepared travel path), rough-terrain (site travel, outriggers), all-terrain/truck crane (road travel, outriggers), and boom truck. Tower cranes are fixed or climbing; overhead and gantry cranes run on rails.
- Capacity is controlled by radius, boom length, counterweight, outrigger beam extension, quadrant, and wire rope parts of line.
- The load moment indicator (LMI) or rated capacity limiter warns before overload; anti-two-block prevents the hook block from contacting the boom tip.
- Rated capacity is the chart value; gross load includes hook block, slings, and all below-the-hook devices.
Worked example: A chart gives 12,000 lb at 30 ft radius. Hook block 500 lb, slings and shackles 800 lb. Allowable payload = 12,000 − 500 − 800 = 10,700 lb. A 10,900 lb load is an overload even though it is below the chart number.
Traps
- Treating chart capacity as payload.
- Mixing radius from the boom pivot with radius from center of rotation; chart radius is from center of rotation.
- Ignoring jib, auxiliary head, or stowed attachment deductions.
- Assuming a crawler crane can travel with a load without a manufacturer travel chart.