How it Works: Mobile Cranes

Cranes help us move heavy objects and have played an important role of the development of cities around the world. Cranes come is different shapes and sizes, but the one they share in common is moving a load from Point A to Point B quickly and safely. This two part series explains what mobile and stationary cranes are, and how they are used.

The most basic type of mobile crane consists of a truss or telescopic boom mounted on a mobile platform on road, rail, or water. They are also called conventional or hydraulic cranes.

1. Hydraulic Truck Cranes – The standard in mobile cranes, these cranes can lift thousands of pounds using hydraulics that rely on forces transmitted through oil pushing the boom’s pistons in opposite directions. Hydraulic truck cranes are essential to building major projects like bridges, buildings, airports, and roadways.

2. All Terrain Cranes – These cranes are multi-functional cranes driven on both smooth paved highways or off-road at speeds up to 40 mph. Liebherr developed them in 1981 out of a need for telescopic cranes in the construction of 3,100 miles of gas pipelines and pumping stations in Siberia. Typically all-wheel drive, all terrain cranes are powered by one or two engines, and feature hydraulically operated winches and a telescopic boom that can reach close to 200 feet and carry up to 130 tons on some models.

3. Rough Terrain Cranes – A type of hydraulic crane, these cranes are designed to operate specifically off-road on rough terrain thanks to their all-wheel drive capabilities and rubber tires. Rough terrain cranes are used for pick-and-carry operations like bridge-building, and large construction projects where high maneuverability and lifting capacity is needed. They are not typically allowed on public highways and must be transported to the work site by truck or lowboy.

4. Crawler Cranes – These cranes are a type of tracked mobile crane available with either telescopic or lattice booms. Because they are self-propelled they are able to move around a construction site and perform jobs without much set-up. They are very expensive to transport from site to site because of their large size and weight. Crawler crane’s tracks provide additional stability since they can operate without the use of outriggers.

5. Carry Deck Cranes – Smaller mobile cranes, carry deck cranes travel on four wheels and are capable of rotating their boom a full 360° (degrees). An American invention, carry deck cranes are designed to work in confined spaces and can transport the loads they pick up on the small built-in deck around their cab.