Truck Mounted Cranes

A crane mounted on a truck carrier provides the mobility for this type of crane.

TRuck Crane

Generally, these cranes are designed to be able to travel on streets and highways, eliminating the need for special equipment to transport a crane to the jobsite. When working on the jobsite, outriggers are extended horizontally from the chassis then down vertically to level and stabilize the crane while stationary and hoisting. Many truck cranes possess limited slow-travelling capability (just a few miles per hour) while suspending a load.

Great care must be taken not to swing the load sideways from the direction of travel, as most of the anti-tipping stability then lies in the strength and stiffness of the chassis suspension. Most cranes of this type also have moving counterweights for stabilization beyond that of the outriggers. Loads suspended directly over the rear remain more stable, as most of the weight of the truck crane itself then acts as a counterweight to the load. Factory-calculated charts (or electronic safeguards) are used by the crane operator to determine the maximum safe loads for stationary (outriggered) work as well as (on-rubber) loads and travelling speeds.

Truck cranes range in lifting capacity from about 8 tons to about 1200 tons.

In addition, new generation (over last 20 years or so) truck mounted cranes have eveolved drasticaly and are capable of handling loads in different and more efficient ways, their configuration is more complex and more safe.

Rough Terrain Crane

A crane mounted on an undercarriage with four rubber tires that is designed for pick-and-carry operations and for off-road and “rough terrain” applications. Outriggers that extend horizontally and vertically are used to level and stabilize the crane for hoisting.
These telescopic cranes are single-engine machines where the same engine is used for powering the undercarriage as is used for powering the crane, similar to a crawler crane. However, in a rough terrain crane, the engine is usually mounted in the undercarriage rather than in the upper, like the crawler crane.

All Terrain Cranes

A mobile crane which has the necessary equipment to travel with high speed on public roads/highways and on the job site in rough terrain with all wheel and crab steering. AT‘s combine the roadability of Truck-mounted Crane and the manoeuvrability of a Rough Terrain Crane.

AllTerrain

AT’s have 2-9 axles and are designed for lifting loads up to 1200 metric tons.

Allterrain Cranes are most common cranes nowdays.

Crawler Cranes

A crawler is a crane mounted on an undercarriage with a set of tracks (also called crawlers) that provide for the stability and mobility of the crane. Crawler cranes range in lifting capacity from about 40 US tons to 3500 US tons.

Crawler cranes have both advantages and disadvantages depending on their intended use. The main advantage of a crawler is that they can move around on site and then perform each lift with very little set-up, as the crane is stable on its tracks with no outriggers. In addition, a crawler crane is capable of traveling with a load. The main disadvantage of a crawler crane is that they are very heavy, and cannot easily be moved from one job site to the next without significant expense.

Typically, a large crawler must be disassembled and moved by trucks, rail cars or ships to be transported to its next location.

Tower Cranes

The tower crane is a modern form of balance crane. Fixed to the ground (and sometimes attached to the sides of structures as well), tower cranes often give the best combination of height and lifting capacity and are used in the construction of tall buildings.
The jib (colloquially, the ‘boom’) and counter-jib are mounted to the turntable, where the slewing bearing and slewing machinery are located. The counter-jib carries a counterweight, usually of concrete blocks, while the jib suspends the load from the trolley. The Hoist motor and transmissions are located on the mechanical deck on the counter-jib, while the trolley motor is located on the jib. The crane operator either sits in a cabin at the top of the tower or controls the crane by radio remote control from the ground. In the first case the operator’s cabin is most usually located at the top of the tower attached to the turntable, but can be mounted on the jib, or partway down the tower. The lifting hook is operated by using electric motors to manipulate wire rope cables through a system of sheaves.

In order to hook and unhook the loads, the operator usually works in conjunction with a signaller (known as a ‘rigger’ or ’swamper’). They are most often in radio contact, and always use hand signals. The rigger directs the schedule of lifts for the crane, and is responsible for the safety of the rigging and loads.

A tower crane is usually assembled by a telescopic jib (mobile) crane of greater reach (also see “self-erecting crane” below) and in the case of tower cranes that have risen while constructing very tall skyscrapers, a smaller crane (or derrick) will often be lifted to the roof of the completed tower to dismantle the tower crane afterwards.

It is often claimed that a large fraction of the tower cranes in the world are in use in Dubai. The exact percentage remains an open question.

Gantry Cranes

A gantry crane has a hoist in a fixed machinery house or on a trolley that runs horizontally along rails, usually fitted on a single beam (mono-girder) or two beams (twin-girder). The crane frame is supported on a gantry system with equalized beams and wheels that run on the gantry rail, usually perpendicular to the trolley travel direction.

These cranes come in all sizes, and some can move very heavy loads, particularly the extremely large examples used in shipyards or industrial installations. A special version is the container crane (or “Portainer” crane, named by the first manufacturer), designed for loading and unloading ship-borne containers at a port.

Overhead Cranes

Also known as a ’suspended crane’, this type of crane work very similar to a gantry crane but instead of the whole crane moving, only the hoist / trolley assembly moves in one direction along one or two fixed beams, often mounted along the side walls or on elevated columns in the assembly area of factory.

Some of these cranes can lift very heavy loads.