A workhorse in the construction industry, cranes tackle heavy-duty material handling tasks. Tower cranes can operate from fixed positions to raise, lower, and transport objects, and mobile cranes can move serious weight over rough terrain and transport objects around construction sites. This article details what the basic crane components look like and how they function so you can choose the best type of crane for your next project.
1. Floats, foundation, tracks, or wheels
Crane operators can use different types of cranes for hoisting and moving heavy loads. This piece of heavy equipment can work on tracks, wheels, floats, and concrete foundations. When choosing a crane, remember that what holds your crane up depends on where and how you want to use it.
Cranes have long been planted on barges or pontoons to dig for natural resources like oil. Floating cranes are often used on oil rigs and at ports.
Tower cranes are always secured in concrete foundations. Because tower cranes reach hundreds of feet in the air, they require a very stable base.
For outdoor jobs on soft ground, crane operators can work on mobile cranes set on tracks. Tracks have to be set into the smooth ground but they provide great stability over most terrains. Speed is sacrificed for this increased stability.
Mobile cranes, like the carry deck and telescopic cranes, are common on outdoor job sites. Their wheels give them excellent maneuverability, even on bumpy terrain.
Outriggers are stabilizing components, usually in the shape of the letter H, that support cranes by offsetting the load. Outriggers are often set at the base of wheeled cranes, such as carry deck and telescopic, and on uneven surfaces.
3. Main boom or mast
A mast or main boom is the supporting structure that is attached to the crane’s base and stretches to the machine’s highest height. Crane operators can extend their reach by adding a jib at the end of a boom on a mobile or all-terrain crane. However, tower cranes are built with jibs that sit on a horizontal turntable, and telescoping cranes contain their own telescoping sections used to extend their reach instead of a jib. The type of boom you use depends on the type of crane you need.
Hydraulic booms look like long poles that extend and bear most of the weight when moving loads. Ideal for compact sites and precise movements, hydraulic booms, which use hydraulic pressure to stretch, are most commonly found on telescopic and folding cranes.
The steel bars welded together in W or V shapes give lattice booms the look of trellises. This design distributes the weight of the load as well as the crane’s weight over the framework, increasing the amount that the crane can lift. Lattice booms, unlike their hydraulic cousins, are set at a fixed length.
Tower cranes have a fixed horizontal jib attached to the mast. Crane operators can add jibs onto mobile and all-terrain cranes as removable attachments to increase the machine’s reach and put distance between a load and the crane’s main support.
5. Operator’s cab
Crane operators control this heavy-duty machine from the operator’s cab. On tower cranes, operator cabins are located near the turntable. On cranes like the all-terrain crane and telescopic crane, crane operators work from the bottom of the heavy machine.
The turntable, or slewing unit, located near the top of the tower crane, allows it to rotate 360 degrees.
On tower cranes, counter-jibs hold the counterweights and balance the weight of the jib. The counter-jib sits behind the operator’s cab.
Counterweights balance the crane by offsetting the load. They sit across from the boom. The amount of counterweight required for each load is different, so the weights are removable and stackable depending on the load sizes.
9. Main winch and motors
Sheaves and wire ropes compose the pulley system that allows the crane to hoist and lower items. The main winch and motors operate this system and sit at the back of the counter jib.
10. Tower peak
The tower peak is the top end of the tower/mast. Its job is to support the jib and counter-jib.
The hoist moves along the bridge girder, a horizontal beam on a tower crane, from left to right. This allows the loads to move the length of the crane. The trolley is the mechanism that supports the hoist and wire rope.
The lifting mechanism, or hoist, is located on the tower crane’s horizontal beam. The hoist uses a hook to lift and lower loads vertically.
13. Main load line
Without the main load line, cranes could not lift heavy objects. For mobile cranes, the main load line is a cable that connects the hook block to the boom. On tower cranes, the main load lines are the wire ropes and sheaves that make up the pulley system, which allows the cranes to lift and lower heavy materials.
14. Hook block
The equipment used to connect loads to a crane, including a hook, bearings, sheaves, and pulleys, is housed in the hook block. The steel piece is heavy enough to hold enough tension on the wire rope when the crane isn’t attached to the lifting material.
How to choose a crane
You can choose from many types of cranes, but one crane works best for each type of project. Consider these factors before selecting a crane for your project:
- Consider the load weight and height needed. Cranes selection must factor in the lifting and height capacities and the horizontal distance the machine needs to cover for the project. Use the crane load chart to calculate the crane’s load capacity at different boom lengths.
- Assess the job-site terrain. The evenness and stability of the terrain at a job site determine whether a project requires a mobile or fixed crane. Plus, crane operators must consider the size and openness of the work area when choosing a crane.
- Check your budget. If you don’t need cranes often, consider renting the equipment rather than buying it. Evaluate your budget and logistics to make sure you factor in transportation and hiring operators, if necessary.
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Renting a crane
Determine the type of crane you need based on the load weight, height, and extension requirements of the project. You may consider renting a crane that suits your job’s needs.