Built as a temporary tower or derrick and secured to the ground or affixed upon an intentionally built vehicle for this purpose, construction cranes typically lift and lower construction equipment and materials using cables and pulleys at job sites. The operator controls the construction crane either from a cab travelling along with the derrick, from a control station push button pendant or radio controls. Types of cranes serve different construction needs, including excavation and roadwork.
Basic and Telescopic
A bottom steel-hinged tower or platform provides the basic type of construction crane, lifting heavy equipment and materials to high and low places under construction using cables or hydraulic cylinders. The telescopic crane consists of tubes fitted inside one another for extending and retracting as needed for lifting and lowering by use of a hydraulic apparatus. Both cranes affix to mobile platforms attached on a rail, wheels or a caterpillar truck.
Balance and Mounted
Once called the balance crane, the modern tower crane typically provides the best combination of height and lifting capacity when affixed to the ground, making it ideal for use in tall building construction. Giving the most usable mobility at construction sites, cranes mounted on rubber tire trucks use vertical and horizontal outriggers for levelling and stabilising mounted cranes during lifting operations.
Mounted on an undercarriage with four rubber tires, the off-road construction crane contains a single engine powering the winch and the mobilised carriage. Unlike other cranes, the motor usually fits in the undercarriage assembly rather than the upper area where the crane sits. Extending vertically and horizontally, outriggers level and stabilise the crane when hoisting materials and machinery at construction sites.
Loading large equipment for delivery and removal at major construction projects by lifting heavy objects on and off trailers, the loader crane uses an articulated arm consisting of one or more joints enabling greater varieties of movement necessary at construction sites. Fitted to a trailer and operated hydraulically, the loader crane folds for smaller space storage when not in use.