CRANE: Facts & Figures Crane

The crane is a construction devise comprised of an arm, a winch, and a wire rope to create mechanical advantage and lift heavy objects. The arm may be hydraulically controlled and connected to a pivot point, or may consist of a vertical mast and a horizontal boom. Many different types of cranes exist, each tailored for a specific purpose, but they all work on the same general principles, particularly leverage.

Cranes may be thought of as the oldest of heavy-equipment machines, having been invented by the Ancient Greeks for the building of temples. Those cranes, right up until the Industrial Revolution, utilized human or animal power to turn the winch or move the crane, though sometimes they could be connected to a water or wind mill. The first mechanically powered cranes utilized steam engines in the late 18th or early 19th Centuries. Modern cranes are powered by either electric or internal combustion engines, and use hydraulics to create even more lifting power.

There are many types of cranes. The one seen most obviously along the skyline is the tower crane, which has a fixed base and is constructed on site and dismantled once a project is complete. These cranes employ a counter balance on the short end of the boom, while the long end does the lifting. Because of their height and their slender base, they must be engineered to withstand forces that would cause them to tip, and are often braced by the very structure they are building. Truck mounted mobile cranes , known as boom trucks, generally employ a telescopic crane mechanism, allowing them to minimize their size for travel to and from job sites. Floating cranes are constructed upon pontoons, and are used mainly in the construction of bridges and ports, though they are sometimes also used to move awkward loads off of ships, and in salvage operations. Some floating cranes have lift capacities of 10,000 tonnes.

Large construction companies may have several cranes among their heavy equipment. For companies which are not regularly using cranes on their projects, many industrial equipment rental stores exist. Rental prices run at about $4000 per week or $11,000 per month for a 5-ton boom truck with a 110-foot reach, while a taller Potain self-erecting crane may run upwards of $8500 per month, though rentals of these are often for a minimum of three months.

Source : heavyequipment.com