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A jib or jib arm is the horizontal or near-horizontal beam used in many types of crane to support the load clear of the main support. [1] [2] An archaic spelling is gib. [3] Usually jib arms are attached to a vertical mast or tower or sometimes to an inclined boom.
A level-luffing crane is a crane mechanism where the hook remains at the same level while luffing: moving the jib up and down, so as to move the hook inwards and outwards relative to the base. [ 1 ] Usually the description is only applied to those with a luffing jib that have some additional mechanism applied to keep the hook level when luffing.
The "hammerhead", or giant cantilever, crane is a fixed-jib crane consisting of a steel-braced tower on which revolves a large, horizontal, double cantilever; the forward part of this cantilever or jib carries the lifting trolley, the jib is extended backwards in order to form a support for the machinery and counterbalancing weight. In addition ...
Mammoet crane (red) set up in Nigg Energy Park, Scotland to load jacket foundations (yellow) for the Seagreen Offshore Wind Farm. A ring crane is a form of large construction crane with a luffing jib. It is distinguished by its slew pivot [i] being in the form of a ring-shaped track, rather than a narrow central spindle. The broad base this ...
The crane had three smaller hoists for lifting 10, 20 and 50 tons. The main hoist has two 125 tonne lifting units which could be coupled for a combined lift of 250 tonnes. The crane had a maximum jib tower height of 81.4 m. The crane is self-propelled with two propellers and floats on pontoons.
It was a luffing-jib tower crane manufactured by Favco that was 200 feet (61 m) tall at the time of the collapse. The accident occurred when workers were attaching a new steel collar to anchor it to the building at the 18th floor, as part of an operation to extend the crane upwards. [ 6 ]
In 2007, Tishman Construction Corporation of New York completed a row of steel columns at the perimeter of the construction site. Two tower crane bases were erected, each base containing a functioning luffing-jib tower crane. By the end of 2007, the tower's footings and foundations were nearly complete. [10]
Early French crane loading coal for a gasworks. A bulk-handling crane is one that, instead of a simple hook that can handle a range of slung loads, has an integral grab for lifting bulk cargoes such as coal, mineral ore etc. Where the grab is a two-piece hinged bucket, it is known as a shell grab or shell bucket. Working the grab requires extra ...