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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.
In 1881, Stothert and Pitt constructed a horizontal jib crane for Sir John Coode's harbour building work on the Kowie River at Port Alfred in South Africa. [6] This was a rail-mounted steam crane, with a fixed horizontal jib carrying a movable trolley or 'crab'. The crane, including the steam plant, could slew on a central king post bearing ...
Jib lengths of up to 160 metres (520 ft) give a lifting radius of up to 100 m (330 ft). They also have a small footprint compared to gantry or Goliath cranes. The performance of super-heavy jib cranes is measured in tonne-metres, the product of weight and lifting radius, typically as much as 100,000 tonne-metres for large cranes. [8]
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.
A jib crane is a type of crane - not to be confused with a crane rigged with a jib to extend its main boom - where a horizontal member (jib or boom), supporting a moveable hoist, is fixed to a wall or to a floor-mounted pillar. Jib cranes are used in industrial premises and on military vehicles.
The crane was erected in 1903 at a cost of £3,352 by German firm Kohncke. [5] The yard was short-lived, lasting from 1899-1930, but saw significant use during the First World War when it built a number of ships for the Royal Navy. [7] The Beardmore Crane was demolished c. 1971. [8] [9]
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.
On March 15, 2008, a crane owned by New York Crane & Equipment collapsed during construction. Seven people were killed and 24 others were injured. [ 5 ] It was a luffing-jib tower crane manufactured by Favco that was 200 feet (61 m) tall at the time of the collapse.