Luffing jib for construction crane

摘要

A massive crane luffing jib is held and loaded under compression atop the main crane boom such as a hydraulically extensible and retractable telescopic boom whose sections may be locked for safety. The luffing jib is pivoted to an adapter atop the boom to enable swinging the jib to a stowed position close to and along the front side of the boom. First, second and third masts are pivotally attached to the jib base section. The second and third masts are connected by foldable tension links. An upper foldable ladder in the pendant line between the point of the jib and bridle assembly forms a hard connection between the first and second masts. A lower foldable ladder including a gooseneck forms a hard connection between the second and third masts following automatic coupling of the gooseneck with the third mast after the tension link becomes fully extended. A safety backstop or stay connected between the luffing jib and the adapter on which it is mounted prevents rearward tipping over of the jib and activates a safety control switch operating mechanism. The several masts, tension links, folding ladders and backstays fold compactly onto the base section of the luffing jib for easy storage and transport without separation and misarrangement of parts. A bridle storage and lifting arrangement is also disclosed.