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US 4,383,616 AGranted
Luffing jib for construction crane
AssigneeKidde, Inc.
InventorsRussell L. Sterner, Reginald P. Whittingham
Life of this patent
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AssigneeKidde, Inc.
InventorsRussell L. Sterner, Reginald P. Whittingham
Estimating the term…
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.
In a crane, a main boom, a luffing jib pivotally mounted on the main boom, a pendant cable line for the support and control of the luffing jib connected with the luffing jib, first, second and third masts having corresponding inner ends pivotally connected with said luffing jib, cable means in said pendant cable line connected between said jib and said first mast, first and second hard pendant links in said pendant cable line, the first hard pendant link being connected between the first and second masts, the second pendant link having one end connected to the second mast, the opposite end of said second pendant link being connected to cable means in said pendant cable line including a bridle assembly, said opposite end of said second pendant link being separated from the third mast but moving into contact with the third mast when the luffing jib swings below a horizontal position and toward a near vertical stored position along said main boom, contact of the second hard pendant link with the third mast arresting movement of the pendant cable line toward said boom as said jib is approaching the stored position.
Dependencies are inferred from the claim text.