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
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.
대표청구항▼
1. 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 sa
1. 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. 2. In a crane as defined in claim 1, and said hard pendant links comprising foldable links of ladder construction. 3. In a crane as defined in claim 2, and the second hard pendant link including a gooseneck terminal adapted to couple with the outer end of the third mast. 4. In a crane as defined in claim 1, and a collapsible tension element interconnecting said second and third masts whereby the third mast is caused to follow the second mast in rotation when the tension element is fully extended and the second hard pendant link is in contact with the third mast. 5. In a crane as defined in claim 4, and said collapsible tension element comprising a folding hard tension link. 6. In a crane as defined in claim 1, and centering guide means on the third mast to guide the second hard pendant link into supportive contact with the third mast. 7. In a crane as defined in claim 1, and a rigid adapter on the nose of the main boom extending beyond one side of the boom and carrying a pivot mounting element for the luffing jib. 8. In a crane as defined in claim 7, and a rest for the third mast on said adapter to support the third mast prior to contact of the second hard pendant link with the third mast. 9. In a crane as defined in claim 8, and a centering guide means for the third mast on said adapter and resisting lateral displacement of the third mast when the third mast is engaging said rest. 10. In a crane as defined in claim 7, and telescoping safety backstay means coupled between the luffing jib and said adapter. 11. In a crane as defined in claim 10, and a pivoted safety control lever and coacting control switch on said adapter, said lever having a connection with an element of the safety backstay means which moves when the safety backstay means is actively resisting swinging movement of said jib. 12. In a crane as defined in claim 10, and cradle means on the luffing jib for the support of the safety backstay means when the latter is uncoupled from said adapter and swung to a stored position on the base section of the luffing jib together with the first, second and third masts, folded hard pendant links and folded tension link in a compact transport array. 13. In a crane as defined in claim 1, and the first mast having a direct pivotal connection with the luffing jib near the pivot of the luffing jib and said second and third masts being pivotally connected with the first mast near the pivot of the first mast. 14. In a crane as defined in claim 13, and said third must being pivotally connected with said second mast near the pivot connection of the second mast with the first mast.
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이 특허를 인용한 특허 (19)
Watts, Samuel Casey; Harrington, Daniel L.; Schnieders, Dennis M., Adaptable boom extension for a mobile crane having a telescoping boom.
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