Claims
- 1. In a crane boom having a fly section carrying a nose block including a pair of parallel cross shafts supporting upper and lower sheaves, the improvement comprising a support base releasably coupled with the pair of cross shafts on the crane boom, said support base comprising a frame having spaced opposite side arms straddling the nose block of the crane boom and the arms having engaging elements at their ends releasably locked in engagement with the projecting shafts on opposite sides of the nose block, a jib structure including at least one extensible and retractable section, a separate hydraulic cylinder inside said jib structure operable to extend and retract said section, a framework carrying the jib structure and projecting from one end thereof near the base of the jib structure, said framework comprising a box-like frame having one corner thereof pivotally connected to the support base between said side arms and spaced from the longitudinal axis of the jib structure, an adapter element at the leading end of said jib structure adapted to be releasably coupled to a mating adapter element of various working devices, and hydraulic luffing cylinder means mounted on the support base and connected to a second corner of said box-like frame on one side of the support base in spaced relationship to the pivot axis of said box-like frame, whereby the jib can be pivoted through a very wide luffing angle.
- 2. In a crane boom as defined in claim 1, wherein said side arms include bifurcated anchors adapted to straddle the end portions of said pair of existing parallel shafts on said crane boom, and means to releasably lock the bifurcated anchors in engagement with said shafts.
- 3. In a crane boom as defined in claim 1, wherein the hydraulic luffing cylinder means comprises, a pair of hydraulic cylinders, and a pair of support members for the hydraulic cylinders on the support base in substantially the same planes occupied by the side arms and projecting beyond corresponding ends of the arms.
- 4. In a crane boom as defined in claim 2, wherein said means to releasably lock the bifurcated anchors comprises, tethered block elements engageable between the bifurcations of the anchors to retain the anchors engaged with said shafts, and tethered locking pins removably engaged with the bifurcations and blocks to retain the blocks in their operative positions relative to the shafts and anchors.
Parent Case Info
This is a division of application Ser. No. 310,768, filed Oct. 13, 1981, now U.S. Pat. No. 4,493,426, dated Jan. 15, 1985.
US Referenced Citations (11)
Foreign Referenced Citations (3)
Number |
Date |
Country |
2444580 |
Apr 1976 |
DEX |
2515562 |
Oct 1976 |
DEX |
1251578 |
Oct 1971 |
GBX |
Divisions (1)
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Number |
Date |
Country |
Parent |
310768 |
Oct 1981 |
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