Abstract: A multi-section crane boom is provided with a fly section and a jib section which may be erected and supported by a mast and pendants on the end of the boom to extend the effective length of the boom. When the fly section and jib section are not used they are stored on the boom, the fly section being supported alongside of and generally parallel to the boom and the jib section being supported in position below the fly section. The fly section can be mounted on the end of the boom alone while the jib section remains in stored position, or, alternatively, the fly section can be mounted on the boom and the jib section can be mounted on the outer end of the fly section. A pair of compact hook shaped resilient connectors serve as backstops which prevent the fly from pivoting in excess of 5.degree. upwardly past longitudinal of alignment with the boom axis when the boom is in a near vertical position.

Abstract: A telescopic boom includes at least two sections and a manual section is sections being extended and retracted by a single hydraulic ram. A first coupling selectively connects or releases the ram's cylinder case from the second boom section while a second coupling connects or releases the other end of the cylinder case to the manual section. The first coupling includes a crank for coupling and uncoupling the cylinder case and second section. The second coupling includes a retrieval pin movable into position for connecting the cylinder case to the manual section when retracting the manual section within the second section, and releasable lock mechanisms are provided to lock the manual section in extended position. The method of operating the boom includes the step of pivoting the boom to a near vertical position prior to extending the manual section relative to the second section.

Abstract: A multi-section crane boom is provided with a fly section and a jib section which may be erected and supported by a mast and pendants on the end of the boom to extend the effective length of the boom. When the fly section and jib section are not used they are stored on the boom, the fly section being supported alongside of and generally parallel to the boom and the jib section being supported in position below the fly section. The fly section can be mounted on the end of the boom alone while the jib section remains in stored position, or, alternatively, the fly section can be mounted on the boom and the jib section can be mounted on the outer end of the fly section. A pair of compact hook shaped resilient connectors serve as backstops which prevent the fly from pivoting in excess of 5.degree. upwardly past longitudinal of alignment with the boom axis when the boom is in a near vertical position.