Boom extension stowage system

摘要

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 DEG upwardly past longitudinal of alignment with the boom axis when the boom is in a near vertical position. The resilient connectors also permit easy attachment of the pendants when slack, and further act as shock absorbers during stowage of the fly and during pivotal erection of the jib relative to the fly in the event the components of the crane are improperly adjusted or the operator negligently operates the machine.