Jib attachment/detachment mechanism

摘要

A jib attachment/detachment mechanism to mount a jib on a boom head includes a guide mechanism including a guide roller and a guide support configured to guide engaging portions of a jib support to positions of engagement with shaft pins of a boom head when the jib support is pulled up with a wire by using a winch and to prevent change of a state of the wire pulled up by the winch when the jib support is rotated around the shaft pins by contracting a cylinder.