起重臂伸缩机构的英文

• boom telescoping device

• 起重臂:    jib loading boom; cargo boom ...
• 伸缩:    stretch out and draw back; e ...
• 机构:    mechanism
• 悬臂伸缩门式起重机:    gantry crane with retractable boom
• 起重臂:    arm of crane; cargo boom; cathead; elevating arm; erecting arm; erector arm; erector beam; gi et; gib arm; gibbet; jib boom; lift arm; lifting beam; loading boom; outrigger; shear leg