Jib
From RitchieWiki
A jib is the horizontal working arm of a crane that in some cases is extendable. As the working arm, the jib is attached to a boom that carries the load via a pulley system suspended from a trolley or wheeled carriage.[1] The trolley moves the load in and out from a central point on the jib.
The jib is also just one component of what is called the slewing unit that comprises a shorter horizontal working arm affixed with motors, electronics, and counterweights, as well as the operator cab.[2]
The jib became a major development in crane design during the Middle Ages when it was added as a horizontal arm attached to a boom that could pivot, permitting a fuller range of motion.[3]
