Folding Boom Cranes, also known as Knuckle Boom Cranes, Loader Cranes, Picker Cranes, or Articulating Cranes, are engineered to work in tight quarters. A HIAB Folding Boom Crane consists of two booms (Main Boom and Outer Boom), which are attached by knuckles that allow the entire boom structure to move in and out, just like the knuckles in a human finger. Along with 360° rotation, and hydraulic winch. This allows for Knuckle Boom Cranes to maneuver in tight areas where other cranes would not be able to operate. It also allows the crane to fold into a small size when transporting materials or squeezing into a small construction site. The mobility of a folding crane also allows an operator to lift the payload off of their own truck deck. A big advantage of Folding Boom Cranes is also being able to operate with overhead obstructions.
Previously, Folding Boom Cranes did not have the lifting capacity and reach of Stiff Boom Cranes. The modern Knuckle Boom Crane can often directly compete with the capabilities of other cranes. In the past if you wanted to have a reach of 70 feet into the air, you needed a stiff boom crane. This is no longer the case, as with the Folding Boom Cranes of today display some impressive specifications.