A knuckle boom is a type of specialty crane equipped with a hinged boom. It is as an alternate to traditional straight-boom cranes for lifting and hoisting a variety of heavy materials. The knuckle boom crane is most often built into the bed of a truck, where it can be used to load or unload the vehicle. These cranes are also found on large marine vessels, where they are designed to lift smaller boats into or out of the water. These articulating cranes may also be used in lumber yards, warehouses, and other settings that handle heavy objects.
The knuckle boom crane is characterized by the design of its boom, which hinges in three places like a human finger. The base of the boom hinges up and down to change the angle of the boom. A hinge along the middle of the boom allows it to bend, and a third hinge near the end allows users to pick objects up using a hoist or hook. One or more of these boom sections may also telescope out to achieve greater reach. When the knuckle boom is in operation, it may feature a claw-like appearance, or that of a beckoning finger.
These cranes are most often used to load and unload a truck bed, and typically are a permanent, integral part of the vehicle. Their placement behind the driver makes it difficult to operate the knuckle boom from inside the vehicle. Instead, the operator steps outside to observe the loading or unloading process as he operates the crane. These machines may be equipped with a remote control or other remote operating system to maximize safety and efficiency. Many automatically fold themselves back up to fit compactly in a portion of the truck bed at the touch of a button.
Knuckle boom cranes offer many advantages to users in a large number of fields. Their articulating design allows them to maneuver objects in small spaces, and also makes them easy to transport in busy urban areas. The hinged boom enables operators to maintain a high level of control over materials, resulting in more accurate placement and fewer accidents.
One disadvantage associated with the knuckle boom is its limited lifting capacity compared to traditional straight-boom cranes. These machines are designed to hoist smaller loads, and don't offer the same power as a standard crane. The increased number of parts in a knuckle boom may also lead to increased maintenance and repairs compared to other types of hoisting systems.
