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Two guy derricks at a granite quarry. A derrick is a lifting device composed at minimum of one guyed mast, as in a gin pole, which may be articulated over a load by adjusting its guys. Most derricks have at least two components, either a guyed mast or self-supporting tower, and a boom hinged at its base to provide articulation, as in a stiffleg ...
American Crane Corporation is an American manufacturer of construction cranes based in Wilmington, North Carolina. It manufacturers lattice boom crawler cranes with capacities ranging from 50 to 275 tons. The American Crane Corporation was founded in 1882 as the Franklin Manufacturing Company, and in 1892 the name changed to American Hoist ...
The lower end is braced or set in a shallow hole and positioned so the upper end lies above the object to be lifted. The pole (also known as a mast, boom, or spar) is secured with three or more guys. These are manipulated to move the load laterally, [1] with up and down controlled by the pulley or block. In tower construction, a gin pole can ...
Chesapeake 1000 (formerly Sun 800) is a heavy lift sheerleg crane ship, owned by Donjon Marine Co., capable of lifting 1,000 short tons (890 long tons; 910 t). [1] [2] It is one of the largest boomable stiff-leg-derrick barges on the eastern seaboard of the United States. [a] [1] [2]
Racking board (#15) is the catwalk along the side of the derrick (usually about 35 or 40 feet above the "floor"). The monkey board is where the derrick man works while "tripping" pipe. Mud motor (not pictured) is a hydraulically powered device positioned just above the drill bit used to spin the bit independently from the rest of the drill string.
Usually jib arms are attached to a vertical mast or tower or sometimes to an inclined boom. In other jib-less designs such as derricks, the load is hung directly from a boom which is often anomalously called a jib. A camera jib or jib arm in cinematography is a small crane that holds nothing but the camera. [4]
In 1959 crane expert R.H.Neal, hydraulics specialist F.Taylor, and design director Bob Lester, integrated all three and modernized cranes. The Coles Hydra Speedcrane appeared in 1962, further modified with the 10-ton fully telescopic hydraulic boom in 1966, followed in 1968 by the 30-ton "Husky" military versions with four-wheel drive .
A level-luffing crane is a crane mechanism where the hook remains at the same level while luffing: moving the jib up and down, so as to move the hook inwards and outwards relative to the base. [ 1 ] Usually the description is only applied to those with a luffing jib that have some additional mechanism applied to keep the hook level when luffing.