A gin pole is a mast supported by one or more guy-wires that uses a pulley or block and tackle mounted on its upper end to lift loads. 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 also be “jumped” up the completed sections of a tower to lift the higher sections into place.
The gin pole is derived from a gyn, and considered a form of derrick, called a standing derrick or pole derrick, [2] distinguished from sheers (or shear legs) by having a single boom rather than a two-legged one.
In addition to being used as simple lifting devices in field operations such as construction, logging, loading and unloading boats, and emergency repairs, gin poles are well suited to raising loads above structures too tall to reach with a crane, such as placing an antenna on top of a tower/steeple, and to lift segments of a tower on top of one-another during erection. When used to create a segmented tower, the gin pole can be detached, raised, and re-attached to the just-completed segment in order to lift the next. This process of jumping is repeated until the topmost portion of the tower is completed. They can also hold a person if strong enough (thus opening stage uses, such as in magic shows).
Gin poles are mounted on trucks as a primitive form of mobile crane, used in combination with a typically front-mounted winch for lifting and relocating loads, and in salvage operations in lieu of a more capable wrecker.
A block and tackle or only tackle is a system of two or more pulleys with a rope or cable threaded between them, usually used to lift heavy loads.
A crane is a machine used move materials both vertically and horizontally, utilizing a system of a boom, hoist, wire ropes or chains, and sheaves used for lifting and relocating heavy objects, typically within the swing of its boom. The device uses one or more simple machines - such as the lever and pulley - to create mechanical advantage to do its work. Cranes are commonly employed in transportation for the loading and unloading of freight, in construction for the movement of materials, and in manufacturing for the assembling of heavy equipment.
A guyed mast is a tall thin vertical structure that depends on guy lines for stability. The mast itself has the compressive strength to support its own weight, but does not have the shear strength to stand unsupported or bear loads. It requires guy lines to stay upright and to resist lateral (shear) forces such as wind loads. Examples include masts on sailing vessels, towers for telecommunications, meteorology, and masts on cranes, power shovels, draglines, and derricks, starting with the simple gin pole.
A guy-wire, guy-line, guy-rope, down guy, or stay, also called simply a guy, is a tensioned cable designed to add stability to a freestanding structure. They are used commonly for ship masts, radio masts, wind turbines, utility poles, and tents. A thin vertical mast supported by guy wires is called a guyed mast. Structures that support antennas are frequently of a lattice construction and are called "towers". One end of the guy is attached to the structure, and the other is anchored to the ground at some distance from the mast or tower base. The tension in the diagonal guy-wire, combined with the compression and buckling strength of the structure, allows the structure to withstand lateral loads such as wind or the weight of cantilevered structures. They are installed radially, usually at equal angles about the structure, in trios and quads. As the tower leans a bit due to the wind force, the increased guy tension is resolved into a compression force in the tower or mast and a lateral force that resists the wind load. For example, antenna masts are often held up by three guy-wires at 120° angles. Structures with predictable lateral loads, such as electrical utility poles, may require only a single guy-wire to offset the lateral pull of the electrical wires, at a spot where the wires change direction.
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 derrick. The most basic type of derrick is controlled by three or four lines connected to the top of the mast, which allow it both to move laterally and cant up and down. To lift a load, a separate line runs up and over the mast with a hook on its free end, as with a crane.
Radio masts and towers are typically tall structures designed to support antennas for telecommunications and broadcasting, including television. There are two main types: guyed and self-supporting structures. They are among the tallest human-made structures. Masts are often named after the broadcasting organizations that originally built them or currently use them.
A rigger or slinger is a skilled tradesperson who specializes in the assistance of manual mechanical advantage device comprising pulley, block and tackle or motorised such as a crane or derrick or chain hoists or capstan winch.
A crane vessel, crane ship, crane barge, or floating crane is a ship with a crane specialized in lifting heavy loads, typically exceeding 1,500 t for modern ships. The largest crane vessels are used for offshore construction.
A hoist is a device used for lifting or lowering a load by means of a drum or lift-wheel around which rope or chain wraps. It may be manually operated, electrically or pneumatically driven and may use chain, fiber or wire rope as its lifting medium. The most familiar form is an elevator, the car of which is raised and lowered by a hoist mechanism. Most hoists couple to their loads using a lifting hook. Today, there are a few governing bodies for the North American overhead hoist industry which include the Hoist Manufactures Institute, ASME, and the Occupational Safety and Health Administration. HMI is a product counsel of the Material Handling Industry of America consisting of hoist manufacturers promoting safe use of their products.
A trailer sailer is a type of sailboat that has been designed to be easily transported using a boat trailer towed by an automobile. They are generally larger than a sailing dinghy. Trailer sailers include day sailers and small cabin cruisers, suitable for living on.
Shear legs, also known as sheers, shears, or sheer legs, are a form of two-legged lifting device. Shear legs may be permanent, formed of a solid A-frame and supports, as commonly seen on land and the floating sheerleg, or temporary, as aboard a vessel lacking a fixed crane or derrick.
A bulk-handlingcrane is one that, instead of a simple hook that can handle a range of slung loads, has an integral grab for lifting bulk cargoes such as coal, mineral ore etc.
Elevated photography is the process of taking aerial photos using a telescoping pole or mast, or other aerial or elevated support systems, to emulate aerial photographs, or video, taken from a commercially licensed aircraft.
A treadwheel crane is a wooden, human powered hoisting and lowering device. It was primarily used during the Roman period and the Middle Ages in the building of castles and cathedrals. The often heavy charge is lifted as the individual inside the treadwheel crane walks. The rope attached to a pulley is turned onto a spindle by the rotation of the wheel thus allowing the device to hoist or lower the affixed pallet.
Ljungström rig is the name for the sailing rig designed by Swedish engineer Fredrik Ljungström with double main sails and rotating mast, but without boom, foresail, forestay and shroud. The early models of the Ljungström sailboat had a stern stay but this was omitted around 1945, before the model 12.
A launching gantry is a special-purpose mobile gantry crane used in bridge construction, specifically segmental bridges that use precast box girder bridge segments or precast girders in highway and high-speed rail bridge construction projects. The launching gantry is used to lift and support bridge segments or girders as they are placed while being supported by the bridge piers instead of the ground.
Carmila Cane Lift is a heritage-listed piece of agricultural equipment at 49 Hindles Road, Carmila, Isaac Region, Queensland, Australia. It was built between the 1920s and the 1960s. It was added to the Queensland Heritage Register on 5 February 2010.
Mount Martin Cane Lift is a heritage-listed piece of agricultural equipment at Mirani Mount Ossa Road, Mount Martin, Mackay Region, Queensland, Australia. It was built before 1939. It was added to the Queensland Heritage Register on 5 February 2010.
The Leap Cane Lift is a heritage-listed piece of agricultural equipment at Bruce Highway, The Leap, Mackay Region, Queensland, Australia. It was built before the 1960s. It was added to the Queensland Heritage Register on 5 February 2010.
A jib or jib arm is the horizontal or near-horizontal beam used in many types of crane to support the load clear of the main support. An archaic spelling is gib.