A mobile crane is a cable-controlled crane mounted on crawlers or rubber-tired carriers or a hydraulic-powered crane with a telescoping boom mounted on

truck A truck or lorry is a motor vehicle designed to transport freight, carry specialized payloads, or perform other utilitarian work. Trucks vary greatly in size, power, and configuration, but the vast majority feature body-on-frame construct ...

-type carriers or as self-propelled models. They are designed to easily transport to a site and use with different types of load and cargo with little or no setup or assembly.

Overview

Mobile cranes generally operate a boom, from the end of which a

hook A hook is a tool consisting of a length of material, typically metal, that contains a portion that is curved/bent back or has a deeply grooved indentation, which serves to grab, latch or in any way attach itself onto another object. The hook's d ...

is suspended by

wire rope Steel wire rope (right hand lang lay) Wire rope is composed of as few as two solid, metal wires twisted into a helix that forms a composite ''rope'', in a pattern known as ''laid rope''. Larger diameter wire rope consists of multiple strands of ...

and sheaves. The wire ropes are operated by whatever prime movers the designers have available, operating through a variety of transmissions.

Steam engine A steam engine is a heat engine that performs Work (physics), mechanical work using steam as its working fluid. The steam engine uses the force produced by steam pressure to push a piston back and forth inside a Cylinder (locomotive), cyl ...

electric motor An electric motor is a machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a electromagnetic coil, wire winding to gene ...

s, and

internal combustion engine An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal comb ...

s (IC) have all been used. Older cranes' transmissions tended to be

clutch A clutch is a mechanical device that allows an output shaft to be disconnected from a rotating input shaft. The clutch's input shaft is typically attached to a motor, while the clutch's output shaft is connected to the mechanism that does th ...

es. This was later modified when using IC engines to match the steam engines' "max torque at zero speed" characteristic by the addition of a hydrokinetic element, culminating in controlled

torque converter A torque converter is a device, usually implemented as a type of fluid coupling, that transfers rotating power from a prime mover, like an internal combustion engine, to a rotating driven load. In a vehicle with an automatic transmission, the ...

s. The operational advantages of this arrangement can now be achieved by electronic control of hydrostatic drives, which for size and other considerations is becoming standard. Some examples of this type of crane can be converted to a

demolition Demolition (also known as razing and wrecking) is the science and engineering in safely and efficiently tearing down buildings and other artificial structures. Demolition contrasts with deconstruction (building), deconstruction, which inv ...

crane by adding a demolition ball, or to an earthmover by adding a

clamshell bucket A bucket (also called a scoop to qualify shallower designs of tools) is a specialized container attached to a machine, as compared to a bucket adapted for manual use by a human being. It is a bulk material handling component. The bucket has an in ...

or a dragline and scoop, although design details can limit their effectiveness.

History

Before 1870 cranes were fixed to a position, except for some mounted on flatcars, railroad cranes, which provided some restricted movement. Appleby Brothers demonstrated steam-powered cranes at Paris in 1867 and Vienna in 1873. In 1922, Henry Coles, manager of Appleby Corp., began producing truck-mounted cranes under the name ''Petrol Electric Lorry Crane.'' In 1939 the Coles were acquired by Steel and Co. Ltd. of Sunderland. Hiab invented the world's first hydraulic truck mounted crane in 1947. The name, Hiab, comes from the commonly used abbreviation of Hydrauliska Industri AB, a company founded in Hudiksvall, Sweden in 1944 by Eric Sundin, a ski manufacturer who saw a way to utilize a truck's engine to power loader cranes through the use of hydraulics. Major crane development events include adoption of the internal combustion engine in 1922 and the invention of telescopic jibs. Before 1960, cranes carried additional booms with them to increase height, which increased operating costs. 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 four-wheel drive, also called 4×4 ("four by four") or 4WD, is a two-axled vehicle drivetrain capable of providing torque to all of its wheels simultaneously. It may be full-time or on-demand, and is typically linked via a transfer case pr ...

. In 1972, Steels was forced to merge with the Acrow Group, losing some of their most valuable employees, including Don Hassel and Johnny Johnson who started a new manufacturing processes plant. With backing from the British Crane Hire Corporation they acquired a small factory unit and ordered every single element of their product from subcontracted suppliers. In 1976, the Cosmos team created a 25-ton crane that combined several new developments. A Liebherr heavy Crane LR 11350 lifted a dome of nuclear power plant with 281 Tonnes 62 Meter high in December 2023.

Types

Gallery

File:A 130t mobile crane.jpg, A 130t mobile crane File:Mobile Cranes.jpg, Demag AC1000, a 1000 ton mobile crane File:Liebherr mobile crane 450T, Brisbane.jpg, Liebherr mobile crane 450T, Brisbane File:Maeder-Kriessern-Rhine-Liebherr LR 11000-32ASD.jpg, Maeder-Kriessern-Rhine-Liebherr LR 11000-32ASD

References

External links

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