Beginning initially as a shipbuilding and repair company, Manitowoc has been manufacturing a variety of cranes of since the mid-1920s. In 1992 they introduced the M-250 lattice boom crawler crane, which was all hydraulic and could be self-erected in as little as three hours. The rated loading capacity was 300 tons.
Lattice boom cranes of this size can be used on a number of different projects: building bridges, stadiums, malls, refineries, and virtually any large construction or industrial application. They can certainly be used in manufacturing applications as well, but their sheer size makes them less desirable in small spaces. Many are utilized in a dragline capacity, as was the M-250, as well as used in dredging efforts using a clamshell bucket system.
The M-250’s rotating bed featured Manitowoc’s FACT (Fast Aligning Connection Technology) system for quick attachment of the rotating module to the carbody, it used alignment devices, power-activated pins, and the H-FACT quick coupler to assist with crane assembly and disassembly. The operator’s station was fully enclosed and insulated, equipped with a sliding door and large safety glass windows on all sides, including the roof. The engine was a Cummins N14-C450 diesel rated for 450 horsepower at 2,100 RPM. The engine came standard with a 120V heater, ether starting aid, transmission disconnect clutch, and hydraulic oil cooler. Manitowoc’s Electronically Processed Independent Control (EPIC) system provided micro-processor-driven control logic, pump control, onboard diagnostics, and service information.
The carbody connected the rotating bed to the crawlers. The steel rotating module mounted to the single-piece carbody via a large (9’8”) diameter turntable bearing. When assembled, the crawlers were 30’9” long with reinforced steel frames, the treads were 4 feet wide, and there were low-maintenance intermediate rollers. Each of the two crawlers was powered independently by two variable-displacement hydraulic motors and a planetary-and-spur gear reduction that drove the chain to the crawler. The crawlers had the additional ability to counter-rotate which allowed superior mobility in confined areas.
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