Overhead crane image courtesy of COH, Inc.
The Pyramids or Stonehenge might seem like marvels to us even today, as modern architecture and construction relies on heavy duty material handling equipment to transport and maneuver beams and other weighty loads, and move them to the necessary heights. Where would society be without our buildings, bridges, cargo ships, and other large vehicles and vessels, and the overhead cranes that help build them?
Most industrial equipment manufacturing and large metalworking processes use built-in overhead traveling cranes to move objects around. Some are part of a facility’s inner workings, providing for a wide range of lifting and positioning applications within a plant and at workstations. Bridge cranes are part of a building’s structure, stretching across ceiling beams as a set of overhead rails or tracks, and are also called track cranes or monorails. Like train tracks, these cranes offer curved paths for the loads to take if necessary, therefore, increasing maneuverability.
Also fixtures in facilities are jib cranes and workstation cranes. The jib is a beam held up on only one side by a vertical support or wall fixture, and many workstation cranes are jibs, with the overhead beam extending from the wall or support on a pivot and the trolley carrying the hoist along the beam. Jibs save factory or assembly workers from continually lifting and moving heavy or awkwardly shaped objects, and they take up little or no floor space and can have portable supports.
In most gantry cranes, the track and trolley beam is bridged by two movable supports. Sometimes, a half gantry will have one side support and then be counterbalanced. The difference between these semi-gantries and jibs is that the gantry’s arm is fixed, but the jib arm typically spans 180 degrees horizontally.
Still more cranes include stacker cranes as an alternative to forklifts in automated warehouse systems. Mobile and loader cranes are alternatives to overhead cranes for all-terrain or hard-to-reach places, and floating cranes are used in nautical applications.
