The Bridge (Overhead Traveling) crane is the workhorse of the industry. Itís designed with a bridge mounted on end trucks that moves along overhead runway rails attached to the building or structure providing a rectangular, three-axis coverage area. They are best suited for moving heavy loads and high duty cycles. There are two types of overhead cranes available, Top running or Underhung. Both are available with two bridge girder designs, either single girder or double girder.
A single girder bridge utilizes one bridge girder, with the hoist and trolley mounted beneath the bridge. They are less expensive than the double girder design. With a double girder bridge design, the hoist and trolley are mounted up between two bridge girders rather than beneath the bridge as with a single girder crane. This allows for greater capacity and stability of the load because it is distributed over a larger area and also offers more headroom with a substantial increase in lift height. Double girder bridges can also be fitted with walkways, crane lights, cabs and other special equipment.