works:

General overhead crane used mainly electric drive, generally in cab control, there are also remote control. Weight of up to 500 tons, span up to 60 meters. Large common bridge crane lifting weight for ease of installation and adjustment, universal coupling drive device often used. Crane agencies generally only four driving and driven wheels, if the starting weight is large, common approaches to reduce the wheel increases wheel pressure. When more than four wheels, a frame must be Hand pallet trucks hinge device, the crane load is evenly distributed on each wheel.