Method and device for automatically converting field of gantry crane

The invention discloses a method and a device for automatically changing the operating area of gantry cranes, mainly comprising a steering wheel, a steering mandrel, a fixed chassis, steel balls and a steering rail. The steering wheel can rotate around the steering mandrel; at least one group of steel balls is arranged between the steering wheel and the fixed chassis; the steering rail arranged on the steering wheel and rotating along with the steering wheel is in parallel butt joint with rails in the operating area or with operating area changing rails; and a lock pin is arranged at the part where the steering rail is in parallel butt joint with rails in the operating area or with operating area changing rails. The device for automatically changing the operating area of the gantry cranes causes the gantry cranes to automatically move from one operating area to a next adjacent one, thus expanding the working range of the cranes, improving the working efficiency and speeding up the construction. With simple structure and convenient operation, the device meets the need of automatic change of operating areas of cranes.