The wheel of a bridge crane can be divided into cylindrical and conical shape according to the characteristics of its tread. At present, the most widely used is cylindrical, cylindrical wheels, which are installed both in the operating mechanism of the crane and in the running mechanism of the trolley.
In general, a cylindrical wheel has two rim (side edges) on the tread, which guides the movement of the wheels and prevents the wheels from breaking away from the rails. However, when the span of a bridge crane is large, the deflection of a bridge crane relative to its running track often occurs. The reason for the deviation is that the wheels are not installed properly, the running track of the overhead traveling crane is not parallel, the torsion of the shaft ends is different, and so on.
When the bridge crane is skewed, the friction of the wheel rim will increase the running resistance greatly, and the friction of the rim to the rail also shortens the working life of the wheel and the rail. It is difficult to eliminate the cause of deflection caused by a bridge. Therefore, when the span is large, a conical wheel is adopted in the operating mechanism of a bridge with four wheels, which depends on the help of the wheel, so that the position of the bridge in the track can be realized automatically.