The Effect of Tapered Treads on the Motion of Overhead Travelling Cranes *

The well-known theory of the motion of a four-wheeled vehicle having pairs of tapered tread wheels joined by an axle is applied to cranes, and is extended to the important case of a four-wheeled crane with only one axle and to eight-wheeled cranes with two pairs of wheels driven by a common shaft. Observations of the actual motion of a number of cranes with parallel and tapered tread wheels are recorded. The tapered tread cranes give sinusoidal curves of motion in good agreement with theory, and design rules for the width of both parallel and tapered treads are suggested.