LEAD WHEEL STEERING SYSTEM FOR A GANTRY CRANE

摘要

A steering apparatus and method are provided for a gantry crane with four corner-mounted wheel assemblies having steerable wheels. The crane is a type which is drivable in either longitudinal or transverse directions, wherein steering control is automatically switched to the "leading" wheels, or more particularly the wheels of the "leading" pair of wheel assemblies. The system detects which two of the wheel assemblies are leading, whether the crane is moving longitudinally frontwardly or rearwardly, or transversely rightward or leftward. The system includes a steering controller which controls steering actuators in such a manner that the wheels of the then-leading wheel assemblies are moved according to steering control input, while the wheels of a remaining pair of then-"trailing" wheel assemblies are moved to and/or held in, a straight alignment.