Mobile harbor crane for the combined handling of containers and bulk materials

A mobile harbor crane for the combined handling of containers and bulk materials, said harbor crane comprising an undercarriage and an upper carriage which is rotatably mounted on the undercarriage, said upper carriage comprising a tower with a boom that can be pivoted about a horizontal axis, said undercarriage comprising

• a base frame having a longitudinal axis and a transverse axis,
• four support beams pivotally connected to the base frame, symmetrically to the longitudinal and transverse axes, each support beam being pivotable about a respective vertical axis between a retracted transportation position and an extended working position, each said support beam having a free end remote from the vertical axis,
• four traveling gear assemblies supporting respective said support beams by means of respective vertically acting leveling cylinders provided at the free ends of the support beams, each traveling gear assembly comprising a plurality of axles carrying a plurality of wheels and balancing means for uniformly distributing supporting forces acting on the assembly among its wheels, and
• four coupling rods pivotably connected to said base frame and to respective said traveling gear assemblies, each said coupling rod being parallel to a respective said support beam and forming therewith a parallelogram linkage, whereby said traveling gear assemblies remain parallel to the longitudinal axis in any pivoted position of the support beams.