METHOD AND APPARATUS FOR TRANSPORTING AND STEERING A LOAD

摘要

A load-carrying transport apparatus for moving a heavy load, such as an o il drilling rig, over a surface includes a substructure for carrying the load, a track member positioned on the surface adjacent the substructure and a plurality o f lift assemblies mounted on the substructure selectively operable for extension toward the surface to engage the track member and raise the substructure above the surface so that it is carried on the track member. The lift assemblies are also operable for retraction to lower the substructure onto the surface. A shifte r mechanism disposed adjacent to the substructure and the track member is selectively operable for displacing the substructure along the track member when the lifting assemblies have been extended toward the surface to raise the substructure above the surface. The shifter mechanism is also operable for displacing the track member on the surface relative to the substructure when the lifting assemblies have been retracted and disengaged from the track member. The track member is dimensioned to provide a steering area and at least one of the lifting assemblies is selectively positionable to a predetermined angle with in a range for moving in the steering area along the track member so that the loa d- carrying apparatus can be steered along a selected direction.