US Patent 9518429 Walking drilling rig

An improved walking drilling rig is disclosed. The walking drilling rig includes a preassembled substructure that includes a first skid beam disposed parallel and spaced apart from a second skid beam. A plurality of crossbeams couple the first skid beam to the second skid beam, and a plurality of extendable legs are supported by the first and second skid beams. An elevatable drill floor is coupled to the plurality of extendable legs and includes a rotary table disposed between a pair of lateral platforms. Each lateral platform has a retracted position and an extended position.