Jack-up MODU and jacking method and apparatus

The MODU jacking system of claim 8 wherein said operator signal provides a warning in the event of an unacceptable load sensed by the load sensor.

In a MODU jacking system comprising a MODU platform, a plurality of MODU supporting legs, and means for providing relative motion between the MODU platform and the plurality of MODU supporting legs, the improvement wherein said means for providing relative motion between the MODU platform and plurality of MODU supporting-legs comprises a plurality of continuous linear motion motors, with at least one such motor for each of the plurality of MODU supporting legs, each of said plurality of continuous linear motion motors comprising N hydraulic piston/cylinder units, and wherein operation of the pistons of said N hydraulic piston/cylinder units is phased during jacking so that N−1 units are engaged with the MODU supporting legs and providing said relative motion at all times while one of said N units is disengaged from the toothed rack and is being repositioned for re-engagement with the toothed rack to provide said relative motion.

In a MODU jacking system comprising a MODU platform, a plurality of MODU supporting legs and means for providing relative motion between the MODU platform and the plurality of MODU supporting legs, the improvement wherein said means for providing relative motion between the MODU platform and the plurality of MODU supporting means comprises a plurality of piston/cylinder units for each MODU supporting leg, each of said plurality of piston/cylinder units having a toothed rack engagement member attached to its piston and each of the MODU supporting legs having a toothed rack, wherein relative motion is provided between the MODU platform and MODU supporting legs by phased engagement of toothed rack engagement members with the toothed racks and phased operation of the pistons of the piston/cylinder units of the engaged toothed rack engagement members, and wherein the MODU platform and MODU supporting legs can be locked together in a stationary position by engagement of all of the toothed rack engagement members of all of the piston/cylinder units with the toothed racks.

In a MODU jacking system comprising a MODU platform, a plurality of MODU supporting legs, and means including a plurality of driving toothed members and a plurality of driven toothed members on the plurality of MODU supporting legs, for providing relative motion between the MODU platform and the plurality of MODU supporting legs, the improvement wherein the plurality of driving toothed members comprise continuous linear motion motors driving pluralities of teeth having planar engagement surfaces, and said plurality of driven toothed members comprise racks with pluralities of teeth having planar engagement surfaces, the planar engagement surfaces of said continuous linear motion motor, and said rack mating so the stresses resulting from the driving force of said plurality of teeth of said continuous liner motion motor are substantially uniformly distributed on the planar engagement surfaces of the engaged teeth.

In a MODU jacking system comprising a MODU platform, a plurality of MODU supporting legs and means for providing relative motion between the MODU platform and the plurality of MODU supporting legs, the improvement wherein each of said plurality of MODU supporting legs includes a plurality of leg chords, each leg chord comprising a tubular column with a toothed rack welded on opposite sides of the tubular column, and wherein the means for providing relative motion between the MODU and the plurality of supporting legs comprises at least one continuous linear motion motor engaged with the toothed racks of each of the leg chords of each of the MODU supporting legs.

In a MODU jacking system comprising a MODU platform, a MODU supporting leg, and means including at least one driving toothed member and at least one driven toothed member on the MODU supporting leg, for providing relative motion between the MODU platform and the plurality of MODU supporting leg, the improvement wherein the driving toothed member and the driven toothed member comprise teeth having mating planar upper and lower engagement surfaces driven by a continuous linear motion motor.