Patent ID: 7934887

Claim:
A complementary locking system configured and operable to lock legs to a deck of a jack-up drilling platform including a plurality of legs, the deck, and a drive mechanism for each leg and supported by the deck, the drive mechanism for each leg comprising at least two groups of opposing pinions supported by the deck, racks opposing the pinions, the racks being fitted onto the leg, and the racks are operable in cooperation with the pinions when the pinions are rotated for displacing the deck between a low position and an upraised, operating position, the complementary locking system being configured and operable to maintain the deck on the legs in the operating position, on each leg the complementary locking system including at least one locking assembly comprising: two opposing counter-racks, each counter-rack comprising a plate having an internal end and an external end, the plate including teeth positioned at the internal end of the plate such that the teeth engage with a respective one of the racks; at least one internal element positioned at the internal end of the plate of each counter-rack and configured to connect the internal ends of the counter-rack plates; and at least one external element positioned at the external end of the plate of each counter-rack and configured to connect the external ends of the counter-rack plates.