Shock absorber and method for offshore jack-up rigs
OwnerJerome L. Goldmaninventor
Life of this patent
Estimating the term…
Abstract
A new and improved shock absorber mechanism and method for use on the leg structure of a jack-up offshore drilling rig is disclosed. The shock absorbing mechanism is designed to be mounted on the bottom of each existing leg of a drilling rig and comprises a pointed piston member which is positioned on the bottom of the leg structure, wherein the piston member projects downward through the can/footing of the rig leg and is held in place by a resilient tension member which is designed to absorb shock forces during vertical/axial impact of the leg structure when contact is made with the ocean floor.
Claims25
A device for absorbing vertically directed impact loads on supporting legs of an offshore structure, each of the legs resting on an individual footing, said device comprising:
- an elongated piston means mounted for a limited vertical movement within an opening formed in the footing of each supporting leg;
- a means for limiting the vertical movement of the piston means carried by an exterior of the piston means;
- and
- flexible resilient tension means for operatively connecting said piston means and said footing and allowing said piston means to resiliently absorb the impact of the footing with an ocean floor, said tension means comprising at least one elongated resilient tension cable fixedly attached at least at one of its ends to a top surface of the footing and connected to a top portion of the piston means, said tension cable causing at least partial embedment of the piston means in the ocean floor during contracting reaction.
A device for absorbing vertically directed impact loads on supporting legs of an offshore structure, each of the legs engaged with a footing at its bottom end, said device comprising:
- an elongated piston means comprising at least one piston body having an upper portion and a lower portion, said upper portion carrying a piston head fixedly attached thereto, and a lower portion carrying an embedment tip to facilitate at least partial embedment of the lower portion in an ocean floor, said piston body being adapted for a limited vertical movement within an opening formed along a vertical axis of the footing;
- a means for limiting the vertical movement of the piston body within said opening, said movement limiting means comprising an annular stopper plate fixedly secured in circumferential relationship to an exterior of the piston body at a distance from the piston head;
- and
- a flexible resilient tension means for operatively connecting said piston means and said footing and allowing said piston means to resiliently absorb impact of the footing with the ocean floor while applying tension on the legs during attempted displacement of the legs caused by wave motions, said tension means comprising at least one elongated tension cable fixedly attached at least at one of its ends to a top surface of the footing and connected to the piston head, said tension cable causing at least partial embedment of the embedment tip in the ocean floor upon contracting reaction.
A method of absorbing vertically directed impact loads on supporting legs of an offshore structure, each of the legs resting on individual footing, the method comprising the steps of:
- providing an elongated piston means mounted for a limited vertical movement within an opening formed in the footing of each supporting leg;
- providing a means for limiting the vertical movement of the piston means carried by an exterior of the piston means;
- providing a flexible resilient tension means for operatively connecting said piston means and said footing, said tension means comprising at least one elongated tension cable fixedly attached at one of its ends to a top surface of the footing and connected to a top portion of the piston means;
- lowering a supporting leg to a distance adjacent an ocean floor;
- allowing the elongated piston to contact the ocean floor, while resiliently absorbing the impact of the footing with the ocean floor by at least partial stretching of the tension cable, allowing the tension cable to contract and facilitate at least partial embedment of the piston means within the ocean floor.
Dependencies are inferred from the claim text.