# US 6,076,996 A · Offshore jackup hull-to-legs load transfer device and elevating and leg guide arrangement > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,076,996 A - Document ID: US6076996A - Status: Granted - Kind: A - Application number: 09/275,613 - Filed: 1999-03-24 - Granted: 2000-06-20 - Earliest claimed: 1997-08-30 - Assignees: Zentech, Inc. - Inventors: Kenneth P. Choate; John S. Laird, II - Web page: https://patentgrep.com/patent/US6076996A ## CPC - E02B 17/0818: {with racks actuated by pinions (lifting jacks B66F3/02 - B66F3/06)} - E02B 17/06: for immobilising, e.g. using wedges or clamping rings {(as elements of the raising or lowering means E02B17/08)} - E02B: HYDRAULIC ENGINEERING (ship-lifting E02C; dredging E02F) ## Abstract An arrangement of a jackup platform's elevating system, leg guides, hull-to-legs load transfer device, and method of operation of the load transfer device for an offshore jackup platform's hull to be supported by legs which have one or more vertical toothed gear racks attached. An apparatus consisting of rectangular blocks with protruding lugs that are shaped for efficient engagement with a portion of the upper faces of the gear rack teeth, that extend vertically on the leg chords of the jackup platform. The rectangular blocks are movable in a direction perpendicular to one side of the gear rack. Powered guide assemblies control movement of the rectangular blocks such that their protruding lugs can move into the spaces in between the gear rack teeth. The protruding lugs of the rectangular blocks can then bear against the gear rack teeth and faces of the rectangular blocks can bear against structure of the hull to transfer hull weight and storm induced interaction forces between the hull and the legs of the jackup platform. ## Claims ### Claim 1 An improved jackup platform elevating system, and an improved hull-to-legs load transfer device for an offshore jackup platform which utilizes at least one gear rack mounted to a leg of said jackup platform with teeth extending in a first direction, and at least one locking lug mounted for straight line movement for insertion from a second direction transverse to said first direction between said teeth of said gear rack, and further comprises rollers, mounted in elevating gear unit housings, and positioned with the perimeters of said rollers tangent to the opposite sides of the chords from the gear racks. ### Claim 2 (depends on 1) The invention of claim 1 further comprising at least one elevating gear unit on one side of each leg chord of said jack up rig and horizontal force counteracting rollers on the opposite side of each of said leg chords from said elevation gear units. ### Claim 3 (depends on 2) The invention of claim 2 further comprising pinned link connections between the elevating gear unit support housings and the hull to transfer vertical loads and provide stiffness for vertical load transfer between the legs and the hull, but to permit torsional movement of the legs about their vertical centerlines within the constraints of the leg guides of the hull. ### Claim 4 (depends on 3) The invention claim 3 wherein lower leg guides are vertically positioned, on the opposite sides of the leg chords from the gear rack teeth, such that the forces applied to the gear rack teeth by the lugs, on said blocks, and the counteracting horizontal forces applied to the leg chords by the lower leg guides, are resolved into vertical reactions collinear with the vertical axes of the leg chords. ### Claim 5 (depends on 4) The invention of claim 4 further comprising at least one powered gear train at each leg for adjusting said platform vertically relative to said legs. ### Claim 6 (depends on 5) The invention of claim 5 wherein said gear train is electrically powered. ### Claim 7 (depends on 3) The invention of claim 3 further comprising at least one powered gear train at each leg for adjusting said platform vertically relative to said legs. ### Claim 8 (depends on 7) The invention of claim 7 wherein said gear train is electrically powered. ### Claim 9 (depends on 2) The invention of claim 2 wherein lower leg guides are vertically positioned, on the opposite sides of the leg chords from the gear rack teeth, such that the forces applied to the gear rack teeth by the lugs, on said blocks, and the counteracting horizontal forces applied to the leg chords by the lower leg guides, are resolved into vertical reactions collinear with the vertical axes of the leg chords. ### Claim 10 (depends on 2) The invention of claim 2 further comprising at least one powered gear train at each leg for adjusting said platform vertically relative to said legs. ### Claim 11 (depends on 10) The invention of claim 10 wherein said gear train is electrically powered. ### Claim 12 (depends on 1) The invention of claim 1 further comprising at least one powered gear train at each leg for adjusting said platform vertically relative to said legs. ### Claim 13 (depends on 12) The invention of claim 12 wherein said gear train is electrically powered. ### Claim 14 An improved jackup platform elevating system, and an improved hull-to-legs load transfer device for an offshore jackup platform which utilizes at least one gear rack mounted to a leg of said jackup platform, and at least one locking lug for insertion between teeth of said gear rack, and further comprises rollers, mounted in elevating gear unit housings, and positioned with the perimeters of said rollers tangent to the opposite sides of the chords from the gear racks; and pinned link connections between the elevating gear unit support housings and the hull to transfer vertical loads and provide stiffness for vertical load transfer between the legs and the hull, but to permit torsional movement of the legs about their vertical centerlines within the constraints of the leg guides of the hull. ### Claim 15 (depends on 14) The invention of claim 14 further comprising at least one powered gear train at each leg for adjusting said platform vertically relative to said legs. ### Claim 16 (depends on 15) The invention of claim 15 wherein said gear train is electrically powered. ### Claim 17 An improved jackup platform elevating system, and an improved hull-to-legs load transfer device for an offshore jackup platform which utilizes at least one gear rack mounted to a leg of said jackup platform, and at least one locking lug for insertion between teeth of said gear rack, and further comprises rollers, mounted in elevating gear unit housings, and positioned with the perimeters of said rollers tangent to the opposite sides of the chords from the gear racks; and lower leg guides vertically positioned, on the opposite sides of the leg chords from the gear rack teeth, such that the forces applied to the gear rack teeth by the lugs, on blocks upon which said lugs are mounted, and the counteracting horizontal forces applied to the leg chords by the lower leg guides, are resolved into vertical reactions collinear with the vertical axes of the leg chords. ### Claim 18 (depends on 17) The invention of claim 17 further comprising at least one powered gear train at each leg for adjusting said platform vertically relative to said legs. ### Claim 19 The invention of claim wherein said gear train is electrically powered.