US4606557A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Subsea wellhead connector
Assignee: FMC Corp
•
Filing: 1983-05-03
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Granted: 1986-08-19
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Expires: 2003-05-03
Abstract
Abstract A pipe connector especially suitable for interconnecting a marine riser to a subsea wellhead, the connector comprising an annular body that telescopes over the wellhead, and a plurality of lockdown screw assemblies extending through radial ports in the body to releasably grip and secure the connector to the wellhead. Each screw assembly comprises a lockdown dog for engaging the recess beneath the wellhead hub flange, a bolt-like dog retainer secured to the dog and slidably extending into a lockdown screw that is threaded into one of the radial ports, and a spring system for biasing the dog away from the lockdown screw towards engagement with the wellhead.
Inventors
- 👤 William M. Coffey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 11:08
CPC Classifications
E; E21; E21B; E21B33/00; E21B33/02; E21B33/03; E21B33/035; E21B33/038; Y; Y10; Y10S; Y10S292/00; Y10S292/24; Y10T; Y10T292/00; Y10T292/08; Y10T292/096; Y10T292/0969; Y10T292/097; Y10T292/0998
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
149 words
A pipe connector especially suitable for connecting a marine riser to a subsea wellhead, said connector comprising: (a) an annular connector body; (b) means for attaching the connector body to a marine riser; and (c) a plurality of lockdown screw assemblies extending through radial ports in the connector body, each of said screw assemblies comprising: (1) a lockdown dog; (2) a lockdown screw movably secured to its respective port in the connector body, said lockdown screw having a central bore and a counterbore communicating therewith; (3) a dog retainer secured to the lockdown dog and slidably extending through the central bore of the lockdown screw, said dog retainer being bolt-shaped with a shank and a head, said shank extending through said bore and said head residing in said counterbore; and (4) a spring system between the lockdown dog and the lockdown screw to bias the dog from the screw.
Claim 2
Dependent Claim
149 words
A pipe connector especially suitable for connecting a marine riser to a subsea wellhead, said connector comprising: (a) an annular connector body; (b) means for attaching the connector body to a marine riser; and (c) a plurality of lockdown screw assemblies extending through radial ports in the connector body, each of said screw assemblies comprising: (1) a lockdown dog; (2) a lockdown screw movably secured to its respective port in the connector body, said lockdown screw having a central bore and a counterbore communicating therewith; (3) a dog retainer secured to the lockdown dog and slidably extending through the central bore of the lockdown screw, said dog retainer being bolt-shaped with a shank and a head, said shank extending through said bore and said head residing in said counterbore; and (4) a spring system between the lockdown dog and the lockdown screw to bias the dog from the screw.
Claim 3
Dependent Claim
15 words
A pipe connector according to claim 1 including a backup plug threaded into said counterbore.
Claim 4
Dependent Claim
17 words
A pipe connector according to claim 1 wherein the dog retainer is threaded to the lockdown dog.
Claim 5
Dependent Claim
37 words
A pipe connector according to claim 1 wherein the lockdown dog includes a tapered surface to cooperate with an edge of a wellhead to establish a camming force tending to move the dog towards the lockdown screw.
Claim 6
Dependent Claim
31 words
A pipe connector according to claim 1 wherein the connector body has an inner annular groove, intersected by the radial ports, and wherein the lockdown dog resides slidably in said groove.
Claim 7
Dependent Claim
17 words
A pipe connector according to claim 1 wherein the spring system comprises a plurality of Belleville springs.
Claim 8
Dependent Claim
41 words
A pipe connector according to claim 1 wherein the connector body comprises an upper body member, a lower body member releasably secured to said upper body member, and means for establishing a pressure seal between said upper and lower body members.
Claim 9
Dependent Claim
17 words
A pipe connector according to claim 4 wherein the radial ports extend through the lower body element.
Claim 10
Dependent Claim
32 words
A pipe connector according to claim 1 including guide means connected to the connector body for correcting misalignment of said connector with respect to a wellhead onto which it is being lowered.
Claim 11
Dependent Claim
34 words
A pipe connector according to claim 1 including a protective cap for the lockdown screw, said cap and screw having cooperative means to removably install said cap over an end portion of said screw.
Claim 12
Dependent Claim
28 words
A pipe connector according to claim 1 wherein the lockdown screw includes means for cooperating with a wrench to rotate said screw with respect to the connector body.
Claim 13
Dependent Claim
20 words
A pipe connector according to claim 1 including means for establishing a pressure seal between the connector and a wellhead.
Claim 14
Dependent Claim
104 words
A lockdown screw assembly for use in a marine riser connector to releasably secure said connector to a subsea wellhead, said screw assembly comprising: (a) a lockdown dog; (b) a lockdown screw having a central bore and a counterbore communicating therewith; (c) a dog retainer secured to the lockdown dog and slidably extending through the central bore of the lockdown screw, said dog retainer being bolt-shaped with a shank and a head, said head residing in said counterbore and said shank extending through said bore; and (d) a spring system between the dog and the screw for biasing the dog away from the screw.
Claim 15
Dependent Claim
104 words
A lockdown screw assembly for use in a marine riser connector to releasably secure said connector to a subsea wellhead, said screw assembly comprising: (a) a lockdown dog; (b) a lockdown screw having a central bore and a counterbore communicating therewith; (c) a dog retainer secured to the lockdown dog and slidably extending through the central bore of the lockdown screw, said dog retainer being bolt-shaped with a shank and a head, said head residing in said counterbore and said shank extending through said bore; and (d) a spring system between the dog and the screw for biasing the dog away from the screw.
Claim 16
Dependent Claim
16 words
A lockdown screw assembly according to claim 18 including a backup plug threaded into said counterbore.
Claim 17
Dependent Claim
19 words
A lockdown screw assembly according to claim 13 wherein the lockdown dog and the dog retainer are threadedly interconnected.
Claim 18
Dependent Claim
18 words
A lockdown screw assembly according to claim 13 wherein the spring system comprises a plurality of Belleville springs.
Claim 19
Dependent Claim
26 words
A lockdown screw assembly according to claim 13 including a protective cap with means for releasably securing said cap to one end of the lockdown screw.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-08-18 | 1990-02-17 | 1990-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-08-18 | 1994-02-17 | 1994-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-08-18 | 1998-02-17 | 1998-08-19 | $7700.00 | Window Closed / Lapsed |