Holddown screw
US4650226A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 31, 1986 |
| Grant date | Mar 17, 1987 |
| Priority date | — |
| Expiry date | Mar 31, 2006 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B33/04
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A holddown screw 10 which features a shank 23 and contact nose 22 of separate construction. The contact nose 22 is provided with a flat bevelled contact surface 32 of predetermined angle to the axis of the screw selected to correspond to the angle of the camming surface 17a with which it is designed to cooperate. The contact nose is carried on the shank 23 and is adapted for relative rotation thereon as the screw is rotated. The back end of the contact nose is provided with an annular surface 22a disposed radially to the longitudinal axis of the screw and adapted to engage an annular shoulder 35 of the shank 23 in flat co-planar relationship therewith. As the screw is rotated and driven inwardly to contact the wellhead component 14 to be actuated, the flat contact surface 32 of the nose of the screw will engage in sliding contact with the cooperating camming surface 17a. Since the contact nose does not rotate against the cooperating camming surface 17 a of the wellhead component and engages over a large contact area, contact stresses are reduced and susceptibility to galling is minimized. The shank 23 includes an externally threaded section 23a adjacent its outer end which receives…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.