Infinitely variable crown block positioning
US4390162A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 20, 1981 |
| Grant date | Jun 28, 1983 |
| Priority date | — |
| Expiry date | May 20, 2001 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B19/02
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
Mounted in the upper part of an oil well drilling derrick are horizontal crown beams having end portions projecting beyond the opposite sides of the derrick. A fast line sheave and a dead line sheave are mounted on those beams near the opposite sides of the derrick, and a crown block is mounted on the beams between those sheaves. The sheaves and the crown block are adjustable along the beams. The fast line sheave is movable outwardly into an inactive position on the adjacent projecting end portions of the beams when the crown block is in a position suitable for supporting a fast line directly, and the dead line sheave is movable outwardly into an inactive position on the adjacent projecting portions of the beams when the crown block is in a position suitable for supporting a dead line directly. When both sheaves are in operating positions, the crown block can be placed in any desired location between them.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.