Rotary power slips
US4681193A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 10, 1986 |
| Grant date | Jul 21, 1987 |
| Priority date | — |
| Expiry date | Feb 10, 2006 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B3/04
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
Rotary power slips mounted in the rotary table of an earth drilling rig and having slips for gripping and releasing pipe in the rotary table. The air transfer ring has concentric grooves in the upper surface. An annular seal ring is secured to the body of the rotary power slips and has a pair of air passageways. The air passageways lead to secondary fluid conduits in the body, which, in turn, lead to each end of the pneumatic cylinders to raise and lower the slips. Expansive rings are secured to the surface of the air transfer ring by mounting the edges of the rings into the grooves in the air transfer ring. When air pressure is applied through one of the primary fluid conduits, one of the expansive rings expands and cooperates with the lower surface of the seal ring to form an expansive fluid duct. The air pressure flows through a perforation in the expansive ring into the expansive fluid duct, and then through the air passageway and the secondary fluid conduit to the pneumatic cylinders. A pilot operated check valve maintains pressure in one end of the cylinders to keep the slips in the upper, retracted position. The check valve is opened when positive pressure is applied to the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.