Downhole stress absorber
US5509475A · kind A · utility
Inventor
Key dates
| Filing date | Apr 13, 1995 |
| Grant date | Apr 23, 1996 |
| Priority date | — |
| Expiry date | Apr 13, 2015 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B17/07
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
In a downhole sucker rod string stress absorber, a relatively inelastic plunger of circular cross-section is mounted on a concentric shaft extending upwardly to an upper portion of the sucker rod string. A resiliently compressible cushion of circular cross-section is disposed below the plunger and above a lower portion of the sucker rod string. A disk may be seated between the cushion and the plunger to distribute forces more evenly on the surface of the cushion. A resiliently compressible cylindrical sleeve, preferably having a plurality of annular grooves spaced thereabout, surrounds the shaft above the plunger. A coupling, adapted for connection to the lower portion of the sucker rod string, has a threaded end with a compressive face which abuts the outer end of the compressible cushion. A guide slidably mounted on the shaft has a threaded end with a compressive face thereon which abuts the outer end of the compressible sleeve. A cylindrical housing connects the coupling and the guide with the compressible cushion, the compressible sleeve and the plunger therebetween, the length of the housing being such that the compressible cushion and sleeve are increasingly partially compres…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.