Varco Shaffer, Inc.
15Patents
1Active
15Granted
34Portfolio score
Filing activity: Dec 8, 1993 → Dec 9, 2003 · 1 expiring within 5 years
Most-cited patents
| Patent | Title | Area | Cited by | Status |
|---|---|---|---|---|
| US5735502A | BOP with partially equalized ram shafts | Fixed Constructions | 101 | Expired |
| US6374925B1 | Well drilling method and system | Fixed Constructions | 99 | Expired |
| US5588491A | Rotating blowout preventer and method | Fixed Constructions | 96 | Expired |
| US5662171A | Rotating blowout preventer and method | Fixed Constructions | 95 | Expired |
| US5400857A | Oilfield tubular shear ram and method for blowout prevention | Emerging Cross-Sectional Technologies | 71 | Expired |
| US6192680A | Subsea hydraulic control system | Mechanical Engineering; Lighting; Heating | 57 | Expired |
| US5897094A | BOP with improved door connectors | Fixed Constructions | 55 | Expired |
| US5575452A | Blowout preventer with ram wedge locks | Fixed Constructions | 54 | Expired |
| US5778918A | Pilot valve with improved cage | Emerging Cross-Sectional Technologies | 53 | Expired |
| US5505426A | Hydraulically controlled blowout preventer | Fixed Constructions | 50 | Expired |
| US5975484A | Door connectors | Fixed Constructions | 49 | Expired |
| US6244560A | Blowout preventer ram actuating mechanism | Fixed Constructions | 48 | Expired |
| US6719042B2 | Shear ram assembly | Fixed Constructions | 37 | Expired |
| US6857634B2 | BOP assembly with metal inserts | Fixed Constructions | 34 | Expired |
| US7380589B2 | Subsea coiled tubing injector with pressure compensation | Fixed Constructions | 0 | Active |
Source: USPTO / EPO open patent data. Counts and citation impact are objective bibliographic measures.