Assignee
NAT OILWELL
US21 patents
Top patents by PatentIndex Score
US4843945AJul 4, 1989
Apparatus for making and breaking threaded well pipe connections
NAT OILWELL181 citations98
US5038871AAug 13, 1991
Apparatus for supporting a direct drive drilling unit in a position offset from the centerline of a well
NAT OILWELL79 citations96
US4951707AAug 28, 1990
Seal for a pump valve
NAT OILWELL119 citations95
US4922957AMay 8, 1990
Valve with replaceable seal element
NAT OILWELL60 citations95
US5127478AJul 7, 1992
Casing suspension system
NAT OILWELL29 citations93
US5346178ASep 13, 1994
Pressure equalized flow control valve
NAT OILWELL24 citations92
US4732061AMar 22, 1988
Power tongs and clamping units therefor
NAT OILWELL41 citations92
US5149143ASep 22, 1992
Connector assembly with detachable sleeve
NAT OILWELL71 citations91
US4809792AMar 7, 1989
Support system for a top driven drilling unit
NAT OILWELL30 citations91
US4746246AMay 24, 1988
Remotely actuated cutting assembly for broken underwater guidelines
NAT OILWELL26 citations91
US4813498AMar 21, 1989
Active counterbalance for a power swivel during well drilling
NAT OILWELL25 citations90
US4787524ANov 29, 1988
Overload protection system for a crane
NAT OILWELL33 citations87
US4981180AJan 1, 1991
Positive lock of a drive assembly
NAT OILWELL71 citations86
US4809733AMar 7, 1989
Fail-safe gate valve with separated actuators
NAT OILWELL88 citations86
US4781359ANov 1, 1988
Sub assembly for a swivel
NAT OILWELL99 citations86
US5051007ASep 24, 1991
Lubrication of a centrifugal pump bearing
NAT OILWELL27 citations80
US4797029AJan 10, 1989
Remotely installing a tubular string
NAT OILWELL14 citations73
US5062667ANov 5, 1991
Connection seal
NAT OILWELL11 citations71
US4782662ANov 8, 1988
Boom crane centering
NAT OILWELL11 citations69
US5246075ASep 21, 1993
Guide post latching mechanism
NAT OILWELL13 citations59
US4877093AOct 31, 1989
Spring actuated power swivel support rollers
NAT OILWELL6 citations59