1
Roderick K Abbott, Padmasiri D Seneviratne, Daniel P Juhasz: Internal elevator. Varco International, William P Green, March 23, 1982: US04320915 (86 worldwide citation)

An internal elevator to be received within and internally grip and support a tubular member such as a well platform supporting pile, and including slips preferably mounted within openings in an outer body and actuable radially outwardly into gripping engagement with the tubular member by powered axi ...


2
Roderick K Abbott, Padmasiri D Seneviratne, Joseph A R Picard: Pipe spinner. Varco International, William P Green, January 3, 1984: US04423645 (2 worldwide citation)

A spinner for turning a well drilling kelly or the like and including a member connectible to the kelly to drive it rotatively, a reversible motor, and a drive between the rotor of the motor and said member including two gears for driving the member in opposite directions respectively, with the two ...