1
George I Boyadjieff: Drilling of wells with top drive unit. Varco International, William P Green, May 22, 1984: US04449596 (182 worldwide citation)

Well drilling apparatus including a top drive drilling assembly having a motor driven stem adapted to be attached to the upper end of a drill string and drive it during a drilling operation, a torque wrench carried by the top drive assembly and movable upwardly and downwardly therewith and operable ...


2
George I Boyadjieff: Apparatus for handling well pipe. Varco International, William P Green, August 23, 1988: US04765401 (179 worldwide citation)

A well pipe handling machine including a vertically extending column structure which carries means for engaging and holding a pipe in vertical condition and is movable with the pipe holding means between a first position in which a carried pipe can be connected to and disconnected from the upper end ...


3
George I Boyadjieff: Top drive drilling systems. Varco International, William P Green, August 12, 1986: US04605077 (156 worldwide citation)

Methods and apparatus for facilitating the drilling of a well with a top drive unit having a motor which is connected to the upper end of the drill string and moves upwardly and downwardly therewith. The methods and apparatus of the invention enable the drill string to be pulled upwardly off of the ...


4
George I Boyadjieff: Well pipe handling machine. Varco International, William P Green, December 1, 1987: US04709766 (118 worldwide citation)

A well pipe handling machine for removing a series of stands of pipe from the upper end of a well pipe string and storing the stands in a rack offset to a side of the well axis and/or returning the stands sequentially from the rack for reconnection to the string. The machine includes a support which ...


5
George I Boyadjieff: Well pipe stabbing and back-up apparatus. Varco International, William P Green, December 2, 1986: US04625796 (117 worldwide citation)

Apparatus for use during connection of a length of pipe to the upper end of a drill string, preferably in a top drive drilling arrangement, and including a back-up tool for retaining the upper end of the drill string against rotation as the added length of pipe is connected threadedly thereto. This ...


6
George I Boyadjieff, Igor Krasnov: Top drive drilling unit with rotatable pipe support. Varco International, William P Green, July 16, 1985: US04529045 (114 worldwide citation)

A top drive well drilling unit which is connected to the upper end of a drill string to drive it rotatively in drilling a well and is movable upwardly and downwardly with the string along a guide structure, and which is provided with pipe handling mechanism beneath the drilling unit for making and b ...


7
Padmasiri Daya Seneviratne: Apparatus and method for rapid replacement of upper blowout preventers. Varco International, Christie Parker & Hale, August 21, 2001: US06276450 (114 worldwide citation)

Apparatus and method for rapid replacement of upper inside blowout preventers (IBOP) on a top drive system (TDS) utilizes a hydraulic pressure booster to increase the operating pressure of a pipe handler/torque wrench, an air amplifier to increase the air pressure to a main shaft brake of the TDS in ...


8
George I Boyadjieff: Link tilting mechanism for well rigs. Varco International, William P Green, December 25, 1984: US04489794 (89 worldwide citation)

Well apparatus including elevator links connected to a hook or other unit suspended in a derrick and hanging therefrom at opposite sides of the well axis to support an elevator or the like, with power actuated means provided for swinging the lower ends of the links laterally outwardly relative to th ...


9
Cornelis L Busink, Johannes W H van Rijzingen, David B Mason: Safety elevator. Varco International, William P Green, August 23, 1994: US05340182 (88 worldwide citation)

An elevator for supporting a string of pipe in a well rig is actuable between a closed condition for gripping of the pipe and an open condition, and includes a safety device for preventing opening of the elevator when a string of pipe is positioned in and supported by the elevator, to thus prevent a ...


10
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 ...