1
Clyde A Willis: Apparatus for gripping a down hole tubular for rotation. W N Apache Corporation, Willian Brinks Olds Hofer Gilson & Lione, August 6, 1991: US05036927 (107 worldwide citation)

An apparatus for gripping a down hole tubular for rotation in a drilling machine includes a support member adapted for connection to the quill of the drilling machine. The support member supports three or more guides which converge toward one another in a selected direction. A clamping dog or engagi ...


2
Willis Clyde A: Apparatus for gripping a down hole tubular for rotation.. Apache, February 3, 1993: EP0525247-A1 (97 worldwide citation)

An apparatus for gripping a down hole tubular for rotation in a drilling machine includes a support member (32) adapted for connection to the quill of the drilling machine. The support member supports three or more guides (44) which converge toward one another in a selected direction. A clamping dog ...