Inventors:
Gary McDaniels - Lafayette LA
Patrick Cummings - Lafayette LA
Michael Hayes - Lafayette LA
Steven Albright - Houston TX
Bernd G. Pietras - Wedemark, DE
Jorg Schulze-Beckinghausen - Garbsen, DE
Andreas Carlsson - Sehnde, DE
Assignee:
Weatherford/Lamb, Inc. - Houston TX
International Classification:
B25B 1700
Abstract:
A new power tong for rotating tubular members for make-up (connection) and break-out (disconnection) operations. In one aspect such a tong has at least one movable jaw with a smooth surface gripping element thereon and pre-load apparatus for applying a pre-load force to a movable jaw so that the jaw does not slip on a tubular to be rotated and so it does not mark or damage the tubular. In one aspect the pre-load apparatus includes a first pre-load device at one end of a movable jaw for breakout operations and a second pre-load device at another end of the jaw for make-up operations. In one aspect a power tong which has unique smooth surfaced jaw inserts made, e. g. , of aluminum. In one aspect a single pivotable pre-load cylinder, fixed to rotary, pivots for pivotable connection to one jaw or the other. This can be done manually or a powered smaller piston/cylinder may be used to pivot the pre-load cylinder. In one aspect a jaw unit which comprises a jaw holder and a jaw movable with respect to said jaw holder, characterized in that said jaw is slidably mounted on said jaw holder.