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.

Abstract: A tong having a flexible belt and an anchor member for it. A belt assembly for mounting, disposing, and moving a flexible belt in a tong or in the rotary of tongs having rotary elements.

Abstract: A power tong assembly wherein a safety latch mechanism includes a power part equipped with two outlet side connections, one of which is connected to a control part for controlling the opening cross section of the tank side connection. The power part has a control element in the form of a piston-shaped valve body with equal sized surfaces on both end faces subject to the pressure of the working medium and with a bore running in the direction of the valve body movement. This bore has a conical extension of its inlet flow end. This blocks the direct connection of the supply with the return to the tank.

Abstract: An apparatus for rotating a tubular member. The apparatus has a housing with a recess for receiving the tubular member; a latch for closing off the recess; an operating means for the latch; a gear rim; discs within the housing to guide and retain the gear rim; a power means for driving the gear rim; and a crescent-shaped carrier member within the gear rim having means for contacting and gripping the tubular member. Either forward or reverse rotation of the gear rim results in the gripping of the tubular member and the imparting of torsion to the tubular member.