US Patent 7337861 Method and a device for preventing pipeskidding

A method and device for preventing a pipe string (5) clampingly arranged in a slips (2) from slipping out of the slips (2) in the event of the pipe string (5) slipping in the slips (2), wherein a pipe clamp/tong (22) is clamped, preferably hydraulically, onto the pipe string (5) at a position above the slips (2) and maintained in the clamped state for essentially as long as the pipe string (5) is held by the slips (2), the pipe clamp/tong (22), in the event of the pipe string (5) slipping in the slips (2), being displaced together with the pipe string (5) until the pipe clamp/tong (22) stops against the wedges (16) of the slips (2).