17 is attached the arms 18 and 19 of an inner jacket 20 pivotably seat on this bolt the inner jacket 20 likewise comprising a u shaped cross section and being seated in a pivotable fashion between the arms 14 and 15 of the outer jacket the claw 9 of the coupling mouth is arranged at the front end of the outer jacket 11 facing away from the pipe 1 on the corresponding end of the inner jacket 20 of the claw 10 of the coupling mouth on extensions of the yoke 12 or the yoke 21 respectively an angle 22 is provided for on the back end of the yoke 21 of the inner jacket 20 facing away from the claw 10 which is adapted to work together with a tensioning means in the present case together with a wedge 23 the wedge 23 is guided in an outer jacket 11 slot 24 which runs diagonally with respect to the longitudinal axis of the pipe 1 the straight side surface 25 of the wedge 23 is supported on the back edge 26 of the opening 24 a wedge surface 27 works as mentioned together with the angle 22 on the inner jacket in such a fashion that this inner jacket 20 turns in a clockwise direction about the pivot bolt 17 when hammering the wedge 23 into the slot 24 to lock the coupling mouth the wedge 23 exhibits on its lower end a bolt 28 which protrudes beyond the outer surface of the wedge and prevents the wedge 23 from being pulled out of the slot 24 provided for in both arms 14 and 15 of the outer jacket the wedge comprises between its narrow.