The pipeline spanner has a polygonal recess from an aperture directed outwards. The dia. of the recess is greater than the width of the aperture. A rib (9) is made with a slit (10) to the aperture (7), in the radial middle plane of the recess (8). The recess with the rib may be made in a nut (5) which has a ratchet device (2) by which it is connected to the grip (4) of the spanner. The nut may have a cover plate. Spring-loaded pawls are pressed against the teeth (11) of the nut to fit in the gaps (14) between the teeth, allowing the nut to turn only one way.
