Abstract: An assembly element, inter alia for scaffolding, used (a) for clamping a cylindrical element after engaging axially or laterally on the cylindrical element and (b) for securing one or more transverse elements on to the cylindrical element, said assembly element comprising two half-rings interconnected by two pins, each half-ring having a deformable inner part adapted to bear against the surface of the cylindrical element and an outer part adapted to co-operate with the inner part to bound spaces to receive the ends of one or more transverse elements, at least one of the two pins being adapted to tighten the two half-rings when the pin is moved with respect thereto.