A securing mechanism cooperating with a device that is to be secured, having a closing part, which can be slipped onto a free end region of the device. Locking elements are rotatably mounted in the closing part and engage into an annular groove of the device by an engaging element to lock it, except in one defined position of rotation. An adjusting member engages in an end region of the locking elements accessible from outside. A spring presses the locking element against a contact area of the closing part in the direction of the axis of rotation thereof forming a brake. A catching structure provided with a plurality of catching points is disposed on an annular surface of the locking elements. A catching element engages into the catching points when the respective locking element is rotated, at least when the closing part is tilted.