in fig4 which illustrates the mutual association of the locking members 4 in the locked position but outside of the hollow shaft projection 3 since the locking members 4 are constructed as structurally identical parts and since they extend in radially facing relationship with respect to the axis of rotation of the hollow shaft projection 3 and because of their mutual engagement in the same plane in orthogonal relationship with the axis of rotation of the hollow shaft projection 3 unbalances resulting from the locking members 4 are essentially excluded and time and efforts for balancing the rotating parts on the shaft 2 are effectively minimized the bores 15 of both locking members 4 each accommodate a compression spring not shown which supports itself on the one hand on the ring 6 extending through the groove 16 and on the other hand in the recess 22 of respectively the other locking member 4 the springs are operative in the direction of the centrifugal force they push the locking members 4 apart i e compress the claws 19 and thus provide a biased starting position when a connection element 8 is now to be coupled it must first spread the claws 19 against the force of the springs to this end the forward end of the locking head 9 includes a truncated enlargement 26 and the contact surface 20 is provided with a corresponding slope once the spring force is overcome the claws 19 of the locking members 4 audibly snap behind.