a u shaped configuration the reset frame 7 is freely movable in perpendicular relationship to the rotor shaft 2 since having of course an u2014 albeit slight u2014 mass the reset frame will assume due to gravity the lowest position u2014 with respect to its freedom of movement u2014 as shown in fig3 it may also be held by a spring in this preferred position since the section 6 configured in the manner of a cam on the rotor shaft is substantially rectangular in shape the reset frame bears with its one in this case upper leg 8 upon the upper longitudinal surface 9 so that the weight or mass of the reset frame secures the rotor shaft in this position and pushes the weight or mass back in the presence of an external pulse as a result of the shape of the section 6 fig5 8 illustrate a further embodiment with fig6 and 8 each showing a different view of the state shown in fig5 and 7 respectively not shown in these figures is the lock cylinder whereas the locking bar acting again in a known manner between the latter and the cylinder core is designated by 13 the locking bar 13 interacts hereby again with an electrically operated actuator 1 i e when the electrically operated actuator 1 is actuated with the rotary lock 12 the locking bar 13 depending on design can be moved away from the position in which it locks.