<p>A controle element cooperating with a spring-loaded pawl is coupled to the winding-up shaft through frictional and positively acting forces, while the control element cooperates with the spring-loaded pawl and moves the latter into blocking position when the intended upper acceleration limit for the winding-up shaft has been exceeded. To this end, the control element may be designed as a one-arm lever which at one of its two end sections has a preferably thin-walled hub by means of which the lever is journalled on the circumferential surface of an extension coupled to the winding-up shaft. The hub may be slotted to form a sort of band slip clutch.</p>
