web 18 which points toward the rollover protection element 7 in a particularly preferred embodiment the rollover protection element is a u shaped bar 19 which is arranged upside down i e downwardly opening in the vehicle the bar 19 therefore has upright bar sections 20 and 21 which are connected via a crosspiece 22 which could also be referred to as the basis of the u the contact structure 17 is attached to the lower side 16 of the covering 12 in such a manner that it interacts with the crosspiece 22 of the bar 19 i e during the upwardly directed extension movement arrow 23 of the bar 19 is struck by the bar 19 such that the covering 12 is displaced by the bar 19 during the upwardly directed extension movement 23 i e can be detached from the opening 11 this releases the path for the rollover protection element 7 the rollover protection element 7 has a manipulation element 24 which is configured as a spike 25 and points toward the covering 12 or the roof skin 8 a manipulation element 24 of this type is basically known from published european patent application ep 1 510 412 a1 mentioned at the beginning and therefore with regard to its function all that needs to be mentioned here is that during the pulse like extension of the rollover protection element 7 it introduces a destructive pulse into the roof skin 8 in particular enters the rear window 9 so that the roof skin or rear window can be destroyed such that the rollover protection element 7 can travel virtually unhindered into its extended protective position as in which at least the crosspiece 22 protrudes over the plane of the roof skin 8 in the exemplary embodiment.