Automatic protection device for a roller blind against unauthorized raising

In an automatic protection device for a roller blind against unauthorized raising from the outside, by means of locking members which are disposed in the end face regions of roller blind bars and are designed as toggle joints, and whose two lever ends are linked in such a manner that, when the closed position of the roller blind shield is reached, the free toggle joint of each locking member is moved against guide channels of approximately U-shaped cross section of the end face regions of the roller blind bars, while upon raising the roller blind shield, the toggle joint of each locking membr is stretched, whereby the locking member can be moved out, perpendicularly to the plane of the roller blind shield, from the end face regions of the bars and can be brought into operative connection with at least one flange of the guide channel, the combination therewith of a compensating member arranged in said end face region of said roller blind bar and movable in said plane of said roller plane shield relative to said roller blind bar exerting on the free toggle joint through the action of an additional force means, a pressure urging said free toggle joint against said guide channel.