Abstract: A security screen having two rams to operate the screen which are located against the panel of the screen, the rams being connected at one of their ends substantially symmetrically relating to the center of the screen at or adjacent the top thereof and, at their other ends, substantially symmetrically relative to the screen to a structure beneath or beside the screen, the connections being such as to permit at least a degree of rotation of the rams relative to the panel and the structure, the arrangement being such that, as the rams are extended, the outward component of forces of the rams are substantially equal and opposite, the resultant being an upward component which can drive the screen upwardly rapidly.

Abstract: A security screen having two rams to operate the screen which are located against the panel of the screen, the rams being connected at one of their ends substantially symmetrically relating to the center of the screen at or adjacent the top thereof and, at their other ends, substantially symmetrically relative to the screen to a structure beneath or beside the screen, the connections being such as to permit at least a degree of rotation of the rams relative to the panel and the structure, the arrangement being such that, as the rams are extended, the outward component of forces of the rams are substantially equal and opposite, the resultant being an upward component which can drive the screen upwardly rapidly.