Abstract: A stiffening device for an electronics cabinet has at least two angle struts that are each formed by profile bars. The profile bars enclose an obtuse angle between them and are pivoted in the upper and lower corner regions of the cabinet frame rack. The angle struts are coupled to each other in a frictional, form-locking manner at their vertices by a tightening assembly when in a closed position. A formed fit over a large area is obtained when tightening the angle struts by attaching the profile bars of each angle strut to a door. The pivots of each angle strut are used for the pivots of the corresponding door. The tightening assembly includes a hole of radius R.sub.1 arranged at the vertex of one angle strut and a hole of radius R.sub.2 arranged at the vertex of the other angle strut. The hole dimensions are such that R.sub.2 is greater than R.sub.1. A tightening latch is arranged in both holes. The tightening latch has a first disc of radius R.sub.1 pivoted in the corresponding hole of radius R.sub.1.