Herein is disclosed a preassembled and pretorqued friction brake comprising at least a pressure plate, a ratchet ring, a friction ring, and a backing plate. In the disclosed device, the rupture areas and the portions of the flanges outside the rupture area are arranged so as to prevent the connected elements from catching after the separation thereof, and to limit the vibrations induced in the element in said rupture areas. A part of a bearer may be served by more than one RAT.