The invention concerns a centrifugal positive blocking
brake for
shutter drives. The
brake includes centrifugal blocks, central spring element, and a
drive motor comprising a
drive shaft. A turntable is coupled with the
drive shaft. The central spring element having a preloaded spring is centrifugally guided in a recess of the turntable. Either side of the spring is connected with a radially movable engaging tab element. Two different radially acting abutments are disposed on the central spring element and are movable towards recess. The engaging tab element has at least one engaging tab pointing radially inwards. The centrifugal block is attached to the engaging tab element. In the de-energized state of the
drive motor, the engaging tab elements together with the centrifugal blocks disposed on them engage into detents of a frame-fixed
detent disc with at least one engaging tab in a frictionally and positively locking manner. When
voltage is applied and the
drive motor starts, the engaging tabs disengage, the individual centres of
mass of the central spring element, preloaded spring, the engaging tab element, the engaging tab, and two centrifugal block parts are on one symmetry axis. This invention creates a centrifugal positive blocking
brake which is small in size and constructively simple and causes locking of the
shutter when de-energized.