Safety device to prevent accidental unwinding of a rolling shutter or rolling overhead door wound on a shaft

Claim 1

A safety device for preventing accidental unrolling of a rolling shutter or rolling overhead door comprising: a cogwheel which is joined for corotation with a winding shaft, said cogwheel possessing recesses opening outward and uniformly distributed on the circumference thereof, said recesses containing radially movable tumblers; a cage which surrounds said cogwheel and which has an abutment in the form of a recess for said tumblers which upon attainment of predetermined rotational speed are raised by the action of centrifugal force; and a fixedly disposed housing in the form of a circumferential ring against which said cage can rotate with the consumption of energy by friction; wherein said cage is made with a smooth-surfaced, continuous outer circumference and consists of two cage halves, said two cage halves being disposed in planes perpendicular to the axis of rotation of said cogwheel and having at least two symmetrical, circular surfaces facing each other and disposed substantially perpendicular to the axis of rotation of said cogwheel which, acting as brakes, engage a compatible discoidal portion of said fixed housing acting as a brake disk and said two cage halves being joined together by a plurality of bolts whose torque is adjustable for varying the pressure of said circular surfaces against said compatible discoidal portion of said fixed housing.