Safety device for motorized rolling shutter

A safety device for a motorized rolling shutter (1) or similar comprising means (7) supplying an electrical signal representing the displacement of the rolling shutter (1) and a logic processing unit (20) capable of working in learning mode and in operating mode, by sampling, and comprising means (29) of storing, in learning mode, value samples corresponding to the signal samples and means (27) of comparing, in operating mode, these stored value samples with value samples obtained in operating mode, and means (20, 25) of controlling a stopping of the motor of the rolling shutter when a difference between the value of the sample obtained in operating mode and the value of the stored sample is greater than a predetermined difference, wherein the means supplying the electrical signal representing the displacement of the rolling shutter comprise a pulley (13) on which is wound a flexible element (9) whose free end is connected to the end of the rolling shutter (1) such that the unrolling of the rolling shutter causes the unrolling of the flexible element, an elastic means (14, 15) ensuring the rewinding of the flexible element on its pulley during the rolling of the rolling shutter and a signal generator (18;

• 30) mechanically connected to a spindle of the pulley and supplying an electrical voltage representing the speed of rotation of the pulley, and wherein the logic processing unit (20) comprises means of sampling the electrical signal supplied by the signal generator.