Darkening device for covering opening with curtain, has spring breakage sensor that is located for monitoring condition of return spring and/or roll-off protection and/or electromagnetic clutch

摘要

The darkening device (1) has return spring (10) that is rotatably supported on a stationary supporting frame (9). The motor shaft (19) is fixed on the axially opposite side of coupling (7). The motor shaft is rotationally fixed to the supporting frame. A spring breakage sensor (23) is located for monitoring the condition of the return spring and/or roll-off protection (41) and/or the electromagnetic clutch (14). Independent claims are included for the following: (1) darkening system; and (2) method for operating darkening device.