Abstract: The invention relates to a cord winding device (1) for a screen, comprising a winding roller (10) arranged for mounting on a rotational shaft of the screen, and a sleeve (20), wherein the winding roller can be received, which sleeve is arranged for mounting on a housing for the rotational shaft. The winding roller is provided with external thread for receiving the cords and the sleeve is provided with internal thread for axial displacement of the winding roller with respect to the sleeve upon rotation of the shaft. The sleeve is provided with a cord passage part with a hole for the cords. The external thread comprises spiral grooves shaped such that the grooves can receive the cords clampingly and in the sleeve at least one pressing element is arranged for pressing a cord into the groove of the external thread.

Abstract: The invention relates to a breaking device for a chain (5) of a screen, comprising a housing formed by first and a second housing parts (10, 20), that are attachable to each other by a detachable coupling. In operational position, first and a second toothed wheel (11, 21) are in engagement with each other and the chain engages onto a sprocket (12) connected to the first toothed wheel (11). The detachable coupling is arranged to release when a pulling force on the chain reaches or exceeds a predetermined threshold value. The first toothed wheel (11) and the second toothed wheel (21) are mutually positioned such that the chain (5) has an engagement side (5A) and a non-engagement side (5B), such that the pulling force (Fup) on the engagement side (5A) can be larger than the pulling force (Fdown) on the non-engagement side (5B).